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>
<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:
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>>
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>>
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
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