There is an impressive flight (figure-of-eight) with a human-powered aircraft shown here:

Given the long wings of the Aerocycle 3, can it be considered to fly in ground effect for the whole flight?

Nothing wrong with that - the Ecranoplans are fascinating creations - but how much more power will be needed to lift it out of the ground effect, should it be desired?

Also, this thing is just screaming to be fitted with an e-bike powertrain...


Ground effect plays a role when the aircraft is within one wingspan of the ground, so the aerocycle is getting the benefit of lowered induced drag. It looks to be flying about a quarter of a span above the ground, so using the graph that is about two thirds of normal induced drag. Flying out of ground effect would therefore require about 50% more power.

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  • $\begingroup$ But, am I wrong in thinking the primary reason for this reduction is due to the disruption of wingtip vortexes? If so, wouldn't the very narrow tip chord of this design already had much of this effect? $\endgroup$ Aug 27 '18 at 17:38
  • $\begingroup$ @MauryMarkowitz Wing tipped vertices aren't the cause of drag, they are simply a by product of lift. Drag is caused by the energy lost from pushing air downwards in order to keep the aircraft in flight. In ground effect the air pushed down quickly hits the ground and is deflected back up. Causing the airplane to generate more lift while having to move less air down. Thus less drag $\endgroup$
    – YAHsaves
    Aug 27 '18 at 17:51
  • $\begingroup$ @MauryMarkowitz The reduction in induced drag is disruption of the bound vortex, which is comprised of vortices along the whole span of the wing including the tips. The shape of the wingtip has only a minor effect on the tip vortex, which also persists in ground effect. $\endgroup$
    – Pilothead
    Aug 27 '18 at 17:59

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