4-stroke ultralight engines?
RB
something that is 30 hp, no more than 70 pounds. Less than $5000 would be a
plus too. Any info is greatly appreciated. Thanks.
RB
Mike Sieweke
I'm only familiar with a couple of flying 4-strokes. The 1/2 VW models
generally run around 80 pounds and 35 hp. There are several places that
sell 1/2 VW engines or plans for conversion. Look in the back of Sport
Aviation or Kitplanes. Also try:
http://www.altimizer.com
http://www.usastores.com/betterhalf/
http://www.ultralightnews.com/news/alteng.htm
The Kohler V-twin can run as low as 63 pounds for around 25 hp. There's a
guy selling conversion plans for the Kohler.
The info pack is $3 refundable on purchase of the plans which are $25.
His snail mail address is:
M.T. Peery
12951 FM 350 South
Livingston, TX 77351
--
Remove the "nospam" from my address if you reply.
Mike Sieweke - msie...@nospam.ix.netcom.com
Yamhill, OR - http://www.netcom.com/~msieweke
HShack
this year. It is 40 HP and about 85 LBS, but it's not actually in production
yet and will cost more than $5K I think.
Get a Rotax 337 or 447 & properly maintain it [for now]. Maybe in a couple
years we'll see a decent 4 stroke.
Howard Shackleford
FS I
SC
Mike Sieweke
> The closest I have heard of is the Amtech Buddy Twin [?] which was at Oshkosh
> this year. It is 40 HP and about 85 LBS, but it's not actually in production
> yet and will cost more than $5K I think.
You can see the Buddy Twin at http://www.amtec-corp.com
At Sun-n-Fun they were projecting a list price of $7000. A couple
of years ago they thought the price would be $3-4000, which would
have sold a lot more engines.
The weight is 69 pounds! That's incredible for 40 horsepower.
Bill_Demerly
for about $3300. He took over the Hummel business. I fly one on my minimax and
wouldn't trade it for any thing.
Bill
Mike Sieweke wrote:
> "RB" <ra...@nwinet.com> wrote:
>
> > Are there any 4-stroke ultralight engines out there? I'm looking for
> > something that is 30 hp, no more than 70 pounds. Less than $5000 would be a
> > plus too. Any info is greatly appreciated. Thanks.
>
> I'm only familiar with a couple of flying 4-strokes. The 1/2 VW models
> generally run around 80 pounds and 35 hp. There are several places that
> sell 1/2 VW engines or plans for conversion. Look in the back of Sport
> Aviation or Kitplanes. Also try:
>
> http://www.altimizer.com
> http://www.usastores.com/betterhalf/
> http://www.ultralightnews.com/news/alteng.htm
>
> The Kohler V-twin can run as low as 63 pounds for around 25 hp. There's a
> guy selling conversion plans for the Kohler.
>
> The info pack is $3 refundable on purchase of the plans which are $25.
>
> His snail mail address is:
> M.T. Peery
> 12951 FM 350 South
> Livingston, TX 77351
>
Dave Loveman
"RB" <ra...@nwinet.com> wrote:
> Are there any 4-stroke ultralight engines out there? I'm looking for
> something that is 30 hp, no more than 70 pounds. Less than $5000
would be a
> plus too. Any info is greatly appreciated. Thanks.
>
>
>
You might want to check out the Ultralight Engine Buyers guide section
at Ultralight News.
--
Dave Loveman
I would like to invite you to browse at:
http://www.ultralightnews.com
http://www.ultralightflyer.com
Sent via Deja.com http://www.deja.com/
Before you buy.
Scrappman
Don't know about this 4 stroke light weight motors. Since aviation has
been around, 4 strokes also have been. I think if there was really a way to
get more H.P. out of a 4 stroke with light weight, the old guys in the old
days would have done it. I realize they didn't have computers, but they did
have slide rules. Maybe some one will come up with a composite or graphite
air cooled motor. Untill then there is plenty rotax around. Going to visit
the factory sometime in 2000. Will let ya know the results. Anybody want to
ride with?(hehehe)
Scrappman
Shotzy
Formula 1 chassis a few years back. do not know if they still do or even if
they exist now. The company/development team was located somewhere on the
east coast. JIM
Scrappman wrote in message <382CAD5F...@microassist.com>...
John Reil
Citroen(sp) conversion. Anyone know of this?
Mike Sieweke
> Poly motors may have something working. They had composites running in
> Formula 1 chassis a few years back. do not know if they still do or even if
> they exist now. The company/development team was located somewhere on the
> east coast. JIM
The Polimotor looked awfully promising, with about 1 pound per hp. But a
couple of months after they had a nice article in Sport Aviation, there
was another blurb saying they were closing their doors. Has anyone heard
anything from them since then?
Even if they only used plastic for the block, that would amount to a big
weight savings - for a water-cooled engine.
Mike Sieweke
> Hey Guys,
> Don't know about this 4 stroke light weight motors. Since aviation has
> been around, 4 strokes also have been. I think if there was really a way to
> get more H.P. out of a 4 stroke with light weight, the old guys in the old
> days would have done it. I realize they didn't have computers, but they did
> have slide rules. Maybe some one will come up with a composite or graphite
> air cooled motor. Untill then there is plenty rotax around. Going to visit
> the factory sometime in 2000. Will let ya know the results. Anybody want to
> ride with?(hehehe)
If we could tolerate the same TBO in our 4-stroke motors as we see with
the Rotax 2-strokes, we would have engines with similar weights. The
Suzuki 3-cylinder 4-stroke is already close to the same weight and
power as the Rotax 582.
In the future we will see lighter 4-strokes and more fuel-efficient
2-strokes because the EPA is cracking down on outboard motors, jet-skis
and snowmobiles.
Shotzy
reviewed in auto pub. They were working with delrin and other similar
compounds to achieve a 500-800 deg heat range. They were using something
like a metal ceramic composite, sleeve type, cylinder liner in the poly
block. Water cooled of course. According to the article they were and had
been actually racing a couple of prototype engines in formula cars. JIM
Mike Sieweke wrote in message ...
>"Shotzy" <Sho...@apex.net> wrote:
>
>> Poly motors may have something working. They had composites running in
>> Formula 1 chassis a few years back. do not know if they still do or even
if
>> they exist now. The company/development team was located somewhere on the
>> east coast. JIM
>
>The Polimotor looked awfully promising, with about 1 pound per hp. But a
>couple of months after they had a nice article in Sport Aviation, there
>was another blurb saying they were closing their doors. Has anyone heard
>anything from them since then?
>
>Even if they only used plastic for the block, that would amount to a big
>weight savings - for a water-cooled engine.
>
Shotzy
vehicles way back in the early 60's. The engines were referred to as 2
stroke diesels. GM coaches, including Augie Bush Jr's Busweiser buses, had
em. My dad worked on them in St. Louis. The engine crankcase was like any 4
popper, wet oil sump, oil pump and breather setup (no crankcase
compression). The cylinders had an air gallery and intake ports in the
bottom same as any 2 popper and the heads had dual, overhead exhaust valves.
The engines were fitted with a GE series 671 rotes type blower to the air
galley and a diesel, into the compression chamber, fuel injection system.
Near as I remember they were 3 cylinder. This is probably over simplified,
but is how my dad explained it to me years ago. JIM
cl...@snyder.on.ca wrote in message ...
>
>>
>>In the future we will see lighter 4-strokes and more fuel-efficient
>>2-strokes because the EPA is cracking down on outboard motors, jet-skis
>>and snowmobiles.
>
>Lightweight 4 strokes already exist - but they usually come with a
>heavy transmission tacked on for motorcycle use. I have a 500cc Honda
>V twin that makes 50HP at 10,000+ rpm. About 50 lbs with all the gears
>stripped out, but you have to get the power out and gear it down about
>3 or 4:1. That adds weight. Since I have 2 that cost me virtually
>nothing, I hope to play around with one.
>As for the Suzuki Automotive triple, it is a bear for torsionals -
>real hard on redrive components, and basically useless in direct drive
>configuration.
>More promising yet will be the closed crankcase, valve timed 2 strokes
>that don't mix oil with the fuel. Heavier than standard 2 strokes -
>almost as heavy as a 4 stroke, but twice the "energy density". We will
>see them in my lifetime, I am sure.
Shotzy
Warsaw, In. (1.219.267.2217) [hpr...@kconline.com] JIM
John Reil wrote in message
<8332-38...@storefull-294.iap.bryant.webtv.net>...
Shotzy
in the empty gearbox ? That would be a less weight, closed, oiled, compact,
geared redrive. The harmonic balance and flywheel setup (I presume) will or
must stay on/in the engine and you would need it for a geared redrive
anyway. I am not familiar with cycles later than the early 3 cyl Bezers.
Surely someone out there knows about gear makers. Post up and see what
response you get. JIM
cl...@snyder.on.ca
SEVTEC
>From: cl...@snyder.on.ca
>Date: Sat, 13 November 1999 09:59 PM EST
>Message-id: <vyMuOBnwu=cIDfpNf+G...@4ax.com>
>>In the future we will see lighter 4-strokes and more fuel-efficient
>>2-strokes because the EPA is cracking down on outboard motors, jet-skis
>>and snowmobiles.
>
>Lightweight 4 strokes already exist - but they usually come with a
>heavy transmission tacked on for motorcycle use. I have a 500cc Honda
>V twin that makes 50HP at 10,000+ rpm. About 50 lbs with all the gears
>stripped out, but you have to get the power out and gear it down about
>3 or 4:1. That adds weight. Since I have 2 that cost me virtually
>nothing, I hope to play around with one.
