>Hi,, Paul:
 >
 >My interrest is in a rotary engine replacement for the Garrett
 >TPE-331-10 (1,000 shp).  Reading your website, I see that Racing Beat in
 >Aneheim built and tested a 900 hp, 3 rotor turbo aircraft engine.  Do
 >you know if they are still developing this engine?  I wonder what a 4
 >rotor version would produce?
 >
 >The engine would be installed in the (still under development) CompAir
 >CA11, single engine pressurized experimental aircraft.  Depending on
 >engine selection, cruise speeds will be anywhere from 260-360 ktas at
 >altitude.  The engine of choice for the CA11 is the TPE-331-14 with a
 >fuel burn of 71 gph (ouch).  Purchase of the engine is around $300k (0
 >time rebuilt) and overhaul is close to that price, as well.  TBO is at
 >least a respectible 5000 hrs.  A rotary engine would be less than all of
 >that, I'm sure, and I look forward to the day that hydrogen is available
 >as a fuel source.
 >
 >Thanks in advance and looking forward to your newsletter.
 >
 >Greg Fleming
 >London, Ontario, Canada
 >
 >
 >The 71 gallons an hour for the turbo prop would be roughly
 >at the 680 HP cruise level.
 >
 >Sounds like a perfect application for a turbo four rotor.
 >Fuel burn at 680 HP level would be about 50 gallons an hour.
 >
 >The engine can be built up from two rotor parts.
 >I would contact Jim Mederer at Racing Beat directly.
 >
 >Jim Mederer <jimmederer@yahoo.com <mailto:jimmederer@yahoo.com>

 >Jim has a lot of experience building rotary engines for aircraft.
 >Here is one example. He built his first couple of 12A turbo's in 1973.
 >
 >Also contact Francois at Mistral. They may be interested in building a
turbo
 >four rotor. François Badoux <f.badoux@mistral-engines.com



