holy smokes YouTube landing

Master Bumper

You are indeed correct. The Akavlieg Braunschweig tried this with the quite
radical SB13 prototype. This Standard-Class glider first flew in 1988. Lots of
details in Dr Fred Thomas' "Fundamentals of Sailplane Design.
15m wingspan, 15 degree sweep, elevons and winglets doubling as vertical
stabilisers. Differential deflection of rudders on the winglets to counter yaw.

It proved to have similar performance to contemporary standard class
gliders.Some advantage in efficiency being generally lost to handling induced
inefficiency. So - There was no compelling efficiency advantage. Conversely
there were substantial operational and controllability issues and high pilot
work load. etc...

For example; It proved impossible to winch launch safely. Apparently
Braunschweig has used the SB13 in contests, and also allows experienced akavlieg
pilots to fly it. There are quotes like "it exhibits very poor flying and
handling qualities in turbulent conditions." It is the subject of at least one
thesis on aeroelastic properties.

Details at:

http://www.akaflieg-braunschweig.de/prototypen/sb13/

And here -

http://www.sailplanedirectory.com/braunsch.htm#SB-13

The Genesis is a more modern design, and presumably learned from the
difficulties they had with the SB13 - which was after all a prototype designed
to investigate innovation, rather than a commercial endeavor.

There have been others with a similar idea, in fact the SB13 was not the first I
know of at improving on the Horten - the BKB1 has that honour. Although the
information is unsubstantiated - there is some info here
http://www.astercity.net/~krisabc/BK...hocki3-en.html

Maybe Jim Marske will develop a giant killer from this concept - but I
personally can't see it happening. It is a fascinating concept -and so we keep
trying to minimise the tail boom (cf Diana 2) But it remains the best way to do
things. Consider - Even Burt Rutan eventually went back to the conventional
layout with the Global Flyer (http://www.scaled.com/projects/globalflyer.html) -
it is not conventional for nothing - it represents the best compromise.

My 2 (South African ) cents worth - not that that means much at ZAR 7 / USD but
there you have it.

bumper wrote:
"Bill Daniels" bildan@comcast-dot-net wrote in message
. ..
Of course, an existing Genesis won't fly without the tail. But the
Genesis CONCEPT could have as evidenced by Jim Marske's designs.

Bill Daniels


Would the resulting aircraft perform better than the much more numerous and
seemingly more successful "standard" planform?

While I admire experimenting and innovation, I wonder why, if the flying
wing concept were so good, at least as applied to gliders, hasn't it been
embraced by major manufacturers? They seem willing to go to great lengths to
eek out as much performance as they can. Could it be that the tweaks needed
to impart longitudinal stability, like reflexed trailing edges, are not
efficient enough over a broad enough speed range?

bumper
Minden, NV

It proved to have similar performance to contemporary standard class
gliders.Some advantage in efficiency being generally lost to handling
induced inefficiency. So - There was no compelling efficiency
advantage.

It should be noted that most all hang gliders are flying wings. The
reason for this has more to do with portability than with performance.
The handling quality of many hang gliders since, say the early '80, are
quite pleasant - remember, this is weight shift contol.

Tony V