David Doshay wrote:

Major breakthrough in low cost 300 HP psru's for the 20B three rotor.
Turns out Ford came out with a beef up of the A4OD heavy duty
automatic transmission used in the larger F350 heavy duty pickup trucks
starting about 1999. Tracy uses this in his 300 HP rated
redrive for the three rotor 20B. This is the unit he is testing in his
RV4 as we speak. He reports even smoother operation over the old
four pinion version. This carrier looks like it is cast from
nodular iron while the four pinion was made from aluminum.

What is the ratio?

Thanks,
David

It is the same as the four pinion with the same configuration. Namely
2.17:1. If power is taken from the planet carrier and the ring gear
is fixed to the housing the ratio then becomes 2.85:1. This is done
by drilling six holes through the pinion shafts and bolting the planet 
carrier to a flange attached to the prop shaft. That of course allows the
engine to rev up more and generate 10 to 15% more power for those that just
joined the news letter.

Paul Lamar
 
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