 >They have a constant speed prop gear box that might be adapted to a four
 >rotor.
 >
 >
 >Paul Lamar
 >
 >I'm absolutely stunned.  Every day I'm learning more and more.  The
 >Wankel rotary engine continues to drop my jaw (I have to make sure it
 >doesn't keep hitting the space bar on my laptop).  No wonder you are
 >fascinated with this design and the promise for an improved aircraft
 >powerplant.
 >
 >
 >
 >Here's my questions / observations so far.  I hope you can answer or
 >comment:
 >
 >
 >
 >    * According to Jim at Racing Beat, they had a lot of problems with
 >      the 3 rotor 900 hp aircraft engine from 1999.  Too much heat
 >      warped the housing shape which led to apex seal spring failures.
 >      They didn't dowl the housing back then which might be a cure, but
 >      with using a 13G, 3 rotor model they would still run into
 >      durability problems.  I asked him if he could go with a 4 rotor
 >      engine, he said it's not available to the public but 4 rotors
 >      would certainly make things more do-able.  With aluminum side
 >      housings and a few other tricks, the weight would not be a big
 >      factor.  He also said the BSFC was 0.6.  Ouch!!  I was hoping for
 >      less than 0.4.  I have since asked him about going with 2 blocks
 >      of 2 rotor to make up a 4 rotor engine, but will have to wait till
 >      Monday for an answer.
 >    * What do you know about the Mazda Renesis II engines?  Are they
 >      available to the public in the 2 block so I could put 2 together
 >      to make a 4 rotor??  I see that Guru Racer makes a 4 lobe e-shaft,
 >      but who is selling 4 rotor engines?  I'm confused.  Can engine
 >      shops mix and match to use the best parts available, or is there
 >      some proprietary thing going on where Mazda only lets the public
 >      use certain components?
 >    * I sent an e-mail to Mistral asking about developing a 900 hp 4
 >      rotor turbo engine.  No answer back yet from Francois.  I like
 >      their PSRU on the website for a couple of reasons.  Constant speed
 >      hydraulic prop (as you had mentioned) and a better, slimmer cowl
 >      shape.  Does Mistral manufacture their own parts/design or are
 >      they using Mazda technology?  They seem to have a nice package in
 >      the 360 turbo version, but I can't tell if they're using the
 >      Renesis design or their own.
 >    * I also enjoy your discussions on turbo-compound.  How would you
 >      set it up on a rotary engine??  I'm thinking the exhaust would
 >      first pass thru the turbocharger for induction air, then the
 >      exhaust would travel a bit further back and thru another
 >      turbocharger housing mounted on one of the back accessory pads,
 >      with appropriate gear reduction to optimize the turbo speed
 >      efficiency, and augment the mechanical power output.  From a 900
 >      hp engine, would there be an extra 50+ hp added to the driveshaft??
 >    * Does ceramic coating peak you interest or do you think the
 >      potential gain in efficiency is too little?
 >    * The Mazda gas/hydrogen hybrid is interesting.  My ultimate goal is
 >      a hydrogen airplane but, with today's technology, there would be
 >      no range due to limited storage.  However, with a hybrid at the
 >      "flick of a switch" (according to Mazda), you could take-off and
 >      climb on gas, then once in cruise, you could switch to H2.  Mazda
 >      claims that the power drops by about 50% when using H2, but that
 >      would work for long range cruise setting.  Sounds too simple but
 >      maybe there's room for development.  I have a few contacts working
 >      on H2 on demand in development.
 >    * After reading the discussions on engine cooling/radiator
 >      placement, I couldn't find any info on how to get the P-51
 >      efficiencies from the radiator.  You know, the hot air exiting
 >      with a force equal to the incoming cool air??  Zero net drag??
 >    * So, how does all this fit together for a guy like me trying to buy
 >      a kit plane that calls for a turboprop, and I want to replace it
 >      with a monster rotary engine?  I will have no problems buying the
 >      plane, but I will need to get everything developed, built, tested
 >      and in place within 5 years to have the engine ready to mount.
 >      Where do I start?
 >    * I would trust Mistral to build the 4 rotor engine, with the PSRU,
 >      the ECUs, the turbos, etc.  but would need someone like Jim at
 >      Racing Beat to modify, enhance, lighten, add the turbo-compound,
 >      etc.  Then I would need a company up to the task of developing the
 >      firewall forward installation with all the hoses, lines, ducting,
 >      wires, mounts, controls.  Wow!!  Maybe 5 years in not enough time.
 >
 >Thanks for your thoughts
 >
 >Greg
 >
 >
 >I know this is going to come as somewhat a shock but Jim is somewhat
 >behind the
 >the times on this. Both Tracy Crook, Mistral, Mazda and others have seen
 >..47
 >BSFC by judicious leaning at cruise HP numbers over the past five years
 >or so.
 >Jim is perhaps being a bit conservative by suggesting .6 BSFC as he is
 >worried
 >about detonation fracturing the apex seals. I 'll discuss this with him
 >at Seven
 >Stock around the 27th of Septemper if I can find him. The only way
 >anybody is
 >going to see less than .4 BSFC in an aircraft engine will be by turbo
 >compounding.
 >
 >Yes engine shops can mix and match parts all the way from 1974 or 1975 13B
 >engines right up to 2008 RX8 engines. At this point in time it is hard
 >to say
 >what is the best exact mix. 1993 to 2004 3rd gen parts appear to be the
 >best
 >choice right at the moment IMHO.
 >
 >Mistral can build and have built non certified engines out of Mazda parts.
 >Generally and currently they are making all their own parts to meet the
 >required
 >FAA certification paper trail.
 >
 >The P51 style cooling system requires a custom designed aircraft as it
 >is not a
 >good idea to cut larger holes in the fuselage unless one knows exactly
 >what one
 >is doing.
 >
 >So far we have had bad results with ceramic coatings. Too risky for
 >aircraft
 >engines at this point in time IMHO.
 >
 >You are quite right. This project is a challenge and nobody has taken on
 >such a
 >project so far. I remain optimistic that someday somebody will. The cost
 >and
 >fuel burn of small turbo prop engines makes it not that far out of
 >sight. I will
 >help as much as I can. If you are located in a reasonable accessible
 >place I
 >could visit if necessary at crucial times.
 >
 >There is no doubt the potential is there.
 >
 >Paul Lamar
 >
 >
 >Paul:
 >
 >I live in London, Ontario, Canada.  Half way between Detroit and
 >Buffalo.  However, I would be fast-building the kit at CompAir near Cape
 >Kennedy, FL.  The engine, avionics and interior would ideally be done
 >back in Canada but, at present, the Cdn. FAA (Transport Canada) does not
 >allow an experimental aiircraft to exceed 4,000 lbs or 4 seats.  I will
 >probably have to register the aircraft in the U.S. and fly it on my U.S.
 >licence.  Silly rules, but there you go.
 >
 >Still curious if you have any knowledge or info on hydrogen fuel in the
 >rotary engine.  All the discussion papers seem to think it's a natural.
 >
 >Thanks
 >
 >Greg
 >
 >
 >No problem running hydrogen. Better than a piston engine in fact.  HP
is half
 >and range is ridiculous.
 >
 >Paul Lamar

