Home> Continental & Lycoming TroubleShoot
Cracked crankshaft at alternator gear drive flange on Continental Aircraft
Engine
1. Sudden stoppage.
A 100 amp gear driven alternator on the Continental aircraft engine operates
at a 3:1 gear ratio. At 100 rpm the alternator contains 600 ft-lbs of kinetic
energy. The impulse this energy places on the crankshaft depends upon how
fast the energy is dissipated. A sudden stoppage where the propeller blades
stop in 90 crank degrees at 1000 rpm requires that this 600 ft-lbs be dissipated
in .015 second. This requires a tangent force on the rotor of 874 pounds.
The gear drive flange on the crankshaft will crack even from this so- called
"minor prop strike".
| 