An all aluminum 20B should be about 300 pounds. P-port with turbo should give an easy 600HP. To get a higher HP capability gear box I would use the Allison HT 640/HT 650 series planetary with approximately
3.5:1 ratio. This transmission was designed for use in 5 ton trucks and buses. These transmissions are readily available and so are spare parts. Probably a lot cheaper than the helicopter PSRU. The design would mimic the current Ross/Tracy box with dimensions changed to accommodate the Allison part dimensions. The weight should be close to the helicopter box and the length should be similar.

Dale Davies

The helicopter box is surprisingly light with magnesium castings at only 45 pounds..

The drawback is; it is $30,000.

Paul Lamar


Dale,
   Do you know which planetary of the Allison has the 3.5:1 ratio ?
Kelly Troyer



I am always blown away at the HP numbers on the rotary engines.
But out of curiosity,  how reliable would an engine like that be for "normal" use.

Barron

Not very. The TTC engine was only tested on the dyno for two minutes.
Since it was not equipped with thermal couples near the spark plugs
it may overheat in critical areas. There is very little else about it that
would not last at the 650 HP level and that includes the eccentric shaft, the
cast iron rotors and the ceramic apex seals. The Bell gear box is also
up to lasting

My improvement to the cooling system would be to bring the cool water
into the centre housings near the spark plugs and remove it from
the centre housing on the opposite side. The centre housing would
have a divider at it's centre to achieve this.

That way the cooling water would flow  fore and aft around the rotor
housings better equalizing the cooling effect on the front and rear rotors.

I would also lower the water pump to make sure the intake side of the
pump  always had a head of water on it. Some what like this 2009 3D and the P51.

The current scheme was a compromise to accommodate traditional car installations.
in other words; water in and out at the front of the engine and the shaft
of the water pump driving a radiator fan. Shaft drive fans are no longer used
in most passenger cars.

Paul Lamar

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