I just did a 3D on the GT40. The turbine scroll is somewhat larger
than the TO4 but it will fit. Making a exhaust manifold out of bends may
be out of the question as there appears to be no room for bends.
Bends have a center line radius of about  3 inches.
I have a few other turbine orientations to try so I am not sure yet.

This GT40 2 rotor configuration has a lot of potential. Perhaps
as much as 600 HP for 15 minutes with anti detonation fluid
(mostly alcohol :)). Long enough for a Reno race if we can
find a gear box that will hold up. Water dribble enhanced
cooling system.

I am currently researching the GM Power Glide. After market
TX people claim 1600 HP for drag racing with straight cut gears.

http://www.importperformancetrans.com/gmpowerglide.shtml

Stage III - Up to 1600 HP


     * Straight Cut Gear Planetary with Vasco 300 Gears with A536-80
Ductile Iron Carrier
     * 4140 Steel Ring Gear - 1.80 Ratio

The 1.8 ratio translates to 2.8:1 with the power taken out of
the planet carrier.

Paul Lamar ...No rotor no motor.

My engineering foreman is currently machining the housing of a planetary
drive in which I fitted the Powerglide 1.82:1 gearset. It would be
interesting to see if your ideas and mine correspond.

Erik Snyman
Messina
South Africa.

Great Erik!!!!!
I would love to see some pictures and drawings Erik.  You are now our
lead man on this project. Here are a bunch of ideas you are free to choose
if you so desire. The off road moto shock absorbing rear hub is from
a dirt bike rear wheel. Standard around the world.

Also some more sources for GM Power Glide HD parts.
http://www.mikestransmission.com/catalog4.html

MT 7423 PG 1.96  9310 gears/4340 shaft/ forged ring
gear.$1450.00..$1295.00

The 1.96 translates to 2.96:1 so the Mazda take off RPM can be increased
to 8000 RPM for more HP while the prop still turns at 2700 RPM.

The Power Glide solution is looking better and better.

------------------------------------------------------------

Forget the power glide. A friend tells me it won't work for a 2.8-2.9:1.
He is right.
I assumed it was a simple planetary. It is not. I was wrong. It is a
compound planetary. Therefore it won't work for us.

I am amazed they can put 1600 HP through it however.

--
Paul Lamar ...No rotor no motor.

The one I am busy with now is for flat 4 engines in lower power classes,
captured ring gear. However, having done the work up to now and having
disassembelled and reassembelled the gearset several times, I will not be
so fast as to say it will not work for the rotary. Driving off the ring
gear is possible with some mods, we will have to see if it holds up in the
200+ hp. class, though.

The mere fact that you stated it will not work, has decided me to try one
for our engines. I have 7 gearsets available, of which one is a 1.71:1
ratio, so I can try a lot of things.

Watch this space for bragging rights!!! :>)

Erik.

This a rotary engine newsletter. We need a roughly 2.8:1 or better PSRU.
1.7:1 will not work with a Mazda rotary in an airplane!

If you have a piston engine and you use a 1.7:1 gear box the max practical
RPM of the engine will be around 4600 RPM. This is because props like 2700
RPM and six feet in diameter or larger. As you shorten the prop and run it at higher RPM the efficiency is reduced and the net thrust you get out of the
prop is also reduced. Airplanes fly on HP. HP is thrust times speed.
This will severely reduce the net HP as most piston engines today generate peak HP at 5500 RPM or above and that includes the Subaru.

It is common for people advocating the Subaru to claim the advertised HP
while installing a gear ratio and prop that could not possibly allow
the max HP RPM.


http://www.rv-9.com/egg.html

"For the past ten plus years, Jan Eggenfellner has been trying to adapt
the Subaru car engine to aircraft use, with varying amounts of success.
The 2.5 liter four cylinder was his first offering. Hundreds were sold,
but with only a handful flying, it was discovered that it was only
producing about 110 horsepower at the prop.  The gear reduction ratio
was apparently too low (1.82) to produce advertised horsepower,
and the gearbox was suffering bearing failures."

BTW Standing next to a piston engine that is generating max HP at its
rated RPM is a frightening experience. You get the impression you
are next to an animated hand grenade getting ready to explode at
any second :) Running the engine with out load at high RPM does
not count. It is not the same thing. Stand next to an engine in
a dyno room sometime.

If you do what I say is not possible try a rotary as it cannot
possibly work either :)
-- 
Paul Lamar ...No rotor no motor.

Erik,
I must agree with Paul on this subject unless you want to run with lower
power, which seems a waste considering the engine HP potential.

Early PSRU's by Tracy were 2.72 [2.17] ( I think) which, although were sufficient,
didn't  generate the HP required by some. Tracy eventually went to 2.82:
Gearsets and hasn't looked back. Early 2.72 [2.17] did however run the engine at
lower RPM's. The RPM of least stress on the engine is 5,800 RPM, so this is
good for cruise. If your running the engine lower than this for cruise it is
unnecessary stress on the engine over a much longer period, than running it
higher periodically for take-off and climb.

You can run the drive off the ring gear but it's running in the opposite
direction to what your normally accustomed. Usual prop differences etc.
Don't get me wrong I like straight cut gears as it eliminates thrust within
the planetary and the gear sets look really well made.

I hope you make it work for your needs, I (for one) am keen to see the
outcomes.
George (down under)

The stresses on the rotor bearings of the 13B are lowest at 6000 RPM.
That is where the compression pressure balances the centrifugal load.
The same number for a piston engine is around 3600 RPM.