Agree with Barannfin, there MUST be ground effect near touchdown.
The Nr energy is being used to power the last part of the touchdown, thus the rotor is producing downwash. Downwash and lift are affected by close proximity to the ground, or else the HIGE and HOGE specs would be meaningless.
I don't see that it should make any difference if either the stored energy in the rotor or an engine is providing the power for the downwash and lift, when the collective is pulled up right before touchdown.
I think though that prior to that last collective pitch up, ground effect would not be much of a factor, since air is flowing up and through the rotor to maintain RPM, thus no downwash is being created.
Last edited by Flight Safety; 28th October 2002 at 02:21.