Yep. The more wing span and less wing chord you got, the more you will need to reinforce and strengthen it, especially for high speed stuff. That's part of why I brought up the slender delta thing: tons of chord and not much span makes for a strong wing.
My experience from flying the FT racer was that the wing root is not super strong, as would be expected from a foam spar. Mine failed spectacularly during a high speed pass causing a big cloud of foam and much hilarity on the flying field.
Recommendations: Strengthen or replace spar with something stronger than foam and if possible have dual throws setup for regular and high speed flight envelopes.
