Auto Engines in Airplanes
Badwater Bill
Think about this.
I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
road at 75 mph on cross country trips. It gets 15 miles/gallon of
gas, so it burns 5 gallons/hour. Now you think about that Chevy
Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
cubic inch engine and burned about 9 gallons/hr or more depending on
how I ran it.
90 fewer cubic inches and almost twice the fuel burn. Kind of makes
me wonder about longevity. The drag car racers rebuild their engine's
after each run. They are built to last 6 seconds and put out 2000
horsepower or so. As you up the fuel burn and the horsepower output,
you decrease the life of the engine. I wonder about using that 262
Chevy engine with 90 cubic inches less than my 350 and burning twice
the fuel per hour?
Just thinking out loud guys. But a simple calculation shows that the
350 was designed to burn 5 gallons per hour for a normal operational
cruise. That's about one gallon/hr, per every 70 cubes. If the 262
is burning 9 gallons/hour in cruise, that's one gallon per hour for
every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
wonder if that engine only lasts less than half as long because of
this? I wonder about running that engine for long periods of time at
2.33 times more torque than my 350? I notice that I'm running about
2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
runs up in the high three thousands...something like 3800 or so. That
means the bearing velocities are much higher than in my 350. They
have to wear out sooner at higher pressures and higher velocities?
Wouldn't you think?
BWB
P.S. what's the BTU's per gallon of gasoline? Anyone know?
Calories/gallon would be better. I'd like to do another calculation
on that engine.
Hank Jarrett
any RPM is the MAXIMUM available, not necessarily the amount being drawn from the
engine. In the early 70s while I was in college we did a measurement on an Olds 88 with
a 350 engine and found it would cruise on the freeway at 70 MPH and was only producing
something like 15 HP! THIS WAS NOT A SMALL CAR! The engine was capable of producing
much more power at that speed and RPM but it DIDN'T NEED TO. In the example the reason
less fuel was used on the bigger engine is that the average power required was much
lower than the sustained power in the airplane.
I'm not going to get into the "car engines don't work in airplanes" argument since
people who know how to set them up have PROVEN that they work. You just need to
remember that cooling and lubrication are required to match the power being pulled not
the RPM. Cars need less cooling and the lubricants are loaded less because they only
see high power requirements for short periods of time. In an aircraft application the
cooling and lubrication requirements not being met will result in shorter life and lower
reliability. If you do meet the requirements you get just as many HP-Hours from a car
engine in an aircraft as a car.
The people who folow the rules of thermodynamics are flying happily behind auto engines
while the people who try to cheat the rules are on the ground saying it won't work.
(By the way, fuel burn is DIRECTLY related to the cooling required, lubrication loads
and power output for all practival purposes. 5 gal/hr in the truck and 9 in the RV-6
just says that the RV-6 is producing 1.9 times the power, even if the big 350 can
produce a lot more power than the 262 when needed.)
Hank Jarrett
O-ring Seals
Bill) wrote:
>
>Think about this.
>
<snipped>
>I wonder if that engine only lasts less than half as long because of
>this? I wonder about running that engine for long periods of time at
>2.33 times more torque than my 350? I notice that I'm running about
>2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
>runs up in the high three thousands...something like 3800 or so. That
>means the bearing velocities are much higher than in my 350. They
>have to wear out sooner at higher pressures and higher velocities?
>Wouldn't you think?
I would expect to last *less* than half as long with twice the power
output. All things being equal , probably 25% as long. But then, you
must consider the duty cycle: operation at a fairly constant rpm,
infrequent accerleation and decelleration, carefully controlled
temperatures, etc.
>
>BWB
>
>P.S. what's the BTU's per gallon of gasoline? Anyone know?
>Calories/gallon would be better. I'd like to do another calculation
>on that engine.
>
I found a reference stating 125,000 btu/gal :
http://solstice.crest.org/renewables/bioenergy-list-archive/msg01549.html
O-ring Seals
Jim Root
at 75 mph daily. It gets 12.5 miles/gallon of gas so it burns 6
gallons/hour. That figures out to about 1 gallon/hour per 76 cubes so does
that mean that your engine will not last as long as mine?
Now I'm not trying to be a smart ass! Well maybe a little. At any rate it
would seem logical that if you are pushing twice the fuel/air through the
engine that it would tend to fail more often. However, I'm not exactly
sure what you're getting at.
If the V6 fails twice as often as a Lycosaurous isn't its per/hour cost
still about half? And as long as we know up front that we need to
overhaul/replace more often the risk should be no more than using a
Lyc/Cont.
:{) Jim
(Just my opinion and worth about what you paid for it. <gr>)
Badwater Bill wrote:
> Think about this.
>
> I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
> road at 75 mph on cross country trips. It gets 15 miles/gallon of
> gas, so it burns 5 gallons/hour. Now you think about that Chevy
> Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
> cubic inch engine and burned about 9 gallons/hr or more depending on
> how I ran it.
>
> 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> me wonder about longevity. The drag car racers rebuild their engine's
> after each run. They are built to last 6 seconds and put out 2000
> horsepower or so. As you up the fuel burn and the horsepower output,
> you decrease the life of the engine. I wonder about using that 262
> Chevy engine with 90 cubic inches less than my 350 and burning twice
> the fuel per hour?
>
> Just thinking out loud guys. But a simple calculation shows that the
> 350 was designed to burn 5 gallons per hour for a normal operational
> cruise. That's about one gallon/hr, per every 70 cubes. If the 262
> is burning 9 gallons/hour in cruise, that's one gallon per hour for
> every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
> wonder if that engine only lasts less than half as long because of
> this? I wonder about running that engine for long periods of time at
> 2.33 times more torque than my 350? I notice that I'm running about
> 2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
> runs up in the high three thousands...something like 3800 or so. That
> means the bearing velocities are much higher than in my 350. They
> have to wear out sooner at higher pressures and higher velocities?
> Wouldn't you think?
>
Chuck Tomlinson
>
>I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
>road at 75 mph on cross country trips. It gets 15 miles/gallon of
>gas, so it burns 5 gallons/hour. Now you think about that Chevy
>Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
>
>90 fewer cubic inches and almost twice the fuel burn. Kind of makes
>me wonder about longevity.
I would guess that the smaller engine in the RV would wear out in
fewer hours than the larger engine in the truck. The truck engine
should last 2000-3000+ hrs before needing a major overhaul.
So (IMHO) even a small fraction of that time should be easy to live
with, given the modest replacement/rebuild cost of most Chevy
engines, and a typical recreational airplane that runs relatively
few hours per year.
I've asked my boating buddies what kind of TBOs they see in their
marine engines, which are little more than converted auto engines,
and run at about the same MP and rpm as they would in an airplane.
The typical answer has been "about 1,000 hrs".
Two other potential(*) longevity data points for auto engines:
commercial trucks, and industrial engines. Auto engines are still
used in things like U-Haul/Ryder trucks, where they have to run at
high power settings to keep pace with car traffic. Also, GM sells
auto conversions as "industrial engines", which seem to be rated for
(AFAIK) continuous operation at 60%-70% of their normal passenger
car ratings. See http://www.gmpowertrain.com for more.
(*)- I don't know how long rental truck engines last, or how long
"industrial" auto conversions are rated for, but I'd be surprised if
they were under 1000 hrs. That'd be long enough for me, but YMMV.
--
Chuck Tomlinson
Charles K. Scott
bill...@earthlink.net (Badwater Bill) writes:
> Think about this.
>
> I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
> road at 75 mph on cross country trips. It gets 15 miles/gallon of
> gas, so it burns 5 gallons/hour. Now you think about that Chevy
> Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
> cubic inch engine and burned about 9 gallons/hr or more depending on
> how I ran it.
>
> 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> me wonder about longevity. The drag car racers rebuild their engine's
> after each run. They are built to last 6 seconds and put out 2000
> horsepower or so. As you up the fuel burn and the horsepower output,
> you decrease the life of the engine. I wonder about using that 262
> Chevy engine with 90 cubic inches less than my 350 and burning twice
> the fuel per hour?
Let's get both engines on the same plane first, then compare them.
Your 4x4 isn't sitting in the worlds most efficient body nor is it
driving through the most economical drive train. My father in law has
an 89 Olds 98 that gets 25 mpg on it's way up to visit us on the
highway. That engine is a 350 cid, I think.
As Hank Jarrett so correctly pointed out, fuel burn is a by product of
power being developed. 60% power producing roughly 120 hp will burn
approximately the same amount of fuel whether it be burned in a big
engine turning slowly or a small engine turning fast. It takes a given
amount of fuel and air to make power and if you are doing that you are
going to get similar fuel burns.
As to whether a modern auto engine will have a lower duty cycle than
the current type aircraft engines I suggest you read the last several
issues from Sport Aviation. An author has been delving into exactly
that subject (or at least I think it's Sport Aviation). His research
indicates that because auto engines are designed for high rpm operation
the old theory that high rpm operation produces higher wear on parts
just isn't true anymore.
And then there's the proof of hundreds of auto engines running out
there with really good records of operation and some with 1500 hours
and no apparent need for overhaul.
Heck, Subaru's with well over 150,000 miles on them STILL HAVE THE
CROSS HATCHING in the cylinders. I know, I've pulled them apart and
checked, and this was more than 15 years ago.
Just because auto engine run faster doesn't mean they will wear out
faster.
Corky (and yes, I realise this could be a troll) Scott
Bob Esser
> I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
> road at 75 mph on cross country trips. It gets 15 miles/gallon of
> gas, so it burns 5 gallons/hour. Now you think about that Chevy
> Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
> cubic inch engine and burned about 9 gallons/hr or more depending on
> how I ran it.
>
> 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> me wonder about longevity. The drag car racers rebuild their engine's
> after each run. They are built to last 6 seconds and put out 2000
> horsepower or so. As you up the fuel burn and the horsepower output,
> you decrease the life of the engine. I wonder about using that 262
> Chevy engine with 90 cubic inches less than my 350 and burning twice
> the fuel per hour?
>
You are also running the smaller engine a lot faster. For the same
displacement, a higher RPM will mean more fuel burn. It may help to
think in terms of fuel per C/I per rpm.
you see a similar thing between a Cessna 150 engine and a Rotax 912S.
About the same power, about the same fuel consumption, but the
displacements are different and the operating RPMs are different.
Another thing to consider is weight and how it figures into
reliability. An article in Kitplanes a while back talked about this and
the general conclusion was that for a 'reliable' engine, you needed
about 2 pounds per horsepower. Generalize by saying (assuming sound
engineering, which is a big if) the more weight of the engine per
horsepower the more reliable it is likely to be. Have a look at the
engine of an 18 wheeler. Those things are huge and heavy but have
surprisingly low volumes (for their size) -- I do not remember what the
volumes are, but I think in the neighborhood of 400 C/I and 1000#.
These engines are much more than 2# / HP, and are very heavy use / high
reliability.
Hopefully with better engineering, we can get a reliable engine with
less than 2 pounds per horsepower, but we have to specify what reliable
is.
Another possible line of thinking is how much does it cost to operate
per mile or minute. If it is a very cheap engine, you can afford to
rebuild or replace it more often. Also initial acquisition costs. A
new IO360 costs something like $30k, so, with a 2000 TBO, you pay $15
per hour just for the engine!
> Just thinking out loud guys. But a simple calculation shows that the
> 350 was designed to burn 5 gallons per hour for a normal operational
> cruise. That's about one gallon/hr, per every 70 cubes. If the 262
> is burning 9 gallons/hour in cruise, that's one gallon per hour for
> every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
> wonder if that engine only lasts less than half as long because of
> this? I wonder about running that engine for long periods of time at
> 2.33 times more torque than my 350? I notice that I'm running about
> 2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
> runs up in the high three thousands...something like 3800 or so. That
> means the bearing velocities are much higher than in my 350. They
> have to wear out sooner at higher pressures and higher velocities?
> Wouldn't you think?
>
Look at the original design installation of the Vortec 262. How many
miles per gallon did it get in a car? How many gallons per hour do
typical 350 Chevys get in an aircraft installations?
--
Bob Esser
res...@glue.umd.edu
Faculty Research Assistant
Dept. Materials Engineering
University of Maryland, College Park
(301)405-1414
Cl...@snyder.on.ca
Bill) wrote:
Bill, Youy have to relate the fuel burn to load. The 350, at 5 gallons
per hour, is producing something less than 100 HP. The Vortec is
putting out closer to 150.
Yes, the 350 will likely outlive the vortec - but the vortec may well
outlive you as the pilot. Think 300,000 miles on the 350 - at 60 miles
per hour that's 5000 hours. Really neglect it and settle for 150,000 =
that's still 2500 hours.. If the vortec's life is degraded by 50%, you
still get 1250 hours - and that's being pretty pessimistic.
>
>Think about this.
>
>I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
>road at 75 mph on cross country trips. It gets 15 miles/gallon of
>gas, so it burns 5 gallons/hour. Now you think about that Chevy
>Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
>cubic inch engine and burned about 9 gallons/hr or more depending on
>how I ran it.
>
>90 fewer cubic inches and almost twice the fuel burn. Kind of makes
>me wonder about longevity. The drag car racers rebuild their engine's
>after each run. They are built to last 6 seconds and put out 2000
>horsepower or so. As you up the fuel burn and the horsepower output,
>you decrease the life of the engine. I wonder about using that 262
>Chevy engine with 90 cubic inches less than my 350 and burning twice
>the fuel per hour?
>
>Just thinking out loud guys. But a simple calculation shows that the
>350 was designed to burn 5 gallons per hour for a normal operational
>cruise. That's about one gallon/hr, per every 70 cubes. If the 262
>is burning 9 gallons/hour in cruise, that's one gallon per hour for
>every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
>wonder if that engine only lasts less than half as long because of
>this? I wonder about running that engine for long periods of time at
>2.33 times more torque than my 350? I notice that I'm running about
>2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
>runs up in the high three thousands...something like 3800 or so. That
>means the bearing velocities are much higher than in my 350. They
>have to wear out sooner at higher pressures and higher velocities?
>Wouldn't you think?
>
Morgans
> Let's get both engines on the same plane first, then compare them.
> Your 4x4 isn't sitting in the worlds most efficient body nor is it
> driving through the most economical drive train. My father in law has
> an 89 Olds 98 that gets 25 mpg on it's way up to visit us on the
> highway. That engine is a 350 cid, I think.
> Corky (and yes, I realise this could be a troll) Scott
>
year was before 89, as those 98's had 3.8 L front wheel drive.
Jim (owner of a 88 and 98, wishing they got 25mpg) in NC
Not argueing against comparing apples with apples.
BRUCE A. FRANK
You are doing this just to stimulate discussion? Horse power is horse power.
Your 350 cid V-8 at 2000 rpm certainly is not producing the HP that the V-6
is at 3800 rpm. Certainly one engine can be more optimized than another, but
with reasonable longevity in mind the idea is to extract the horse power
needed at the lightest weight reasonably (cost wise) available. Yes, the V-8
can produce the same horse power at the V-6 at a lower stress level and
wear rate, but the cost is several hundred more pounds of weight to carry
around. At the same horse power levels both engines are going to consume
pretty much the same amount of fuel (+ or - a few %).
Bruce A. Frank
Badwater Bill <bill...@earthlink.net> wrote in message
news:39f4245f...@news.earthlink.net...
Mike Sieweke
> Think about this.
<snip>
> Just thinking out loud guys. But a simple calculation shows that the
> 350 was designed to burn 5 gallons per hour for a normal operational
> cruise. That's about one gallon/hr, per every 70 cubes. If the 262
> is burning 9 gallons/hour in cruise, that's one gallon per hour for
> every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
> wonder if that engine only lasts less than half as long because of
> this? I wonder about running that engine for long periods of time at
> 2.33 times more torque than my 350? I notice that I'm running about
> 2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
> runs up in the high three thousands...something like 3800 or so. That
> means the bearing velocities are much higher than in my 350. They
> have to wear out sooner at higher pressures and higher velocities?
> Wouldn't you think?
Yes, almost definitely true. But how soon? There are auto engine
conversions that have over 1000 hours without a major overhaul. The
GM and Ford V6s have proven good durability in ac. And a major only
requires replacing a few hundred dollars worth of parts (pistons,
valves, springs, bearings, etc.) and a few machining operations.
If you're totally paranoid (and you should be), you can replace
a few other critical parts (water pump, etc.) and still not spend
$1000 in parts.
BTW, my car has over 220,000 miles on it with no major repairs (water
pump, distributor, timing belt, and alternator replaced). That's over
4,000 hours. It still doesn't use any oil and runs well. I would
expect your 350 to perform similarly. If the Vortec in the RV only
gets half as many hours, that ain't bad.