What do you anticipate for a lifetime for the Honda? I do not believe these
engines can sustain anywhere near their stated power levels in an aircraft
application.
>As for the Suzuki Automotive triple, it is a bear for torsionals -
>real hard on redrive components, and basically useless in direct drive
>configuration.
Do you personally have any experience with this engine? Where does this
information come from? I am working on a Geo (Suzuki) right now for
installation in one of my surface skimmers, and would like to find out as much
as possible from people who have had hands on experience with the engine.
Incidentally, the Suzuki is not particularly light for its horsepower. It is
just that the aircraft people do horrible things to it, like removing most of
the flywheel, or they simply lie about the weight. I know! I have weighed the
thing.
My installation will call for 45hp at 4500rpm, max from this engine, about what
it would see while pulling a freeway grade at wide open throttle. It is easy
to put on 8 hours of operation a day on a surface skimmer, where the typical
ultralight may fly for an hour or so.
Barry Palmer, for <A
HREF="http://members.aol.com/sevtec/sev/skmr.html">Sevtec</A>
CedarDecks
>in the empty gearbox ? That would be a less weight, closed, oiled, compact,
>geared redrive. The harmonic balance and flywheel setup (I presume) will or
>must stay on/in the engine and you would need it for a geared redrive
>anyway. I am not familiar with cycles later than the early 3 cyl Bezers.
>Surely someone out there knows about gear makers. Post up and see what
>response you get. JIM
>
>cl...@snyder.on.ca wrote in message ..
You ever herd of V-MAX, from YAMAHA.
They put that motor into every thing.
Just don't tell them you want it for your plane.
Cedar Decks
Mike Sieweke
> Mike: I did not know they got a blurb in aviation pub. Last I knew they were
> reviewed in auto pub. They were working with delrin and other similar
> compounds to achieve a 500-800 deg heat range. They were using something
> like a metal ceramic composite, sleeve type, cylinder liner in the poly
> block. Water cooled of course. According to the article they were and had
> been actually racing a couple of prototype engines in formula cars. JIM
From what I read, the Polimotor folks did fairly well in racing. I think
they had one second or third place finish. The Sport Aviation article was
in the February 1992 issue.
Mike Sieweke
> >As for the Suzuki Automotive triple, it is a bear for torsionals -
> >real hard on redrive components, and basically useless in direct drive
> >configuration.
>
> Do you personally have any experience with this engine? Where does this
> information come from? I am working on a Geo (Suzuki) right now for
> installation in one of my surface skimmers, and would like to find out as much
> as possible from people who have had hands on experience with the engine.
>
> Incidentally, the Suzuki is not particularly light for its horsepower. It is
> just that the aircraft people do horrible things to it, like removing most of
> the flywheel, or they simply lie about the weight. I know! I have weighed the
> thing.
>
> My installation will call for 45hp at 4500rpm, max from this engine, about what
> it would see while pulling a freeway grade at wide open throttle. It is easy
> to put on 8 hours of operation a day on a surface skimmer, where the typical
> ultralight may fly for an hour or so.
Talk to the folks at Raven - http://www.raven-rotor.com . They can tell
you the real weight. Their brochure lists 118 lbs DRY weight, which
compares well to the Rotax 582. That's for their lightest model, with
all possible weight reduction applied. They don't recommend that one
because it is carbureted; the fuel injected setup is much nicer, and
it gets you a few more horsepower.
The Raven folks sell a redrive with a damping hub to eliminate the
torsional problem, but it will set you back around $2000. If you
want to apply all the weight reduction, that will cost about $800
additional to save about 11 pounds.
I heard that one problem with this engine is you don't want any
side loads on the crank. There are other people running non-damped
redrives with this engine, but the drive sprocket is fully supported.
Mike Sieweke
> I am trying to do the Geo project without throwing money at it! That defeats
> the program before you start. I do worry about its cast iron crank.
>
> The engine with stock carburetor and manifold and air cleaner weighs 108#. Add
> the flywheel, 12#, and you are over Raven's claimed weight. What about the
> starter, 6#, alternator, 8#, radiator 8#. When I get the whole engine
> installation up it will be around 150#, I figure. People who state engine
> weights should state that the engine is without essential accessories.
They lighten the flywheel and use lighter exhaust, starter, and alternator.
They use a Bing carb, which probably drops a few more pounds, too. The
radiator is not part of the dry weight. If you look at Rotax's quoted
weight for the 582, it does not include radiator, exhaust, engine mounts,
and a few other incidentals.
Does your 108# weight include exhaust manifold or oil?
SEVTEC
>Date: Sun, 14 November 1999 09:17 PM EST
>Message-id: <msieweke-141...@prt-or28-149.ix.netcom.com>
>Remove the "nospam" from my address if you reply.
>
>Mike Sieweke - msie...@nospam.ix.netcom.com
>Yamhill, OR - http://www.netcom.com/~msieweke
>
I am trying to do the Geo project without throwing money at it! That defeats
the program before you start. I do worry about its cast iron crank.
The engine with stock carburetor and manifold and air cleaner weighs 108#. Add
the flywheel, 12#, and you are over Raven's claimed weight. What about the
starter, 6#, alternator, 8#, radiator 8#. When I get the whole engine
installation up it will be around 150#, I figure. People who state engine
weights should state that the engine is without essential accessories.
SEVTEC
>They use a Bing carb, which probably drops a few more pounds, too. The
>radiator is not part of the dry weight. If you look at Rotax's quoted
>weight for the 582, it does not include radiator, exhaust, engine mounts,
>and a few other incidentals.
>
>Does your 108# weight include exhaust manifold or oil?
>
>Remove the "nospam" from my address if you reply.
>
>Mike Sieweke - msie...@nospam.ix.netcom.com
>Yamhill, OR - http://www.netcom.com/~msieweke
>
The 108# is without oil or exhaust manifold.
I am still trying to find out who "they" is in the cases of broken crankshafts,
and the nature of the installation. After all, how do you line up an outboard
bearing without disassembling the engine, and such bearings would tend to
unload the nearest journal should the rolling element bearing really take the
load.
We have a Subaru 1.4 L that has seen hard times for about 300 hours, including
an Anacortes, WA run to Juneau, AK that has no outboard bearing, but the crank
delivers power off both ends.
I also have a 1.8L EA 82 with perhaps 50hr on it where I mounted the crankshaft
to a bearing fixed to the engine mount, so the journals cannot see any major
loads, and this works also.
It should be noted that I use the full flywheel, and veebelt drives, which may
be in themselves torsional dampers in spite of the flywheel being between crank
and output shaft.
I cannot have a whole lot of faith in Raven as they show installations with and
without crankshaft outboard bearings. Is there anyone out there flying one of
these engines? Anyone with first hand experience with crank breakup on the
Suzuki 3 cyl?
Shotzy
Mike Sieweke wrote in message ...
>
>> Mike: I did not know they got a blurb in aviation pub. Last I knew they
were
>> reviewed in auto pub. They were working with delrin and other similar
>> compounds to achieve a 500-800 deg heat range. They were using something
>> like a metal ceramic composite, sleeve type, cylinder liner in the poly
>> block. Water cooled of course. According to the article they were and had
>> been actually racing a couple of prototype engines in formula cars. JIM
>
>From what I read, the Polimotor folks did fairly well in racing. I think
>they had one second or third place finish. The Sport Aviation article was
>in the February 1992 issue.
>
Shotzy
boat anchor (Just my personal opinion Guys) JIM
SEVTEC wrote in message <19991114204906...@ng-ft1.aol.com>...>>Date: Sun, 14 November 1999 09:17 PM EST
>>Remove the "nospam" from my address if you reply.
>>
>>Mike Sieweke - msie...@nospam.ix.netcom.com
>>Yamhill, OR - http://www.netcom.com/~msieweke
>>
>
defeats
>the program before you start. I do worry about its cast iron crank.
>
>The engine with stock carburetor and manifold and air cleaner weighs 108#.
Add
>the flywheel, 12#, and you are over Raven's claimed weight. What about the
>starter, 6#, alternator, 8#, radiator 8#. When I get the whole engine
>installation up it will be around 150#, I figure. People who state engine
>weights should state that the engine is without essential accessories.
Shotzy
near bremerhafen in late 1980. had the van since almost new. never ran it
over 75mph and it was all stock factory. It just let go about 65mph ! cost
me 2000dm in towing, ecology cleanup and fines. JIM
SEVTEC wrote in message <19991114230510...@ng-cj1.aol.com>...>>Date: Sun, 14 November 1999 10:15 PM EST
>>Message-id: <msieweke-141...@prt-or28-149.ix.netcom.com>
>>
>>sev...@aol.com (SEVTEC) wrote:
>>
>>> I am trying to do the Geo project without throwing money at it! That
>>defeats
>>> the program before you start. I do worry about its cast iron crank.
>>>
>>> The engine with stock carburetor and manifold and air cleaner weighs
108#.
>>Add
>>> the flywheel, 12#, and you are over Raven's claimed weight. What about
the
>>> starter, 6#, alternator, 8#, radiator 8#. When I get the whole engine
>>> installation up it will be around 150#, I figure. People who state
engine
>>> weights should state that the engine is without essential accessories.
>>
alternator.
>>They use a Bing carb, which probably drops a few more pounds, too. The
>>radiator is not part of the dry weight. If you look at Rotax's quoted
>>weight for the 582, it does not include radiator, exhaust, engine mounts,
>>and a few other incidentals.
>>
>>Does your 108# weight include exhaust manifold or oil?
>>
>>Remove the "nospam" from my address if you reply.
