I had a response that got lost in the ether .... probably forgot to hit POST .. I think I fell asleep ....
.... anyway the basic point was that we talk about tail volume coefficient (TVC) at length as a measure of how well the plane will damp after a corner. Its a good figure of merit, although not totally the answer to damping. But, remembering that the tail volume coefficient wasn't something that someone set out to derive. TVC is just a collection of terms that just happen to be floating around in the equations of motion. We group together these terms Sh /Sw * Lt / c into TVC. But .... the eom's have something else for the moment terms. There is another Lt / c present. So we really should be using TVC * Lt/c for the comparison for stunt ships one to another The Lt/c term is squared, which makes the Lt very significant.
The fly in the ointment is that as the tail length increases, the induced incidence angle on the stab/elev as it swings through the turn kills its purpose in the first place. That's with a standard 50/50 stab elevator. We need an all flying tail to overcome this effect. It is notable that the Berringer designs have elevator flippers. The long tailed Eratix and Giles converted 3D RC's that we used have flippers. The problem with all flying tails or flippers though, is that you potentially have trouble flying level.
The initial feeling with a long tailer, is that you cant believe how well the corner is damped. But then .... gee I'd like a little tighter turn, and you can't seem to get it. You need flippers that become active at a higher deflection but are invisible around neutral.
Topic: Berringer Sportster? (Read 2056 times)
