The Bell 47 with a 900 series transmission is limited to 280 HP, 5 minute limit.
In the Soloy Conversion, it is torque limited to 65 psi of torque pressure. You don't use all the thermodynamic power of the engine until you go up to altitude.
At altitude it becomes temp limited (810 degrees C).
The C20B weighs 161 pounds without a starter generator.
The 300 weighs 176 pounds without a starter generator.
Max TOT on the 300 is 782 degrees C. Less temperature margin at altitude.
The C20B has better altitude performance, and is a lighter engine.
Last edited by rotormatic; 14th October 2012 at 17:02.