The A-90 Orlyonok was designed to operate in ground effect (altitude significantly lower than its wingspan). If I understand correctly, when in ground effect, the L/D ratio is better due to induced drag being lower. Thus, I imagine the L/D ratio of the A-90 is high when cruising near at low altitude, but I failed to find any figure *. Moreover, according to Wikipedia, this aircraft have a ceiling of 3000m (not really in ground effect).

I'm interested in the performance differences between flying at ground effect altitude and at almost 10000ft AGL.

What were the L/D ratio of the A-90 Orlyonok at its different operating altitudes (when in ground effect, at its ceiling, and at any other altitude it would spend time flying at)?

* I only find a paper that states GEV in general have a L/D ratio of 23 without saying if it applies to the A-90 nor at what altitude this L/D ratio is found

  • $\begingroup$ As I read it, the 23:1 L/D value is for the Lippisch X-112. Of course there cannot be just one value, especially without giving a height at which this value applies. $\endgroup$ Commented Sep 18, 2020 at 3:21


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