Image from www.iconaircraft.com

I've been looking at the website for the Icon A5 amphibian LSA and noticed the wing section clearly has two different cross sections, presumably to facilitate the stall and spin resistance of the aircraft. One of the videos on the site shows the wing as it stalls and the tell-tales attached to the wing clearly show the flow separation for the inboard section of the wing while the outer section still indicates attached flow. I would guess that this wing must have either some performance trade offs or else it's a significant cost, otherwise why wouldn't most GA aircraft have this feature? Perhaps fabrication in sheet metal would be difficult as I believe this aircraft is mostly composite construction.


1 Answer 1


Though performance details of the aircraft are not available, there seems to be a significant weight penalty associated with making the aircraft spin resistant.

It appears that the aircraft had to get a specific exemption for increased MTOW (1680 lb as against 1430 allowed) due to the incorporation of spin resistant design. Note that the weight given by the manufacturer is 1510 lb, still more than allowed.

As required in the exemption, the aircraft had to be fitted with a ballistic recovery complete-aircraft parachute system, affecting the payload. The engine power is also limited to 135 hp. The range is also low (~300nm).

  • $\begingroup$ Not sure if the weight is due to the wing design, but I guess an overall aerodynamic penalty is incurred by wing twisting. $\endgroup$
    – yankeekilo
    Dec 9, 2015 at 12:47
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    $\begingroup$ Yeah I would tend to think the weight issue is more a result of the amphibious design rather than the wing. $\endgroup$
    – Joel M.
    Dec 9, 2015 at 15:25
  • $\begingroup$ Perhaps worth noting too that with two airfoils, by definition you cannot be using the most efficient airfoil - there's going to be at least some level of drag penalty $\endgroup$
    – Jon Story
    Dec 9, 2015 at 19:56
  • $\begingroup$ As of 2020-07, the Icon A5 Specifications page says Range: 427nm (45 min reserve). $\endgroup$ Jul 22, 2020 at 6:32

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