Sandnat

Hey Guys, thanks for the thoughts and stories. The day I flexed the wing on mine or around that time frame I was playing the high speed dive zoom pass game pretty hard. Buzzed a flight control in the dive and fortunately nothing fell off. I had heard they would do that and chopped the throttle in time even though I buzzed it twice before it dawned on me what I was hearing . I think it was an aileron, Bunch of slack in the aileron torque hole.

Dgrant mentioned the tail flutter. I am not real happy with what I am seeing om my build at the elevator deck . Looked to me the die cut main side skins tail deck has a lot of stabilizer built in nose down , which I copied as accurately as I could, based off the assumption the main horizontal fuselage jig is the zero reference. The top spine runs out almost to the end of the stab deck also and when seated properly down the entire fuselage, wound up about an eighth of an inch below the stabilizer mount in my kit copy. I will see if I can figure out what is going on there by getting down my old fuselage and taking a look

Did a search on the subject flutter and twist and this post by Littlera popped up:


Aileron flutter can progress to flutter of the wing, depending on the stiffness (mostly torsional) of the wing and control surfaces and mechanical interplay between the wing and offending aileron. It can actually happen the other way around, with the wing driving flutter of the control surface.

This kind of interplay is what is suspected to have caused the wing to fail in the Gee Bee crash from the early 1930's that was captured on film and has probably been seen by most of us. Keep in mind, however, that a WING can actually flutter independently of the control surface. It is rare, but can and does happen occasionally. I have had it happen wilth glider wings with high aspect ratios and relatively inadequate torsional stiffness. You can make a yard stick (wooden only) do this by whipping it like a sword in your hand. Try it! You will also hear the sound of flutter, which of course has come to be known as the death rattle of any airplane that is experiencing it.

Any wing or aileron (or other control surface for that matter) can flutter under the right conditions. Mass balance and proper stiffness are employed on full size aircraft and by modelers if they are smart. The stiffness and balance serve to keep the flutter "envelope" outside of the operational envelope (mostly speed, but load and other factors to a smaller extent) of the airplane.

Keep in mind that on a typical light aircraft the control systems are "free floating." They are tied to movable controls. Our models controls are tied to servos that are not easily moved by aerodynamic inputs from the control surfaces. When connected by properly stiff control rods and cables, this arrangement tends to prevent (damp) the onset of flutter in MOST (NOT ALL) cases. This is why we typically get by with improperly hinged, improperly balanced, and improperly aligned control surfaces without disaster.



Soo....Where it stands now I have cut the notches in the ribs for the 1/4 square bottom spar. Got to thinking after reading the above and Yall's comments. Laid thee sticks across the top of the wing and thought....Why not three small spars across the top? Will cut down the scalloping on the top of the nose of the wing and add a bunch of torsional strength. Will be easy to do and won't add a lot of weight. Nothing is glued yet.