>>
>>Mike Sieweke - msie...@nospam.ix.netcom.com
>>Yamhill, OR - http://www.netcom.com/~msieweke
>>
>
Mike Sieweke
> The 108# is without oil or exhaust manifold.
>
> I am still trying to find out who "they" is in the cases of broken crankshafts,
> and the nature of the installation. After all, how do you line up an outboard
> bearing without disassembling the engine, and such bearings would tend to
> unload the nearest journal should the rolling element bearing really take the
> load.
The word I got was that Canadian AirMotive - makers of the CAM-100 - were
developing the Suzuki/Geo engine before they did the CAM-100. They had
several broken cranks due to torsional resonance, and they eventually gave
up on the engine after spending lots of money.
> We have a Subaru 1.4 L that has seen hard times for about 300 hours, including
> an Anacortes, WA run to Juneau, AK that has no outboard bearing, but the crank
> delivers power off both ends.
You can't compare a Sub with the Suz/Geo engine. The Sub has a much
stouter crank, and with 4 cylinders it has much less trouble with
torsional resonance. Or is the 1.4L a 3-cylinder? I haven't heard
of it before.
> I also have a 1.8L EA 82 with perhaps 50hr on it where I mounted the crankshaft
> to a bearing fixed to the engine mount, so the journals cannot see any major
> loads, and this works also.
>
> It should be noted that I use the full flywheel, and veebelt drives, which may
> be in themselves torsional dampers in spite of the flywheel being between crank
> and output shaft.
Yes, the v-belt drives will act as torsional dampers. But lots of people
are using cog-belt redrives on the Sub engines with no outboard bearing
support. The Sub engine is a totally different beast. Using the full
flywheel will definitely help with torsionals, but most people flying
Subes are using no flywheel at all.
> I cannot have a whole lot of faith in Raven as they show installations with and
> without crankshaft outboard bearings. Is there anyone out there flying one of
> these engines? Anyone with first hand experience with crank breakup on the
> Suzuki 3 cyl?
I do have a lot of faith in Raven, because they are flying their engine
conversions. I suspect the reason they can use a drive with no outboard
bearing support is because they have torsional damping and because the
drive sprocket is rather large (less belt force) and because this option
is offered *only* on their low-powered, carbureted engine and because they
keep a lightened flywheel.
I'm looking for around 30 hp, but if I were in the market for a larger
engine, I wouldn't hesitate to fly a Raven conversion. I'm watching
them very closely for the future when I might move up in power.
Scrappman
This might sound dumb, but, why can't the cam on a 4-stroke be used for the
re-drive? Its supported, bearinged, and the reduction is????????
Scrappman
Mark Smith
>
> Hey Guys,
> This might sound dumb, but, why can't the cam on a 4-stroke be used for the
> re-drive? Its supported, bearinged, and the reduction is????????
> Scrappman
>
Eipper Aircraft did that exact thing back in 1984 with the Lotus engine
they were assisting with the design of.
--
Mark Smith mailto:tri...@trikite.com
Tri-State Kite Sales
1121 N Locust St
Mt Vernon, IN 47620 http://www.trikite.com
Mike Sieweke
> Anybody want 2 3cyl turbos? After discussing it with several guys who
> had tried them, with very poor results, these engines have become
> surplus. Both low mileage - the highest mileage unit was dissassembled
> and checked. Been sitting almost 2 years.
> The belts cannot stand up to the extreme torsionals involved. There
> are a couple real smart engineer types working on it right now - have
> not heard in the last month, but their progress has been painful and
> slow. Do yourself a favour and get a 1.3 litre 4 cyl. Much better
> suited for the application.
The folks at Raven have licked the torsional problem, but the cost
is high - $2000 for the redrive. I agree that the 4-cylinder model
is much less trouble.
The 3-cylinder engines have a good history in cars, but only if
you keep the oil level up. From what I heard, they wear out
pretty quickly if you let the oil level get low.
cl...@snyder.on.ca
wrote:
weke wrote:
>
>> sev...@aol.com (SEVTEC) wrote:
>>
>> > The 108# is without oil or exhaust manifold.
>> >
>> > I am s> Hey Guys,
> This might sound dumb, but, why can't the cam on a 4-stroke be used for the
>re-drive? Its supported, bearinged, and the reduction is????????
> Scrappman
>
Ratio is exactly 2.0:1 - not bad. However, the belt/gears/chain used
are not designed to handle the power.
cl...@snyder.on.ca
(Mike Sieweke) wrote:
>sev...@aol.com (SEVTEC) wrote:
>
>> >As for the Suzuki Automotive triple, it is a bear for torsionals -
>> >real hard on redrive components, and basically useless in direct drive
>> >configuration.
Anybody want 2 3cyl turbos? After discussing it with several guys who
had tried them, with very poor results, these engines have become
surplus. Both low mileage - the highest mileage unit was dissassembled
and checked. Been sitting almost 2 years.
The belts cannot stand up to the extreme torsionals involved. There
are a couple real smart engineer types working on it right now - have
not heard in the last month, but their progress has been painful and
slow. Do yourself a favour and get a 1.3 litre 4 cyl. Much better
suited for the application.
BD5ER
2 to 1 reduction unit. If I remember correctly this is what was in some Cessna
175's
> This might sound dumb, but, why can't the cam on a 4-stroke be used for
>the
>re-drive?
I've got an Ace in the hole --------------------- but my arm ain't long 'nuf.
SEVTEC
>Date: Mon, 15 November 1999 08:27 PM EST
>Message-id: <J64wOOTkST4Qd7...@4ax.com>
The reality is I have to build something my builders can build. The Suzuki
engines are all over the place, and the airplane people have devoured the stock
of smaller Subarus and the EA 81, or the smaller engines are so old they are
runouts.
I already have larger designs out with the EA 81 or 82, and I am trying to
fill the void between lawnmower and auto engines with a new design. If this
engine can be made to work in the auto, it should be workable in a surface
skimmer.
As I use vee belts I will not have the same problems that have occurred with
cog belt drives, and the choice of too small of a pitch diameter for the driver
pulley. It may not be just torsionals that are destroying the belts.
As for ultralights, there are many twin cylinder lawnmower engines of more
modern design that can be easily employed in single place ultralights.
The Briggs Vanguard 18hp (not quite) 89lb engine (Japanese manufacture) would
be ideal, plenty of power to drive an airframe designed for the engine. Drive
would be via vee belt. Forget direct drive, even though the engine is rated at
3600rpm. These engines can be driven for 8 hours and be put away wet. I have
done this with Vanguard surface skimmers, and after a salt water operation, we
just turn the hose on the engine, while it is still running, to get the salt
off. There are many other engines in the lawnmower area that are on line and
some coming on line in this power range up to 26hp by their rating, not quite
by my observations.
Don't believe 18hp is enough power? Just look to the past, the two place
Piper cub, 70Kt on just 40hp.
Shotzy
following reasons.
1. almost all cams are cast instead of forged
2. bearings are small diameter and will not support large radial loads
3. small thrust bearing surface will not support large axial loads
4. propeller loads will amplify the torsional loads on the cam shaft
5. drive and driven gears are mostly single helical milled design. to
transmit the required torq will require herring bone design gears so the
driving force to the cam produces neutral axial thrust of the cam shaft
6. normal case hardening range of the cam gear teeth is not high enough to
prevent metal transfer (galling, spalling)
7. Normally the gear tooth wiped area is not large enough to support the
additional required load transfer (galling, spalling) assuming the case
hardening is adequate
It is a good idea Scrapman and will no doubt work well; IF the engine is
designed from the git-go with the intent to use the cam shaft as the
propeller shaft and dynamic balancing is done. JIM
Scrappman wrote in message <3830A264...@microassist.com>...
> Hey Guys,
> This might sound dumb, but, why can't the cam on a 4-stroke be used for
the
>re-drive? Its supported, bearinged, and the reduction is????????
> Scrappman
>
>Mike Sieweke wrote:
>
>> sev...@aol.com (SEVTEC) wrote:
>>
>> > The 108# is without oil or exhaust manifold.
>> >
Steve Lyons
I am a triker and a hovernaut and plan on buying/building a small SEVTEC
next year. I can give you the names of a few guys who are running the
Geo/Raven setup on their trikes. One guy is located in Phoenix,
Arizona. His name is Hal McSwain. His e-mail address is
hmcs...@uswest.net He has a friend by the name of Patrick Turner who
is also running the GEO/Raven on his trike. Hal can give you the
contact info. for Patrick. There might be some other guys on the Fly-UL
list who are running this engine/redrive combo too. Hal might know some
others who are in the preliminary installation stages as well. Hope
this helps you out.
dann mann
The one in my car is going very strong with 200,000 miles and no
troubles at all
Uses no oil to speak of and never leaks.
Has carb and gets 45 mpg.
I think it would be terrific but maybe there is something I'm missing.
Maybe too heavy. Nobody builds better small engines than Honda. Seems
like a natural choice
Dan
Scrappman
done for under the $10,000.00 cost of setting up a 4-stroke with a redrive?
Could a dampning system be set up externaly? These re-drives are fairly heavy,
right?
Scrappman
Shotzy
designing, building and testing a new prototype engine from scratch. Making
the blocks and cases to cast a crankcase with the right size bosses to
machine out for the thrust bearings, having a heavier camshaft made from a
billet. finding the right gears and suitable "off the shelf" crankshaft. (on
and on, the things to be created) you get the concept of the magnitude of
things to be addressed. To do it inexpensively, making this type engine
from scratch is in the category of a lifelong hobby.
