Pulling/pushing aircraft by the prop

[mad_jock]

the centrifugal forces at the root of a 10kg blade at 2700 rpm may be in the region of 50 tons whereas the total thrust from the propeller is only likely to be in the region of a few hundred lbs. The resulting vector will therefore be within a fraction of a degree of the axis of the propeller blade.

Might be a bit more than a few hundred but will still keep keep the vector well inside the blade geometry. Where as the further out you go it quite quickly gets non-linear if its not rotating.

Also as well the whole blade is in tension while rotating and all bending moments will do is reduce one side of it. A static pull will cause compression on some bits.

If the prop is a single unit type ie its bolted on the front and both blades are a single unit it is extremely unlikely your going to do anything to the prop. Fibre props are a different kettle of fish because they arn't very strong in compression and you don't know if the matrix has been crushed with the bending moment.

Some of the bigger props which I call knife props but thats not the proper namr for them have all sorts of handling instructions on them for supporting them off aircraft and also not to use prop stands what ever they are.

[tdbristol]

Rear edge of composite props can be fragile

The rear edges on the composite prop on my aircraft are very fine and taper down to maybe 3 mm thick (just about this thin all along the rear edge, even towards the prop root).
I have personally seen these rear edges damaged when pulling on the prop, by a rampie with rings on his fingers, where the rings rolled over the rear edge when pulling - chipped the rear edge in a few places, requiring repair.
Pushing at the root seems ok [where you are pushing on the wide front edge], but having seen this myself I would never pull on a composite prop (and to save misunderstanding I insist that rampies never push or pull on my prop).

[Crash one]

I would go with MJ on this. The helicopter analogy is a bit extreme but is perfectly relevant. When the prop is rotating, by & large it is generating an even load on both sides of the disc.
Pulling/pushing on one side static is a completely different can of worms, even for a skinny girl.
Who was it said "Give me a lever long enough & a place to stand & I will move the world"?
I, at 75kg, can easily lift one side of a two ton machine tool with a 6ft crowbar. Does that mean I can apply 1/2 ton side load to a prop hub with a blade length of 3ft?
Stay in the middle no problem.