All the rear drive accomplishes is to dampen the engine pulses to the prop so 
that other than wood props can be used, and the theory is that that end of the 
engine is designed for the rotational stress.  No added torque or Hp is 
achieved with the direct drive model. Use of a PSRU on the rear end model 
multiplies the TORQUE output from the engine by whatever the reduction is, 
while Hp remains the same.  PSRU also allows for the use of alternative props 
and allows the engine to spin up onto the cam profile while allowing the prop 
to spins slower making both more efficient. The GP rear drive also makes for a 
slight thinner profile of the cowling for better aerodynamics, and allows for 
the use of "correct" rotation props that rotate counter clockwise looking at 
the front, clockwise to the pilot looking out. 

Colin & Beverly Rainey
Apex Lending, Inc.
crai...@apexlending.com
407-323-6960

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