IT is possible that there is an "off the shelf" engine out there
that could be modified this way (most of the parts changed / modified
instead of made from scratch) You would have to look at the innards of a
quite a few engines that are suitable for air use in hopes of finding one.
Unfortunately I do not know of one.
I am not up to speed on dynamic dampening of recips, as we only dealt with
the power trains of helios and rotor systems. I will say this about
re-drives though, I believe that satisfactory, inexpensive ones can be
fabricated from the rear wheel components of some of the smaller import
front wheel drive autos.
Think about the radial and axial loads imposed in the automotive
environment. AS for lubrication, the bearing speed factors will certainly be
in the same range as on the auto or most likely less. How often do you
grease them and how often do they fail ?? I know that 3 of them with the
brake drums make one hell of a wide throat band saw. JIM
Scrappman wrote in message <38336570...@microassist.com>...
dann mann
and making a crankcase from scratch that would employ the proper thrust
bearing we need for redrive. Many performance motorcyle engines could be
the basis for this if the case was milled from billet on modern CNC
equipment.
I know of course this would be expensive but might fill the bill for a
decent 4 stroke UL powerplant.
Maybe someone is doing this and I don't know about it, but many web
searches have turned no results
Dan
Pete Plassmann
to drive it via belt? This would certainly be cheaper and easier than
making a new case.
Pete P.
Shotzy
CNC milling is not so expensive in it's own right,But the programming to
guide the machine is. Falls in the same category as die casting in metal and
injection molding in composites. the making of the dies is where the real
costs of development is. another idle thought, given that programming and
die making are both "one time" expensive, would diecasting show a production
run economy over CNC machining from a billet ? How about combining the best
of both ? I believe CNC machining of a diecast case just might prove to be
the cost effective solution. Diecast advantage is Very little machining of
the finished part is left to do. which would reduce the program development
time and machining time. Using cycle parts has the advantage that most of
the case is already there as a pattern to add and subtract from. Your
comment be good food for thought. JIM
dann mann wrote in message
<202-383...@storefull-156.iap.bryant.webtv.net>...
Shotzy
most UL engines. It does have some draw backs and disadvantages. What we are
brainstorming here is, " can we do the reduction on our recips as simply, as
trouble free and light weight as it is done on turboshaft engines", and of
course more economically.
Good to have you join us. Every additional braincell is worth having
on these discussions. Example above. I had only thought in terms of
converting auto engines. A cycle engine base to start from has obvious
built in advantages. JIM
Pete Plassmann wrote in message <38357AC9...@erols.com>...
>Why not build the thrust bearing separately, and use and existing
powerplant
>to drive it via belt? This would certainly be cheaper and easier than
>making a new case.
>
>Pete P.
>
>dann mann wrote:
>
Pete Plassmann
SE5 look alike aircraft. The prop was driven directly off the driveshaft. I
often wonder how this worked out.
There are lots of folks who could perform the kind of custom case work you guys
are descibing. I see it all the time on custom race bikes. I don't know if the
rest of the engine cases would stand up to the thrust, however, as they are
built to take a force directly along the drive chain or shaft. These would have
to be strengthened or braces installed. Also, if the drive is off the
crankshaft, the clutch/transmission assembly can be eliminated, saving even more
weight.
A good starting off point would be the Kawasaki or Suzuki 1000/1100cc engines of
the late 70s/early 80s. These have been hightly developed by racers (mostly
drag) and most parts are available from several sources, and not limited to the
manufacturer. The aftermarket parts are heavily strengthened and might suit
aircraft work.
Hmm. This doesn't sound so hard, after all. How come no one's done it?
Pete
Shotzy wrote:
> Good concept Dann: That had not occurred to me.
> CNC milling is not so expensive in it's own right,But the programming to
> guide the machine is. Falls in the same category as die casting in metal and
> injection molding in composites. the making of the dies is where the real
> costs of development is. another idle thought, given that programming and
> die making are both "one time" expensive, would diecasting show a production
> run economy over CNC machining from a billet ? How about combining the best
> of both ? I believe CNC machining of a diecast case just might prove to be
> the cost effective solution. Diecast advantage is Very little machining of
> the finished part is left to do. which would reduce the program development
> time and machining time. Using cycle parts has the advantage that most of
> the case is already there as a pattern to add and subtract from. Your
> comment be good food for thought. JIM
>
> dann mann wrote in message
> <202-383...@storefull-156.iap.bryant.webtv.net>...
pr...@inforum.net
Gentlemen,
for a lot of links into the engines we are all looking for, and some
that we didn't know we were looking for, use above URL and if anyone
has had any experiance with any of these, I patiently wait for your
feedback on this thread
pr...@inforum.net
Of course if your interested in a truly great little engine, try this
URL on for size
70 hp @ 2500 RPM (no need for heavy reduction sys.)
121 lbs.
Supercharged and turbocharged 1.3 litre diesel designed for aircraft.
pr...@inforum.net
Jan./Feb. 1996)
Funny thing about some developments - founded on sound principles,
they work well, they beat the competition on cost and
performance and yet they fade away for no apparent reason. Some
unjustly die forever, like the Betamax domestic video
recorder, some simmer away gently, awaiting technology improvements,
like electric cars waiting for batteries, or
man-powered aircraft awaiting Kevlar and carbon, others emerge
eventually as true victors.
The development fo diesel engines for aero applications is not new:
there were several aircraft diesel engines built in the 1930s
by such illustrious names as Rolls-Royce, Packard, Junkers, and Fiat.
At last it may be that this particular development,
simmering away for so long, has finally been brought to the boil by
Michael Zoche in Munich, a company which has been
working on aero diesel development for 12 years.
Before we dive into the details of his particular engine range, it may
be a good idea to look at some of the reasons why a diesel
engine would be a surprisingly good choice for an aeroplane.
ECONOMY - what really counts here is the specific fuel consumption, ie
the weight of fuel used per horsepower. A typical,
well developed petrol engine might use around 0.45 lb/hp.h. This
figure applies to modern car engines (and the Rotax 912
whose figure is 0.475 lb/hp.h), and has only come about because of
intense development and particular attention to lean
burning, plus good gas flows, sometimes nasty fuel additives such as
lead and benzene and sophisticated engine management
systems. By contrast a diesel is capable of 0.26 lb per hp.h, nearly
twice as much, with hardly any of this fuss. But there´s more
to it than that.
The petrol engine runs at its most efficient when the fuel:air ration
is 17:1. Unfortunately the spark is barely able to ignite the
mixture at such lean ratios and as a result the leanest practical
ratio is around 14:1. Even with this richer mixture, a stratified
charge is necessary, ie a richer mixture is required near the plug to
initiate combustion. Moreover, the power output of a petrol
engine is controlled by restricting its air intake and hence its
ability to burn its fuel charge completely. As a result, at partial
throttle setting it runs at less than full theoretical efficiency.
The diesel engine on the other hand always has a full charge of air
drawn (or pumped) into the cylinder and the fuel required to
be burned is metered and injected into the cylinder. In this way all
the fuel is burned under optimum conditions, even at part
load.
A fact of thermodynamic life is that thermal efficiency increases with
compression ratio. Diesel engines again score over petrol
engines because the fundamental limitation of the petrol engine´s
compression ratio, detonation of the pre-mixed charge, is
avoided in a diesel. In the Zoche diesel the compression ratio is 17:1
- twice that of a typical petrol engine.
And let´s not forget that diesel fuel is consideralby cheaper than
avgas.
RELIABILITY - Diesels have generated a reputation for reliability in
motor cars. A very large number of failures in petrol
engines are caused by electrical ignition system failure. In a diesel
engine, there is no electrical ignition system, the fuel is ignited
by the compression of the mixture in the cylinder. This also means
there is no ignition system electrical interference generated by
the engine.
Petrol engines dilute their lubricant with the light hydrocarbons and
acids; diesel has considerably less of these and their times
between major overhauls are consequently longer (though diesels do
need frequent oil and filter changes).
Simplicity goes hand in hand with reliability. It is possible to
design a very simple diesel engine, particularly a two-stroke, and
still retain a high level of efficiency.
SAFETY - Diesel fuel ignites with much greater reluctance than petrol.
SMOOTH RUNNING - Generally diesel engines can avoid the fluctuation in
ignition pressures common in spark ignition
engines and this results in reduced vibration. The symmetrical
configuration Zoche engines in particular, exploit a cylinder
configuration which can be completely balanced.
GOOD HIGH ALTITUDE PERFORMANCE - if the engines are supercharged (the
Zoche range is both supercharged and
turbocharged) then high power output can be obtained at low air
densities.
FUEL AVAILABILITY - like most Geordies, diesels are not too fussy
about what they drink. Zoche makes the point that
fuels like avgas, with high lead contents, will fall prey to
environmental pressures to eliminate lead. This will result in Avgas
having a high price and limited availability in future. Many
manufacturers even now are derating their engines to operate on
lead-free mogas with consequent reductions in performance. The Zoche
engines will drink diesel or jet fuel.
THE ZOCHE DEVELOPMENTS
If you were sat next to a friend on a cross-Channel ferry and you told
him the ship was powered by a two-stroke, he´d look at
you a bis askance (I have and he did). Yet two-stroke diesels are
capable of the very best in efficiency and are commonly used
for marine and some truck engines. The petrol two-stroke msut use
fuel/air mixture to purge exhaust gases from the cylinder
after combustion. This results in fuel wastage since the timing of the
ports is necessarily a compromise between purging the
exhaust gases completely and minimising the loss of unburnt fuel
through the exhaust port. With a diesel engine, this limitation
disappears since the purging gas is clean air, and in the case of the
Zoche diesel, under high pressure - very effective for
clearing out exhaust gases. These joint benefits of high thermal
efficiency and good fuel charge replacement results in the
diesel´s exceptional economy.
