Vmc in ground effect
I would like to hear what you think about how ground effect changes Vmc. The fact that FAR 23.149 specifies that the aircraft has to be out of ground effect might indicate that is has some effect on Vmc.
I was taught that in ground effect the reduction in induced drag has the same effect as increasing thrust, thus highering Vmc. However this never made too much sense to me, and for this reason I am not teaching this to my students (I just tell them that the effect on Vmc, if any, is trivial).
What I am having a hard time understanding is how a reduction in induced drag in ground effect would affect the airplane in an asymmetrical way. In other words, if the reduction in induced drag is the same on both wings, the asymmetrical thrust would not change (and therefore Vmc would not change). A fellow instructor was speculating that the wing on which the operating enginine is mounted would be producing more lift due to the induced lift by the propwash (therefore producing more induced drag, and thus experiencing a larger drag reduction than the oher wing). However this does not make sense to me. If one wing was producing more lift than the other, we would have a constantly accelerating roll towards the dead engine. Since the wings are level (or at least not rolling), there MUST be a roll-wise balance of forces. Therefore each wing is producing the same amount of lift overall.
The only thing I can think of, it that maybe the distribution of lift on each wing might be different and this might somehow lead to asymmetrical reduction of induced drag. But this is just pure speculation.
So can anyone clear up all the confusion that is going on in my crazy mind?
I am wrong in assuming the effect on Vmc, if any, is almost trivial?
Thanks for your input.
palgia