Comment on hirth F30 110HP engine
Dave Maree
in my Mini 500 helicopter. On paper it looks good from a performance and
weight point of view, Evan at 1000rpm less than max rpm it has power to
spare.
Is there anybody who can comment on this motor, good or bad
as there not many of them running here.
David Maree
South Africa
d...@global.co.za
Charles K. Scott
"Dave Maree" <d...@global.co.za> writes:
David, a lot of people will watch your conversion with interest. Be
aware, no other installation, if in fixed wing application, will have
been run as hard as will be required in the Mini-500. It's the
continous need for wide open, maximum power that appears to be the big
problem with the engine.
If you go this way, it would be great if you kept us informed of your
progress.
Good, and I mean this, Luck.
Corky Scott
Bill Berle
I agree, it seems that a usable and reliable powerplant installation
would do wonders for the viability of the aircraft. I suggest one item
to think about, however. Make sure that the cooling air flow through the
cylinder fins is taken into consideration. The Hirth engine was probably
designed to be in a moving airplane, not a helo. If there is a fan, or
cooling shroud then it should be made to work in that environment. If
not, then perhaps speak to the factory about how they would suggest
cooling the engine in a rotary wing installation. I suspect that a well
designed set of baffles, cooling shroud, and an engine driven fan might
be the way to go.
Bill Berle
Juan Jimenez (TeamB)
instead of standard carburetors, as well as the fan-cooling option.
You'll eliminate the jetting adjustment issue, which is really one of
the basic problems with the Rotax 582, as well as reduce weight and
simplify maintenance. The Nikasyl process that Hirth uses to line the
cylinder walls is also supposed to help quite a bit in avoiding the
engine seizure problems that have plagued the Rotax in the Mini-500
installation. I'm not sure which fuel injection they are using; the one
I am having installed in my 2SI is the Airflow Performance system, which
comes highly recommended. If Hirth doesn't offer that fuel injection
system, you might also want to inquire with Airflow Performance to see
if they offer a setup for the F30EP.
Juan
Kevin Morris
In my experience the engine never had a chance to prove it's self. The fan
system provided by the Canadian Hirth distributor was a complete waste. It
failed several times, requiring redesign before we took it out of the
country in a gyro. The pictures of the cooling system provided now are very
different and hopefully it's much improved. The good news is that until melt
down the engine made great torque in the midrange where you need it for
rotor rpm recovery. I second the fuel injection idea on two strokes as
cheap, crude carburetors don't seem up to the task.
Before anyone risks their butt in a M-500 I would suggest 50 to 100 hrs. of
ground run time with the machine tethered on isolation springs, the idea
being to permit it to vibrate as naturally as possible and allow to worst
design boo-boos to show up in the safest environment. After some mechanical
confidence is acquired on the ground then get ready for some real excitement
in flight at altitude!
Best of luck. Remember, don't fly any higher than you're willing to fall.
Kevin Morris
Dave Maree <d...@global.co.za> wrote in message
news:7ul786$8j9$2...@ctb-nnrp2.saix.net...
JF
Looking for an engine for a Sonex.
JF
Juan Jimenez (TeamB)
Borut Horvat
J.D. GUINN
Ron Hansen
be true! Is there anybody flying one that can confirm this low fuel burn?
Ron
Juan Jimenez (TeamB)
reference of the fuel injected F30 to find out if it's true. I find it
hard to believe as well. The 2760E burns 3-4 according to one dealer
who's done extensive testing on it and it's 2 cyl, fuel injected, 65 hp
max.
Richard Isakson
>A 129 Lb., 110 HP "2-cycle" engine that only burns 6 GPH? Sounds too good
to
>be true! Is there anybody flying one that can confirm this low fuel burn?
These numbers are consistent with the way Rotax publishes their numbers.
But, there's a trick to it. The weight that Rotax uses don't include little
things like the gearbox, the exhaust system, the starter, the carburetors,
the entire cooling system, ect. By the time you add all these things in the
weight of the engine is not all that much lower than a four stroke engine.
I would assume that Hirth is doing the same thing.
Two stroke engines are very fuel inefficient. Typically, their SFC is 0.7
to 0.8 lbs/hr/HP. That's fifty percent worse than their four stroke
counterparts. But, when they quote fuel flows, it's usually at fifty
percent power. In this case six gallons per hour at fifty-five horsepower
gives a SFC of 0.65. Perhaps a bit optimistic. Again, I'm assuming Hirth
uses the same standards as Rotax.
An interesting aspect of these two factors is that, for the same mission, a
fully fueled two stroke powered airplane is heavier than a similar four
stroke airplane.
Rich Isakson
Juan Jimenez (TeamB)
>
> But, when they quote fuel flows, it's usually at fifty
> percent power. In this case six gallons per hour at fifty-five horsepower
> gives a SFC of 0.65. Perhaps a bit optimistic. Again, I'm assuming Hirth
> uses the same standards as Rotax.
The 6 gal/hr number in the Hirth chart at
http://www.recpower.com/F302c11.htm is pointing at 5700 RPM, a little
over 100 hp and 90 ft/lb of torque. Somehow I don't think this number is
realistic, even with fuel injection. Problem is I don't think Hirth has
started delivering the F30 with fuel injection in the US yet, at least
not that I know of.