For an aeroplane this is important for it means less fuel to carry
around. Also two-strokes are inherently lighter than
four-strokes and these two features combine to offer the aircraft
designer the most important benefit of all - low weight. All the
Zoche diesel are two-strokes.
Zoche´s design aim was an engine gor GA which was light and compact,
efficient, easy to operate and not dependent on
expensive avgas. Much of the design work has been focused on weight
reduction.
There are three enignes in the Zoche range: the ZO 02A, an 8-cylinder
radial of 5.33 litres developing 300 hp; the ZO 01A, a
4-cylinder radial developing 150 hp and the ZO 03A, a V-twin of 1.33
litres developing 70 hp. The units are at an advanced
stage in their development and so far have clocked up about 2500 hours
of bench testing. Designed to be certified engines from
the start, they will comply with JAR-E and FAR 33; unfortunately
uncertified versions at a reduced price will not be available
for homebuildera and microlights. This means that they will compete
with the Lycomings and Continentals at around their prices
- ie they will probably be prohibitively expensive for us chaps.
Flight testing will start in 1996 with first applications including
the Westinghouse airship and the Extra 300 aerobatic aircraft.
There are said to be about 40 different aircraft being designed around
Zoche diesels as well as the possibility of retro fits for
existing popular GA aircraft.
It is interesting to note that the company has consulted the results
of engine research carried out in the 1930s and 1940s.
DESIGN FEATURES
BOOST - Diesel engines lend themselves to being both supercharged or
turbocharged and the Zoche engines are both. There
is almost no practical limit to cylinder pressure on a diesel and
there are big benefits to be gained such as high power output at
low air densities. From a reliability point of view, these add-ons are
not quite as risky as when fitted to a petrol engine. The
diesel´s high compression ratio means it also has a high expansion
ratio following combustion; this leads to cooler exhaust gases
and an easier life for the turbo.
SIMPLICITY - Great care seems to have been taken to make the Zoche
engines as simple and as light as possible; this effort
has resuted in a very low parts count. (Zoche claims less than 100
threads on the 8 cylinder radial). Modern computer-aided
design, including finite element analysis, permitted parts to be
optimised for weight and strength. Most of the engine parts are
light alloy, including the pistons, cylinders and even the connecting
rods. A major effort has been made by Zoche to make most
components interchangeable between engine types. This reduces tooling
costs, facilitates production, eases parts handling and
storage and simplifies quality control.
SIZE - The radial layout was chosen for its benefits of lightness and
compactness - the frontal area of the Zoche diesels is
claimed to be less than nost competitors and the diameter of the 8
cylinder radial "equals the diameter of high performance
gliders". This is possible on the Zoche two-strokes because of the
absence of valve gear on the cylinder tops. The intake
manifold, fuel injection and feed pump, fuel filter and associated
plumbing are all integrated into the crankcase assembly.
LOW SPEED - maximum power is developed at only 2500 rpm; no reduction
drive is required which helps keep weight and
complexity low.
STARTING - One inherent disadvantage of the diesel engine is the hich
power required for starting, exacerbated by havin a
supercharger. Instead of opting for the easy, but heavy,
battery/electric motor solution, Zoche has devised an ingenious
solution:
it has a patented air starter system which releases air at 435 psi
from an 8 litre reservoir to accelerate the gear-driven
supercharger. The reservoir is presumably replenished during running.
With few notable exceptions, there is little doubt that the aero
enignes which have powered our light aircraft for decades are
dinosaurs. Developed in the ´50s, because of certification costs and a
limited and dwindling market in the USA, they have not
benefitted from the dramatic imporvements made to their land-based
cousins. They are heavy, thirsty and outrageously
expensive for what they are. With a little luck Zoche may just be
poised to place them where they all belong.
pr...@inforum.net
ENGINE FOR THE FUTURE?
As our dinosaurs of aircraft engines slouch toward eventual extincion,
a small German firm is running the first in a new
evolutionary line of production light aircraft engines. General
Aviation is facing quite a few problems of late, including
unrealistically high prices and limited availability of aircraft and
the whole product liability boondoggle. Unfortunately, these
problems have affected the light aircraft industry more than any other
segment of the market. Faced with mounting costs and
difficulties, most airframe manufacturers have seen fit to concentrate
their research, development, and product improvement
efforts - such as they are - on their high-performance,
turbine-powered corporate barges (where their profit margins are
greatest). By so concentrating their efforts, these manufacturers are
putting relatively fewer aircraft (and only those which are
most often professionally flown) into the field to risk yet more
liability suits. Powerplant development has suffered similarly.
True, there have been a few new designs, notably the elegant, but
heavy, oh-so-costly, and now discontinued Porsche Aero
Engine, as well as Continental´s liquid-cooled "Voyager" series. Among
homebuilders, various conversions of automotive
engines have found similarly various levels of success and acceptance.
By and large, though, we´re still stuck with the same old
warmed-over 1930s and 1940s technology: slow-turning,
large-displacement, opposed, air-cooled engines, sometimes fuel
injected and turbocharged but often equipped with carburetors, and
invariably with magnetos that Henry Ford would have had
no trouble recognizing or even overhauling. In a way, I suppose, you
can´t blame the engine manufacturers: Why divert bucks
from lucrative turbine programs toward recips when the market for
airplanes in which those recips could be installed has been
systematically choked off by the same lawyers who warn their bosses
that the risks are high? It´s something of a vicious circle:
with few new aircraft, there are a few new engines, driving the cost
of those that are built toward the stratosphere. At the same
time, spiralling insurance costs are making overhauls, and even parts
for overhauls, ever more expensive. Then, there´s the
question of fuel. Avgas has always been expensive, and it´s getting
even more costly. Future EPA regulations in the USA may
require removal of the last vestiges of tetraethyl lead from 100 LL
gasoline, which will require reduced-power operating limits
for many current engines (and may accelerate valve and guide wear in
older ones to unacceptable limits). In Europe, avgas is
even more horrendously expensive than here; on a recent transatlantic
ferry in a turbine, I blithely paid $ 1.86/gal for Jet A
while a Baron driver going the other way was soaked for $ 11.50 (!) a
gallon. In many Third World countries, avgas is simply
unobtainable at any price. Sounds gloomy, doesn´t it? There may,
however, be some light at the other end of the tunnel. On a
recent trip to Germany I had a chance to look closely at one of our
best and brightest hopes for the future. How would you like
an air-cooled engine that weighs less than 200 lbs for 150 hp - or
comes out to well under a pound per horsepower at 300 hp?
How about an absence of valves and valve gear? A starting system that
weighs only a couple of pounds and requires no
battery? The ability to run on jet fuel, diesel oil, heating oil - in
fact, just about anything except gasoline? What about a new cost
about the same as that of current engines, but with a guaranteed-cost
factory replacement (not overhaul) program at the end of
the TBO, and other operating costs at only about half those of current
gasoline recips? Well, that engine exists and is running -
in fact, I´ve seen and heard it run myself. What kind of supermodern
technology does it take to achieve these feats? Hold on to
your decoder rings, Buck Rogers fans: Michael Zoche´s truly
revolutionary recip powerplant is a supercharged (!) and
turbocharged (!!) radial (!!!) ... DIESEL (!!!!) "What? A diesel?!" I
hear you cry. "Diesels are heavy, underpowered, and
inefficient, suitable only for ships, big rigs, earth-moving
equipment, and yuppie eco-snails displaying their Greenpeace stickers
to each other in the slow lane." Really? If they´re so inefficient,
why do trucking companies - who are only in business to make
some money - use virtually nothing else? If they´re so underpowered,
how come bulldozers don´t run blown big-block
Mopars? And have you driven any of those eco-snails lately (assuming
you could afford one)? You might be surprised at more
than the price. Actually, airborne diesels - and German ones in
particular - have a long and distinguished history. The diesel
engine itself, of course, is a German invention, and its basic concept
offers a number of advantages including simplicity - any
diesel gets by without an ignition system and two-stroke ones can even
do without valves! - and economy. To a certain extent,
the amount of useful work that can be wrung out of a given amount of
fuel in an internal combustion engine depends on the
compression ratio of the engine in which it´s being burned, and
diesels operate at significantly higher compression rations than
gasoline engines; moreover, diesel fuel contains considerably more
energy per gallon than gasoline. (As a side benefit, an engine
built to withstand those high compression ratios tends to be pretty
rugged. Additionaly, diesels operate at considerably lower
exhaust temperatures than gasoline engines, and thus last longer; most
18-wheelers are "just getting broken in" at about the
half-million mile mark!) As far as aviation is concerned, German
diesels flew from the early Zeppelin days on. Between the
wars, German-derived technology was used in Packard diesel aero
radials in the USA. The big development push came,
however, as Germany started to expand her long-range overwater routes,
particularly to South America, in the late 1930s; the
only engines offering their Junkers or Blohm and Voss seaplanes both
sufficient range and adequate reliability were Junkers´
own mechanically scavenged "Jumo" Diesels. By the end of the war, one
turbocharged and intercooled version of this series
was producing 1800 continuous hp in a package smaller and lighter than
a 1250-hp Rolls-Royce Merlin. Michael Zoche has
long been fascinated with the idea of diesel aero engines. In fact,
only a handful of the fabulous Jumo engines mentioned above
still exist, with their unique arrangement of two opposed pistons
running in each common cylinder bore, with geared dual
crankshafts at the top and bottom of the engine. One, a 450-hp
version, was put together from old parts and is displayed
partially cut away in the German Museum in Munich; another, in
virtually perfect working order and with only test-cell time
since new, gleams proudly in the entrance hall of Michael Zoche´s
Munich home. How does a diesel work? Basically, very
much like a gasoline engine - except rather than a fuel-air mixture
being taken into the cylinder, compressed, and then ignited by
a spark plug, air - and only air - is taken in and compressed until it
reaches a temperature above the flash-point of the fuel. At
this point, the fuel is sprayed, under very high pressure, into the
combustion chamber, and immediately begins to burn; thus, all
diesels are, by definition, fuel-injection engines - and since
ignition is strictly by engine compression, such things as magnetos or
distributors, spark plugs, and all the associated wiring (two sets of
everything, for airplanes!) become superfluous. What´s not
there, can´t fail. Moreover, diesels lend themselves very well to