> P.S. what's the BTU's per gallon of gasoline? Anyone know?
> Calories/gallon would be better. I'd like to do another calculation
> on that engine.
It used to be easy to answer a question like that. Straight gasoline
has about 20,300 BTUs per pound - or about 121,800 BTUs per gallon.
Unless you're talking about aviation gasoline, that's no longer true.
100LL should be pretty much straight gasoline, but auto gas is filled
with additives that bring down the total.
Methyl alcohol has 9760 BTU/lb; ethyl has 12,780. I have no idea what
MTBE or ETBE have.
--
Remove the "nospam" from my address if you reply.
Mike Sieweke - msie...@nospam.ix.netcom.com
Harlem, GA - http://www.netcom.com/~msieweke
Jim Root
Orval Fairbairn wrote:
>
>
> Actually, if the engine fails over Alligator Swamp or the Yeti Mountains,
> the cost/hr is a HELL of a lot GREATER than the Lycosaurus.
>
I guess I wasn't clear. If we KNOW the failure rate is TWICE that of a
lycosaurous the we WOULD overhaul/replace TWICE as often. If the engine fails
over an Alligator Swamp or the Yeti Mountains it doesn't matter if it is a Auto
conversion, a Lyc or a turbine; a glider doesn't know what kind of engine
failed.
Kevin O'Brien
says...
>
> Now you think about that Chevy
>Vortec six cylinder engine I used to fly in that RV-6a.
Would that be the same RV-6A that handed you 'motorglider surprize' one sunny
day?
cheers
-=K=-
Rule #1: Don't hit anything big.
jerry wass
the same heat of combustion--approx 40,000 btu/lb.
Badwater Bill wrote:
>
> Think about this.
>
> I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
> road at 75 mph on cross country trips. It gets 15 miles/gallon of
> gas, so it burns 5 gallons/hour. Now you think about that Chevy
> Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
> cubic inch engine and burned about 9 gallons/hr or more depending on
> how I ran it.
>
> 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> me wonder about longevity. The drag car racers rebuild their engine's
> after each run. They are built to last 6 seconds and put out 2000
> horsepower or so. As you up the fuel burn and the horsepower output,
> you decrease the life of the engine. I wonder about using that 262
> Chevy engine with 90 cubic inches less than my 350 and burning twice
> the fuel per hour?
>
> Just thinking out loud guys. But a simple calculation shows that the
> 350 was designed to burn 5 gallons per hour for a normal operational
> cruise. That's about one gallon/hr, per every 70 cubes. If the 262
> is burning 9 gallons/hour in cruise, that's one gallon per hour for
> every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
> wonder if that engine only lasts less than half as long because of
> this? I wonder about running that engine for long periods of time at
> 2.33 times more torque than my 350? I notice that I'm running about
> 2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
> runs up in the high three thousands...something like 3800 or so. That
> means the bearing velocities are much higher than in my 350. They
> have to wear out sooner at higher pressures and higher velocities?
> Wouldn't you think?
>
> BWB
BARR DOUG
all day long.
The other thing is I think you should compare fuel burn per hour
based on horsepower, not cubic inches.
Final point is, as speed goes up, the drag due to air is squared,
so double the speed requires 4 times the power (minus a little).
In article <39f4245f...@news.earthlink.net>,
Orval Fairbairn
> I have a 4 x 4 pickup truck with a Chevy 454 in it. I run it down the road
> at 75 mph daily. It gets 12.5 miles/gallon of gas so it burns 6
> gallons/hour. That figures out to about 1 gallon/hour per 76 cubes so does
> that mean that your engine will not last as long as mine?
>
> Now I'm not trying to be a smart ass! Well maybe a little. At any rate it
> would seem logical that if you are pushing twice the fuel/air through the
> engine that it would tend to fail more often. However, I'm not exactly
> sure what you're getting at.
>
> If the V6 fails twice as often as a Lycosaurous isn't its per/hour cost
> still about half? And as long as we know up front that we need to
> overhaul/replace more often the risk should be no more than using a
> Lyc/Cont.
>
Actually, if the engine fails over Alligator Swamp or the Yeti Mountains,
the cost/hr is a HELL of a lot GREATER than the Lycosaurus. We have to
determine whether the failure is "soft" or "hard", i.e. is it still
producing thrust after failure?
We have to put these factors into the equation.
I have a localfriend who pulled the V-8 out of his Stewart S-51 after
about four flights -- all of which had major engine problems from warped
valves to a recalcitrant fuel controller. He stuck a Walter turbine in it
and is now feeling it out. I must say that it is an incredibly gorgeous
piece of work!
DSowder
>so double the speed requires 4 times the power (minus a little).
This figure is optimistic. It's true that drag increases with the square of the
speed, so 2X speed = 4X drag. But don't forget that work = force X distance,
and power is work per unit time. So, if you've doubled the speed, your engine
is overcoming 4 times the drag, but you're going twice the distance in a given
amount of time. 4 times the force thru twice the distance means that going 2X
as fast requires 8X the power.
In other words, power required increases as the cube of the speed.
Doug Sowder
Scott Tipps
vehicles. If you are running around 2000 rpm on the 350 and approx
35-3800 on the vortech at the same speed, the vortech equipped vehicle
is geared lower than the 350 equipped vehicle with an overdrive. A
transmission(automatic) on a vehicle with no overdrive in third gear
(drive) is at a ratio of 1:1. A automatic transmission equipped with
overdrive in fourth gear( overdrive) is geared .72:1. There are a lot of
variables in the engines you are tring to compare. Everything now is
fuel injected supposedly for fuel economy and really some of the
injected cars are less economic than a norally aspirated car. I did
however roll your figures around in my head and you are correct for the
most part. Not eal sure about the bearing thing yet though, could you
explain youre theory on that it is very interesting. Oh bye the way, not
all drag racers rebuild after every run, the motors are producing around
6200 horsepower (fuel motors) not 2000, and they are running mid four
second passes in the quarter. Blue Skies to ya commrad and get back with
me on the bearing thing
Scotty
Kevin O'Brien
>90 fewer cubic inches and almost twice the fuel burn. Kind of makes
>me wonder about longevity.
C'mon Bill. Where have you stashed the physicist? Or at least the tinkerer?
Cubic inches are only one facet of any motor. You can dial up GM and order a 5.7
litre crate motor that produces 165, or 355, or 430 HP. These are all the same
damned block (as far as HP production is concerned; the bottom ends are also
different to support different RPM ranges). The power-production differences
being principally air flow and the volumetric efficiency of the motor.
Technology is available to wring far more power out of a given displacement too.
A few things you might have seen that are in no GM 350 are: multivalve heads,
overhead cams, and desmodromic valvetrain, all of which are common in other
applications (and predate World War II, even). Other legacy powerplants like
Harley Davidsons, Lycomings, and Continentals also lack these refinements. I
can't speak for HD's (I think they just don't dare change anything now that they
finally stopped oil drip) but you won't see these in aero motors for these
reasons:
Multiple valves add complexity. Complexity threatens reliability.
Overhead cams eliminate pushrod trains, which produce a lot of friction but
are very reliable. OHCs add a belt or gear cam drive, which is a single
point of catastrophic failure (compare consequiences of cam drive failure
to pushrod or lifter failure).
Desmo valves likewise add complexity -- and are best used with OHC. Also
most of the benefits come at high RPM (where valve float is a problem) --
so you see them in F1 cars and Ducati superbikes.
In engineering everything is a trade-off somewhere. When there is a win-win to
be found, somebody found it already or it takes Burt Rutan-scale thinking to
find. I'm too lazy to pull out my SAE cheat books so I'll bash around the web
for some HP calculators and the fuel numbers you ask for. Or maybe I won't, it's
going on three. Do yourself a favour and buy a book called Desktop Dynos. It
comes with software that lets you model an engine. It was within 60 HP on my
late lamented Fontana block (and that was on a chassis dyno, so probably some of
the error was my misestimation of drivetrain losses). It is a car thing so it
focusses on peak RPM and torque. It's also a great tool for getting kids
interested in engineering.
Charles K. Scott
> 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> me wonder about longevity. The drag car racers rebuild their engine's
> after each run. They are built to last 6 seconds and put out 2000
> horsepower or so. As you up the fuel burn and the horsepower output,
> you decrease the life of the engine. I wonder about using that 262
> Chevy engine with 90 cubic inches less than my 350 and burning twice
> the fuel per hour?
By now I'm sure you have the answers you were looking for, here's
another take on the longevity issue.
Let's just say that the V-6 has half the longevity of the typical
Lycosaurus, I don't believe it does but let's just assume that. How
many hours does the typical homebuilder fly in a year? Does he get out
every weekend and fly? Is the weather conducive to an hour a week?
Two? Let's be real generous and say that he/she flies two hours per
week, that's 104 hours per year. That means you will fly more than 9
years before requiring an overhaul, and what happens when you overhaul?
Even if you replace pistons and valves along with all the gaskets, you
still aren't going to spend more than $1500 to $2000. And usually you
don't need to replace everything.
But in fact auto engine conversions aren't disintegrating at the
magical 1000 hour mark, they are running way past, according to
anecdotal evidence.
Corky Scott
Ronald James Wanttaja
Kevin O'Brien <ke...@useorganisationasdomainname.com> wrote:
>In article <39f4245f...@news.earthlink.net>, bill...@earthlink.net
>says...
>>
>>Vortec six cylinder engine I used to fly in that RV-6a.
>
>day?
IIRC, it wasn't...it was an RV-6 built by an ex-Luftwaffe friend of
Bill's, and had a Lycoming.
Ron Wanttaja
want...@halcyon.com
http://www.halcyon.com/wanttaja/
Badwater Bill
>I guess I wasn't clear. If we KNOW the failure rate is TWICE that of a
>lycosaurous the we WOULD overhaul/replace TWICE as often. If the engine fails
>over an Alligator Swamp or the Yeti Mountains it doesn't matter if it is a Auto
>conversion, a Lyc or a turbine; a glider doesn't know what kind of engine
>failed.
I think you are wrong on this Jim. The PSRU and the engine for an
RV-6 run about $12k the last time I looked. This is for a new set up
with NO aluminum heads...just the cast iron case and heads. There are
a lot of mods to do too. Jess found that they had to do some things
with the intake manifold, weld up a tuned exhaust, replace the exhaust
valve seats with stainless plus some other things I've forgotten
about. I know I can buy a once run O-320 for about $4000 and rebuild
it to ZERO specs for about $5000.
If I have one half the failure rate with the Lycosaur I'm money ahead
by a factor of two. These guys are taking once run Vortecs and
rebuilding them...they are not new. This is an advantage however, and
most people don't know that. The cases are stress relieved, the cams
have proven themselves, so have the cranks. Once you put 100,000
miles on those items alone, you know they were cast right. Same thing
with a rebuilt Lycosaur. I'm running one right now. I've got 400
hours on it with absolutely no problems. The crank has about 2500
hours on it and so does the CAM. Jess re-profiles the CAM for this
application anyway. I'm sure he feels must better with a CAM that's
once run and has not failed. I know I do.
Anyway, my point is that they are really about the same cost to
produce. The big advantage of the automobile engine is the cost of
parts when you work on it. Spark plugs are 88 cents instead of $15
bucks, etc.
But, if you are sucking twice the power per cubic inch out of it,
common sense says that you will wear it out twice as fast. O'ring is
probably the one here who is right. He says he thinks it would last
about 25% as long. So do I. I don't think it's linear.
Hank Jarret makes some real good points about heat transfer and
lubrication too.
BWB
Badwater Bill
>On Sun, 22 Oct 2000 17:40:57 GMT, bill...@earthlink.net (Badwater
>Bill) wrote:
>
>Bill, Youy have to relate the fuel burn to load. The 350, at 5 gallons
>per hour, is producing something less than 100 HP. The Vortec is
>putting out closer to 150.
>
>Yes, the 350 will likely outlive the vortec - but the vortec may well
>outlive you as the pilot. Think 300,000 miles on the 350 - at 60 miles
>per hour that's 5000 hours. Really neglect it and settle for 150,000 =
>that's still 2500 hours.. If the vortec's life is degraded by 50%, you
>still get 1250 hours - and that's being pretty pessimistic.
Good points. All of them.
Here's a little calculation just for fun. O'ring says a gallon of
gas has 125,000 BTU's in it. One BTU is 1060 Joules and Joule/sec is
a Watt. There are 746 Watts in a horsepower. So let's crank it out.
From the conversions above, one gallon of gas is 1.325 x 10^8 Joules
Five gallons/hr is 6.62 x 10^8 Joules
Dividing by 3600 second/hr gives: 1.84 x 10^5 Joules/sec
Dividing by 746 Joules/sec per Horsepower gives: 246 horsepower
Now we all know that these gasoline engines have a maximum
thermodynamic efficiency of right at 32%, and that the reality of the
situation is more like 25% fuel burn to actual usable energy.
That gives us 61 horsepower.
So, to make my truck go down the road at 75 miles/hr requires about 60
horsepower. I'm running that big 350 Vortec at 60 horsepower in a
maximal condition. The Chevy 262 Vortec is burning 9 gallons per
hour. Doing a simple proportion, i.e.
x/9=60/5 gives x= 108 horsepower.
of course if you do the ratios per cubic inch, you will get the same
2.33 ratio of running that 262 vs. the 350.
Let's do it just for fun.
108 hp/262 cubes = 0.41
60 hp/350 cubes = 0.17
Taking the ratios of these numbers to compare the engines once again
yields 2.33 if I'd have carried out all the round off errors (the
actual ratio here is 2.4).
Now, let's just think a bit about this one more time then I'll stop
beating a dead horse. I'm using a Vortec 350 to put out 60 hp in my
truck. If you use that Vortec 262 V-6 in a Chevy S-10 pick-em-up
truck you'll use about 45 horsepower all day long to go down the road
at 75 mph. If you put it in an aeroplane you use 108 hp which is 2.4
times more power than the engine was designed to put out in a normal
"Standard" application.
However, as Hank said in the first place up there, you can't just do
that straight away. You have to make some modifications in cooling,
exhaust, lubrication...and there are more too.
Once you've made all these modifications and you have an $11,000
package that weighs a lot more than a Lycosaur too, is it really worth
it to do the experiment? Another thing. I put the first 100 hours on
Jess Meyer's RV-6a with that 262 in it. It's very heavy without the
$4000 aluminum heads. I like the way my RV-6 flies and feels much
better with my O-320 E2D in the nose. Yes, my engine is old
technology, inefficient and the spark plugs cost $15 bucks each. But
I'm telling you that the initial cost's are about the same if you take
a once run O-320 and rebuild it yourself.
I've been around this stuff for four years now and I'm still not
convinced that using that auto engine is a good idea or I'd have done
it myself. The alloys of the auto engine are even better too. GM
builds a million of them a year and you don't see them failed all over
the place. In fact you see them come into the rebuild shop at 100,000
miles and many have never had their oil changed...or the oil filter
(you know how women are). They have been absolutely abused and they
still went 100,000 miles.
So...are these engines so over built for the galactically stupid that
they will run and last just fine for a high level mechanic/pilot like
most homebuilders are? People who will change the oil regularly, re
torque the heads periodically, run the engine with care, never over
heat it...on and on?
Maybe
BWB
Badwater Bill
<baf...@worldnet.att.net> wrote:
>Bill,
>
>You are doing this just to stimulate discussion? Horse power is horse power.
>Your 350 cid V-8 at 2000 rpm certainly is not producing the HP that the V-6
>is at 3800 rpm. Certainly one engine can be more optimized than another, but
>with reasonable longevity in mind the idea is to extract the horse power
>needed at the lightest weight reasonably (cost wise) available. Yes, the V-8
>can produce the same horse power at the V-6 at a lower stress level and
>wear rate, but the cost is several hundred more pounds of weight to carry
>around. At the same horse power levels both engines are going to consume
>pretty much the same amount of fuel (+ or - a few %).
>
>Bruce A. Frank
Just wondering about failure rate and longevity Bruce. But as Chuck
T. pointed out above, maybe it doesn't matter. If my 350 will run for
4 or 5 thousand hours and the 262 runs just over a thousand, what the
hell difference does it make? I know if I were running a Vortec 262,
I'd probably rebuild it at a thousand hours anyway. Hell, you can
rebuild it for a few hundred bucks.
BWB
Badwater Bill
>
>Let's get both engines on the same plane first, then compare them.
>Your 4x4 isn't sitting in the worlds most efficient body nor is it
>driving through the most economical drive train. My father in law has
>an 89 Olds 98 that gets 25 mpg on it's way up to visit us on the
>highway. That engine is a 350 cid, I think.
