As well, if the covering will shrink and hold the new shape you could use a covering iron to warp in some washout. But many of the commercial ARF coverings won't shrink with heat and some even get more baggy. If that happens then you're back to Paul's answer.


PS: OK, there's one other bandaid that may help. Add a spanwise stripe of electrical tape slit to a narrow 1/8 inch width to the outer 1/3 of the wing on the upper side about 1/2 inch behind the leading edge. Build it up with a second layer over the first. Yes, it needs to be this narrow so don't cheat. This is a turbulator strip and it may help delay the tip stall to a lower airspeed.