two-stroke operation. In a gasoline-powered two-stroke, the
incoming charge of fuel-air mixture purges, or "scavenges", most of
the previous stroke´s exhaust gases from the cylinder;
inevitably, though, and despite advances such as Schnuerle porting,
there is some intermixing and loss of efficiency. In a
supercharged two-stroke diesel, on the other hand, the incoming charge
is nothing but air, and it comes in pretty briskly with the
supercharger behind it! Scavenging is complete and efficiency
increases. Valves? Why bother, when you can just use the piston
itself to cover and uncover intake and exhaust ports in the side of
the cylinder as it moves back and forth? Of course, no valves
also means no springs, no guides, no seats, no valve timing, no valve
adjustment, no camshaft, no gears to run it, no lifters, no
pushrods, no rockers... The above should give you a few answers to the
question, "Why a diesel?" The next one that Michael
and his marketing force (actually, his large and cheerful family;
their display engines and motorhome have become something of
an Oshkosh fixture the last five years or so) have to field most
frequently is "Why a radial?" Again, there are some pretty good
reasons; bear in mind, gentle reader, that the most successful and
highest-performing fighters (on all sides!) of World War II
were powered by air-cooled radials like the R-2800, while other than
the Jumo Diesels, the pinnacle of aircraft recip
powerplant design was reached with such mighty engines as the Wright
R-3350 Turbo Compound or the Pratt & Whitney
R-4360 "Corncob" - once again, turbocharged multirow radials. When you
start getting to higher power levels, radials start to
make a lot of sense. First of all, compared to the long and somewhat
"whippy" crankshafts of typical opposed engines, a
radial´s crank is short and stout - particularly appealing given the
somewhat brusque power pulse of some diesels. (Zoche uses
a unique arrangement with four cylinders per row and a nifty
proprietary connecting rod arrangement with all of the rods
identical and no "master rod".) Even more important is cooling; with
all the cylinders in one plane for a single-row radial like the
150-hp Zoche, cowl design for effective and equal cooling is greatly
simplified. Even two-row radials like the Zoche 300 (or,
for that matter, the R-3350) cool effectively, since the rows of
cylinders are arranged so that the back ones fill the spaces
between the front ones, getting alomst as good a "shot" at the
incoming air. About the only compromise a radial has to make,
particularly for single-engined airplanes, might be ground visibility
(something to which I, as an erstwhile Cessna 195 driver, can
attest!). On the other hand, tri-gear radial-engine ships (for
example, a T-28) offer terrific ground visibility at the price of a
tall
landing gear. In the case of the Zoche engines, it shouldn´t really be
a problem even in a taildragger; even the 300-hp mill has
external dimensions smaller than those of its Continental or Lycoming
equivalents, and its prop shaft line is only about three
inches lower (relative to the centroid of the whole engine) than that
of the flat opposed mills. Its radial design, freedom of
vibration (of which more shortly), and good thermal characteristics
also mean it could be very tightly cowled. For a small
family-run firm, Zoche Aero Diesels strikes me as a cut above most
budding engine developers. First of all, they´re adequately
capitalized; Michael has a successful background in the large-scale
laundry industry. Second, and in keeping with this, they also
can afford to take their time and get it right; in fact, one of my own
major frustrations with the program is that every year
Michael and his family (including two sons, one of whom served an
apprenticeship at Cosworth in England) show up at
Oshkosh with a later and more impressive prototype version of the
engine, but are never quite ready to let me have one to
design a hot homebuilt around! As of this writing, it looks like the
design is finally "frozen"; by the time you read this, engines
that would be pretty close to a certification artice may well be
nearing installation on a couple of test aircraft in Germany. So
what does it look like? Basically, like a very neat, compact radial
without a lot of the additional stuff like pushrod housings or
ignition harness with which existing radials are festooned. In fact,
with the clean lines of the round cylinders unbroken by a big
cylinder head with valve gear, they look as if they come from an
immense model plane engine! Each has a single exhaust pipe
coming off a standard flange on its rear surface, while the spark
plug-size injector nozzle sticks in at the top; that´s all! Instead
of intake plumbing as such, intake passages in the cylinder base mate
with similar ones in the crankcase. Apart from cowling
and baffling considerations, changing a cylinder on one of these
engines (should it ever be necessary - unlikely with a max EGT
of less than 1000 deg. F) might take as long as ten minutes. The one
thing that´s a bit arresting on first glance is the number and
arrangement of cylinders: four per row, exactly opposite each other.
When did you last see a radial with an even number of
cylinders per row? Shows what you can do when you don´t use a master
rod - possible only in a two-stroke, where every
cylinder fires once per revolution. Most accessories (prop governor,
vacuum pump, ect.) mount on AN-standard pads on the
front of the crankcase; the engine is direct-drive, with no crankshaft
gearing. Also on the front of the engine, gear-driven from
the crankshaft, is the mechanical supercharger. In a typical display
of Zoche "niftiness", the supercharger serves a dual purpose:
since diesels require a high cranking force (due to the high
compression ratio), as well as needing to reach ignition temperatures
in the cylinders to ignite the fuel, they´ve traditionally been
considered hard to start, requiring heavy starters, big batteries, and
even glow plugs in the cylinders. Michael didn´t like that idea; his
starter is nothing more than a nozzle built into the
supercharger that directs a blast of 450-psi compressed air against
its impeller to spin the engine (at the same time, the air itself
goes on into the intake manifold to spin up the turbocharger and help
get the initial cylinder pressure up for starting). Every time
I´ve seen the engine start, cold or hot, it´s fired up within the
first turn; in fact, there´s no perceptible "starting" process at all
-
you push the button and it´s running! Once the engine has started, a
free-piston compressor powered by engine manifold air
(and weighing about a pound and a half) recharges the basketball-size
starting air bottle; in case of a problem, regular shop air
(or even half an hour with a foot pump if you´re a bush pilot!) can
also operate the compressor to build up enough pressure for
a start or two. Compressed-air starting also means your airplane´s
battery now needs to be only large enough to run a few
lights and radios before startup or in case of a generator failure -
say, a medium-size gelled-electrolyte type. No more big,
heavy lead-acid battery; no more big, heavy cables; no more battery
box and acid drain jar, etc... A diesel, since it always
needs the full air charge to reach ignition temperature, generally has
no throttle, but runs at "full bore" all the time. To vary
power, the amount of fuel delievered by the variable-displacement
fuel-injection pumps for each power stroke can be changed.
The prototype Zoche engine used Bosch automotive pumps mounted in a
gang outside the crankcase; the production version
uses a considerably more elegant arrangement of improved Bosch pumps
spaced around the crankcase near the cylinder bases
and operated by an internal cam ring. Pump timing is essentially fixed
- one less thing to worry about. At the back of the engine,
the cylinder exhausts come together to run the turbocharger. Since
manifold pressure in a diesel is high and constant, it´s not
used for power setting. For that matter, since exhaust gas temperature
(at around 550 deg. C / 1000 deg. F) is always
considerably lower than the limits on the turbocharger, there´s no
particular reason to monitor that, either. A diesel-powered
aircraft will use rpm and either fuel flow, or merely calibrated
throttle position, as its primary power setting reference. Althought
you can´t see it, another important accessory is at the back of the
engine: the alternator is a group of simple fixed coils inside the
crankcase and a cobalt alloy rotor at the rear of the crankshaft. As
impressed as I was examining how compact, efficient, and
well thought-out this engine appears, I was even more impressed after
visiting Zoche´s test cell facility not far from Munich. A
prototype 150-hp engine, festooned with the test engineer´s usual
rat´s nest of thermocouple wires and pressure sensure tubes,
was installed on the test fixture, swinging a three-blade composite
prop. I´d like to be able to write that "startup was
straightforward", but in fact for all practical purposes there´s no
perceptible startup at all: move the power lever out of its
"cutoff" detent, hit the starter button, and the engine is idling with
no real transition from its "at rest" state. If you watch and listen
very closely, you can hear a split-second hiss of compressed air and
see one prop blade moving 60 degrees or so; then the
engine is running and the blades vanish in the usual blur. On the
first start-up, the engine was stone-cold; we repeated it a few
times with the engine warm, and there was no difference. With the
engine running, Michael invited me to get up next to it, which
I did after gingerly edging past the spinning prop, and put my hand on
the crankcase. There was almost no perceptible vibration
at any engine sped from idle to full throttle; in fact, had I been
able to find a location on the engine shielded from the prop blast,
I have no doubt I´d have been able to balance a nickel on edge. Only
on shutdown is there a momentary shudder, just as with
any other engine. We moved into the soundproof test cell control room
for further demonstrations. I don´t profess to
understand the meanings of various traces marching across the computer
screen, but according to Michael they show that the
engine reaches compressions and temperatures sufficient for starting
within the first turn. Power lever response seemed near
instantaneous - and, of course, since there´s no throttle and the
engine is running "wide open" all the time, you can move the
lever quickly without worrying about overboosting. Shutdown is a
simple matter of bringing the power back around a gate to
cut off the fuel. Before leaving the test cell area, Michael explained
the firm´s planned overhaul policy. Rather than offering
factory overhauls or remanufactured engines for the aviation market,
Zoche will guarantee a price at the time when the customer
first buys an engine. When TBO - which is planned at 2000 hours for a
mature engine - rolls around, the engine is returned to
Zoche for a core credit and the customer will receive a brand-new
engine, while the old one is refurbished as necessary and
resold for non-aviation applications (for example, firefighting
pumps). This guarantees the customer all the newest modifications
and improvements, as well as minimum downtime; it´s planned that Zoche
distributors will draw from a pool of ready engines,
so an airplane normally wouldn´t be scheduled for engine replacement
unless a new one were already available. Overall, this is
an extremely impressive project, and one of which I expect to hear
great things in the future. Not only does this engine offer a
level of technical sophistication far beyond that of existing aircraft
engines; it should cost no more to acquire, considerably less
to operate, provide a superior power-to-weight ratio, reduced
maintenance - and run on jet fuel, which is readily available
anywhere in the world. I can only hope that production versions appear
within the next three to five years.
