High speed flutter.. I too have seen it in action, it's too fast to react to. The one I witnessed only took one second of elevater flutter before all the tail planes on one side had departed the aircraft. Only a short section of the left side horizontal stab spar remained. Everything on that side fluttered down to earth as small bits.
The flutter had the sound of a very loud machine gun. That convinced me, I simply won't fly anything without balanced flight control surfaces in the experimental category. I don't mind experimenting, but not with that. Cheers! jg On Sun, Apr 14, 2024, 14:24 Larry Flesner via KRnet <krnet@list.krnet.org> wrote: > > > > > I'm guessing that is more "general" than safe or correct. The plans > > for the KR2 calls for balanced ailerons with a 200 mph red line. I > > also had a friend get his legs beat up with rudder flutter in a 100 > > mph little bi-plane of some type. Just as Ralph Nader declared the > > Corvair "unsafe at any speed", so too can unbalanced control surfaces > > be unsafe at any speed, totally dependent on design. Several KR's > > have been flight tested beyond 200 mph, some by accident, without > > balanced control surfaces but is your KR identical in control surface > > size, shape, weight, distance from hinge point to T.E., and identical > > cable tension? I've watched model aircraft disintegrate in flight from > > control surface flutter and it took about 2 seconds. Without testing > > we can only hope the designer knew what he was doing and follow the > > plans. > > > > Larry Flesner > > > +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > > > Don't overlook the trim tab either. A loose or sloppy trim tab is > capable of flutter also. It was a loose or broken elevator trim tab on > the P51 at the air race that took several lives. I went with a servo > trim tab on the elevator of 211LF to eliminate the slop in a long > adjustment cable. If you can hold the elevator and wiggle the trim tab, > fix it. > > Larry Flesner > > -- > KRnet mailing list > KRnet@list.krnet.org > https://list.krnet.org/mailman/listinfo/krnet >
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