Juan
Richard Isakson
>The 6 gal/hr number in the Hirth chart at
>http://www.recpower.com/F302c11.htm is pointing at 5700 RPM, a little
>over 100 hp and 90 ft/lb of torque.
I hadn't seen that web page. I've been looking at the Rotax pages. I don't
see how the Hirth engines can be any better. I love magic engines. All
those little magic engine fairies running around trying to hold the pistons
together. I think I'll put this engine in the same folder as the Zoche
diesel.
Rich Isakson
Juan Jimenez (TeamB)
that Hirth engines are significantly more reliable than Rotax engines.
Certainly Hirth has been in business longer than Rotax, and what's also
interesting is that Hirth has been sinking a lot more money into
2-stroke R&D than Rotax. One person to talk to about this is
sa...@bd-micro.com, Skeeter Karnes. He had been doing a lot of research
and testing on both Rotax and Hirth engines and chose to become a Hirth
dealer.
Juan
J.D. GUINN
from time to time.
BUT, it seems as if Hirth has gotten its'
act together and is starting to produce some good engines, although a
lot of people will say that the jury is still out on that one. Check
with Chuck S., he is using a 2706 with good results.
What is being advertised does make sense, but like they say, the proof
is in the pudding.
Best Regards,
J.D. Guinn
Juan Jimenez (TeamB)
Charles K. Scott
"Richard Isakson" <r...@whidbey.com> writes:
> I hadn't seen that web page. I've been looking at the Rotax pages. I don't
> see how the Hirth engines can be any better. I love magic engines. All
> those little magic engine fairies running around trying to hold the pistons
> together. I think I'll put this engine in the same folder as the Zoche
> diesel.
>
> Rich Isakson
Well, except that the Zoche engine has been run for a number of years
in various configurations from prototype to proof of concept to
production based assembly. The thing that hasn't happened is it's
appearance in the market. But the performance figures aren't out of
line from other diesel engines.
Remember also that Zoche is not selling anything. They aren't offering
stock and aren't offering fictional engines to unwary buyers. They may
never bring it to market for one reason or another but at least they
aren't pulling a Bede or Moeller; no one's been burned by them.
Disappointed yes, burned no.
Corky Scott
BOb U.
>I hate to do this since agreeing with Juan seems to draw serious AA fire
>from time to time.
>BUT, it seems as if Hirth has gotten its'
>act together and is starting to produce some good engines, although a
>lot of people will say that the jury is still out on that one. Check
>with Chuck S., he is using a 2706 with good results.
>What is being advertised does make sense, but like they say, the proof
>is in the pudding.
>
>Best Regards,
>J.D. Guinn
I spoke with Chuck at Sun N' Fun last summer.
He seemed pleased with the Hirth he had mounted.
BOb U.
Richard Isakson
Charles K. Scott wrote ...
>Well, except that the Zoche engine has been run for a number of years
>in various configurations from prototype to proof of concept to
>production based assembly. The thing that hasn't happened is it's
>appearance in the market. But the performance figures aren't out of
>line from other diesel engines.
>
>Remember also that Zoche is not selling anything. They aren't offering
>stock and aren't offering fictional engines to unwary buyers. They may
>never bring it to market for one reason or another but at least they
>aren't pulling a Bede or Moeller; no one's been burned by them.
>Disappointed yes, burned no.
I'm not questioning Zoche business ethics. I'm question their performance
predictions. It's one thing to make an engine run. It something else to
meet extraordinary claims. You say they're not out of line, so which engine
meets these goals? A cruise SFC of 0.357, a TBO of 2,000 hours and a weight
to power ratio of 0.90. Yes, a diesel engine can make the SFC goal 0.357
and better. Yes, a diesel engine can go 2,000 hours and much better. You
might even be able to make a 300 HP diesel engine that only weighs 271
pounds. But all three at the same time? Show me an example that comes even
close.
My question about the claims for the Hirth F30 is similar. While all other
two stroke engines have a SFC above 0.7, they're claiming a SFC of 0.32.
Absolute MAGIC!
Rich Isakson
Charles K. Scott
"Richard Isakson" <r...@whidbey.com> writes:
> I'm not questioning Zoche business ethics. I'm question their performance
> predictions. It's one thing to make an engine run. It something else to
> meet extraordinary claims. You say they're not out of line, so which engine
> meets these goals? A cruise SFC of 0.357, a TBO of 2,000 hours and a weight
> to power ratio of 0.90. Yes, a diesel engine can make the SFC goal 0.357
> and better. Yes, a diesel engine can go 2,000 hours and much better. You
> might even be able to make a 300 HP diesel engine that only weighs 271
> pounds. But all three at the same time? Show me an example that comes even
> close.
Mmmm, tough request. You want to be shown an example like the Zoche
that proves the Zoche. Yet no one has built an engine like the Zoche
before, it's unique.
Since the engine performance specs came from a running engine, and they
are certainly capable of weighing it and reporting the weight, I'm
assuming the only thing you have a problem with is the TBO.
