Shear Pins for Propellors?

Dave Stadt wrote:

"John T Lowry" wrote in message
k.net...

Sounds to me like an idea worth pursuing. Could have two shear pins,
with visually checkable integrity during preflight inspection, to
counter the problem of one failing.

John Lowry
Flight Physics



Now you have added two additional points of failure.


Just to play devil's advocate (1): I would think that the pins could
be designed to have a mean time between failures at least as long as
that of the engines themselves.

Just to play devil's advocate (2): Would failure of a shear pin
be qualitatively any different than any other engine failure?

Just to play devil's advocate (3): Logic would suggest that a
propellor shaft shear pin failure would most likely occur during
take-off, since that's when the engine is delivering the most power.
Just how much torque is the propellor applying to the shaft at this
time?

(Disclaimer: I really do understand everyone's concern about adding
potential failure points to the system.)

Rich Lemert

A 300-hp direct-drive engine is producing 583 lb-ft of torque at 2700
rpm.