Originally posted by CAP232CM
Not to start a war but how many wings have you seen break in the middle. It's a good idea to glass the center section for extra security but the wing will most likely break 6" to 8" out past the center section where most of the force is. Good Luck with that extra they are a great flying plane.
As a matter of fact, I have seen a wing joint failure in several ARF's. Sig has determined (at least this is what they told me) that wing failure in the SU31 ARF is due to wing sheeting being too soft and allowing flexing at or near the wing joint. The failure actually occurs at the inboard corner of the aileron on the wing. The flexing allows flutter to develope and from there it progresses until failure. The application of glass cloth at the wing joint has a dual function. Not only does it substantially strengthen the joint, it also hardens the wing sheeting past the joint to prevent or minimize flexing. I agree with your contention that the wing will probably break 6" to 8" past the joint. The glassing greatly minimizes this possibility.
Vince