Peter Lert / Air Progress, April 1993, p. 35-37, 66
pr...@inforum.net
Mazda Wankel 13B Engine Aircraft Use
Edward L. Anderson
21 October 1997
back
The following is a summary of adaptations made to accommodate a Mazda
Rotary engine for aircraft use.
It is provide free for education purposes with the assumption that the
reader is fully aware of the risks
involved. The author assumes no responsibility or liability for its
use or consequences of its use by others.
Description: The Mazda Wankel 13B engine is unique in that it employs
two rotors with 3 faces on each
rotor which are similar in function to a reciprocating engine’s
pistons. The total displacement of the engine,
as conventionally measured, is 80 cubic inches. However, because each
rotor face completes a cycle of
intake, compression, combustion and exhaust every revolution and there
are two rotors with a total of six
faces, the engine produces a very high amount of power given its small
displacement. The typical horse
power range in automobile applications have ranged from 150-250 HP. In
highly modified race
applications over 350 HP has been achieved ( with reduction in
reliability). The RPM red-line for normal
automobile application is 8500 RPM. In this adaptation for aircraft
use the upper limit is 6500 RPM which
is an operating range well within its limits.
Reliability and Safety Benefits of the Design: The design is
inherently more reliable than
reciprocating engines in that there are fewer moving internal parts.
There are no Cam shafts, valves, valve
springs or keepers, no valve rocker arms, no connecting rods or piston
wrist pins. Furthermore, there are a
number of other features which contribute to reliable and safe
operation. The rotors which revolve on an
eccentric shaft (crankshaft) are of a iron alloy while the housing (
or chamber) they rotate in is of an
aluminum alloy. Loss of coolant and resulting overheating resulting in
the aluminum housing expanding
faster than the iron rotors, this increases the clearances between
moving parts (rotor) and stationary parts
(the housing) which greatly reduce the potential for engine sizing due
to over heating which can quickly
occur with loss of coolant in reciprocating engines.( If fact, one
installation of a 13B in an aircraft did lose all
coolant and while the temperature red-lined, the engine continue to
function until the pilot could land. A
subsequent tear down and inspection of the engine revealed no damage
other than a number of rubber
seals were damaged due to the excess heat and required replacement.)
The wankel engine has been used in
automobile race events for a number of years and has a wide spread
reputation for durability under
extreme operating conditions.
The Wankel engine is inherently smoother than a reciprocating engine
in that there are no linear to
rotational translations as exists in a reciprocating engine. This
greatly reduces vibration and inertial loads
caused by pistons reversing direction in a cylinder several hundred
times a minute. Additionally, the
power pulses are more frequent, but of a much lower magnitude that a
typical four cylinder aircraft engine.
This reduces airframe and component fatigue effects and also reduces
pilot and passenger fatigue. It also
lowers the magnitude of the propeller torsion response to the power
pulses.
A number of studies on the predicted TBO of the Wankel in aircraft use
have been done by industry and
research centers. While the upper limit estimated has varied,
depending on a number of conditions, the
consensus appears to be that there is no reason to expect any less
than the typical 2000 hour TBO of a
certified aircraft engine and some indications are that it could be as
much as 4000 hours. Only actually
aircraft usage will provide the ultimate answer. But, given a first
class remanufactured engine costs from
$1600-$3200, the wankel adaptation is cost effective even if the TBO
turns out to be only 1000 hours.
ENGINE SUBSYSTEMS
LUBRICATION SUBSYSTEM: Lubrication of moving parts is as crucial for
this engine as a reciprocating
engine. However, even in the case of lubrication subsystem failure the
failure mode is gradually, with the
engine actually slowing down to a stop as the friction increases
rather than suddenly sizing as piston
engines are inclined to do.
The internal design does require oil to be injected into the rotor
chamber for lubrication. In automotive use
the engine draws on oil from the crankcase for this purpose. This is
not a desirable feature for aircraft usage
in that it can result in exhaustion of lubricating oil in the
crankcase, if not frequently checked, and the
carbon deposits from combustion of automobile engine oil causes
internal wear of the seals of the rotors.
Most non-automobile applications eliminate the crankcase oil injection
subsystem and instead mix 2 cycle
oil in the gasoline. This has proven to be a reliable method and
removes the possibility of crankcase oil
exhaustion and improves the rotor seal life. It does, however, require
mixing the 2 cycle oil with each
gasoline fill up. A future, nice to have, but not necessary,
modification being considered is to develop an
oil injection system which draws from a 2 cycle oil reservoir rather
than crankcase oil.
Heat ejection by the lubrication subsystem is crucial for maintaining
engine temperature within design
limits. This is accomplished through an oil cooler with a fin surface
equal to that used in the automobile
application. Only stainless steel braided oil lines with a design
bursting pressure of 1500 psi are used in
the subsystem. An Air Wolf firewall mounted remote oil filler
completes the lubrication subsystem.
Lubrication Subsystem Instrumentation: The lubrication subsystem is
instrumented with an oil
pressure and oil temperature gauges mounted in the instrument panel. A
dipstick provides for oil quantity
measurement.
ELECTRICAL/IGNITION SUBSYSTEM: Additional features relative to safety
is that each rotor
chamber has two spark plugs with two independent ignition coils for
each plug set. There is one plug per
rotor chamber referred to as the "Lead" and one referred to as the
"Trailing" plug. The trailing plug in the
automobile application is set to fire approximately 15 degrees after
the lead plug fires. The engine will run
on just the trailing plug setting for auto application, however, there
is considerable power loss. While the
trailing plug was designed principally to meet auto emission and fuel
economy standards, it can be
recalibrated to fire essentially in sync with the lead plug providing
true redundant ignition for the engine
in aircraft application. An aftermarket ignition computer is used
which provides two independent ignition
CPUs and a feature for checking each ignition coil subsystem
independently similar to a checking of the
aircraft magnetos.
The adaptation includes two 25AH Concord RG batteries, each of which
is capable of carrying the essential
minimum electrical load for up to 2 1/2 hours should the alternator
charging subsystem fail. Additionally,
there is an automatic battery charging/management subsystem that
automatically keeps each battery fully
charged and give visual indication of abnormal voltage conditions.
Furthermore, each battery can be
manually isolated from the bus circuit should it malfunction (such as
an internal electrical short in the
battery).
The electric charging is accomplished with a Bosch alternator (know
for its reliability in automotive usage).
Electrical Subsystem Instrumentation: The electrical subsystem is
instrumented with a High/Low
voltage visual indicator as well as a voltmeter which can be switched
between each of the two batteries and
the alternator.
COOLING SUBSYSTEM: Since the engine is liquid cooled the adverse
effects of "shock" cooling which
can cause cylinder damage on air cooled engines does not occur. Again,
a positive feature. Due to the fact
that this small displacement engine does produce so much power
relative to its displacement, adequate
cooling is a critical need to remove the excess heat from the block.
Approx. 1/3 of the heat rejection (above
that not ejected by the exhaust gases) is by the lubrication system
through an oil cooler. The remaining
(approx. 2/3 of the waste heat) is ejected through a water based
coolant system using radiators.
Given the crucial aspect of the coolant system, the adaptation employs
only stainless steel braided hoses
for all coolant lines. The bursting pressure rating for each hose is
750 psi, many times the nominal
operating pressure of 15 psi. This provides a significant safety
factor in reducing the possibility of leaks.
The heat content of the coolant is ejected by two Harrison heat
exchangers positioned in front of the
traditional air intake ports on each side of the propeller shaft. The
air flow is captured by a fiberglass duct
and directed through the 3" thick heat exchangers. The fin or cooling
surface of each heat exchanger is
sufficient to reject adequate heat to keep the block temperature
within design limits (maximum of 210
degrees Fahrenheit as it exits the engine block). The coolant sensor
is located immediately after the water
pump (positive pressure side).
Additionally, since the engine is liquid cooled, cabin heat is derived
from an heat exchanger in the cockpit
to transfer heat from the coolant system into the cockpit. The heat
exchanger has a manual coolant cutoff
valve as well as a manually controlled fan. This approach removes the
danger of carbon monoxide leaking
into the cabin through the typical exhaust muff approach to heating
most GA aircraft.