I don't know if Zoche is running an engine to the 2,000 hour mark but
if I'm remembering what Greg Travis has said about the certification
process here in the states, actually running the engine to it's
intended TBO is not required and has never been done. If I'm not
remembering that right, I'm sure he'll correct me. Zoche is intending
to certify it both in Europe and the States.
Corky Scott
Daryl1953Ma
>I spoke with Chuck at Sun N' Fun last summer.
>He seemed pleased with the Hirth he had mounted.
Damn! How much Muzzleloader did it take to inspire that ill fated attempt.
Dont scratch your head, Bob, Stricker will explain it to you.
D (he's BAAAAAACk <g>)
Jim Vandervort
In front of god and everybody???
assa9
BOb U. <SPA...@worldnet.att.net> wrote in message
news:382ce304...@netnews.worldnet.att.net...
>
> >I hate to do this since agreeing with Juan seems to draw serious AA fire
> >from time to time.
> >BUT, it seems as if Hirth has gotten its'
> >act together and is starting to produce some good engines, although a
> >lot of people will say that the jury is still out on that one. Check
> >with Chuck S., he is using a 2706 with good results.
> >What is being advertised does make sense, but like they say, the proof
> >is in the pudding.
> >
> >Best Regards,
> >J.D. Guinn
> +++++++++++++++++++++++++++++++++++++++++++++
>
> I spoke with Chuck at Sun N' Fun last summer.
> He seemed pleased with the Hirth he had mounted.
>
>
> BOb U.
>
JStricker
--
John Stricker
"I didn't spend all these years getting to the top of the food chain just to
be a vegetarian"
Daryl1953Ma <daryl...@aol.com> wrote in message
news:19991108161442...@ng-fd1.aol.com...
> Uncle Bob writes:
>
> >I spoke with Chuck at Sun N' Fun last summer.
> >He seemed pleased with the Hirth he had mounted.
>
BOb U.
I'm tellin' Miss Geeters about all you guys.
You'll be sorry !
We'll see how funny this is when she washes
your steenking mouths out with lye soap!
Ha, haa.
++++++++++++++++++++++++++++++++
>He "mounted" it???
>In front of god and everybody???
>
>assa9
>
>>
>> >I hate to do this since agreeing with Juan seems to draw serious AA fire
>> >from time to time.
>> >BUT, it seems as if Hirth has gotten its'
>> >act together and is starting to produce some good engines, although a
>> >lot of people will say that the jury is still out on that one. Check
>> >with Chuck S., he is using a 2706 with good results.
>> >What is being advertised does make sense, but like they say, the proof
>> >is in the pudding.
>> >
>> >Best Regards,
>> >J.D. Guinn
>> +++++++++++++++++++++++++++++++++++++++++++++
>>
>> I spoke with Chuck at Sun N' Fun last summer.
>> He seemed pleased with the Hirth he had mounted.
>>
>>
>> BOb U.
>>
>
highflyer
>
> I don't know if Zoche is running an engine to the 2,000 hour mark but
> if I'm remembering what Greg Travis has said about the certification
> process here in the states, actually running the engine to it's
> intended TBO is not required and has never been done. If I'm not
> remembering that right, I'm sure he'll correct me. Zoche is intending
> to certify it both in Europe and the States.
>
>
I think most of the complaints about the Zoche stem from the many years
it has been exhibited and run at Oshkosh, with its continueing
unavailability.
Everyone hoped they would be able to buy one for a couple of thousand
bucks
and bolt it to the front end of their "super hotrod" homebuilt and outdo
the whole world.
Reality, unfortunately, intervenes. The Zoche people decided, probably
wisely, to obtain certification on the engine in their primary market
areas BEFORE starting any kind of production. Now they are also in the
process of FLYING the engine on a few selected platforms to get sound
and accurate performance and reliability data.
I can't fault their caution, but I do wish I could go out and BUY one
to bolt onto my homebuilt! Even for $5000! :-) Unfortunately, with all
the costs that have been incurred, and the anticipated production
volumes
that will be reasonable in the current GA aircraft engine market, I
would
expect the price to be closer to $25,000 than $5,000! :-(
--
HighFlyer
Highflight Aviation Services
David Bonorden
the fuel consumption numbers published on the Rec Power web page for the
F30 are wrong. Compare them to the Hirth 2706 (which I believe to be
fairly accurate). The Hirth 2706 is about half of an F30. In fact,
taking the torque, HP and fuel consumption from the 2706 chart and
doubling it would give you an optimistic ballpark figure. We did buy a
2706 with the EFI system and we like it, but I don't yet have any solid
data on it.
There are some simple sanity checks you can do on torque/HP/fuel
consumption claims.
1) power (in HP) ALWAYS equals torque (in lb-ft) at 5252 RPM.
This is just physics and I won't bore everyone with
the derivation. The formula is
Power(HP)=Torque(lb-ft)xRPM/5252.
Be careful to consider gear reductions here - make sure
you're comparing torque and RPM at the same shaft.
If the HP/torque curve doesn't match this, then the
curve is inaccurate to some extent. Sometimes small
inaccuracies are caused by unit conversions from
newton-meters to ft-lb, KW to HP, etc.