That's not the comparison I am making. I'm not talking about
efficiency of the car body vs. the airplane. A car is essentially a
flat plate going through the air. All I'm doing is comparing
horsepower output vs. cubic inches. That's all I'm doing. You could
do it on a dyno for all I care. What you get is that big 350 loping
along and the Vortec 6-cylinder 262 cranking out 2.33 times the power
per cube. That's the comparison I want to make.
>
>As Hank Jarrett so correctly pointed out, fuel burn is a by product of
>power being developed. 60% power producing roughly 120 hp will burn
>approximately the same amount of fuel whether it be burned in a big
>engine turning slowly or a small engine turning fast. It takes a given
>amount of fuel and air to make power and if you are doing that you are
>going to get similar fuel burns.
Yes, I know that. What I said is the 262 is burning 9 gallons/hr, the
350 burning 5gal/hr. Assuming the efficiencies are somewhat
equivalent, the 262 is putting out 2.33 times the HP per cubic inch
(now I've said it three times).
>
>As to whether a modern auto engine will have a lower duty cycle than
>the current type aircraft engines I suggest you read the last several
>issues from Sport Aviation. An author has been delving into exactly
>that subject (or at least I think it's Sport Aviation). His research
>indicates that because auto engines are designed for high rpm operation
>the old theory that high rpm operation produces higher wear on parts
>just isn't true anymore.
You are getting two things confused here Corky. What they are showing
is "Although the automobile engines run at higher rpm, the bearing
velocities are similar to those in aircraft engines running at lower
rpm." It's just like my Honda 750 out there in the garage. I run
that baby all day long at 4500 rpm to go 60 mph. You take an old farm
engine like one of those old Onan's and you'd blow it up at 4000rpm.
It runs about 100 rpm. So, the bearing sizes and surface areas are
determined by the bearing velocities and pressures commensurate with
whatever rpm the device will run at.
>
>And then there's the proof of hundreds of auto engines running out
>there with really good records of operation and some with 1500 hours
>and no apparent need for overhaul.
Yep. I know there is. But, I find it sort of contradictory
considering you are pulling more than twice the HP per cubic inch.
>
>Heck, Subaru's with well over 150,000 miles on them STILL HAVE THE
>CROSS HATCHING in the cylinders. I know, I've pulled them apart and
>checked, and this was more than 15 years ago.
I'm not so sure what that means. That could mean that you never had a
good seal with the compression or oil rings too and she was running
real lose.
>
>Just because auto engine run faster doesn't mean they will wear out
>faster.
Here's where you lost track of my comparison once again. I didn't say
this, and I know this already. My Honda runs fast as I've said.
Here it is for the FOURTH time Corky. Now read it closely:
The Vortec 262 six cylinder is sucking 2.33 times more horsepower per
cubic inch than my VORTEC 350 in my 4 x 4. Both engines were designed
for automobiles. Both engines run about the same in automobiles. The
Vortec 262 and the 350 burn about 5 gallons/hr in an automotive
application, which they were designed for. If you put either one on a
sled with a flat plate on it, you'd get this number. I'm not talking
about aerodynamics, I'm not talking about bearing speeds, I'm not
talking about rpm (necessarily). I know the Vortec's can run at 4000
rpm all day long. What I don't know is if they can do it with high
torque and therefore high horsepower (you know that rpm multiplied by
torque is horsepower). You can run an engine with no load at 4000 rpm
for an eternity. So, rpm is not the key function here. It's rpm
times torque (HP).
As Hank put it above, it's the horsepower you are generating that
needs to be handled correctly. There's excess heat, more friction and
higher bearing loads and pressures for the same rpm's.
The end result, which is horsepower is the key ingredient to be
measured, not the torque, not the rpm, not the exhaust temp or bearing
speeds. All of those are results of a certain horsepower and change
with horsepower. BUt, HP is the key measurement. If you are running
2.33 times the HP per cubic inch, I'll bet the thing wears out much
sooner and is not as reliable. I don't care if it's a snowmobile
engine on a test stand. That does not matter. It's just plain common
sense. O'ring is probably dead on when he says he figures it will
last about 25% as long in general. That in itself may be quite
conservative. Yes, some have gone 1500 hours. But, as Hank Jarret
say above, there are a lot of things you need to do if you want to
pull more HP than the constant HP that engine was designed to put out
on a road at 5 gal/hr. Jess has found this out himself. You can't
run it stock.
My question still is that I wonder what the final statistical outcome
would be of running a million engines on a dyno at the loads you see
in the automotive application where the engine was designed to run,
vs. a million engines on a dyno at the loads you see in aircraft
applications where the engine was NOT designed to run but is running
with sufficient modifications for cooling, lubrication etc.
BWB
Charles K. Scott
bill...@earthlink.net (Badwater Bill) writes:
> But, if you are sucking twice the power per cubic inch out of it,
> common sense says that you will wear it out twice as fast. O'ring is
> probably the one here who is right. He says he thinks it would last
> about 25% as long. So do I. I don't think it's linear.
Times have changed, engineering has changed and metalurgy has changed
over the last 30 years in the automotive world. little pistons spinning
faster than big pistons does not equate to excessive wear... anymore.
Remember both are putting out approximately the same amount of power to
keep the airplane up in the air (Lycosaur or auto conversion). It's
true that auto engines do not normally see a lifetime of 60 to 75%
rated output but that does not mean they cannot do it. For proof I
should print in full the manner in which the auto industry tests
proposed engines. It is absolutely phenominal what torture they put
them through and it's so much more rigorous than the developmental
testing required of aircraft engines I hesitate to even mention it in
the same sentence.
Hundreds of cycles in which the engine is cooled to sub zero
temperatures, started and then run instantly to full power for a period
of time then shut down and cooled off, then fired up and run again to
full power. This is a real gasket buster.
Hundreds of hours of full power running with loads and full power
shifts through transmissions, up and down. They typically wear out
several transmissions before the engine needs work.
Here are some other differences. The bore of auto engines is uniform
from top to bottom and the piston fit is tighter (Lycosaurs have a
taper bore and the piston fit is more loose). This eliminates piston
slap. The tension on the rings is less which reduces friction. The
piston weight is way down compared to aircraft engines which means
higher rpms can be sustained without overstressing the rods. Because
the rod length is shorter, even though the rpms are higher the piston
speed isn't all that different. The smaller combustion chamber means a
smaller power impulse which contributes to overall lower stresses. The
crankshaft is more compact then Lycosaurs which means less stress to
the crank.
It all adds up to auto engines managing to survive despite being run
harder than they normally would be on the street.
Corky Scott
Charles K. Scott
bill...@earthlink.net (Badwater Bill) writes:
> Once you've made all these modifications and you have an $11,000
> package that weighs a lot more than a Lycosaur too, is it really worth
> it to do the experiment?
No question, the Vortec V-6's are heavier than an equivelant power
aircraft engine. Almost the entire engine is cast iron. There are
some engines you can buy that are not entirely cast iron, the Ford V-6,
for one.
They are incredibly cheap to buy used, I found two for $150 each.
Bruce Frank can give you an accurate figure for the total amount the
parts cost for a zero time rebuild but it's less than $2000.
The big catch is the PSRU. No question they are not cheap. Most are
in the vicinity of $4000 complete, if you buy a finished product. It
is possible, and people have done this, to build your own PSRU. If you
do this your costs are a significant fraction of that $4000. I'm not
sure I'm brave enough to do that.
But add that with the rebuild cost and you still have $6150 not
including the cooling system. I have the radiator, it was costly at
$175. Now we're up to $6325 and I need some tubing and connections say
another $200 and we're at $6525. Now what does a runnout 320 cost and
where do you find them? Would $6K for parts to rebuild a 320 that's
runnout be reasonable? Can you find a 320 for $6K?
But I actually need more power which pretty much rules out the 320.
360's are just about untouchable in my world.
Corky Scott
Morgans
"Charles K. Scott" <Charles...@dartmouth.edu> wrote in message
news:8t1qpb$c38$1...@merrimack.Dartmouth.EDU...
Plus the arguement ; look at the marine engines out there, that are just
auto engines with a different exhaust, intake and carb.
Not unusual to see 1000 hours plus, at airplane type outputs and RPM. I
know of a RV-6 with a Vortec in it that is not run as hard as my Dad's Ford
marine 351.(when I am behind the wheel) <g>
Jim in NC
Owen Smith
The engine to which you refer is at the bottom of the food chain in terms of
what is being flown in Stewart 51s. It's about a close to a crate motor as
you can get. Nevertheless, there are at least 2 of these engines flying
with no serious difficulties reported yet.
The Walther turbine, altough much lighter and somewhat less costly than
V8 engines with (hopefully) similar reliability, is an imperfect substitute
for the V8, at least in the Stewart 51. Calculations predict that the
substantial lengthening of the nose necessary to get it into the airframe
will cause the aircraft to be unrecoverable in a spin unless the
area of the vertical stabilizer is increased. And say hello to Bob.
Owen Smith
Mike Sieweke
> Once you've made all these modifications and you have an $11,000
> package that weighs a lot more than a Lycosaur too, is it really worth
> it to do the experiment? Another thing. I put the first 100 hours on
> Jess Meyer's RV-6a with that 262 in it. It's very heavy without the
> $4000 aluminum heads. I like the way my RV-6 flies and feels much
> better with my O-320 E2D in the nose. Yes, my engine is old
> technology, inefficient and the spark plugs cost $15 bucks each. But
> I'm telling you that the initial cost's are about the same if you take
> a once run O-320 and rebuild it yourself.
Bill,
Why use one of the worst examples to show a cost comparison? Start with
an engine that doesn't require $4000 heads to get a reasonable weight,
and you're only looking at $7000 to get flying. That compares a whole
lot better with your $9000 for a zero-timed O320.
Take a Subaru, for instance.
Russell Kent
> Good points. All of them.
>
> Here's a little calculation just for fun. O'ring says a gallon of
> gas has 125,000 BTU's in it. One BTU is 1060 Joules and Joule/sec is
> a Watt. There are 746 Watts in a horsepower. So let's crank it out.
>
> From the conversions above, one gallon of gas is 1.325 x 10^8 Joules
>
> Five gallons/hr is 6.62 x 10^8 Joules
>
> Dividing by 3600 second/hr gives: 1.84 x 10^5 Joules/sec
>
> Dividing by 746 Joules/sec per Horsepower gives: 246 horsepower
>
> Now we all know that these gasoline engines have a maximum
> thermodynamic efficiency of right at 32%, and that the reality of the
> situation is more like 25% fuel burn to actual usable energy.
>
> That gives us 61 horsepower.
>
Which nicely jives with another calculation. Most auto engines have a BSFC
of about 0.5 lbs/HP/hr.
(5 gallons/hr) * (6.5 lbs/gal) = 32.5 lbs/hr
(32.5 lbs/hr) / (0.5 lbs/HP/hr) = 65 HP
> So, to make my truck go down the road at 75 miles/hr requires about 60
> horsepower. I'm running that big 350 Vortec at 60 horsepower in a
> maximal condition. The Chevy 262 Vortec is burning 9 gallons per
> hour. Doing a simple proportion, i.e.
>
> x/9=60/5 gives x= 108 horsepower.
(9 gals/hr) * (6.5 lbs/gal) = 58.5 lbs/hr
(58.5 lbs/hr) / (0.5 lbs/HP/hr) = 117 HP
> of course if you do the ratios per cubic inch, you will get the same
> 2.33 ratio of running that 262 vs. the 350.
65/350 = 0.186
117/262 = 0.447
0.447/0.186 = 2.40
> Let's do it just for fun.
>
> 108 hp/262 cubes = 0.41
>
> 60 hp/350 cubes = 0.17
>
> Taking the ratios of these numbers to compare the engines once again
> yields 2.33 if I'd have carried out all the round off errors (the
> actual ratio here is 2.4).
>
> Now, let's just think a bit about this one more time then I'll stop
> beating a dead horse. I'm using a Vortec 350 to put out 60 hp in my
> truck. If you use that Vortec 262 V-6 in a Chevy S-10 pick-em-up
> truck you'll use about 45 horsepower all day long to go down the road
> at 75 mph. If you put it in an aeroplane you use 108 hp which is 2.4
> times more power than the engine was designed to put out in a normal
> "Standard" application.
>
> However, as Hank said in the first place up there, you can't just do
> that straight away. You have to make some modifications in cooling,
> exhaust, lubrication...and there are more too.
Yes. It is sometimes possible to get the chart (I forget the name) that
shows where all the energy goes. For example, on the Wankel engine the
energy is distributed as:
5% heat of unburned gas (engine at 1.14 * stochiametric)
41% heat of exhaust gas
18% heat absorption by cooling water
6% heat absorption by lubricating oil
28% effective heat (i.e. what goes out the crankshaft)
2% others
[Numbers from a graph I have; I think it was extracted from a SAE paper.
Email me if you want a copy.]
So 28% of your 246 HP would be 69 HP.
> Once you've made all these modifications and you have an $11,000
> package that weighs a lot more than a Lycosaur too, is it really worth
> it to do the experiment?
With a Vortec? Probably not. With a much lighter Ford? That you got for
$75 (like Corky)? Maybe. With an aircooled VW? Seems like alot of
people have said yes.
Russell Kent
Michael Golden
Where can I find info on it?
How costly is it?
>
> The Walther turbine, altough much lighter and somewhat less costly than
> V8 engines with (hopefully) similar reliability, is an imperfect substitute
> Owen Smith
Tony W,
Kevin O'Brien <ke...@useorganisationasdomainname.com> wrote in message
> I can't speak for HD's (I think they just don't dare change anything now
that they
> finally stopped oil drip)
They did that almost 20 years ago and since then they have introduce 3 new
engines.
Tony
BRUCE A. FRANK
BRUCE A. FRANK
several dozen close to the 1000 hour point. There have been a few
catostraphic engine failures (catostraphic to the engine) such as broken
valves, broken valve springs, only one broken crank that I know of, and one
or two cases of broken OEM pistons (I know of no broken Wiseco pistons--the
recommended substitute--but other brand names will work just as well), two
cases of rods comming loose(assembly problems), and 4 or 5 instantces of
engine stoppages caused by failure of the builders to heed the information
about the selection of correct length pushrods.
This sounds like a lot, but it represents almost 15 years of flying this
engine starting with rather limited knowledge. We now pretty much understand
all the things necessary to make this engine produce the HP desired and last
a reasonable length of time. We are not beating it up with the power
demands, at least according to Ford. We are not having to make major changes
in structure or install expensive components (no $5000 crankshafts). It is
still possible, as you talk of doing with a Lycoming, to build the engine
yourself for less than $2000 expenditure. The PSRU is some what of a
stumbling block, as Corky says, but there are some who are building their
own for less than $1500. And as you note, a pe-emptive overhaul at 1000
hours is CHEAP... about $400 to $800.
All in all, dispite Lamar's protestations, the Ford V-6 has exhibited itself
well since Blanton proposed this inexpensive alternative.
One last thing about auto-conversions; several of the points you make about
the conversion of the Chevy are true, particularly the weight versus the
cost to reduce such. But, it does require relative lost cost mods to push
the HP envelope while retaining durability of the Chevy. That dial-a-horse
power attribute of most GM engines can easily offset the weight.
Also, these days, I am impressed with the track record of the Soob engines.
Some of the latest 6 cylinder introductions could make me forsake the
Ford...............nah, not yet!
Bruce A. Frank
Badwater Bill <bill...@earthlink.net> wrote in message
news:39f760fd...@news.earthlink.net...
Badwater Bill
>Plus the arguement ; look at the marine engines out there, that are just
>auto engines with a different exhaust, intake and carb.
>
>Not unusual to see 1000 hours plus, at airplane type outputs and RPM. I
>know of a RV-6 with a Vortec in it that is not run as hard as my Dad's Ford
>marine 351.(when I am behind the wheel) <g>
>
>Jim in NC
I know. Those guys in the marine environment basically tear the shit
out their engines. Turn em on and peg them all day. That's the
marine environment. I have watched them do that to 2-strokes in
amazement for years while Mini-500's fall out of the sky in a very
similar kind of load environment and rpm. Something is different.
Maybe like Hank says, it's cooling in this case. There's lots of
cooling alright.
BWB
Badwater Bill
>This figure is optimistic. It's true that drag increases with the square of the
>speed, so 2X speed = 4X drag. But don't forget that work = force X distance,
>and power is work per unit time. So, if you've doubled the speed, your engine
>is overcoming 4 times the drag, but you're going twice the distance in a given
>amount of time. 4 times the force thru twice the distance means that going 2X
>as fast requires 8X the power.
>In other words, power required increases as the cube of the speed.
>
>Doug Sowder
You are right. At low velocities it's linear up to about 20 mph then
goes quadratic to about 200 mph then cubic.
