Drum dia and torque

On Sat, 20 Nov 2004 22:05:06 -0600, "Bob Johnson"
wrote:

Hi Bill --

Today we towed in light wind and so turned 2300 engine RPM in the climb. The
454 c.i. torque/hp curves show the engine was generating about 430 lb-ft
torque and 200 hp at these revs.

Now here is where I tend to go off the rails. Just 75 hp is required to lift
a 1100 lb sailplane 1700 ft in 45 sec.

I know there are some aerodynamic and mechanical losses but it's hard to
believe they amount to some 125 hp.

"The 454 c.i. torque/hp curves show the engine was generating about
430 lb-ft torque and 200 hp at these revs." ... your fallacy is that
"was generating" should read "was capable of generating". The engine
could have been running 2300 with no load (as it was right after the
hook was released)