2) gasoline 2 stroke engines rarely have better (lower)
brake specific fuel consumption (BSFC) than
.70 lb/(hp-hr). So Fuel consumption (in lbs) is
BSFC x HP. Divide that by 6.1 lbs/gal for gasoline
to get fuel consumption in gal/hr.
For the 120 HP F30, that would be
Fuel consump = .70 x 120 / 6.1 = 13.8 gal/hr
at full throttle, assuming your prop is allowing
you to reach max power RPM.
Rotax 2 strokes are about .8 lb/(hp-hr) at high
power settings and get worse as throttle settings
go down.
My own BSFC "sanity check" numbers are as follows:
diesel engine - .38
4 stroke gasoline - .45
2 stroke gasoline - .65
turbo prop - .70
I know that any given engine is very unlikely to beat these numbers and
that most engines won't achieve these numbers.
Dave Bonorden
Ron Hansen wrote:
>
> A 129 Lb., 110 HP "2-cycle" engine that only burns 6 GPH? Sounds too good to
> be true! Is there anybody flying one that can confirm this low fuel burn?
>
> Ron
--
David B. Bonorden
Vice President, Engineering (409) 268-6840
Freewing Aerial Robotics Corp (409) 260-5992 fax
3800 Raymond Stotzer Pkwy bono...@freewing.com
College Station, TX 77845 http://www.freewing.com/
highflyer
> <snip>
>
> My own BSFC "sanity check" numbers are as follows:
> diesel engine - .38
> 4 stroke gasoline - .45
> 2 stroke gasoline - .65
> turbo prop - .70
>
> I know that any given engine is very unlikely to beat these numbers and
> that most engines won't achieve these numbers.
>
Good post, Dave. The above numbers are good ballpark figures and should
get you pretty close to the actuality in almost every case. It will be
close, usually a tad higher rather than lower.
For four stroke gasoline engines like most airplanes use, I have always
figured about 12 horsepower for each gallon per hour of gasoline.
Remember, a 200 horsepower engine at a 75% cruise is producing 150 HP
and should likely be burning a little bit less than 12 1/2 gallons per
hour. A 150 HP Lycoming running at 75% would be about three forths of
that or about nine gallons per hour.
That is intended to be a conservative estimate that will keep you out of
the bushes at the end of a long flight, so you will probably burn just a
bit less than those numbers. Perhaps quite a bit less if you are flying
high and leaning aggressively.
Charles K. Scott
highflyer <high...@alt.net> writes:
> Unfortunately, with all
> the costs that have been incurred, and the anticipated production
> volumes
> that will be reasonable in the current GA aircraft engine market, I
> would
> expect the price to be closer to $25,000 than $5,000! :-(
They always stated that the price should be "competitive" with a
Lycoming or Continental of similar power.
I've e-mailed them a couple of times and always eventually got a
response. They once mentioned that in order to certify the airplane as
a bolt on to current commercial aircraft, they must engineer the entire
firewall forward package, including a new cowl. This must be done for
each and every model for which they intend to have an engine. That's
why they have their own wind tunnel facility and also why it is taking
so long. They also talked about proper acoustical design for the cowl
to make sure the entire system is as quiet as it can be.
I think HF is correct in that it appears at least some of the comments
are the result of people REALLY wanting the engine right NOW, and
knowing that it could have been on the market years ago if they'd
intended it for homebuilders. But they've chosen to go commercial,
which takes a lot longer.
I'll also repeat that they've run into some unforseen delays: They
discovered that some minister had passed on some propriatary secrets to
direct competitors and had to drop everything to bring suit. The suit
was successfully prosecuted, apparently one of the first in Germans
history to manage this, but valuable time was lost. Then they had to
build new facilities which included new labs, new testing facilities
and a new wind tunnel. All of this took time.
Corky Scott
Richard Isakson
>that proves the Zoche. Yet no one has built an engine like the Zoche
>before, it's unique.
>
>Since the engine performance specs came from a running engine, and they
>are certainly capable of weighing it and reporting the weight, I'm
>assuming the only thing you have a problem with is the TBO.
My problem with the Zoche diesel is the weight of the engine. You say that
the engine is unique. Perhaps you can help me see what's unique about it.
It's an air cooled, turbo charged, two stroke diesel engine. They claim a
specific weight of 0.9 pounds per horsepower. The best aircraft diesel
engine ever produced was the German Jumo from World War II. A water cooled,
turbo charged, two stroke diesel engine with opposed pistons. It had a
specific weight of 1.9. So, what is Zoche doing the allows this weight to
be cut in half? That's a huge jump.
Here's an interesting quote from a book written in 1943.
"The relative merits of the diesel and spark-ignition engine present a
problem that never fails to arouse spirited argument among groups of men
interested in engines. All sorts of arguments have been used to explain the
absence of the diesel from the high-power aircraft-engine field. As a
matter of fact, as this is written there is not a single high-performance
aircraft diesel in military use anywhere in the world, not even in Germany
where so much research work has been done on the problem.[I believe the Jumo
was being use in a long range amphibian in 1943-RWI] This is mainly due to
the fact that the engine weight is largely a function of the peak pressure
developed in the cylinder during combustion. The peak pressure in a diesel
cylinder is much greater for a given mean effective pressure (mep) than in a
spark-ignition engine. This means that for a four-stroke cycle engine of a
given size and power output, the diesel must inevitably be heavier."