BWB
Badwater Bill
<ke...@useorganisationasdomainname.com> wrote:
>In article <39f4245f...@news.earthlink.net>, bill...@earthlink.net
>says...
>>
>> Now you think about that Chevy
>>Vortec six cylinder engine I used to fly in that RV-6a.
>
>Would that be the same RV-6A that handed you 'motorglider surprize' one sunny
>day?
>
>cheers
>
>-=K=-
No, that was an RV-6, not a 6a. That engine failure was due to
improperly plumbing a christen eagle inverted oil separator. The old
German who built the airplane plumbed it so when I rolled it inverted
a check valve closed and tied the engine's top breather to the bottom
breather sealing off the crank case. I blew the front seal and pumped
all the oil overboard in about two minutes. I had no choice but to
stick it in the desert that day. It was not Lycoming's fault though.
It was that thick headed old German. I told him too, not to ever fill
that damn thing with gas while I was test flying it. He couldn't
listen. That day I checked Tim out was the middle of July two years
ago. When I got to the airport the old German said, "Ya bull. You
have complete fuel volume." My response was, "Why? It's 110 out now,
Tim weighs 220, I weigh 230 and now you stuck 240 pounds of fuel in
this for a 30 minute flight?????"
Ding, ding, ding! You could hear the bells go off in the old German's
head. Well, it cost him. Because when we stuck it in the desert, it
rolled a long way through lots of boulders and it broke up both wheel
pants plus an aileron. I was in the right seat and Tim had the
brakes. Turns out his stubby little legs didn't work real well on the
toe brakes. I just sat there completely helpless as we shot over
ditches, boulders and plants. One other thing happened that day too
that I'll never forget. I was carrying lots of speed on final and
S-turning to see and to get down for my landing point (the windscreen
was completely covered with hot oil). I mean, I had a lot of speed
there at the end...110 mph I think...way more than a normal glide. I
came over this hill with full flaps and sunk into the flood control
basin at about 80 mph. As I eased back on it, I stalled the right
wing first at about 70 mph and 5 feet. I dropped pretty good but that
right wing dropped first to a good 15 degree angle and bashed in the
aileron. I had never flown the airplane that heavy before and at a
density altitude of about 9000 feet. Had I not been on the deck, it
would have killed me. It was a classic stall spin entry but it got
stopped by the main gear hitting the ground first. If that would have
happened at 50 feet, I'd have been inverted in a heartbeat and laying
dead in the desert. That's the only time in 30 years an airplane
stalled on me with absolutely no warning and without me expecting it.
I was scared shitless and shaking during the whole approach as I shut
the engine down to save it and cranked off the fuel valve, turned off
the electrical etc.
I knew I was scared because the assholes in the tower couldn't figure
out where I was to send the medevac helicopter. So I squawked 7700.
I remember seeing my hand and fingers shaking as I turned the Xponder
knobs...first to 7600 then to 7700. I was shook up alright. Of
course only three minutes earlier I thought we were on fire at 5000
AGL when the cockpit filled with smoke from burning the oil as it hit
the exhaust manifold.
Anyway, what all this nervousness did to me (and I'm an old timer
pilot too) is cause my depth perception to be off. Plus, I was
landing in a big flood control basin that was about 800 feet wide and
all dirt, rocks and weeds. The perspective was like sinking into a
hole...you know, like landing on a real wide runway. You ease down
real gentle until you kiss on. Well, being all shook up, and not
being able to see out the front of the canopy because it was
completely covered with oil, threw off my peripheral vision and
peripheral depth perception by about 5 feet. I thought I was on the
deck at about 1 foot but I wasn't. Then, still at a pretty high
speed, higher than I'm used to, it quit me and that right wing
dropped. I heard it bang into the ground too and knew I'd broken it.
All I could think of is "get this fucker stopped and NOW before you
hit a rock and end up inverted and on fire."
When Tim finally mashed on what brakes he could muster we came to a
stop. I had already popped the canopy on short final in case we had
to get the hell out fast with everything warped in a crash. We both
just sat there for a couple seconds, then II threw back the canopy to
get a fresh breath of air instead of oil smoke, looked over at Tim,
smiled and said, "Ah Ha...we made it <grin>. We'll live to fly another
day it looks like." Tim got this big grin on his face and shook my
hand. There was a C-182 overhead and I radioed him to relay to the
police helicopter that we needed no medical attention. In a few
minutes the helicopter was there, it was 112 degrees and I was
dehydrated. Lots of cars showed up, the press, the TV people.
Finally I got out of there and drank about three gallons of water then
went out to my RV-6, untied it and took it out for a spin. It was
hotter than hell but I knew I had to fly and wipe the slate clean.
I was talking about this a couple days ago to Tim's partner and found
out that he canceled all his students for the day and went home. We
all handle crisis differently. I needed to get my ass right back out
there, do some more rolls, a couple loops and so forth. I buzzed the
sight too as the old German was out there in 120 degrees now, working
on taking the wings off the bird to tow it out.
All I could think of was that 40 gallons of gas in that thing. Hell,
he had gas cans all over the place from syphoning out all that
weight...I mean fuel...the dumb shit. I'll never forget it. As I
flew by I saw about 15 blue 2.5 gallon plastic water containers lined
up in the desert, all full of fuel that could have barbecued me good.
Actually I'm the dumb shit. I should have told him I refused to fly
it that morning unless he drained out some gas...but then I'd have
looked like the asshole. There are just some days when you really
ought to stay on the damn ground....that was one of them.
Badwater Bill
Badwater Bill
>me on the bearing thing
> Scotty
Scotty: I didn't do that bearing calculation but Tom Jones did. He
was the main mechanic on the project. I'll try to get the figures
from him sometime this week and post them.
Bill
Badwater Bill
>The engine to which you refer is at the bottom of the food chain in terms of
>what is being flown in Stewart 51s. It's about a close to a crate motor as
>you can get. Nevertheless, there are at least 2 of these engines flying
>with no serious difficulties reported yet.
It was a crate motor. It cost $1800 IIRC.
Bill
>
>The Walther turbine, altough much lighter and somewhat less costly than
>V8 engines with (hopefully) similar reliability, is an imperfect substitute
Badwater Bill
>
>Yes. It is sometimes possible to get the chart (I forget the name) that
>shows where all the energy goes. For example, on the Wankel engine the
>energy is distributed as:
>
> 5% heat of unburned gas (engine at 1.14 * stochiametric)
> 41% heat of exhaust gas
> 18% heat absorption by cooling water
> 6% heat absorption by lubricating oil
> 28% effective heat (i.e. what goes out the crankshaft)
> 2% others
>
>[Numbers from a graph I have; I think it was extracted from a SAE paper.
>Email me if you want a copy.]
Would love that chart please.
Best Wishes,
Bill
Badwater Bill
>
>Also, these days, I am impressed with the track record of the Soob engines.
>Some of the latest 6 cylinder introductions could make me forsake the
>Ford...............nah, not yet!
>
>Bruce A. Frank
Oh Oh!!!!!! You look like a man about to change Gods Bruce.
The last time I saw this was from Dennis Fetters when he married Muna.
He had to change his name and his God! I'll tell you something,
that's got to be some damn mean pussy to make a man change Gods!
The Soob might just be the new ticket for all this stuff Bruce. I've
been pretty impressed myself. It's real light weight too compared to
the crate engine we used in that RV-6a.
Bill
'RJ' Cook
power all day long....they are light..reliable...relatively economical for
the horsepower produced...and can be turbocharged. :) Guys say ya...but
their fuel consumption is higher...well if they have an integrated
turbocharger system with exhaust afterburner their efficiency is close to a
4 strokes...and the power to weigh ratio is then only exceeded by
turboprops.....just some food for thought.
RJ
--
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"Hank Jarrett" <hjar...@hroads.net> wrote in message
news:39F332...@hroads.net...
> One of the things that a LOT of people forget about HP curves is that the
power shown at
> any RPM is the MAXIMUM available, not necessarily the amount being drawn
from the
> engine. In the early 70s while I was in college we did a measurement on
an Olds 88 with
> a 350 engine and found it would cruise on the freeway at 70 MPH and was
only producing
> something like 15 HP! THIS WAS NOT A SMALL CAR! The engine was capable
of producing
> much more power at that speed and RPM but it DIDN'T NEED TO. In the
example the reason
> less fuel was used on the bigger engine is that the average power required
was much
> lower than the sustained power in the airplane.
> I'm not going to get into the "car engines don't work in airplanes"
argument since
> people who know how to set them up have PROVEN that they work. You just
need to
> remember that cooling and lubrication are required to match the power
being pulled not
> the RPM. Cars need less cooling and the lubricants are loaded less
because they only
> see high power requirements for short periods of time. In an aircraft
application the
> cooling and lubrication requirements not being met will result in shorter
life and lower
> reliability. If you do meet the requirements you get just as many
HP-Hours from a car
> engine in an aircraft as a car.
> The people who folow the rules of thermodynamics are flying happily behind
auto engines
> while the people who try to cheat the rules are on the ground saying it
won't work.
> (By the way, fuel burn is DIRECTLY related to the cooling required,
lubrication loads
> and power output for all practival purposes. 5 gal/hr in the truck and 9
in the RV-6
> just says that the RV-6 is producing 1.9 times the power, even if the big
350 can
> produce a lot more power than the 262 when needed.)
> Hank Jarrett
>
> Badwater Bill wrote:
> >
> > Think about this.
> >
> > I have a 4 x 4 pickup truck with a Chevy 350 in it. I run it down the
> > road at 75 mph on cross country trips. It gets 15 miles/gallon of
> > gas, so it burns 5 gallons/hour. Now you think about that Chevy
> > Vortec six cylinder engine I used to fly in that RV-6a. It's a 262
> > cubic inch engine and burned about 9 gallons/hr or more depending on
> > how I ran it.
> >
> > 90 fewer cubic inches and almost twice the fuel burn. Kind of makes
> > me wonder about longevity. The drag car racers rebuild their engine's
> > after each run. They are built to last 6 seconds and put out 2000
> > horsepower or so. As you up the fuel burn and the horsepower output,
> > you decrease the life of the engine. I wonder about using that 262
> > Chevy engine with 90 cubic inches less than my 350 and burning twice
> > the fuel per hour?
> >
> > Just thinking out loud guys. But a simple calculation shows that the
> > 350 was designed to burn 5 gallons per hour for a normal operational
> > cruise. That's about one gallon/hr, per every 70 cubes. If the 262
> > is burning 9 gallons/hour in cruise, that's one gallon per hour for
> > every 30 cubes or a ratio of 2.33 more per cubic inch than my 350. I
> > wonder if that engine only lasts less than half as long because of
> > this? I wonder about running that engine for long periods of time at
> > 2.33 times more torque than my 350? I notice that I'm running about
> > 2000 rpm in my truck in overdrive at about 75-80 mph. The Vortec 262
> > runs up in the high three thousands...something like 3800 or so. That
> > means the bearing velocities are much higher than in my 350. They
> > have to wear out sooner at higher pressures and higher velocities?
> > Wouldn't you think?
> >
> > BWB
> >
> > P.S. what's the BTU's per gallon of gasoline? Anyone know?
> > Calories/gallon would be better. I'd like to do another calculation
> > on that engine.
Bob Esser
>
> Don't forget outboard motor power heads...engines that run very well at full
> power all day long....they are light..reliable...relatively economical for
> the horsepower produced...and can be turbocharged. :) Guys say ya...but
> their fuel consumption is higher...well if they have an integrated
> turbocharger system with exhaust afterburner their efficiency is close to a
> 4 strokes...and the power to weigh ratio is then only exceeded by
> turboprops
What is this engine? I guess I have never seen one. Are there web
sites that describe them?
--
Bob Esser
res...@glue.umd.edu
Faculty Research Assistant
Dept. Materials Engineering
University of Maryland, College Park
(301)405-1414
k8do
Summer Winter Difference
114,500 112,500 1.7%
The energy content of conventional gasolines also varies widely from batch
to batch and station to station. The table below shows this variation within
each season.
Energy Content (btu per gallon)
Minimum Maximum Difference
Summer 113,000 117,000 3.4%
Winter 108,500 114,000 4.8%
denny
"Badwater Bill" <bill...@earthlink.net> wrote in message
news:39f4245f...@news.earthlink.net...
Charles K. Scott
"'RJ' Cook" <rjc...@ghg.net> writes:
> Don't forget outboard motor power heads...engines that run very well at full
> power all day long....they are light..reliable...relatively economical for
> the horsepower produced...and can be turbocharged. :) Guys say ya...but
> their fuel consumption is higher...well if they have an integrated
> turbocharger system with exhaust afterburner their efficiency is close to a
> 4 strokes...and the power to weigh ratio is then only exceeded by
> turboprops.....just some food for thought.
>
> RJ
That sounds great in theory but may be difficult or EXTREMELY expensive
to create in the real world.
A guy who has been attempting to use a Mercury outboard for some 3
years has finally given up trying (Experimenter, this month) Some of
the difficulties he encountered appeared to be non engine related but
he finally apparently got too scared to continue development.
His last words were that he felt the engine could be used but was going
to leave it up to someone else to do the development.
Others who had thought developing a different engine have been smacked
with reality as they developed it. The Deltahawk and Zoche come to
mind. Maybe next year.
Corky Scott
Morgans
>
> >
> >Also, these days, I am impressed with the track record of the Soob
engines.
> >Some of the latest 6 cylinder introductions could make me forsake the
> >Ford...............nah, not yet!
> >
> >Bruce A. Frank
>
>
> The last time I saw this was from Dennis Fetters when he married Muna.
> He had to change his name and his God! I'll tell you something,
> that's got to be some damn mean pussy to make a man change Gods!
>
> The Soob might just be the new ticket for all this stuff Bruce. I've
> been pretty impressed myself. It's real light weight too compared to
> the crate engine we used in that RV-6a.
>
> Bill
>
I think I saw where Soob is about to come out with a 2.8L engine. V-6 or
flat?
Jim in NC
highflyer
I don't remember the BTU per gallon for gasoline off hand. However,
I do know that the specific fuel consumption of the average gasoline
engine will be around .45 to .5 pounds per horsepower per hour.
Using those numbers, you pickup if cranking out about 60 horses at
75 mph on the highway. Not bad. On 350 cubes that is about six
cubes per pony, which is appropriate for 1500 rpm in an unblown
engine.
In the Vortec you are burning 9 gph, which tells me you are producing
about 108 horses. Out of 262 cubes that is a bit under 2 cubes per
pony.
Most small aircraft engines get their max rated power at the rate of
1 horsepower for every two cubic inches. That drops to one pony for
three inchs at cruise. Examples. Lycoming O-320. 320 cubes, 160 HP.
Continental O-300, 300 cubes, 145 HP. Lycoming O-360, 360 cubes,
180 HP. etc.
1/2 horsepower per cubic inch seems to allow for a reasonably reliable
engine. The Vortec should be reasonable up to about 130 HP MAX. At
reasonable cruise, around 100. The one you flew could do all right
if the other details are up to par.
You pickup is just loafing at 75 per! :-)
--
HighFlyer
Highflight Aviation Services
Mike Sieweke
Bill,
It varies from plane to plane. At double the best L/D speed, there is
2.125X drag, requiring 4.25X power. When you double again it is very
close to 4X drag and 8X power.
Drag at best L/D is half induced drag and half parasitic drag. When you
double the speed, induced drag is quadrupled and parasitic is 1/4.
Tony W,
Morgans <jsmo...@twave.junk.net> wrote in message
news:lDlJ5.20$P54...@e420r-sjo3.usenetserver.com...
>
> I think I saw where Soob is about to come out with a 2.8L engine. V-6 or
> flat?
>
> Jim in NC
They discontinued their 3.3L flat 6. IT was in the SVX it was a good car
but didn't sell well.
Tony
Lee Phillips
If you burn more fuel, you are making more heat. If the heat turns the prop,
you are making horsepower. If not, you are warming your headers or the
cooling system.
If you look at the crankshaft bearing areas on both Lycoming 320/360
engines, and the Chevrolet 350, you will see big differences. The Lycoming
is A LOT bigger. The Chevrolet will produce its rated horsepower at about
4500 RPM for a comparatively short time. The Lycoming makes its horsepower
at about 2600 RPM all week long. The Chevrolet 350 is just not made to
produce 75% power (or more) for any significant length of time. This would
mean running it at about 4500 RPM at nearly full throttle. And, by the way,
if you would do this (a la NASCAR) you would find that the fuel burn is A
LOT more than 5 gallons per hour. Even running it full throttle at 3300 RPM
would increase your fuel burn to around 8.4 GPH.
For example, look at what it takes in fuel to push a motor home down the
road.