 >engine selection, cruise speeds will be anywhere from 260-360 ktas at
 >altitude.  The engine of choice for the CA11 is the TPE-331-14 with a
 >fuel burn of 71 gph (ouch).  Purchase of the engine is around $300k (0
 >time rebuilt) and overhaul is close to that price, as well.  TBO is at
 >least a respectible 5000 hrs.  A rotary engine would be less than all of
 >that, I'm sure, and I look forward to the day that hydrogen is available
 >as a fuel source.
 >
 >Thanks in advance and looking forward to your newsletter.
 >
 >Greg Fleming
 >London, Ontario, Canada
 >
 >
 >The 71 gallons an hour for the turbo prop would be roughly
 >at the 680 HP cruise level.
 >
 >Sounds like a perfect application for a turbo four rotor.
 >Fuel burn at 680 HP level would be about 50 gallons an hour.
 >
 >The engine can be built up from two rotor parts.
 >I would contact Jim Mederer at Racing Beat directly.
 >
 >Jim Mederer <jimmederer@yahoo.com <mailto:jimmederer@yahoo.com>
<mailto:jimmederer@yahoo.com <mailto:jimmederer@yahoo.com>>>
 >
 >Jim has a lot of experience building rotary engines for aircraft.
 >Here is one example. He built his first couple of 12A turbo's in 1973.
 >
 >Also contact Francois at Mistral. They may be interested in building a
turbo
 >four rotor. François Badoux <f.badoux@mistral-engines.com
<mailto:f.badoux@mistral-engines.com>
 ><mailto:f.badoux@mistral-engines.com
<mailto:f.badoux@mistral-engines.com>>>
 >They have a constant speed prop gear box that might be adapted to a four
 >rotor.
 >
 >
 >Paul Lamar
 >
 >I'm absolutely stunned.  Every day I'm learning more and more.  The
 >Wankel rotary engine continues to drop my jaw (I have to make sure it
 >doesn't keep hitting the space bar on my laptop).  No wonder you are
 >fascinated with this design and the promise for an improved aircraft
 >powerplant.
 >
 >
 >
 >Here's my questions / observations so far.  I hope you can answer or
 >comment:
 >
 >
 >
 >    * According to Jim at Racing Beat, they had a lot of problems with
 >      the 3 rotor 900 hp aircraft engine from 1999.  Too much heat
 >      warped the housing shape which led to apex seal spring failures.
 >      They didn't dowl the housing back then which might be a cure, but
 >      with using a 13G, 3 rotor model they would still run into
 >      durability problems.  I asked him if he could go with a 4 rotor
 >      engine, he said it's not available to the public but 4 rotors
 >      would certainly make things more do-able.  With aluminum side
 >      housings and a few other tricks, the weight would not be a big
 >      factor.  He also said the BSFC was 0.6.  Ouch!!  I was hoping for
 >      less than 0.4.  I have since asked him about going with 2 blocks
 >      of 2 rotor to make up a 4 rotor engine, but will have to wait till
 >      Monday for an answer.
 >    * What do you know about the Mazda Renesis II engines?  Are they
 >      available to the public in the 2 block so I could put 2 together
 >      to make a 4 rotor??  I see that Guru Racer makes a 4 lobe e-shaft,
 >      but who is selling 4 rotor engines?  I'm confused.  Can engine
 >      shops mix and match to use the best parts available, or is there
 >      some proprietary thing going on where Mazda only lets the public
 >      use certain components?
 >    * I sent an e-mail to Mistral asking about developing a 900 hp 4
 >      rotor turbo engine.  No answer back yet from Francois.  I like
 >      their PSRU on the website for a couple of reasons.  Constant speed
 >      hydraulic prop (as you had mentioned) and a better, slimmer cowl
 >      shape.  Does Mistral manufacture their own parts/design or are
 >      they using Mazda technology?  They seem to have a nice package in
 >      the 360 turbo version, but I can't tell if they're using the
 >      Renesis design or their own.
 >    * I also enjoy your discussions on turbo-compound.  How would you
 >      set it up on a rotary engine??  I'm thinking the exhaust would
 >      first pass thru the turbocharger for induction air, then the
