Jim Logajan wrote:
Newps wrote:

How are stones going to defy the laws of physics? The plane is moving
forward. Rocks don't leap off the ground and jump into the prop.


I believe there is a low-pressure area in front of the prop which causes an
inflow of air from the area forward of the prop to compensate for the air
that is being directed aft. Combine that with the usual preferential
headwind takeoffs and it seems likely stuff on the ground can be wind blown
and/or sucked off the ground and into a prop.

There is a short video that you can see that shows a Cessna running its
engine up while parked in a puddle. The water is maybe an inch deep,
hard to tell. The prop will create a little tornado directly beneath
its lowest point. This is what causes prop damage. Get the plane
moving just slightly and this effect is lost. Any air being sucked in
from the front, and I don't believe there is, is not strong enough to
pick up rocks.