Originally Posted by xlcrlee

Sure. And that adds more drag in a turn.

No, the use of the flap changes the distribution of the circulation and that adds not more or less drag than the same movement of birds. The only difference is the distribution of the proportion of the induced drag and the profile drag.
Birds use much less change of profile drag for control than human airplanes.

I still don´t know what you will tell us
Control with the the induced drag?

Stabilization without the side surfaces at low measure of stability is not a problem with sweep, not much more is needed.
The problems start with the control.
Control only with induced drag is possible.
Prof. Karl Nickel flew with a ULA (no Horten, elliptical lift distribution) without side surfaces only controlled by changing the induced drag with soft, twistable elevons in 1980´s.

If the idea is a twistable wing or something similar, the following links will perhaps be interesting for you

http://das-nurfluegelteam.de/flex_flue.html

http://www.stephanb.rchomepage.com/d...y.html#anker2b (look for "Twisteuse")

Regards,

Uwe.

Originally Posted by Tail Saw

I still don´t know what you will tell us
Control with the induced drag?

Uwe.

yes

and also stabilize

and save energy by automatically flying into lift and avoiding sink [unless pilot-overridden]

the "strange" example of the green-air seeking, sink-avoiding gliding/soaring "Acrobird" [not its toy ftn. of looping, etc.] shows me that this is clearly possible .... by dealing with the spanwise flow and resulting tip-vortices in a similar way, or at least to get the same or similar result.

I don't know what part was pure accident, what part conscious cleverness and what part subconscious, but I do know that I was quite surpürised when I discovered or observed this, and also that there were several differently pointing or aligned cone-like camber-twists involved. And of course, because of the low Rn's involved, the twists were far more exaggerated and easier to see than at model and fullsize.

It IS possible, and as noted in the start of this thread, some top aerodynamicists think that I might have stumbled onto something important.

I have already used this info in some toys, and made this thread only as a kind of "heads-up" for any other boy-scientists out there who like to wing it ....


Lee