X-Mozilla-Keys:                                                                                 
F. Marc de Piolenc wrote:

Paul wrote:

The bathroom scale reads out half the torque.
You must multiply the bathroom scale reading
by two to get tha actual

Oops. That's not true. The force on the scale times the radius of the
arm from the center of the crankshaft IS the torque. To prove this to
yourself, draw the arm as a free body, ignoring its own weight. You have
a torque at the crankshaft end, reacted by a force at the scale. An
equal and opposite force at the crankshaft is needed to balance that
force at the scale. But only the force at the scale reacts against the
torque at the crank, hence torque is scale reading times moment arm -
there is no factor of two.

Marc de Piolenc
Mass Flow

Check the drawing on the ACRE NL web site below Marc. 
The moment arm is two feet long.
 
Paul Lamar
 
The Aircraft Rotary Engine Newsletter.              Powered by Linux.

http://home.earthlink.net/~rotaryeng/            http://www.linux.org