John, Flutter is initiated by resonance, not by force. The resonance frequency of vibration causes amplitude to increase to infinity causing structural failure. Manner of excitation, stiffness, dampning/energy absorption are all factors. I can no longer do the math, but this us why balancing controls and respecting VNE are so important.
On Sat, Jun 4, 2022, 6:37 PM John Gotschall via KRnet <krnet@list.krnet.org> wrote: > thanks. > > I have observed structures in flight. > > I have flown several rc airplanes beyond vne and witnessed the crafts > begin control surface flutter and the event continues through to > destruction of horizontal stabs for elevator flutter and wing destruction > from aileron flutter. > > I have built replacement rc aircraft and modified the control surfaces > with weights forward of the hinge location to eliminate flutter, but I have > never targeted neutral balance. instead I target balance to exist forward > of the hinge. > > like an arrow in flight I want a rigid structure that is "nose heavy" for > stability. > > I have not found the engineering analysis that can quantify the forces > allowing for prediction of flutter events. > > jg > > > > > On Sat, Jun 4, 2022, 2:58 PM David Maultsby <dmault...@win.net> wrote: > >> John, >> >> >> >> I believe doing a quick “Google” search for “Flutter Analysis” will lead >> you to a much fuller understanding of calculating your correct control >> balances. If you still have questions, please send me your specific >> requirements and I will attempt to work through them for you. My basic >> understanding is to balance each control surface with the same weight ahead >> of it’s hinge point as behind it. As evidenced by the loss of a P-51 at >> Reno, higher speeds may even require balancing trim tabs. >> >> >> >> Sent from Mail <https://go.microsoft.com/fwlink/?LinkId=550986> for >> Windows >> >> >> >> *From: *Ted Sanders via KRnet <krnet@list.krnet.org> >> *Sent: *Wednesday, May 25, 2022 10:34 AM >> *To: *krnet@list.krnet.org >> *Cc: *Ted Sanders <tedsande...@gmail.com> >> *Subject: *KRnet> Flight Corvair for sale >> >> >> >> I have a flight corvair available for sale. If anyone is interested I >> can provide details of the rebuild and photos. It is located in Chino >> California >> >> >> >> >> >> On Mon, May 16, 2022 at 6:33 PM John Gotschall via KRnet < >> krnet@list.krnet.org> wrote: >> >> Can anyone recommend a good book or source for info on how to calculate >> the correct control balances for a variety of wing/horizontal stab types? >> >> >> >> jg >> >> >> >> -- >> KRnet mailing list >> KRnet@list.krnet.org >> https://list.krnet.org/mailman/listinfo/krnet >> >> >> -- >> KRnet mailing list >> KRnet@list.krnet.org >> https://list.krnet.org/mailman/listinfo/krnet >> > -- > KRnet mailing list > KRnet@list.krnet.org > https://list.krnet.org/mailman/listinfo/krnet >
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