PPRuNe Forums - View Single Post - Damage due to pulling/pushing on Propeller
Old 26th June 2012 | 21:51
  #32 (permalink)  
ChrisVJ
20 Anniversary
 
Joined: Jan 2003
Posts: 517
Likes: 37
From: Kelowna Wine Country
I have seen props used for pulling aircraft for years, though personally I wouldn't do it to a wobbly. Jemima has a composite ground adjustable prop however since she is a pusher and the prop isn't accessible for pulling or pushing I had not really thought about it for a long time.

I can see how a composite prop might be susceptible to damage even though designed to be robust enough for flight.

Jemima has an IVO 3 blade. Each blade is held by two bolts and goes about 3 inches into the hub behind the front plate. The prop is hollow too with a steel rod down it for adjustment., With the right hub it can be adjusted in flight by twisting along it's length by twisting the rod at the hub. (So the hub end is not just solid composite material.)

During flight there is a strong centripetal force which might mean that the prop is 'advancing' and applying force at the hub but not a leveraging force, (ie, it works like a helicopter blade.) When stopped and a load is applied to the prop the force at the hub would be all leverage and the point of the hub in contact with edge of the front plate could receive a load several times the actual load applied, say, 10 or 12 inches along the prop.

Not saying it could not take it. Just thinking out loud
ChrisVJ is offline  
Reply