Lee
Badwater Bill <bill...@earthlink.net> wrote in message
news:39f4245f...@news.earthlink.net...
Ian Stirling
>>Final point is, as speed goes up, the drag due to air is squared,
>>so double the speed requires 4 times the power (minus a little).
>This figure is optimistic. It's true that drag increases with the square of the
>speed, so 2X speed = 4X drag. But don't forget that work = force X distance,
>and power is work per unit time. So, if you've doubled the speed, your engine
>is overcoming 4 times the drag, but you're going twice the distance in a given
>amount of time. 4 times the force thru twice the distance means that going 2X
>as fast requires 8X the power.
>In other words, power required increases as the cube of the speed.
All else being equal, for the same payload, the frontal area goes down as
the speed goes up.
So it may not be quite as bad.
--
http://inquisitor.i.am/ | mailto:inqui...@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
"Melchett : Unhappily Blackadder, the Lord High Executioner is dead
Blackadder : Oh woe! Murdered of course.
Melchett : No, oddly enough no. They usually are but this one just got
careless one night and signed his name on the wrong dotted line.
They came for him while he slept." - Blackadder II
Frank van der Hulst
> I have a 4 x 4 pickup truck with a Chevy 454 in it. I run it down the road
> at 75 mph daily. It gets 12.5 miles/gallon of gas so it burns 6
> gallons/hour. That figures out to about 1 gallon/hour per 76 cubes so does
> that mean that your engine will not last as long as mine?
Yup... I have a 2.0L Ford Telstar which I run around at about 120kph
most of the time... it gets about 10km/litre. Converting these to
American units, it's 123cu in., running 70mph, and gets about 24mpg.
That's about 3gph, and 1.8gph per 76 cubes. I guess this makes my engine
a grenade.
But it's a grenade with a long fuse -- it's still running pretty well
after 313,000km (almost 200,000 miles). It had 150,000km on it when I
bought it, so I don't know anything about the first half of its life.
However, even with the failures I've had, it's still got me home each
time. Including a trip where the water pump seal failed... I had to stop
every 15km (10 miles or so) to refill the radiator. Not something to
contemplate in an aircraft!
> At any rate it
> would seem logical that if you are pushing twice the fuel/air through the
> engine that it would tend to fail more often.
I guess that would be right. But I think it's non-linear. And not
exponential... doubling the power/capacity ratio won't quarter the
engine's life. In fact, I'd be surprised if it halved it.
Things that adversely affect an engine's life are things like cold
starts, allowing the engine to sit for long periods and corrode,
excessive RPMs, and high power settings on cold engines. Continuous high
power settings (within design constraints) shouldn't harm an engine at
all.
> And as long as we know up front that we need to
> overhaul/replace more often the risk should be no more than using a
> Lyc/Cont.
True enough. However, at this stage we don't know when a conversion
needs replacing. So far, the evidence seems to suggest "about the same
interval as a Lyc".
Frank.
Frank van der Hulst
I have a similar chart for a Rolls Royce Merlin. From memory, it's about
the same level of efficiency... about 1/3 of the energy is used.
Frank.
Chuck Tomlinson
>
>If you look at the crankshaft bearing areas on both Lycoming 320/360
>engines, and the Chevrolet 350, you will see big differences. The Lycoming
>is A LOT bigger.
The small block Chevy's crank bearings are *big enough*. Main
bearing problems are very rare in SBCs, even in very high output
racing engines. Clearly, the SBC has proven its durability in
marine and commercial applications.
>The Chevrolet will produce its rated horsepower at about
>4500 RPM for a comparatively short time. The Lycoming makes its horsepower
>at about 2600 RPM all week long.
"The Chevrolet"? *Which* of the countless Chevy 350s are you
referring to? Sure, some SBCs may have lo-perf internals designed
to take Grandma to the grocery store, but IMHO it would make sense
for an airplane builder to choose a SBC with production parts that
were designed for high-stress use (e.g., marine parts).
And of course, the SBC aftermarket offers the fruits of 45 years of
continuous racing/high-performance/marine development.
>The Chevrolet 350 is just not made to
>produce 75% power (or more) for any significant length of time. This would
>mean running it at about 4500 RPM at nearly full throttle.
Depends on how you define "100% power". If the SBC is rated
conservatively (considering its component list and build prep),
there's no reason why it can't run indefinitely at 75% of the output
of, say, a 540 ci Lycosaur. The off-the-rack industrial 350 SBC is
rated at 201 hp @ 3000 rpm, which I suspect is a continuous rating.
--
Chuck Tomlinson
Charles K. Scott
"Lee Phillips" <phil...@ridgecrest.ca.us> writes:
> If you look at the crankshaft bearing areas on both Lycoming 320/360
> engines, and the Chevrolet 350, you will see big differences. The Lycoming
> is A LOT bigger. The Chevrolet will produce its rated horsepower at about
> 4500 RPM for a comparatively short time. The Lycoming makes its horsepower
> at about 2600 RPM all week long. The Chevrolet 350 is just not made to
> produce 75% power (or more) for any significant length of time.
Lee, There is a reason the Lycosaur has large bearings, especially the
one right next to the prop flange; the crankshaft has to support a
heavy metal prop which imparts side loads during maneuvering and
turbulence. Bitter experience taught the engine designers long ago how
much bearing area they needed.
But few of the V-8 auto engines utilize direct drive, they have a psru
bolted to the back of the engine which is turned around facing the
front. All psru's are designed to withstand thrust and prop loads
while the engine just supplies the turning force. Properly designed,
NO side loads are applied to the end of the crankshaft so the engine
just sits there happily spinning away exactly as if it were turning an
automobile transmission. In this configuration the engine is operating
well within design limits.
As to whether the Chevy 350 is "not designed to produce 75% power for
any significant length of time", you must not be fully aware of what
goes on during engine development. Those engines were run at full
power by programmed dynos for days on end. The engines literally ran
till they broke and were then disassembled to find the problem,
redesigned and run again with the same torturous program.
75% power for long periods for Chevy V8's would not be a difficult task
for them since they managed FULL power for hundreds of hours.
Corky Scott
Charles K. Scott
subject.
This is a long post so move on now if you don't want to read it
through.
Max Freeman is the engineer in charge of GM’s Premium Engine programs
and has written an article for Mick Myal in the latest "Contact!"
magazine regarding the development and testing of their new PV6
aluminum 90° bank angle V-6. It’s a lot of technical stuff about why
they chose this configuration or mechanical design over that, which is
why I like it.
He also wrote about the kind of developmental testing done on the
engine to make sure that customers get an engine they can depend on,
and I’d very much like to quote that section in full because it should
lay to rest the question of whether auto engines can take the kind of
power settings aircraft engines routinely manage.
"PERFORMANCE
The engine in production form for 1999 develops 215 HP at 5600 RPM and
230 foot pounds of torque at 4400 rpm. As a routine part of an engine
development program we tested the engine at full power, maximum RPM.
We ran it at 6000 RPM, pulling 215 HP at wide open throttle, for 265
hours. That’s a continuous 265 hours of wide open throttle, far worse
than autobahn driving, because even on the German Autobahn, you
wouldn’t be at 6000 RPM. THAT IS A STANDARD DURABILITY TEST. (emphasis
mine) We run many engines through this test as a matter of course.
Specific development focus is on the crank, pistons, rods, block
structure, timing drive wear; we get a lot of full load cycles in a
hurry. It isn’t necessarily designed to replicate customer driving but
to get development answers. Wear and fatigue are accelerated. The
test is particularly applicable in proving out dampers and their
effectiveness. If the damper is not properly tuned to the engine the
crankshaft will inevitably break in that time period. (note, this is
evidence you should not discard the stock damper when using the auto
engine for aircraft power)
A number of other engine tests are utilized. We use a variety of
specific tests to accelerate engine wear and to look at fatigue
failures. The cyclic endurance test is now called PTED (power train
endurance). It closely approximates cyclic durability. The engine is
cycled from its torque peak to its horsepower peak, at wide open
throttle, then down to idle, then accelerates up to shift points, then
back down to the torque peak and then horsepower peak. This test is
run for 400 hours. Once again, it’s a wide open throttle test for 400
hours. The RPM for this engine, ranged between 4400 and 6000 RPM, back
and forth in about a 5 minute cycle. The dyno computer will
occasionally bring the engine down to idle, up to 6500 RPM shift
points, and then back to the 4400 – 6000 RPM 5 minute cycle.
Thermal cycle tests are run to define engine capability under cold
weather condition. We run the engine at full throttle at 4000 RPM,
bring it down to idle, stop it, switch the coolant valves to drain the
hot coolant, pump the chilled coolant from the chiller until the metal
temperature stabilizes at 0 degrees F. Frost forms on the outside of
the block, as the cold coolant rushes into the engine. When it
stabilizes at 0 F, we motor the engine, start it, come to full throttle
at 4400 RPM, the valves switch and the coolant temperature starts to
climb. It climbs back up to 260 degrees F. It takes 10 –11 minutes to
complete one cycle. The engine must pass 600 cycles without any sign
of failure. We typically run 1200 cycles and a probe test will run
1600 cycles. That’s a (sic) excellent gasket killer test. Head
gaskets are the first to fail because of the rapid expansion and
contraction.
A powertrain endurance test simulates in-vehicle operation. The
Ypsilanti plant uses it for testing transmission. We, of course, use
it to look at engine performance. The equipment consists of an
engine/transmission combination, which sits on a dyno with large steel
inertia wheels. The inertia wheels are being driven by the
transmission output shaft, just like in a car. They cycle is brutal;
the engine is at idle in gear. The engine accelerates wide open to
6200 RPM, upshift occurs, 6200 RPM is reached, upshift occurs to 3rd,
6200 RPM is reached, upshift occurs to 4th, the wheels turn up to 135
MPH depending on the application. The second half of the cycle calls
for a closed throttle down to 70 MPH, then wide open throttle with a
downshift to 2nd, the engine goes back up to top speed, coasts down so
that the transmission selects down to a lower range. The engine is in
an overrun condition all the way down to idle; i.e., the engine is
being used for braking. That’s one cycle. One transmission life cycle
is typically 12K – 13K cycles of the above test. We will run an engine
through 4 or 5 transmissions. This is a very harsh schedule for the
engine, particularly because of the overrun braking. Cylinders and
rings suffer the most on this test.
We run some idle tests to verify low speed operation. The engine is
run at idle for about 2000 hours to make sure of adequate oil flow at
idle.
We use all those engine tests in addition to fleet tests and extensive
vehicle road testing. The customer can be assured that the PV6 engine
is a thoroughly tested advanced design that matches or exceeds
competing offerings."
I don’t believe engine testing for aircraft certification approaches
this intensity, duration or severity.
My thanks to Mick Myal for his continued excellence in publishing is
magazine.
Corky Scott
'RJ' Cook
Mercury. The concepts of integration of a burner-can enhanced turbocharger
system are published in some turbocharger texts, but I don't know about the
net. They are hybrid engine systems, part turbine, and part piston. The
exhaust afterburner can be active, that is fed with fresh air and fuel,
operating like a small turbojet burner-can, or chemical afterburner such as
a catalytic converter. The energy of the added fuel, and/or the exhaust's
unburned petrol products, are recovered by the turbochargers turbine wheel
and used to scavenge the engine and maintain sea level performance to some
given altitude, generally 19-25,000 feet. This system has a very high power
to weight ratio, has very smooth power out put due to the 2-stroke engine
and associated doubling of power pulses per revolution, and therefore
relatively light reduction drive and prop requirements.
Experimenters, a wide open area here, SICKUM! :)
Glad to help.
RJ
--
-----------------------------------------------------
Click here for Free Video!!
http://www.gohip.com/freevideo/
"Bob Esser" <res...@glue.umd.edu> wrote in message
news:39F5EADA...@glue.umd.edu...
>
> >
> > Don't forget outboard motor power heads...engines that run very well at
full
> > power all day long....they are light..reliable...relatively economical
for
> > the horsepower produced...and can be turbocharged. :) Guys say
ya...but
> > their fuel consumption is higher...well if they have an integrated
> > turbocharger system with exhaust afterburner their efficiency is close
to a
> > 4 strokes...and the power to weigh ratio is then only exceeded by
Ian Stirling
>>This figure is optimistic. It's true that drag increases with the square of the
>>speed, so 2X speed = 4X drag. But don't forget that work = force X distance,
>>and power is work per unit time. So, if you've doubled the speed, your engine
>>is overcoming 4 times the drag, but you're going twice the distance in a given
>>amount of time. 4 times the force thru twice the distance means that going 2X
>>as fast requires 8X the power.
>>In other words, power required increases as the cube of the speed.
>>
>>Doug Sowder
>You are right. At low velocities it's linear up to about 20 mph then
>goes quadratic to about 200 mph then cubic.
And then drops down to quadratic at over mach 1 or so.
--
http://inquisitor.i.am/ | mailto:inqui...@i.am | Ian Stirling.
---------------------------+-------------------------+--------------------------
'Where subtlety fails, we must simply make do with cream pies' -- David Brin
Russell Kent
Maybe we can get this included in Ron's FAQ, perhaps as an appendix?
Russell
Kevin O'Brien
says...
>
>On 22 Oct 2000 23:36:17 -0700, Kevin O'Brien
><ke...@useorganisationasdomainname.com> wrote:
>
>>In article <39f4245f...@news.earthlink.net>, bill...@earthlink.net
>>says...
>>>
>>> Now you think about that Chevy
>>>Vortec six cylinder engine I used to fly in that RV-6a.
>>
>>Would that be the same RV-6A that handed you 'motorglider surprize' one sunny
>>day?
>>
>>cheers
>>
>>-=K=-
>
>No, that was an RV-6, not a 6a. That engine failure was due to
>improperly plumbing a christen eagle inverted oil separator. The old
>German who built the airplane plumbed it so when I rolled it inverted
>a check valve closed and tied the engine's top breather to the bottom
>breather sealing off the crank case.
>It was that thick headed old German.
Is this the fellow you told of, who built an RV with excellent workmanship, but
just couldn't get the hang of piloting? A caution to those who plan to learn in
their project plane...
<snip>
>My response was, "Why? It's 110 out now,
>Tim weighs 220, I weigh 230 and now you stuck 240 pounds of fuel in
>this for a 30 minute flight?????"
And that is also partly a lick on you... I bet now you would leave Tim, offload
fuel, or wait until early the next morning when it's *only* 85F, wouldn't you?
>As I eased back on it, I stalled the right
>wing first at about 70 mph and 5 feet.
One thing about an overweight plane, because the wing loading is higher some of
the buffet you might feel at stall onset if you're a 150-pounder flying the same
ship solo, won't be there. Just like a heavier wing loading plane damps out some
of the unpleasant effect of turbulence, it also makes it harder to feel the
plane. Of course, these effects are not only from plane to plane but in the same
plane, when loaded to differnt conditions. That's why some planes have three
different gross weights when operated in three different categories, and Van
publishes a gross and an acro gross for his designs. She was sluggish when you
rolled her, too, I bet... Since the builder is the auteur or his own test
programme, I wonder if it isn't wise to develop stall speeds throughout the
weight and density altitude profile of the complete plane. Likewise to calculate
tolerable load factors, etc. You can do most of this mathematically, but you
need to validate the numbers with test flights.
You don't need me to point out that you were way, way over the sea level,
standard day acro weight for an RV-6/6a. Of course you saved more weight by
leaving the chutes on the ground. :) That saved the plane (though under the
circumstances most of us would have glid rather than jumped) but only at the
expence of a few grey hairs for you and Tim.
Acro weight is not a concern of course if you stick with 1G maneuvers.
>It was a classic stall spin entry but it got
>stopped by the main gear hitting the ground first. If that would have
>happened at 50 feet...<snip>
Yeah, that's the sort of thing that you just deal with when it happens, then you
go back and play 'what if' and scare yourself incontinent.
<snip>
>I remember seeing my hand and fingers shaking as I turned the Xponder
>knobs...first to 7600 then to 7700. I was shook up alright.
Scared is actually good to a point because a massive dose of adrenalin and other
endorphins dump into your system. This among other things produces the familiar
effect wherein time slows down... as long as your brain keeps inside the loop
you're OK. If your brain overloads, that's what panic is, and it produces
paralysis of thought. I wonder if anti-panic medication would be something worth
pursuing. You know, sniff the ampoule and your mind works faster and more
calmly. The military has used stimulants experimentally but AFAIK found them
unsuitable.
<snip>
> three minutes earlier I thought we were on fire at 5000
>AGL when the cockpit filled with smoke from burning the oil as it hit
>the exhaust manifold.
