I do have concerns about buying the Chrysalis because of the need it has for washout.

I have read comments on the need to have just the right amount in order to turn tightly. I would like to know just what washout has to do with turning radius. Is it just the fact that most people try to fly to slowly to turn tightly without washout preventing tip stalls?

From : Don Stackhouse

First of all, the Chrysalis does not need washout for turning any more than any other plane does. Secondly, and contrary to popular opinion, washout does NOT significantly help turning radius or tip-stalling tendencies in turns.

The Chrysalis does have a type of wing structure that allows you to readjust washout by re-shrinking the covering, and we've found that the airplane's basic stability can be increased a bit (although it's already extremely stable to begin with) by adding extra washout, at the expense of a small amount of high-speed performance (in other words, launch height and penetration). We explain this in the instructions as an option for a beginner who happens to want even more stability. There are also other stability-related options included, such as two different sizes of conventional tails.

As far as turning radius and washout are concerned, the basic problem in extremely tight turns cannot be fixed by washout. The inside wingtip in such a turn is flying slower than the outside wingtip, with an airspeed difference in some cases of 2:1 or more. This means that the inside wingtip could be asked to develop more than four times the lift coefficient of the outside wing tip (which could be even more than the lift coefficient at the wing root), with only half the Reynolds number! If it doesn't succeed in this, the lift developed by the two wings will not be equal, and the airplane will therefore not be able to hold a constant bank angle. The only way to properly fix this efficiently is through clever tailoring of the airfoils and chords along the span, which I did in the design of the wing of the Chrysalis. It was a huge amount of engineering work to get it right, with non-linear tailoring and blending of airfoils all along the span, but the results made it well worth the effort.

If you tried to fix this problem with washout, you would simply force the plane to yaw more or use more aileron in a turn to make enough lift on the inside wing panel to hold the bank angle constant, and the inside wingtip would still stall at the same angle of attack. The only way to significantly help the point of tip-stall would be to use so much washout that the tips would both stop producing much lift, forcing the center section to do all the work of supporting the plane. This would be extremely inefficient, resulting in a 1.5 meter model with the performance of a 1.0 meter model! In all probability, such a plane would turn even worse than one that didn't use excessive washout. It would also have very bad level flight high-speed performance since the tips would almost certainly be lifting downwards! The proper fix is to determine what's expected aerodynamically at each location along the span during a turn, and design the local airfoils and chords to deal with these requirements naturally (as we did in the design of the Chrysalis), without resorting to major distortions in the lift distribution from the use of excessive washout.

Don Stackhouse
DJ Aerotech