Rich Isakson
Charles K. Scott
"Richard Isakson" <r...@whidbey.com> writes:
> My problem with the Zoche diesel is the weight of the engine. You say that
> the engine is unique. Perhaps you can help me see what's unique about it.
> It's an air cooled, turbo charged, two stroke diesel engine. They claim a
> specific weight of 0.9 pounds per horsepower. The best aircraft diesel
> engine ever produced was the German Jumo from World War II. A water cooled,
> turbo charged, two stroke diesel engine with opposed pistons. It had a
> specific weight of 1.9. So, what is Zoche doing the allows this weight to
> be cut in half? That's a huge jump.
I've seen that engine Richard and it's a kind of bizzarre thing with a
horizontal layout and two crankshafts on the outside feeding a center
combustion chamber, if it's the right one. It's no wonder an engine of
this configuration weighed a bunch.
Now look at the Zoche radial. One crankshaft (and it's very short) and
four or eight short connecting rods. It doesn't develop the same heat
as a typical gas powered four stroke cycle engine and doesn't have any
water jacket. It also doesn't have a heavy starter and is a smallish
displacement engine that develops the power it's capable of because of
a mechanical and turbo supercharger linked together.
Like I said, Zoche isn't making the figures up. The weight is what
they weigh and the output is what's being read off the dynomometer.
You only have to look at them to see that they will of course not have
the same specific weight as that strange WWII Junkers Jumo diesel.
All engines are not alike, comparing the Zoche to the pre-war Junkers
engine isn't logical, they are different as night and day. To me.
Corky Scott
Richard Isakson
>they weigh and the output is what's being read off the dynomometer.
>You only have to look at them to see that they will of course not have
>the same specific weight as that strange WWII Junkers Jumo diesel.
>
>All engines are not alike, comparing the Zoche to the pre-war Junkers
>engine isn't logical, they are different as night and day. To me.
You're right it's a strange engine but I choose it because it was the best
diesel engine that's been developed for aircraft. The air-cooled radial
engines that were developed were all much worse. Some with specific weights
as high as 7.0. The opposed-piston engine is an efficient two stroke design
but it does have a higher parts count. The Jumos were very reliable.
The development of aircraft diesel engines is very important right now.
We're going to be running out of light crude oil within our lifetimes and
it's a lot cheaper to make diesel fuels from heavy crudes than it is to make
gasoline. Having said that it's also important to not buy into claims that
seem extreme. For now, I'll leave the Zoche diesel in the folder with the
Hirth F30 and the 100 MPG carburetor.
Rich Isakson
JStricker
> I've e-mailed them a couple of times and always eventually got a
> response. They once mentioned that in order to certify the airplane as
> a bolt on to current commercial aircraft, they must engineer the entire
> firewall forward package, including a new cowl. This must be done for
> each and every model for which they intend to have an engine. That's
> why they have their own wind tunnel facility and also why it is taking
> so long. They also talked about proper acoustical design for the cowl
> to make sure the entire system is as quiet as it can be.
Hi Corky,
With no direct knowledge to go on (but that's not unique to this group) I
still think there's more going on here.
First off, if you were developing a new engine Corky, what would you do?
Let's assume you were planning on certifying it, what would be THE first
step? Of course, identify the market. Where are you going to sell it, and
to whom?
Now, while they may very well have a point that it takes a lot of time, and
they need a wind tunnel, etc., etc., there are other engine substitutions
out there that haven't needed these facilities.
I've seen projects like this in the past, and my sense is that there is no
clearly defined direction here. They are using the scattergun approach.
"We're going to make it work on anything with a radial that's in that HP
range and we're not selling a one of them until they're ALL right."
Well, I don't think that's a smart approach, or even particularly noble if
that's the case. They need to pick an aircraft, get it done FOR THAT
AIRCRAFT, and get it out in the field.
I don't care how many dyno hours, R&D hours, wind tunnel hours, or any other
hours it has. The one thing I can guarantee is that when it hits the field,
it's gonna break in a way they didn't expect or plan on. It's the nature of
the beast. And they're not going to find this out UNTIL they get it in the
field.
I'm no genius in this regard. You (and they) know everything I just said.
So, why isn't there at least a few examples of this flying? There's a
reason, and just the fact that they "want it right" ain't it.
JMHO
Juan Jimenez (TeamB)
>
> I looked at the Hirth F30 for a drone project a while back. Clearly,
> the fuel consumption numbers published on the Rec Power web page for the
> F30 are wrong. Compare them to the Hirth 2706 (which I believe to be
> fairly accurate). The Hirth 2706 is about half of an F30.
Actually, this is not quite correct. The Hirth 2706E is a 65hp 625cc
engine. The F30 is an 80 hp engine, 1042cc. The F30EP/2c is the exact
same engine as the regular F30 but 110 hp and fuel injected. So the 2706
is actually more like more like 2/3rds of an F30.
