Stu,

Stuart & Kathryn Fields wrote:
I'll try one: What are the sources of 2/rev vibration in a two bladed helo?
I know that I don't have any significant 2/rev in hover, but do in forward
flite.


A WAG says that its the due to the blades being
aligned with the airframe twice per revolution (at
0 and 180 degrees). As each advancing blade comes
out of that alignment and hits the airstream I'll
bet it gets a small quiver which you feel as 2/rev
vibration. That would explain why you don't see
it in hover, but do in forward flight.

Right??

Don W.