 >      exhaust would travel a bit further back and thru another
 >      turbocharger housing mounted on one of the back accessory pads,
 >      with appropriate gear reduction to optimize the turbo speed
 >      efficiency, and augment the mechanical power output.  From a 900
 >      hp engine, would there be an extra 50+ hp added to the driveshaft??
 >    * Does ceramic coating peak you interest or do you think the
 >      potential gain in efficiency is too little?
 >    * The Mazda gas/hydrogen hybrid is interesting.  My ultimate goal is
 >      a hydrogen airplane but, with today's technology, there would be
 >      no range due to limited storage.  However, with a hybrid at the
 >      "flick of a switch" (according to Mazda), you could take-off and
 >      climb on gas, then once in cruise, you could switch to H2.  Mazda
 >      claims that the power drops by about 50% when using H2, but that
 >      would work for long range cruise setting.  Sounds too simple but
 >      maybe there's room for development.  I have a few contacts working
 >      on H2 on demand in development.
 >    * After reading the discussions on engine cooling/radiator
 >      placement, I couldn't find any info on how to get the P-51
 >      efficiencies from the radiator.  You know, the hot air exiting
 >      with a force equal to the incoming cool air??  Zero net drag??
 >    * So, how does all this fit together for a guy like me trying to buy
 >      a kit plane that calls for a turboprop, and I want to replace it
 >      with a monster rotary engine?  I will have no problems buying the
 >      plane, but I will need to get everything developed, built, tested
 >      and in place within 5 years to have the engine ready to mount.
 >      Where do I start?
 >    * I would trust Mistral to build the 4 rotor engine, with the PSRU,
 >      the ECUs, the turbos, etc.  but would need someone like Jim at
 >      Racing Beat to modify, enhance, lighten, add the turbo-compound,
 >      etc.  Then I would need a company up to the task of developing the
 >      firewall forward installation with all the hoses, lines, ducting,
 >      wires, mounts, controls.  Wow!!  Maybe 5 years in not enough time.
 >
 >Thanks for your thoughts
 >
 >Greg
 >
 >
 >I know this is going to come as somewhat a shock but Jim is somewhat
behind the
 >the times on this. Both Tracy Crook, Mistral, Mazda and others have
seen .47
 >BSFC by judicious leaning at cruise HP numbers over the past five
years or so.
 >Jim is perhaps being a bit conservative by suggesting .6 BSFC as he is
worried
 >about detonation fracturing the apex seals. I 'll discuss this with
him at Seven
 >Stock around the 27th of Septemper if I can find him. The only way
anybody is
 >going to see less than .4 BSFC in an aircraft engine will be by turbo
compounding.
 >
 >Yes engine shops can mix and match parts all the way from 1974 or 1975 13B
 >engines right up to 2008 RX8 engines. At this point in time it is hard
to say
 >what is the best exact mix. 1993 to 2004 3rd gen parts appear to be
the best
 >choice right at the moment IMHO.
 >
 >Mistral can build and have built non certified engines out of Mazda parts.
 >Generally and currently they are making all their own parts to meet
the required
 >FAA certification paper trail.
 >
 >The P51 style cooling system requires a custom designed aircraft as it
is not a
 >good idea to cut larger holes in the fuselage unless one knows exactly
what one
 >is doing.
 >
 >So far we have had bad results with ceramic coatings. Too risky for
aircraft
 >engines at this point in time IMHO.
 >
 >You are quite right. This project is a challenge and nobody has taken
on such a
 >project so far. I remain optimistic that someday somebody will. The
cost and
 >fuel burn of small turbo prop engines makes it not that far out of
sight. I will
 >help as much as I can. If you are located in a reasonable accessible
place I
 >could visit if necessary at crucial times.
 >
 >There is no doubt the potential is there.
 >
 >Paul Lamar
 >