> In fact, taking the torque, HP and fuel consumption from the 2706 chart and
> doubling it would give you an optimistic ballpark figure. We did buy a
> 2706 with the EFI system and we like it, but I don't yet have any solid
> data on it.
Following your example, and taking as a given your statement that the
2706 numbers are fairly accurate, the fuel consumption figures listed in
the chart for the F30 should be accurate as well (6.5 gal/hr at
WOT/6500 RPM for the 2706 vs 9 gal at WOT/6500 RPM for the F30). The
F30EP/2c is listed as consuming 8.5 gal at WOT/6500 RPM, and considering
it's using fuel injection rather than carburetors, I don't think it's
unreasonable to expect it to consume slightly less fuel. I think your
tests on the 2706E with fuel injection will validate this premise. I've
know at least one authorized dealer, BD Micro Technologies, who has
confirmed the factory fuel consumption numbers for the 2706E as being
slightly lower than for the 2706 with carburetors.
Juan
Mark Hickey
>My problem with the Zoche diesel is the weight of the engine. You say that
>the engine is unique. Perhaps you can help me see what's unique about it.
>It's an air cooled, turbo charged, two stroke diesel engine. They claim a
>specific weight of 0.9 pounds per horsepower. The best aircraft diesel
>engine ever produced was the German Jumo from World War II. A water cooled,
>turbo charged, two stroke diesel engine with opposed pistons. It had a
>specific weight of 1.9. So, what is Zoche doing the allows this weight to
>be cut in half? That's a huge jump.
Look at the HP output of the humble V8 in the same period. More than
doubled, due to engineering and material improvements.
>Here's an interesting quote from a book written in 1943.
>
>"The relative merits of the diesel and spark-ignition engine present a
>problem that never fails to arouse spirited argument among groups of men
>interested in engines. All sorts of arguments have been used to explain the
>absence of the diesel from the high-power aircraft-engine field. As a
>matter of fact, as this is written there is not a single high-performance
>aircraft diesel in military use anywhere in the world, not even in Germany
>where so much research work has been done on the problem.[I believe the Jumo
>was being use in a long range amphibian in 1943-RWI] This is mainly due to
>the fact that the engine weight is largely a function of the peak pressure
>developed in the cylinder during combustion. The peak pressure in a diesel
>cylinder is much greater for a given mean effective pressure (mep) than in a
>spark-ignition engine. This means that for a four-stroke cycle engine of a
>given size and power output, the diesel must inevitably be heavier."
One thing the Zoche is doing different is making the head and jug
integral - no bolts. That means it can withstand that tremendous
pressure MUCH better for a given weight, or as well as a much heavier
"traditional" arrangement.
Mark "burning jet fuel sounds sooooo cool" Hickey
highflyer
>
> My problem with the Zoche diesel is the weight of the engine. You say that
> the engine is unique. Perhaps you can help me see what's unique about it.
> It's an air cooled, turbo charged, two stroke diesel engine. They claim a
> specific weight of 0.9 pounds per horsepower. The best aircraft diesel
> engine ever produced was the German Jumo from World War II. A water cooled,
> turbo charged, two stroke diesel engine with opposed pistons. It had a
> specific weight of 1.9. So, what is Zoche doing the allows this weight to
> be cut in half? That's a huge jump.
>
That was generally about the weight decrease obtained when any
multicylinder
engine was converted from an inline watercooled design to an aircooled
radial design. The reduced weight in the crankshaft alone accounts for
a
large share of the difference, not to mention the reduced weight due to
the elimination of cooling fluid and water jackets. Couple this with
the
significant weight reduction in diesel engines that has taken place,
even
in diesel TRUCKS, since the 1930's and there doesn't seem to me to be a
problem here. I would suspect Zoche's engineering if they DIDN'T show
a major weight decrease from the 1930's designed Jumo.
> Here's an interesting quote from a book written in 1943.
>
> "The relative merits of the diesel and spark-ignition engine present a
> problem that never fails to arouse spirited argument among groups of men
> interested in engines. All sorts of arguments have been used to explain the
> absence of the diesel from the high-power aircraft-engine field. As a
> matter of fact, as this is written there is not a single high-performance
> aircraft diesel in military use anywhere in the world, not even in Germany
> where so much research work has been done on the problem.[I believe the Jumo
> was being use in a long range amphibian in 1943-RWI] This is mainly due to
> the fact that the engine weight is largely a function of the peak pressure
> developed in the cylinder during combustion. The peak pressure in a diesel
> cylinder is much greater for a given mean effective pressure (mep) than in a
> spark-ignition engine. This means that for a four-stroke cycle engine of a
> given size and power output, the diesel must inevitably be heavier."
>
And, of course, we have learned nothing and made no progress since 1943!
:-)
Actually, diesel cylinders DO have to be substantially more robust.