Coolant Subsystem Instrumentation: The coolant system is instrumented
with both a coolant
temperature gage and a coolant pressure gage. The coolant pressure
gage will immediately indicate any
abnormality and provide early warning of a leak giving time for a
flight to be terminated before complete
loss of coolant. If only a coolant temperature gage were used,
considerable loss of coolant is possible
before a rise in temperature would indicate a problem existed.
Therefore, the coolant pressure gage is
considered a crucial feature of any liquid coolant system in an
aircraft.
PROPELLER SPEED REDUCTION UNIT (PSRU): A PSRU is used to reduce the
engine RPM to that
required for efficient and safe propeller operation. The unit is a
Ross Aero PSRU designed for the Mazda
13B using planetary gears providing a 2.17:1 reduction. This provides
for the engine to be turning approx.
5000 RPM giving a static propeller RPM of 2300 RPM. This PSRU design
has been used on a number of
automobile engine adaptations giving reliable operation. The PSRU case
is of a cast aluminum alloy
designed to handle the inertia and torsion loads of a propeller. An
engine RPM of 6300 would result in a
propeller RPM of 2900. While the engine is capable of reliable
operation up to 8500 RPM, maintaining
propeller speed/efficiency and preventing the tips from going sonic
will require the engine to be redlined
(max operation RPM) of 6500 RPM. This is well within the engines
design specifications and 1000 RPM
below the auto application limit of 7500 RPM.
Lubrication for the PSRU is derived by tapping off of an oil galley in
the block. A restricter with an 0.040"
dia hole controls the oil flow to the PSRU which is then returned to
the crankcase oil pan. The oil provides
for both lubrication and cooling of the PSRU.
PSRU Instrumentation: There is no direct instrumentation of the PSRU,
however, the engine is
instrumented with a tachometer triggered off the ignitional subsystem
which provides a reading of engine
RPM. A close approximation of propeller RPM is found by dividing the
engine RPM by two.
The engine oil pressure and temperature instruments provide an
indirect indication of state of the PSRU
operation.
FUEL SUBSYSTEM: The fuel subsystem is comprised of aftermarket
components including a throttle
body (two 2" dia throats with two injectors in each throat), a HALTECH
Fuel injection CPU, and an original
fuel delivery design. There are two independent high pressure fuel
pumps each with its own fuel filter.
One pump is automatically controlled by the Fuel Injection CPU and the
other (backup) is operated
manually by a switch on the instrument panel. A fuel pressure
regulator and a fuel pressure gage is also
part of the subsystem.
Each of the pumps is independently plumbed to a small header tank
(3X3X8") mounted on the firewall.
Fuel is drawn from this header tank by the high pressure fuel
injection pump(s) and provided to the fuel
injectors; excess fuel in the line not used by the injectors is
returned to the header tank. The results is that
any fuel injected into the engine is not returned to header tank, this
creates a partial vacuum in the header
tank which is connected through a tank selector switch to the wing
fuel tanks. This partial vacuum is more
than adequate to draw fuel from the tanks even without the fuel boost
pump (which is installed between
the wing tanks and header tank). This has been verified by running the
engine and feeding fuel into the
header tank from an external plastic marine fuel tank. (The vacuum is
not only sufficient to draw fuel
vertically two feet from the marine fuel tank (which was placed on the
ground) into the header tank, but on
one occasion when I failed to open the fuel tank vent, the resulting
vacuum actually caused the plastic fuel
tank to collapse.)
All fuel lines FWF consist of stainless steel braided hoses. Fuel
lines internal to the airframe and wings
consist of aluminum tubing with AN fittings. The fuel system plumbing
was pressurized with air to test for
leaks.
The HALTECH Electronic Fuel Injection (EFI) is an open loop subsystem
which calculates injection time
based on a number of engine parameters including: RPM, Manifold
Pressure, coolant and air temperature.
The CPU is programmed via a lap top computer which provides a
graphical display of injector timing,
RPM, and manifold pressure. The CPU retains the programmed parameters
even with power removed.
Also, the programming subsystem permits recording of engine and
injector parameters during operation
which permits post run analysis of the results. The EFI does have a
mixture control feature that permits the
engine air/fuel mixture to be "leaned or enriched".
(A engine fuel priming subsystem is planned for future installation.
While this can aid during cold starting,
the principal reason is to provide a crude backup system for injecting
fuel into the engine. It will be
operated through an electric solenoid which can be trigger through a
button on the instrument panel. In the
unlikely failure of the EFI subsystem, engine operation could be
maintained by continuous/intermittent
depression the "primer" button. While crude, it does offer a degree of
redundancy and has been shown to
keep a engine functioning although with increased pilot workload. It
is intended only as a last resort
measure.)
The only unique failure mode (other than EFI, pump or filter) for the
fuel delivery system could be an air
leak in the header tank which could result in the loss of the partial
vacuum. Even though this failure mode
is unlikely, as the header tank is a welded aluminum construct which
has been pressure tested to over
150psi. The first indication would likely be erratic and dropping fuel
pressure on the indicator. However,
should it occur, activation of the boost pump will maintain adequate
fuel flow to the header tank until a
safe landing could be made.
Fuel Subsystem Instrumentation: The fuel subsystem is instrumented
with a left and right fuel
quantity indicator and a fuel pressure gauge.
EXHAUST SUBSYSTEM: The exhaust subsystem is straightforward. The
engine has two exhaust ports
on the bottom of the block. Each port is routed down and under the
block through 2" dia stainless steel
tubes exiting the engine cowl underneath the airframe and to the rear.
Each tube is mated through exhaust
"ball" joints (to accommodate heat expansion and stress) to two
separate 36" stainless steel mufflers. This
design promotes excellent exhaust gas ejection, is simple, and lowers
the sound level to a quite acceptable
level. Each exhaust muffler is mounted to reinforcement plates
underneath the fuselage. The fittings
holding the mufflers employs four 3/16" AN 3 bolts for each muffler.
Each muffler weights 8 lbs. Given the
maximum "G"s (6 gs) of the aircraft design the maximum loading for
each muffler would amount to 48lbs.
Therefore, the four AN 3 bolts (for each muffler) are far more than
adequate to secure the muffler against
expected loads. The mufflers also has 1/4" airspace between them and
the airframe to preclude excessive
heating of the fuselage skins. Normal airflow in flight will preclude
the temperature of the mufflers from
exceeding 200 degrees F. Even in ground operations the airflow from
the propeller will maintain a safe
operating temperature.
Exhaust Subsystem Instrumentation: Each exhaust tube has a
thermocouple probe which senses
exhaust gas temperature and displays it on a Exhaust Gas Temperature
gauge mounted on the instrument
panel.
MISCELLANEOUS: Several other modifications were made to enhance safe
reliable operation. The
crankshaft and alternator pulleys were replaced with dual belted
pulleys oversized to reduce the auxiliary
equipment’s operating RPM and to provide redundancy over the single
belt alternator and water pump
design employed in the automobile application. An oversize oil pan is
used to allow for 8 quarts of
crankcase oil. A 20 psi radiator cap is used to ensure that even with
lower atmospheric pressure at altitude,
there is more than adequate cap pressure to preclude the coolant
pressure from forcing coolant past the
cap. The engine motor mount was designed and fabricated professionally
and is more than adequately
designed from aerobatics loads. The mount is attached to the firewall
at the airframe designed locations.
TESTING ACCOMPLISHED
The entire engine subsystem was mounted on a test stand for initial
testing and monitoring of all its
subsystems. With the exception of a low oil pressure problem which was
corrected by replacement of an
"O" ring there were no problems encountered. The engine has been
operated for 4 hours including
operating at 5000 RPM which resulted in the 68x72 wood propeller RPM
of 2300. Based on these
parameters, the propeller manufacture stated that the engine was
developing a strong 165 HP. This test
was conducted with very restrictive mufflers (in order not to disturb
neighbors) which resulted in
considerable back pressure. Exhaust back pressure is detrimental to
engine performance, but particularly
so for the Wankel which is very sensitive to back pressure. For the
aircraft application, two less restrictive
mufflers are used. This should result in a gain of 10-15 HP with the
engine in flight.
SUMMARY
In summary, I believe the engine has a number of inherently desirable
features and benefits for aircraft use.
The adaptations to make it suitable for aircraft use have been
carefully thought out and failure modes
thoroughly examined. I have designed the subsystems for fail-safe and
redundancy, wherever feasible. I
have spend over 18 months developing and testing the engine and its
subsystems. I will conduct an
extended taxi and flight test program to further ensure its
reliability and safety.
I believe, I have prudently and carefully assessed the benefits and
drawbacks. I have placed safety and
reliable operation at the top of any design decision. I am confident
that safe operation of the aircraft with
this powerplant has not been compromised.
An individual in Florida, Tracy Crook has over 500 hours on an RV-4
powered by a Mazda Wankel 13B
engine. Tracy has produced an excellent "conversion" manual for the
13B and has a newsletter on the
engine. There are several others such as PowerSport Inc. ,whom have
essentially design a Wankel Rotary
engine from the ground up for aircraft use and have achieved
extrodinary performance with the engine
mounted in an RV-3. To my knowledge, there have been no accidents or
engine failures resulting in
accidents from their use of the Wankel Rotary engine.
Scrappman
the redrive,,,beef up the bearings? An external dampning system or a bearing
system for the loads.
Scrappman
J.D. GUINN
years. The biggest problem I have encountered was with cast cranks,
especially when trying to slightly hot rod a VW with one. Spend the
extra few bucks and get a forged crank, or spend a lot of bucks and find
yourself a billet crank.
Best Regards,
J.D. Guinn
FrJn
And what might the price for this engine be?
Fr. John Elledge
mark smith
don't get excited, if this is the one I'm thinking of, it has never
actually flown on anything,,,,