Paul, Greg.


There will be at least four major hurtles IMHO in order of importance
with this project.

1. Getting a RELIABLE 1000 hp from a 4 rotor,

2. Finding the space in the aircraft for heat exchangers to keep all of
those ponies cool.

3. Designing a turbo-compound unit to catch the extra 100+ hp energy.

4. Development of, or finding a PSRU to handled the power at the prop rpm
you want it at.

If the desired max hp was 680Hp then we know it can be done and there is
data that the four rotor engine can endure  75% to 85% cruise settings
for at least 24 hours with close to zero wear.  That is not the same as
saying it will endure it for three or even two thousand hours of
intermediate use. There is a shop here in Japan that makes up an unique
e-shaft with the outer rotors sleeved-on that could make this engine.
Other shops in other countries could do this as well.

If you want to fly an aircraft using  only hydrogen for more than one
hour, then that hydrogen had better be in a balloon supporting the
craft:)  If on the other hand you plan to use H2  in the I.C.E. as an 1%
additive to increase fuel burn efficiency, then I suggest  Hydroxl gas.
H-O-H-O. Mono atomic hydrogen and oxygen. It is much more effective,
lighter, and safer to make on board than any other water to hydrogen
electrolizer or alkaloid and water to hydrogen-on-demand system.

Boosting the four rotor Lemans style I.C.E. with the high comp. (10:1)
rotors is tricky and requires an accurate fuel map and  boost control to
prevent detonation.  With lower comp. rotors boosting to make 1000+hp is
of course easier and again has been done by many people in the racing
world.  That is near similar to saying a half size 13B can be boosted to
make 500 hp.  Also done and then some.  However.... these engines are
used in race cars that routinely travel less distance than the CA11's
proposed take-off roll:)

To expect  680 Hp or perhaps a 780Hp with a small boost may  warrant the
choice of a smaller  aircraft like the Lanceair or acceptance of  poorer
time to climb performance with the CA-11. Boosted at altitude to recover
full sea level performance is where the turbo-compound rotary really
starts to shine. Greg, what is your average flight mission?  Three to
four hour business trips with six passengers? pleasure jaunts with the
family?  Knowing these facts  and understanding the amount of $$$ and
time that will be required to develop the numerous system  may influence
your decision. The bird you picked is real  beauty though.

IMHO 1000 hp. figures put us into the realm of at least six rotors and
even Mistral, I am sure, will scream foul and that I am being too
optimistic.  If those rotors are all in row, then the engine gets very
long and turbine-like but coolant flows and engine twist become
speculative.  I have heard a six rotor was made before over in Japan but
I have never seen it.  Consider it vapor ware. Since I am speaking of
vapor ware here is another concept that has been kicked around before.
Again it is in the realm of  'should work OK' consensus reality.

Here goes:  Say we have two 20B P-ported engines both oriented plugs up,
and the starboard engine is assembled backwards. Both are  joined to a
section that contains a very simple spur geared psru. with the  prop
shaft on journal bearings. The geared feeds could come from both ends to
the central shaft. If one rotor or even one engine goes south it is not
a big deal. rotors can be disabled and the engine continues to run.  The
PSRU is dirt is simple and the loads are balanced 90 degrees to the
central shaft  with power input torque pulses  turbine smooth.  The
exhaust is straight down and out to the turbines (plural) and then on to
the remaining turbo compound axial turbine  opposite the prop side of
the engine.  The axial turbine has its exhaust going where ever one
desires and this turbine connects to the rear of the prop shaft with a
hydraulic torque converter.  Most oil pathways can be contained within
the engine,  fuel lines are  on the cool upper side and rammed air
inlets to the turbochargers come in from the side scoops. The  engine
could be as narrow as 30 inches.