That's one of the problems with adrenalin, after your body uses it there is a
'crash' just like any un-natural stimulant (one of the reasons the military
dropped amphetamines), so if you have an extended emergency you can run out of
reserves and funk yourself to death. A good example is the AeroPeru (757?)where
the wash crew stuck tape over the static ports and forgot to take it off. The
experienced, trained aircrew never disgnosed the problem properly (an airspeed
of 950 kt with the wings still on should have rung bells). They stalled it and
dropped it in the ocean IIRC, with the loss of the ship and all aboard. Reading
the CVR xcript you can see these guys panicking. (Mike has it stashed on AvWeb
somewhere).
<snip good stuff about optical illusions>
>I had already popped the canopy on short final in case we had
>to get the hell out fast with everything warped in a crash.
Which canopy did this RV have? I like the visibility of the front hinge type,
but don't fancy it for egress at all.
We both
<snip>
>smiled and said, "Ah Ha...we made it <grin>. We'll live to fly another
>day it looks like." Tim got this big grin on his face and shook my
<snip>
>Finally I got out of there and drank about three gallons of water then
>went out to my RV-6, untied it and took it out for a spin. It was
>hotter than hell but I knew I had to fly and wipe the slate clean.
>
> I was talking about this a couple days ago to Tim's partner and found
>out that he canceled all his students for the day and went home. We
>all handle crisis differently.
For most people it's usually bad to walk away from something that scares them;
it just builds back up in their minds and becomes a greater risk of future
panic, I think. I have always operated on the get back on the horse what throwed
ya basis and so has the SF organisation (So I probably got the value from them).
We had few parachute accidents (serious ones; small glitches like tree landings
or the splashdown on my web page are no big deal) but the usual thing is to haul
any survivors right up in a helo and throw them out over the same DZ if
possible. The AF used to do this with pilots too, but is now so sissified that
they ground people for the duration of the investigation (which lately usually
finds that an unqual mech installed something backwards, or mistakenly put the
bad part back in and sent the good one for repair). On the other hand they have
so few training hours now, in some wings you could be grounded and not really
notice.
One pretty general thing I have seen in the aftermath of real danger is both a
pronounced sexual urge, and (fortunately) increased attractiveness to the
opposite sex... meaning any time I've been nearly croaked I've had a terrible
urge to get laid, and I usually could (by no means a sure thing otherwise). This
seems to hold true for the gang as well. I think that something deep and
biological is at work here.
>Actually I'm the dumb shit. I should have told him I refused to fly
>it that morning unless he drained out some gas...but then I'd have
>looked like the asshole.
Ah, the same conclusion I reached, above. So we agree again, proof positive
you're smart... or I'm smart... or something. Somehow I missed this on me first
Evelyn Wood read through your post.
Thanks for sharing this tale... some value comes out of a bad flying day if is
instructive... I would rather learn this lesson from your experience than mine!
cheers
-=K=-
Rule #1: Don't hit anything big.
Charles K. Scott
Russell Kent <ke...@titania.tye.sc.ti.com> writes:
> Corky,
> Maybe we can get this included in Ron's FAQ, perhaps as an appendix?
>
> Russell
I have no objection Russell. Best to store good information in more
than one location.
Corky Scott
Kevin O'Brien
>
>What is The Walther turbine?
>Where can I find info on it?
>How costly is it?
>
>>
>> The Walther turbine, altough much lighter and somewhat less costly than
>> V8 engines with (hopefully) similar reliability, is an imperfect substitute
>
Actually, it's a 'Walter' turbine. The Walter company dates to the
Austro-Hungarian empire but is now in the Czech Republic. The Walter 601 is a
turboprop engine, often used with an Avia prop (also from that part od the
world). It's a _very_ similar design to a PWC PT-6, but available in both
certified and experimental versions for far less money, and unbelievably far
less money, respectively. It has been used in a number of experimentals
including a Glasair, a couple of Lancairs, lots of CompAir utility planes, and a
Seawind (that didn't work out well, but that's more the fault of the airframe
and the company selling the kits, in my opinion. If you want a flying boat buy a
Lake). They are a common retrofit in ag planes, the italien Canguro (Kangaroo)
utility plane is being designed around them, and Walters have been stuffed into
other certified aircraft as well.
You can save even more money by using a used Walter (turbines have loooooong
TBOs compared to piston engines). Costs vary and I don't want to create an
expectation that vendors can't meet. You can, however, have a 650 HP turbine,
with more TBO remaining than a Lyc, for less money than a high end Lyc or TCM.
Prop prices are about equiv to a high end Hartzell or Mac c/s prop for a TIO-540
or 550 (i.e. lower than a PT-6 prop). The Aerocomp package has prices, and
complete FWF is about $52k including options for a used engine in the 1000/1500
hour neighbourhood (that's alarming time if you just know pistons. Think a
300-400 hour piston engine).
To find info, and answers to your cost questions, start here:
http://www.turbinedesign.com/ --this site USED to be more informative
but they have redesigned some of the
information out. Doug Karlsen will answer
cost questions if you ask (this used to
be on the site). They have a lot of
interesting projects in train.
http://aerocompinc.com/news/Spring00/autostart.htm
--this describes an option for Aerocomp's
Walter FWF. Lots of meaty detail. The links
to turbinedesign from here are mostly
broken!
http://www.walter.cz/ --the mothership. (Yes, it's in English). A
few years ago I exchanged emails with
their sales and marketing staff. I speak
Czech but their English is fine.
Some people are turned off by the Czech thing. Even in Warsaw Pact days the
Czech people looked to the West and their country is now democratic, stable, and
a valuable NATO ally. (They all have relatives in Chicago, it seems). I would
say that the political risk of going with a Walter is nil, and the economic risk
is much lower than some other engines -- every LET-410 is powered by two 601s
and there are thousands of them, plus operators of things like King Airs are
starting to discover that a Walter STC pays for itself. So the company isn't
going anywhere but up. Here are the US distributors of the Walter engine (from
the Walter website). Most of these work mostly on ag projects:
Darryl Riddell
Riddel Flying Service
+1 870 572 9011
Lindley Johnson
Johnson Airspray
+1 218 437 6415
Douglas Karlsen
Turbine Design
+1 904 736 8262
Kirby Spangler
Ryan International
+1 316 640 7880
Ron Broyles
ACE Aviation
+1 415 472 0227
(Note that the 4- and 6- cylinder engines sold under the Walter name are from a
different branch of the company no longer affiliated with the turbine end...
think of it like the split between wooden and metal Sensenich).
Hope this gets you started towards answers.
Tony W,
<Cl...@snyder.on.ca> wrote in message
news:E3T3OSmyeaX83UR5G=I0ISF=9t...@4ax.com...
>>
> >
> >They discontinued their 3.3L flat 6. IT was in the SVX it was a good car
> >but didn't sell well.
> >
> >Tony
> sell!!
Damn, I can hardly wait. I was going to buy a new car next year anyway.
Tony
Kevin O'Brien
says...
<snip>
> Now what does a runnout 320 cost and
>where do you find them? Would $6K for parts to rebuild a 320 that's
>runnout be reasonable? Can you find a 320 for $6K?
>
>But I actually need more power which pretty much rules out the 320.
>360's are just about untouchable in my world.
The 320s and 360s are priced even higher than most aero motors because they are
used in many popular certified and homebuilt (can you say RV?) aeroplanes. Since
you need more juice... I have forgotten what you're building, I think it's a
christavia, which I don't know... can you use a 470?
The comp-air people have a couple of them for sale cheap, 230-240 HP, one's zero
time new (NOS) and one's 400 Hrs SMOH. $6 and $7k. They might have a 220
Franklin or two lying around as well. Smooth six cylinder engines, the
Franklins. If these don't fit your ship, sorry. There's also a good page about
the luck that their builders have had with auto engines (in a word, rotten).
Steve is still open minded about auto engines but his customers have been voting
them out and certifieds back in... one guy has a Subary SVX six with some
promise. http://www.aerocomp.com/
Kevin O'Brien
Russ & Frank -- if you have those pictures in electronic format how about
posting them to alt.binaries.pictures.aviation? (yes, there are binary groups
that aren't skin).
The Merlin and the Wankel are both highly efficient, and might not equate in
efficiency to the Lycosaur, although the chemistry is basically the same. I have
read that the Merline/Griffon/DB605 were the high water mark of internal
combustion gasoline engine design, and that engineering on this technology
stopped advancing for thirty plus years once the war-driven, government
subsidised research stopped (when the turbine became the engine of war). New
advances began again subject to the dictates of both governments for reduced
pollution (=more combustion efficiency) and of markets for increased mileage
(=more combustion efficiency) in the late seventies. Don't know if that's true
or not, but it was asserted most positively.
Lee Phillips
have put out some of the most horrible crap anyone ever saw on rare
occasions (e.g., main bearing saddles out of alignment). But, I do have some
experience designing pistons for race cars, NASCAR in particular. This
experience is admittedly about 23 years old now. I have a very good idea of
what happens to piston pin holes at 7000 RPM in the course of a 500 mile
race.
Sure, the Lyc (and the Continental) have large prop-supporting bearings, and
a PSRU would not need them, no question. Even so, take another look at the
sizes of the respective rod bearing surface areas, the fact that V-8 motors
share a journal between two rods; allow for the differences in forces on the
rod due to the large differences in bore. After that, remember that oil's
main job after making things slippery is cooling; remember how the oil pump
is driven, and how distributor gears frequently wear a lot during racing
activities. Check the piston speed in surface feet per minute at or above
4500 RPM. Realize that a lot depends on this number. Check it again with
regard to the Lycoming or Continental product. Reliability and longevity
revolve around these numbers.
I'm not against using a v-8 configuration based dimensionally on some of the
SBC features for aviation. 350s have a good rod angle. Smokey Yunick had
some pretty good ideas for making them last. It can be done. I just doubt it
is real safe with stock motors (cast pistons, cast cranks,cast rods, piston
pins [although there are a lot of good forged parts around, some factory].
If I was to do it, I would use an aluminum block with dart heads. If I could
get some production started on the Moser 4 valve heads (mid 70's), I would
prefer to use them. GOOD forged pistons, Carillo rods, Moldex or wreath
crank, gear drive for the roller camshaft, marine dry sump with scavenge
and external oil cooler, and a reverse flow cooling system (heads get the
coolant first), a computer controlled timed port fuel injection and a good
PSRU. Of course, then it wouldn't any of it be Chevrolet, and the cost would
exceed the cost of a comparable Lycoming or Continental. It would sure be
fun, though, in a 2/3 replica P-38. I would be running about 10.5:1
compression on 100LL, with turbocharging not to exceed 30 in. hg (1
atmosphere at sea level).
If someone wants to run a junkyard motor, or even a Mr. Goodwrench Crate
motor, it is no skin off my nose, as long as I am not under it or in it.
We've seen it before, and no doubt will see it again. It might even work out
OK. "Might" just isn't good enough to suit me. If you do the engineering
studies first it might just save you a little grief. An acquaintance is
using a 302 Ford in a LongEZ with pretty good results, albeit direct drive.
Seems to me most of the motor is wasted in that configuration, but at least
it is fairly safe.
You might take a look at "The Internal Combustion Engine in Theory and
Practice", Charles Fayette Taylor (Volumes I and II) ISBN 0-262-70026- {1 |
3}, Massachusetts Institute of Technology, 1996. This work traces all
aspects of the development of I.C. engines, and was originally based on the
engines for the DC-7, including the work done by Art Sparks et al. in the
development of forged pistons (giving rise to the ForgedTrue Corporation,
which made automotive racing pistons, first and best, for many years). Much
work has been added since then. The work is quite complete, and is based on
engineering data borne out by empirical testing and research.
Enjoy!
Lee
Charles K. Scott <Charles...@dartmouth.edu> wrote in message
news:8t6lo6$mg8$1...@merrimack.Dartmouth.EDU...
Kevin O'Brien
says...
>
>"BRUCE A. FRANK" <baf...@worldnet.att.net> wrote:
>>What is the size of this engine?
>
>The new 212 hp/210 lb-ft Subaru six is a 3.0L. From a description
>at http://www.canadiandriver.com/news/000918-1.htm , it is 0.8"
>longer and 100 lb(!) heavier than the 165 hp 2.5L four.
>--
>Chuck Tomlinson
>
Variable intake a la Porsche. Meaning among other things that you would need the
ECU. It might altitude compensate nicely. DOHC, 24 valves (4/cyl), alloy block
and heads. Unrelated to the 3.3l six as used in the SVX.
Cl...@snyder.on.ca
wrote:
>
>Morgans <jsmo...@twave.junk.net> wrote in message
>news:lDlJ5.20$P54...@e420r-sjo3.usenetserver.com...
>
>>
>> I think I saw where Soob is about to come out with a 2.8L engine. V-6 or
>> flat?
>>
>> Jim in NC
>
BRUCE A. FRANK
Bruce A. Frank
<Cl...@snyder.on.ca> wrote in message
news:E3T3OSmyeaX83UR5G=I0ISF=9t...@4ax.com...
Chuck Tomlinson
The new 212 hp/210 lb-ft Subaru six is a 3.0L. From a description
Charles K. Scott
Kevin O'Brien <ke...@useorganisationasdomainname.com> writes:
> The Merlin and the Wankel are both highly efficient, and might not equate in
> efficiency to the Lycosaur, although the chemistry is basically the same. I have
> read that the Merline/Griffon/DB605 were the high water mark of internal
> combustion gasoline engine design, and that engineering on this technology
> stopped advancing for thirty plus years once the war-driven, government
> subsidised research stopped (when the turbine became the engine of war). New
> advances began again subject to the dictates of both governments for reduced
> pollution (=more combustion efficiency) and of markets for increased mileage
> (=more combustion efficiency) in the late seventies. Don't know if that's true
> or not, but it was asserted most positively.
>
> cheers
As far as liquid cooled aero engines are concerned what you read is
correct. All development of this type of engine stopped with the end
of WWII because jets were already flying and their developmental
potential made prop fighters instantly obsolete.
But it wasn't just the engine technology that stagnated, the technology
used to cool them, which pretty much peaked with the P-51 Mustang, also
remained unadvanced.
The result is that up until just a few years ago the only information
available to guide homebuilders in designing cooling systems that did
not slow the airplane down like a parachute was gleaned from 60 year
old German technical papers.
You can scale down the Mustang's system but it's really designed to
cool a WWII fighter at 400+ mph at 30,000 feet. That kind of capacity
not only isn't required for a 180 hp homebuilt, the intake opening and
shape of the intake lips would be wrong.
On the other hand recent examination of successfully flying Ford V-6
powered Piper based homebuilts indicates that one doesn't have to
reinvent the cooling duct to get effective cooling. A number are
flying with significant impediments to effective airflow through the
radiator yet they cool none the less. Some have no ducting whatsoever,
just openings beside the prop and a hole underneath the radiator which
is configured to lay flat. The air has to pass by the psru, engine and
exhaust **BEFORE** getting to the radiator and then pops out at right
angles to the airflow past the fuselage. Yet this configuration does
the job.
It appears I have been agonizing over cooling design way too much. ;-)
Corky Scott
Cl...@snyder.on.ca
<baf...@worldnet.att.net> wrote:
>What is the size of this engine?
>
Can't remember exactly, but 3 o3 3.3 litre rings a bell.
BRUCE A. FRANK
end you will have spent as much as you would have for a new Lycoming and
made little improvement on the longevity. The point is to fly safely
cheaply.
We have tens of thousands of cumulative hours behind the Ford and Chevy V-6s
and V-8s now. There are no chronic failure points. Cast crank are not
breaking (unless you want to direct drive the prop), rods and rod bolts are
handling the 4000 to 5000 rpm range just fine. Stock pistons work OK with
mild mods to the HP output. Even the stock valve trains do the job at
reasonable RPMs (today's V-6s run forever at 5000 RPM).
Ten years ago Lamar claimed we had no right to endanger him by flying auto
engines over his house. We had no right to imperil the amateur-built
movement by falling out of the sky with such poorly conceived ideas as auto
engine conversion. If the present record is not enough to convince anyone
that auto conversions are viable then they don't want to be confused by the
facts. For the unimaginative the manufactures will continue to sell Lycs
and Conts. If you embrace the word "experimental" and understand what it
takes to provide durability then one of a myriad of alternative engines
could easily provide safe and economical power for your project.
Bruce A. Frank
Lee Phillips <phil...@ridgecrest.ca.us> wrote in message
news:8t8c9f$lun$1...@delphi.ridgenet.net...
BOb U.
"BRUCE A. FRANK" <baf...@worldnet.att.net> wrote:
>For the unimaginative the manufactures will continue to sell Lycs
>and Conts. If you embrace the word "experimental" and understand what it
>takes to provide durability then one of a myriad of alternative engines
>could easily provide safe and economical power for your project.