Both
the peak pressure and the peak temperature are significantly higher in a
diesel engine than in a gasoline engine. That is why they are more
efficient! :-) Any heat engine is limited by the difference between the
hottest temperature in the cylinder and the lowest temperature in the
cylinder. You can't extract any more of the energy from your little
bonfire. The peak pressure results from the diesel ignition concept,
where small droplets of fuel are sprayed into a superheated fluid. This
causes EACH tiny droplet of fuel to start burning instantly over its
entire surface. With a gasoline engine you have a mixture that is
flammable and is LIT by a match ( spark ) at one or two points and the
flame front has to spread. That spread takes a significant portion of
the cycle and reduces the peak pressure and delays the pressure rise.
This is compensated for, to some extent, by advancing the ignition
event so that the pressure is starting to rise by the time the piston
reaches its upper extent of travel and is in a position to be shoved on
down.
Does this make the diesel engine inherantly heavier? Perhaps, but not
enough to make a serious objection. The accessories are somewhat less
complex and may be lighter. For example, it is the trend these days to
utilize a similiar injection system for fuel for both diesel and
gasoline
engines, with similiar fuel pumps. However, the diesel engine has a
much simpler throttle system and NO requirement for an ignition system.
The fuel has a greater power density, and the operating RPM's are in a
better range for propellor efficiency without heavy and expensive
gearing.
Admittedly, much of this decrease in diesel disadvantage is a result of
advances in metallurgy and manufacturing processes that were not
available fifty years ago.
David Bonorden
You've re-introduced me to the r.a.h rule that I learned years ago but
apparently forgot - don't write from memory! Look it up! I'm guilty!
Also, I didn't mean to sound the least bit negative about the F30. I
think it has the potential to be a great engine. Matt Dandar at Rec
Power has always been a real pleasure to deal with. But this one aspect
of the F30 web page just can't be correct.
So looking it up.......... I see that the info on the web page has
changed since I was studying this 9 months ago. The F30 I was looking
at was rated at 120 hp. Now the EFI version is listed as 110 HP. But
the fuel consumption curve has not changed. The 120HP was my basis for
saying the 2706 was close to half of an F30. Not a very scientific
statement, obviously.
So lets compare fuel consumption at peak HP between the 2706 and the
F30. The relevant web pages are: (the chart at the very bottom of the
page).
http://www.recpower.com/F302c11.htm
http://www.recpower.com/2706.htm
For both engines, peak power occurrs at 6200 rpm (or is it actually 6250
- hard to tell from the graph).
The 2706 graph claims 7 gal/hr at 65 HP at 6250 rpm.
The F30 graph claims 7 gal/hr at 110 hp at 6250 rpm.
So the 110HP F30 has the _SAME_ total fuel consumption as the 65HP
2706?
According to the 2706 graph, the BSFC is .66 lb/(hp-hr), which I'll buy.
According to the F30 graph, the BSFC must be .39 lb/(hp-hr), better than
the best 4 stroke engines on the planet. I just don't think so.
Still 110 HP in a 129 lb package with .66 lb/(hp-hr) fuel consumption is
looking pretty good to me. No oil sump to worry about. No mixture to
worry about. Stable EGTs. Ready-made inverted capability. It might
turn out to be a GREAT engine. I know that the engine is being used on
a helicopter drone, based on a two-place helicopter kit (by Ultrasport?)
and I think it's being used in at least one other UAV. You'll need to
get serious about backup electrical power, though. The 2706 EFI system
draws 8 amps, 6 amps for the fuel pump and 2 for the injectors. If the
EFI quits, so does the engine.
Dave Bonorden
>
> Following your example, and taking as a given your statement that the
> 2706 numbers are fairly accurate, the fuel consumption figures listed in
> the chart for the F30 should be accurate as well (6.5 gal/hr at
> WOT/6500 RPM for the 2706 vs 9 gal at WOT/6500 RPM for the F30). The
> F30EP/2c is listed as consuming 8.5 gal at WOT/6500 RPM, and considering
> it's using fuel injection rather than carburetors, I don't think it's
> unreasonable to expect it to consume slightly less fuel. I think your
> tests on the 2706E with fuel injection will validate this premise. I've
> know at least one authorized dealer, BD Micro Technologies, who has
> confirmed the factory fuel consumption numbers for the 2706E as being
> slightly lower than for the 2706 with carburetors.
>
> Juan
--
Philip Carter
> Still 110 HP in a 129 lb package with .66 lb/(hp-hr) fuel consumption is
> looking pretty good to me. No oil sump to worry about. No mixture to
> worry about. Stable EGTs. Ready-made inverted capability. It might
> turn out to be a GREAT engine. I know that the engine is being used on
> a helicopter drone, based on a two-place helicopter kit (by Ultrasport?)
> and I think it's being used in at least one other UAV.
The F30 is used in the 2-place Ultrasport helicopter, and according to a
company rep they are very happy with it. When I spoke to them the only
problem they had experienced was cooling fan belts breaking.
Apparently there is a light helicopter built in Italy ("Dragonfly" or
similar) using the F30 which has been certified under European regs
(JAR's). That says something for the engine's reliability.
Hirth got a bad name from the aviation use of their early snowmobile
engines (most infamously in the BD-5). The present generation of Hirth
aviation engines are no comparison and far superior to Rotax (and more
expensive) "You get what you pay for."