A prop governor can also be built into the central unit feeding the
hollow propshaft. This set-up then becomes a very compact high
performance reliable engine with many options as to where to drive the
accessories.  But this is only an idea.  I could draw a picture but it
would still remain only a concept, albeit one I would love to see made:)
Such is the fate of inventors and architects. We still have to find ways
to cool that puppy for those five minutes at take-off power, and twenty
minutes at cruise climb settings.  That implies finding somewhere to
put 3,000 cubic inches of  heat exchangers.  At 2 inches thick and 15
inches wide that would imply two units 50 inches long each.  TOO LONG.
If four inch thick in the dual pass style, that would be 15 by  25
inches long. Possible.  Don't forget the area needed for the inlet and
exit ducts. Perhaps the oil coolers could fit in the nose cheeks and the
water coolers at 5 and 7 o'clock along side the engine thereby saving
space by exiting straight out the sides.  Concerning Jim's stated 0.6
SFC,  he most likely was using fuel to cool the engine.

In closing I would say it is hard to beat a turbo prop climb to altitude
performance, and its weight,  and size to hp merits.  Yes fuel burn is
less than stellar.  The attraction is reliability and for people in a
hurry, in which saving 15 minutes on a three hour flight is a big
desire.  If $$$$ are driving your attraction for having a 1000 hp engine
then I  would venture to say you could buy two  turbo prop engines for
the money it would be required to develop the various rotary systems at
your horsepower desires.

However if you have the burning desire and $$$ to develop an unique
engine that will absolutely smash any BSFC records, count me in as a
technical supporter.  Many of the challenges you will face are similar
to ones  people on this forum have solved in the past ten years.

Doug in Japan

Paul and Doug:

I might be loosing the bubble here.  I think my original question has
been answered regarding the possibility of a 4 rotor engine as a
potential replacement for a Garrett turboprop, but with lots of
qualifiers and technical tangents. The answer seems to be a clear
and unqualified "maybe".    This is all new ground for me being a
newcomer to the Wankel engine world, but familiar ground for conceptual
discussions on mechanical theory and aircraft.

A couple of points should be clarified.  My mission targets are flying 4
man crews, on average, 200-600 miles on a time sensitive schedule (and I
mean right now).  A Pilatus PC-12 is overkill, and a TBM850 cabin is too
tight.  They are both P&W, both around 280-300 kts, and both good
aircraft but don't match (on paper) the future CA11.  By the way, the
attached picture that was in the last e-mail was of the CA12, a larger,
direct future competitor of the PC-12.  I've attached the picture of its
little brother, the CA11.

I could just go with the CA11 turboprop "as is" when finally available,
but we all know that's no fun.   I, like the rest of you, feel that
there's a better engine out there, even if we have to build it ourselves.

So, we are discussing good potential in a radial engine (turbo-compound,
Hydroxyl additive, twin engine, might even add the theory of engine
coolant flowing thru the wings as a heat sink), but Doug, your last
comment really hit home when you said that I could buy a couple of
turbines for the $$$ is will cost to develop this unique brute.   So, I
think we're getting close to the $1 million ballpark for starters.  Just
not worth it.  Not a good investment on my part

However, smashing the BSFC record with any size engine would be of
interest.  But, with the exception of huge marine diesels, the
automotive turbo-diesels come in at about the best fuel economy I've
seen.  The Volkswagen 3.3 V8 TDI is 0.337 SFC, the Audi 2.5 diesel is
0.326, even better is the Volvo 290 hp truck diesel at a stunning 0.309
SFC.  Of course, they're all too heavy (power to weight) to be
considered for aircraft so I don't know what the best numbers are for
aviation engines to start this challenge.  Is it possible to build a
_*reliable*_ 2-3 rotor Renesis II and pump it up to, say, 500 hp with
everything we've diiscussed?  Would the BSFC ever come down to 0.30?
Even with Hydroxyl additive and turbo-compounding?  This would be a more
obtainable goal and Mistral might not cry foul.  There might also be a
(small) market for a 500 hp engine for cost sharing the development.
That pencils as a much better investment.  And, who knows what might
follow from there.

Greg

Look at all our youtube vidios. Key word UTUBPLEASE.  The leader in diesel right now is the Detroit Diesel turbo compound DD15.

Also diesels lose a lot of the advantage when running in the higher percentage
HP range typical of aircraft engines. See the attached chart.

Paul Lamar