>
>Bruce A. Frank
++++++++++++++++++++++++++++++++++++++++
OUCH!
I can't believe you are painting all us LyCON addicts.......
UNIMAGINATIVE.
First, it ain't so.
Second, you do your cause no good with such flaming rhetoric.
Third, you know this, so why did you do it?
Bad hair day?
Who do you think you are anyway?
ME!?!?!?!? <g>
BOb U.
Charles K. Scott
BOb U. <r...@swbell.net> writes:
>
> "BRUCE A. FRANK" <baf...@worldnet.att.net> wrote:
>
>
> >For the unimaginative the manufactures will continue to sell Lycs
> >and Conts. If you embrace the word "experimental" and understand what it
> >takes to provide durability then one of a myriad of alternative engines
> >could easily provide safe and economical power for your project.
> >
> >Bruce A. Frank
> ++++++++++++++++++++++++++++++++++++++++
>
> OUCH!
>
> I can't believe you are painting all us LyCON addicts.......
>
> UNIMAGINATIVE.
>
>
> First, it ain't so.
> Second, you do your cause no good with such flaming rhetoric.
> Third, you know this, so why did you do it?
> Bad hair day?
I did not see this as a flame, although with the entire group rather
sensitized lately I can understand how some may feel that way.
What Bruce did do was point out that auto engine cores, the basic
block, are not breaking in the manner and areas predicted by the
several rancorous individuals who professed to be experts. Paul Lamar
actually should be considered an expert as he was a member of the
Chaparal team that made innovative race engineering a by word back in
the 60's. That's why it's so hard for me to understand his underlaying
belief which was and still is that automotive V-type piston engines
would (not might but definately would) catastrophically disintegrate
after a short while if used to power airplanes.
He should have known better having been an engineer for a team who's
catch phrase was "find a way to make it work." Team Chaparal was THE
most innovative group on the road racing circuit having pioneered the
use of moveable flaps to increase downforce on the track and automatic
transmissions. As one of several engineers on the team, it was his job
to make ideas work.
He should have known that with proper inspection and assembly, using
known high strength parts where necessary and then understressing the
engine that it would last at horsepower ratings not normally seen for
great lengths on the street.
Just because people don't drive them that way on the street doesn't
mean they cannot manage it when built properly. If the engines can
last hundreds of hours during the torture testing they go through in
development then they will not self destruct when run for long periods
at 60 and 75% power. The evidence so far is that the various blocks
are up to the task.
I repeat again for the record that the blocks are not the problem, they
can be made to last. But there are problems that each builder must
address if he or she is to fly successfully and safely. The prop speed
reduction unit must be well engineered and strong enough to handle prop
disc loading and thrust. Induction can be problematic; if a carb is
used then some provision must be made for leaning the mixture. If fuel
injection is used then single point failure modes should be eliminated.
Ignition really should be doubled up because there are several parts
of electronic ignition where failure results in total loss of ignition.
I am mystified by those who claim that having two fully independant
ignition systems simply doubles the possibility of failure. Yes
electronic ignition is ridiculously reliable these days, but it's not
100% reliable, failures still do occur.
Corky Scott
BRUCE A. FRANK
be a derogatory remark; just a point about "experimental" aviation.
Bruce A. Frank
BOb U. <r...@swbell.net> wrote in message
news:llmivs8utvafubk7i...@4ax.com...
BOb U.
wrote:
>In article <llmivs8utvafubk7i...@4ax.com>
>BOb U. <r...@swbell.net> writes:
>
>>
>> "BRUCE A. FRANK" <baf...@worldnet.att.net> wrote:
>>
>>
>> >For the unimaginative the manufactures will continue to sell Lycs
>> >and Conts. If you embrace the word "experimental" and understand what it
>> >takes to provide durability then one of a myriad of alternative engines
>> >could easily provide safe and economical power for your project.
>> >
>> >Bruce A. Frank
>> ++++++++++++++++++++++++++++++++++++++++
>>
>> OUCH!
>>
>> I can't believe you are painting all us LyCON addicts.......
>>
>> UNIMAGINATIVE.
>>
>>
>> First, it ain't so.
>> Second, you do your cause no good with such flaming rhetoric.
>> Third, you know this, so why did you do it?
>> Bad hair day?
>
>I did not see this as a flame, although with the entire group rather
>sensitized lately I can understand how some may feel that way.
>
>What Bruce did do was point out........
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
A rose by another name is still a rose. <g>
But, no big deal.
My relationship with Bruce is such that I feigned offense with this post of his,
but certainly not his message. I respect his genius... and civility.
This was but a rare opportunity for a small chide on his, otherwise, impeccable
wordsmithing.
BOb U
SOB U.
wrote:
>I am sorry Bob, I wrote it with a smile on my face. I did not intend that to
>be a derogatory remark; just a point about "experimental" aviation.
>
>Bruce A. Frank
+++++++++++++++++++++++++++++++++++++++
I had a SIMILAR smile when I wrote my post.
I know fukk well where you are coming from. <g>
See my post/response to Corky.
SOB U.
SOB U.
Oops...full
peter
>Badwater Bill wrote:
>
>> Good points. All of them.
>>
>> Here's a little calculation just for fun. O'ring says a gallon of
>> gas has 125,000 BTU's in it. One BTU is 1060 Joules and Joule/sec is
>> a Watt. There are 746 Watts in a horsepower. So let's crank it out.
>>
>> From the conversions above, one gallon of gas is 1.325 x 10^8 Joules
>>
>> Five gallons/hr is 6.62 x 10^8 Joules
>>
>> Dividing by 3600 second/hr gives: 1.84 x 10^5 Joules/sec
>>
>> Dividing by 746 Joules/sec per Horsepower gives: 246 horsepower
>>
>> Now we all know that these gasoline engines have a maximum
>> thermodynamic efficiency of right at 32%, and that the reality of the
>> situation is more like 25% fuel burn to actual usable energy.
>>
>> That gives us 61 horsepower.
But at 2,800 rpm and like 1/3 throttle you don't get 32% efficiency
(that is about peak for a well tuned DOHC engine with well matched
intake and exhaust systems), you don't get 25% (that is about peak at
WOT for a pushrod car engine with factory fitted unmatched cast
manifolds), more like 17% = 40bhp The higher the state of
(comparative) tune the worse it is. Specific fuel consumption changes
from about 0.5lb/hp.h to over 1.0lb/hp.h as the throttle is shut. But
as power goes from say 100bhp at WOT down to 50bhp at 1/3 the actual
fuel consumption drops, 0.5*100 = 50lbs/h, 0.65*50=32.5lbs/h
>>
>
>Which nicely jives with another calculation. Most auto engines have a BSFC
>of about 0.5 lbs/HP/hr.
Only in a very limited region of operation! About +10% -20% rpm of
peak torque and in excess of 3/4 throttle.
>(5 gallons/hr) * (6.5 lbs/gal) = 32.5 lbs/hr
>(32.5 lbs/hr) / (0.5 lbs/HP/hr) = 65 HP
>
>> So, to make my truck go down the road at 75 miles/hr requires about 60
>> horsepower. I'm running that big 350 Vortec at 60 horsepower in a
>> maximal condition. The Chevy 262 Vortec is burning 9 gallons per
>> hour. Doing a simple proportion, i.e.
>>
>> x/9=60/5 gives x= 108 horsepower.
Is this truck an 18 wheel rig?
Lets go look at top speed / brake hp for a few cars.
VW 1959 1.2L - 25 bhp 60mph
VW 1964 1.2L - 34 bhp 70 mph
Austin Mini ? 1L - 45 bhp 80 mph
Nissan 1.8SSS 1980 1.8L - 104 bhp 117mph
Toyota Celica 2.0XT 1984 2L - 108 bhp 120mph
Citroen BX16 1990 1.6L - 96 bhp 109 mph
Nissan 200SX S13 1990 1.8L turbo - 165 bhp 140mph (enough for me)
Nissan 200SX S14 1996 2L turbo - 200 bhp 155mph (enough for anybody)
BHP = Cd x A x V^2 (ignoring rolling resistance) hence Bhp2 = Bhp1 x
(V2 / V1) ^ 2. So power for above cars at 60 and 75 mph is (approx -
and required power if car not actually capable)
VW 1959 = 25, 39
VW 1967 = 25, 39
Austin Mini = 25, 39
Nissan 1.8SSS = 27, 42
Toyota Celica 2.0XT = 27, 42
Citroen BX16 = 29, 45
Nissan 200SX S13 = 30, 47
Nissan 200SX S14 = 31, 47
I think the rise as performance increases is due to not taking rolling
resistance and weight variation into account (and the Citroen is just
plain crap). If you increase the load carried then power required
goes up - figures I have for a 1100cc 7cwt van (think it's a Morris
Minor) show 25bhp for unladen at 60mph and 35bhp fully laden - empty
the trunk / pickup bed.
Fuel consumption?
The VW's and Mini would do about 45mpg at a very very steady 45mph -
1gall/hr. But if you tried to get an on road average speed of 45mph
it would rise to about 1.5gall/hr. The rest - about 2.3 gall/hr at a
road average close to 70mph (needs about 85mph cruise on the good
bits) but these are full size UK gallons! I've been doing round trips
of 240 miles once a month for over ten years in 4 of the above cars so
I have a pretty good idea. Usually takes about 1hr 45min each way if
takes over 2 hours it's a bad run - road works or other hold ups.
Expect to get about 30mpg - best was 36mpg (about 60mph) worst 25 mpg
(about 70mph) both in nasty French Lemon = Citroen.
The manufacturers produce fuel maps to setup their injection systems.
These are displayed in 3d. Best lb/hp.h fuel usage is typically at
3/4 throttle and about the same rpm as peak torque. Peak efficiency is
always at full throttle, any throttling reduces efficiency. Basically
if you run an engine that's too big for the normal load you will pay
with high mpg. I think you need to cut about half that engine off to
get it right. But then it may be under torqued for dragging that tree
out of the woods once a year. What you need in your truck is a 2.5L
turbo diesel!
Then there is transmission loss - manual gearbox at light load and low
rpm 96% efficient. Due to oil stir / air windage / friction it will
reduce to a bit less than 90% at full load. If you have an automatic
then you may get up to 80% - a bit more with a lock up clutch..
Over 55 years ago the Merlin hit nearly 100BHP/L - 27L giving all out
2620bhp (combat 2340bhp at 3000rpm). 20 years ago I would not look at
a production 4 stroke street bike with less than 100bhp/l and expected
over the counter 2 stroke race bikes to give 250bhp/l. 10 years ago
turbo charged production road cars were doing 90bhp/l with 100bhp/l
available just by turning up the boost and Renault's F1 1500cc V6
produced 1400bhp in qualifying tune (20min running time - 2 sessions -
out lap, 2 pace laps, 1 hell for leather, 1 lap slow down). Current
best for normally aspirated production road car engines is about
75bhp/l (Honda civic 1.5L vtec). BMW's M3 may do better but it's
already been through the tuning shop.
Against this - how long did WWII Merlin's go before full overhaul?
None of the race stuff above would run much more than 200 hrs before
total rebuild. 2 strokes would need new rings every 4 hours and crank
overhaul at about 100hrs. 4 stokes would do a 200h season. (If you
want 40,000hrs on wing get a three shaft turbo fan - made like God and
nature intended).
If you are going to use a water cooled automotive engine for aviation
it should put out about 100bhp/l. Or at least 60bhp/l - like double
the 29bhp/l of the O-300. If it just clunks along at 40/45/50bhp/l
(like 200/225/250 bhp from an undertuned 'crate' 5L engine - Rover (ex
Buick) 3.5L all alloy V8's are available at these power outputs) then
you lose out on installed weight - alloy / iron block, air / water
cooling and have to pay in fuel to haul that weight around. A turbo
Subarau looks about best. As for PSRU's - Merlin's had them why
shouldn't you? It seems to come down to American v's European /
Japanese automotive engineering. American - build it big and lazy,
lug 2 tons of metal around, 3 speed auto gearbox and stuff the gas
consumption it's real cheap. European / Japanese - small, light and
hard working - weigh about one ton, 5 speed manual gearbox and it
better use about half the gas an American motor uses because it costs
3 times as much!
<snip>
>
>Yes. It is sometimes possible to get the chart (I forget the name) that
>shows where all the energy goes. For example, on the Wankel engine the
>energy is distributed as:
>
> 5% heat of unburned gas (engine at 1.14 * stochiametric)
> 41% heat of exhaust gas
> 18% heat absorption by cooling water
> 6% heat absorption by lubricating oil
> 28% effective heat (i.e. what goes out the crankshaft)
> 2% others
>
>[Numbers from a graph I have; I think it was extracted from a SAE paper.
>Email me if you want a copy.]
>
>So 28% of your 246 HP would be 69 HP.
Only at WOT! Once the throttle is partly shut the engine gasps for
air and Volumetric efficiency drops. On a somewhat old graph
(suspect side valve!) I have, full power gives 30% cooling (oil, water
and air), 23% exhaust, 15% radiation and 22% useful work. At 1/4 full
power holding the same revs 60% coolant, 20% exhaust, 10% radiation
and that gives 10% for useful work. As no one flies at 1/4 throttle
it's not a problem for aircraft. But it is a big big problem for
cars, bikes etc. where part load operation is the norm. Gas turbine
part load operation is even worse, which is why the Rover 15/60 and
GM's never really got off the bench. They had to start looking at
'afterheating' the air from the compressor using the hot gas from the
turbine outlet.
>
>> Once you've made all these modifications and you have an $11,000
>> package that weighs a lot more than a Lycosaur too, is it really worth
>> it to do the experiment?
>
>With a Vortec? Probably not. With a much lighter Ford? That you got for
>$75 (like Corky)? Maybe. With an aircooled VW? Seems like alot of
>people have said yes.
>
>Russell Kent
>
Wouldn't want to fly on any motor that did not have forged pistons and
good rods. I also don't like automotive pushrods having seen the ones
that came out of a friend's car - 5 of them looked like a bolt of
lighting. We think the timing gear had sheared the key. There again
if it had been a rigid OHC valve train the rods and pistons would have
needed replacing and possibly the crank if the sudden stop at high
load caused it to twist.
--
Peter Hill
Can of worms - what every fisherman wants.
Can of worms - what every PC owner has.
Charles K. Scott
peter <peter...@skyshack.demon.co.uk> writes:
> Wouldn't want to fly on any motor that did not have forged pistons and
> good rods. I also don't like automotive pushrods having seen the ones
> that came out of a friend's car - 5 of them looked like a bolt of
> lighting. We think the timing gear had sheared the key. There again
> if it had been a rigid OHC valve train the rods and pistons would have
> needed replacing and possibly the crank if the sudden stop at high
> load caused it to twist.
>
> --
> Peter Hill
Thanks Peter for all the interesting factoids. Most of those who use
the Ford 3.8L V-6 are using forged pistons although some are not and so
far appear to be surviving.
Corky Scott
O-ring Seals
Bill) wrote:
<snipped>
>But, if you are sucking twice the power per cubic inch out of it,
>common sense says that you will wear it out twice as fast. O'ring is
>probably the one here who is right. He says he thinks it would last
>about 25% as long. So do I. I don't think it's linear.
Of course it is not linear Billy. You mentoined the fuel dragsters
lasting for only a few seconds. See what kind of curve that fits!
Bobby
>
>Hank Jarret makes some real good points about heat transfer and
>lubrication too.
>
>BWB
>
>
Russell Kent
> Then there is transmission loss - manual gearbox at light load and low
> rpm 96% efficient. Due to oil stir / air windage / friction it will
> reduce to a bit less than 90% at full load. If you have an automatic
> then you may get up to 80% - a bit more with a lock up clutch..
80% ?? So 20% of the produced HP goes where? Heat?
Using your numbers, that means my Nissan at 75 MPH is radiating roughly 9 HP (47
* 1.2 - 47) through the transmission housing (no tranny cooler). I don't have
the formulas around here; someone convert that to BTUs. Doesn't seem likely
anyway.
> If you are going to use a water cooled automotive engine for aviation
> it should put out about 100bhp/l. Or at least 60bhp/l - like double
> the 29bhp/l of the O-300. If it just clunks along at 40/45/50bhp/l
> (like 200/225/250 bhp from an undertuned 'crate' 5L engine - Rover (ex
> Buick) 3.5L all alloy V8's are available at these power outputs) then
> you lose out on installed weight - alloy / iron block, air / water
> cooling and have to pay in fuel to haul that weight around. A turbo
> Subarau looks about best. As for PSRU's - Merlin's had them why
> shouldn't you?