BTW, I am told there is a 150hp liquid cooled version in the works, with
similar power/weight ratio.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Philip Carter - ESOTEC Developments
http://www.visionpacific.com/hummingbird
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Juan Jimenez (TeamB)
>
> You've re-introduced me to the r.a.h rule that I learned years ago but
> apparently forgot - don't write from memory! Look it up! I'm guilty!
I know the feeling. :)
> Also, I didn't mean to sound the least bit negative about the F30. I
> think it has the potential to be a great engine. Matt Dandar at Rec
> Power has always been a real pleasure to deal with. But this one aspect
> of the F30 web page just can't be correct.
That may be so, but still, 13 gal/hr for 110 hp with fuel injection out
of a 1024cc engine sounds a bit too high, no? Even at WOT for the minute
or so you're allowed to do that, it seems high to me.
> For both engines, peak power occurrs at 6200 rpm (or is it actually 6250
> - hard to tell from the graph).
Well, peak HP, but the torque curves are very different and peak at
different places.
> The 2706 graph claims 7 gal/hr at 65 HP at 6250 rpm.
> The F30 graph claims 7 gal/hr at 110 hp at 6250 rpm.
Hmm. We must be looking at different graphs. The F30, non fuel injected,
graph shows peak HP at 5,500 RPM with a fuel consumption of 7.8 gal/hr.
The 2706 indeed peaks at 6,200 and 7 gal/hr.
> So the 110HP F30 has the _SAME_ total fuel consumption as the 65HP 2706?
Oh, I see, you -were- referring to the F30EP.
Well, there are other differences. The 2706 is not fuel injected. The
110hp F30 is. Without fuel injection the peak HP fuel consumption is a
little over 10% higher.
> According to the 2706 graph, the BSFC is .66 lb/(hp-hr), which I'll buy.
> According to the F30 graph, the BSFC must be .39 lb/(hp-hr), better than
> the best 4 stroke engines on the planet. I just don't think so.
Hmm. Looked at from that viewpoint what you're saying makes sense to me.
I wondered if looking at it in terms of peak torque instead of peak HP
yields similar doubts, though. Here's what I came up with.
Peak torque on the 2706 happens at something like 5700 RPM where the
engine is putting out something like 57 ft/lbs at 6.3 gal/hr. On the
normally aspirated F30 the same event happens at between 4500 and 4750
RPM. The graph is not clear on this, but a little interpolation yields
about 5.35 gal/hr for something like 77-78 ft/lbs of torque. 20 ft/lbs
more of torque yet the fuel consumption is lower with 2 more cylinders?
But look at the RPM's, it's running at least 1000 RPM slower. The
F30EP/2c's torque curve peaks out at 5700 RPM, 6 gal/hr and barely 2
more ft/lbs of torque, if that much. That's an increase of more than
half a gallon of fuel burned in an hour. No real increase in torque, but
higher RPM's will require more fuel.
Hmm. Well, it does stand out like a sore thumb. How does Hirth get 50%
more torque out of the same 6 gals of fuel from an F30EP as compared to
a 2706 at the same RPM but with two more cylinders and 1/3 more CC's? I
don't think fuel savings from the fuel injection system can account for
that. Seems to me you have a pretty good point! :)
> Still 110 HP in a 129 lb package with .66 lb/(hp-hr) fuel consumption is
> looking pretty good to me. No oil sump to worry about.
Oh, but wait for the oil-injection option to come out. :)
I kinda like the idea of not having to measure oil every time I put fuel
in my tanks. :)
> No mixture to worry about.
You prefer fuel injection with no mixture control? Why? (I ask because
I'm having my AMW 225-3 engine fitted with Airflow Performance's package
-with- mixture control.)
> You'll need to get serious about backup electrical power, though. The 2706 EFI system
> draws 8 amps, 6 amps for the fuel pump and 2 for the injectors. If the
> EFI quits, so does the engine.
That's why I'm going with Don Rivera's all-mechanical system. :)
Juan
Dustrpilot
Juan,
not trying to sound like a 'xpert here but I happen to know of lots of
motorcycle and boat engines locking up due to the oil injecter not working. Its
not all that exspensive to fix usually, but it makes for a long ride home
mike
Richard Lamb
but customers wanted them, so...
Juan Jimenez (TeamB)
considering Hirth's track record of success with their introduction of
new features, this is one I'm looking fwd to seeing.
Juan
relling...@gmail.com
> I am interested in replacing my existing Rotax motor with a Hirth 110hp F30
> in my Mini 500 helicopter. On paper it looks good from a performance and
> weight point of view, Evan at 1000rpm less than max rpm it has power to
> spare.
>
> Is there anybody who can comment on this motor, good or bad
> as there not many of them running here.
>
>
> David Maree
> South Africa
> d...@global.co.za
Hello David,
I have a complete kit but without engine.I have to buy but which engine is perfect ? Get you any experience ? I saw a mini 500 with a Yamaha engine on
you tube. The turbine engine will give fun but it drinks to much fuel !
For me i like to have a ready to install solution, do you have a idea ?
Hermann