[gratuitous ethnic slam snipped]
So how does 450 HP/liter strike you? There's a fellow who has one in his race
car with between 100 and 200 hours on it (not all racing). He has "had some
problems" at that power level, and thinks that 300 HP/l is a more sustainable
rate for continuous duty. His name is Jim Mederer and he owns Racing Beat. The
engine is a substantially modified 3 rotor turbocharged Mazda 20B.
> Wouldn't want to fly on any motor that did not have forged pistons and
> good rods.
If your engine has pistons and rods, you've got the wrong engine. :-)
Russell Kent
Brian Rauchfuss - PCD
>The engines are the powerheads used in boats' outboard motors, like OMC or
>Mercury. The concepts of integration of a burner-can enhanced turbocharger
The problem with using an outboard in an airplane is cooling it. The
boat has a wonderful supply of cooling water which is unavailable to the
airplane, and is hard to recreate with a radiator.
Brian
hamst...@my-deja.com
>(no tranny cooler).
For an automatic? Better check again - you'll probably find lines to
an ATF cooler within the glycol radiator.
_All_ the automatic-equipped cars I've ever worked on have heat
exchanger coils within the radiator that let the glycol conduct heat out
of the ATF.
Hammy
Sent via Deja.com http://www.deja.com/
Before you buy.
Russell Kent
Russell
cl...@snyder.on.ca
How about a Toyota UP7? Had no radiator, and a powerglide type 2 speed
automatic.
Many early automatics, and low powered automatics looked after the
cooling internally.
cl...@snyder.on.ca
PCD) wrote:
This has been discussed here before - and frankly, it's BS.
The outboard has a thermostat and water pump like an automotive engine
- and a radiator will do just fine for cooling. The big problem is
plumbing - due to the wet exhaust and a few other features. Heat load
is not a serious problem.
Rich Shankland
news:deMAOvDKoCIdWb...@4ax.com...
My Powerglide '65 Corvair doesn't seem to have one.
--
Rich Shankland
http://www.harbornet.com/folks/shankland/emeraude.html
Bob Atkins
After reading the entire thread with interest I'm trying to figure out
what the true driving reason is for putting an automotive engine in an
airplane. From all accounts it appears to be a cost factor. The
prevailing wisdom seems to be saying that auto engines are cheaper than
an airplane engine such as a Lycosaur. However, several good arguments
have been made that show that after an auto engine is converted that the
overall cost comes out very close to a similar horsepower Lycosaur. The
mods required to make an auto engine airworthy and reliable are
significant and complex - requiring that almost all stock internal
components (rods, pistons, pushrods, rocker arms, valves, etc.) and
cylinder heads be changed out in order to achieve a reliable result. The
recipe requires internal components from several different sources and
relies heavily on the builder's knowledge of how to build a high
performance engine practically from scratch.
Considering the need for a prsu and the overall added weight plus the
requirement of running an auto engine at higher rpm (and therefore much
higher piston travel per unit of distance flying) and that an auto
engine will ultimately end up using about the same fuel per hour to
achieve the same horsepower as a Lycosaur. The auto engine _may_ reach a
2000 hour TBO but the piston travel (due to higher rpm) is a killer that
makes a 2000 hour TBO hard to acheive consistently. Personally I
consider a 2000 hour TBO to be on the low end of the scale and that we
should be shooting for 3000+ hour TBOs these days.
What about all of the 'other' stuff that has to be done to run an auto
engine? The details of the fuel delivery, ignition system (single plug),
valve timing system and so on in order to make a truely airworthy
engine? Surely a fair amount of investment is needed?
It appears to me that cost isn't the sole factor driving the interest
and use of an auto engine in aircraft. Liquid cooling also seems to be a
benefit both in terms of engine reliability and reduced cooling drag.
Auto engine's cooling systems are a weak link when it comes to running
at higher sustained power. Water pumps and head design simply aren't
refined enough to handle sustained durations of high power output - even
if you do have a large enough radiator. Granted aftermarket cylinder
heads have improved the coolant circulation to reduce and/or eliminate
steam pockets. However, stock and even so called hi performance water
pumps rarely supply the necessary flows and pressures to ensure
*efficient* cooling of the cylinder heads.
Now what if you could have a liquid cooled Lycosaur?
How about an O-360 or O-540 with a properly designed liquid cooling
system?
Granted cost will be an issue - but if we put that aside for a moment
what about the other advantages?
. A tried and true direct drive airplane engine
o No prsu required - less weight amd less to go wrong
o Major engine mods not required
o No internal reciprocating parts changed
. A more consistent engine from a quality control standpoint
. Lower cooling drag
. No shock cooling/heating
. No detonation
. *Much* lower piston travel
. More conventional installation
. Use of advanced ignition and fuel delivery systems
. Smaller - custom built radiator
. 3000+ hour TBO without difficulty
. Available today.
(Yes, they really are!)
Just curious as to whether or not the benefits of a liquid cooled engine
are really what this thread is about?
---
Bob
Bill Daniels
I know there is a group doing this. Will there be STC's for certified
aircraft? I'm thinking of glider towplanes.
However, I think you shortchanged the auto engine concept a little. To
it's benefit I would add:
A PSRU is required, however, adding one allows a much slower turning
propeller which is much quieter and more effecient.
Turning an 8 cylinder engine faster than a direct drive 4 or 6 is very
smooth and quiet.
Even though adding high reliability components in the buildup can be costly,
the overhaul costs are likely to be much lower.
While the fuel burn for an auto conversion, for a given HP, is going to be
about the same, it will be cheaper mogas.
Bill Daniels
cl...@snyder.on.ca
wrote:
>
>After reading the entire thread with interest I'm trying to figure out
>what the true driving reason is for putting an automotive engine in an
>airplane. From all accounts it appears to be a cost factor. The
>prevailing wisdom seems to be saying that auto engines are cheaper than
>an airplane engine such as a Lycosaur. However, several good arguments
>have been made that show that after an auto engine is converted that the
>overall cost comes out very close to a similar horsepower Lycosaur. The
>mods required to make an auto engine airworthy and reliable are
>significant and complex - requiring that almost all stock internal
>components (rods, pistons, pushrods, rocker arms, valves, etc.) and
>cylinder heads be changed out in order to achieve a reliable result. The
>recipe requires internal components from several different sources and
>relies heavily on the builder's knowledge of how to build a high
>performance engine practically from scratch.
>
This is definitely not required. MANY stock automotive engines are
flying, safely and reliably
>Considering the need for a prsu and the overall added weight plus the
>requirement of running an auto engine at higher rpm (and therefore much
>higher piston travel per unit of distance flying) and that an auto
>engine will ultimately end up using about the same fuel per hour to
>achieve the same horsepower as a Lycosaur. The auto engine _may_ reach a
>2000 hour TBO but the piston travel (due to higher rpm) is a killer that
>makes a 2000 hour TBO hard to acheive consistently. Personally I
>consider a 2000 hour TBO to be on the low end of the scale and that we
>should be shooting for 3000+ hour TBOs these days.
A Soob with a 2:1 reduction has the same piston speed as a LycoSaurus
direct drive.
>
>What about all of the 'other' stuff that has to be done to run an auto
>engine? The details of the fuel delivery, ignition system (single plug),
>valve timing system and so on in order to make a truely airworthy
>engine? Surely a fair amount of investment is needed?
Not much HAS to be changed, and most of what does is less expensive
than what comes off. Less complex for sure. Dual ignition is nice, but
dual plugs are not required.
>
>It appears to me that cost isn't the sole factor driving the interest
>and use of an auto engine in aircraft. Liquid cooling also seems to be a
>benefit both in terms of engine reliability and reduced cooling drag.
>Auto engine's cooling systems are a weak link when it comes to running
>at higher sustained power. Water pumps and head design simply aren't
>refined enough to handle sustained durations of high power output - even
>if you do have a large enough radiator. Granted aftermarket cylinder
>heads have improved the coolant circulation to reduce and/or eliminate
>steam pockets. However, stock and even so called hi performance water
>pumps rarely supply the necessary flows and pressures to ensure
>*efficient* cooling of the cylinder heads.
>
Have you seen what an automotive engine goes through in testing before
production? Full power. full speed untill it breaks - fix it and try
again. MUCH more severe than any certified engine has ever been tested
under.
>Now what if you could have a liquid cooled Lycosaur?
>
>How about an O-360 or O-540 with a properly designed liquid cooling
>system?
>
>Granted cost will be an issue - but if we put that aside for a moment
>what about the other advantages?
>
>. A tried and true direct drive airplane engine
> o No prsu required - less weight amd less to go wrong
> o Major engine mods not required
> o No internal reciprocating parts changed
>
>. A more consistent engine from a quality control standpoint
>
>. Lower cooling drag
>
>. No shock cooling/heating
>
>. No detonation
>
>. *Much* lower piston travel
>
>. More conventional installation
>
>. Use of advanced ignition and fuel delivery systems
>
>. Smaller - custom built radiator
>
>. 3000+ hour TBO without difficulty
>
>. Available today.
> (Yes, they really are!)
>
>Just curious as to whether or not the benefits of a liquid cooled engine
>are really what this thread is about?
>
My auto engine conversion candidate is air cooled, direct drive - and
looks like an aircraft engine. ANd it sure won't break the bank to
build, or overhaul. More expensive than many auto engines due to
scarcity of parts for 35 year old engine.
CORVAIR!!!!
>---
>Bob
Bruce A. Frank
Bob Atkins wrote:
>
> After reading the entire thread with interest I'm trying to figure out
> what the true driving reason is for putting an automotive engine in an
> airplane. From all accounts it appears to be a cost factor. The
> prevailing wisdom seems to be saying that auto engines are cheaper than
> an airplane engine such as a Lycosaur. However, several good arguments
> have been made that show that after an auto engine is converted that the
> overall cost comes out very close to a similar horsepower Lycosaur. The
> mods required to make an auto engine airworthy and reliable are
> significant and complex - requiring that almost all stock internal
> components (rods, pistons, pushrods, rocker arms, valves, etc.) and
> cylinder heads be changed out in order to achieve a reliable result. The
> recipe requires internal components from several different sources and
> relies heavily on the builder's knowledge of how to build a high
> performance engine practically from scratch.
Guess you didn't read my thread about the Ford V-6s.
>
> Considering the need for a prsu and the overall added weight plus the
> requirement of running an auto engine at higher rpm (and therefore much
> higher piston travel per unit of distance flying) and that an auto
> engine will ultimately end up using about the same fuel per hour to
> achieve the same horsepower as a Lycosaur. The auto engine _may_ reach a
> 2000 hour TBO but the piston travel (due to higher rpm) is a killer that
> makes a 2000 hour TBO hard to acheive consistently. Personally I
> consider a 2000 hour TBO to be on the low end of the scale and that we
> should be shooting for 3000+ hour TBOs these days.
The engines are not being highly taxed by turning twice the RPMs of Lycs
or Conts. I haven't read claims that more or equal HP can be produced
using less fuel. The valid claim about auto engines is that since they
are liquid cooled, their tolerances can be tighter and their efficiency
made somewhat better than an air cooled engine. Also slightly less fuel
can be used as it isn't needed to directly cool the engine. With
optimized systems air cooled engines usually consume 3% to 10% more
fuel than a liquid cooled.
I feel like I have just revisited the discussion of TEN YEARS AGO.
--
Bruce A. Frank, Editor "Ford 3.8L Engine and V-6 STOL
BAF...@worldnet.att.net Homebuilt Aircraft Newsletter"
| Publishing interesting material|
| on all aspects of alternative |
| engines and homebuilt aircraft.|
*------------------------------**----*
\(-o-)/ AIRCRAFT PROJECTS CO.
\___/ Manufacturing parts & pieces
/ \ for homebuilt aircraft,
0 0 TIG welding
J Vandervort
assa9
"Rich Shankland" <cap...@nospam.harbornet.com> wrote in message
news:UK5M5.161$JS3...@newsfeed.slurp.net...
Ray Leonard
<"bafrank"@worldnet.**NO SPAM**att.net> wrote:
>
>
Bruce - perhaps Bob's full sig will provide a proper context in
which to consider his remarks.
>Bob Atkins
>President
>Liquid Cooled Air Power
Ray
Peter Buckley
engine? The rear engine on Burt's Voyager was liquid cooled (at least
partially), and a larger version went into production (Approx. 350 hp?)
I have seen adds for a converted Cessna 414 with these engines, so I'm
guessing they were fully certified.
P. Buckley
Bruce A. Frank
auto-engine thus to suggest that his cooling system on a Lyc would be a
better choice! OK, I'll quit whimpering and pulling my hair out now.
S O BOb
>However, I think you shortchanged the auto engine concept a little. To
>it's benefit I would add:
>
>A PSRU is required, however, adding one allows a much slower turning
>propeller which is much quieter and more effecient.
Not exactly..... and adds ANOTHER weight/complexity penalty.
>Turning an 8 cylinder engine faster than a direct drive 4 or 6 is very
>smooth and quiet.
And SLOW turning V8's 's are even better.
>Even though adding high reliability components in the buildup can be costly,
>the overhaul costs are likely to be much lower.
Without extensive research, the costs cannot be calculated until after the
history is written.
>While the fuel burn for an auto conversion, for a given HP, is going to be
>about the same, it will be cheaper mogas.
>Bill Daniels
I burn mogas to my hearts content now in my 150 HP 0-320 Lycoming.
The biggest problem is keeping track of what airports have it in the first place
and secondly.. which ones have it at a practical savings over Avgas.
Not many where I normally travel.
Bear in mind the only real savings comes when I lug it to my plane from an off
airport gas station. For that, I have to invest sweat equity and take on the
fire hazard risk.
So.. not exactly a free lunch, but worthwhile to folks on a pension.
>
>Bill Daniels
highflyer
>
> Bob, while a liquid cooled 0-360 or 0-540 would be interesting and welcome,
> I know there is a group doing this. Will there be STC's for certified
> aircraft? I'm thinking of glider towplanes.
>
at least the cylinder heads of aircraft engines. There was a time
when the large majority of aircraft engines were water cooled. The
coolant system was a source of many problems for aircraft engines.
Not too many years ago, I can recall changing a water pump in order
to get a water cooled airplane out of a field in Iowa. I must admit
that the water cooled aircraft engine in that situation was a Curtiss
OX-5. By the same token, it was relatively easy to change the
externally
mounted water pump.
> However, I think you shortchanged the auto engine concept a little. To
> it's benefit I would add:
>
> A PSRU is required, however, adding one allows a much slower turning
> propeller which is much quieter and more effecient.
>
That is true. Many aircraft engines over the years have been equipped
with PSRU's to allow greater horsepower from higher engine RPM without
degrading propellor performance with excessive RPM. The "modern"
direct drive aircraft engine only provides a fraction of the thrust
per horsepower of the early slower turning aircraft engines. However,
they DO provide more horsepower per cubic inch and per pound of engine
weight. On slower aircraft, much of that increased power is lost
through poor thrust conversion at the higher RPM's they turn.
> Turning an 8 cylinder engine faster than a direct drive 4 or 6 is very
> smooth and quiet.
>
Turning a six cylinder geared aircraft engine at higher RPM's also makes
a smoother and quieter engine. However, people tend to carefully avoid
the geared aircraft engines. Truthfully, they have had many problems
with PSRU's on aircraft over the years. It is also true that the
majority
of these problems could have been avoided through proper operation of
the engine, PSRU, propellor system. People who operate these engines
regularly and correctly have very few problems with the PSRU.
> Even though adding high reliability components in the buildup can be costly,
> the overhaul costs are likely to be much lower.
>
That may be true. However, very few homebuilt aircraft have managed to
accumulate over 1000 hours, even though some have been flying now for
nearly fifty years. I have myself, been a member of the EAA for well
over forty years. They have a "thousand hour circle" at Oshkosh for
homebuilts with over a thousand hours on them. It is not terribly
crowded! :-) Since the "TBO" of a Lycoming, for example, is given as
"two thousand hours or six years, whichever occurs first" the hours to
TBO seems a bit moot in any case for an airplane flown purely for fun.
The airplanes that tend to reach TBO are the ones that are used in
commercial service, where the props have to keep turning to keep
paying for the airplane. :-) Even a 500 hour TBO would represent
many years of flying for the average homebuilt.
> While the fuel burn for an auto conversion, for a given HP, is going to be
> about the same, it will be cheaper mogas.
>
Many aircraft engines also burn the cheaper mogas! Several of the
airports around here have mogas available on the field for those who
are avoiding 100LL for one reason or another. In a couple of years,
the new "Avgas 82" will be all that is available. All that IS is a
bit of mogas that has been given special treatment to provide the
FAA mandated paper trail. I expect it to cost more than 100LL.
Perhaps I am unduly pessimistic, but I did notice that the price of
mogas went up when they took the lead out! :-)
--
HighFlyer
Highflight Aviation Services