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Flying wing rotates for supersonic flight

Posted: Tue Oct 16, 2012 1:42 pm
by MSimon

Posted: Tue Oct 16, 2012 3:28 pm
by DeltaV
Barf. On par with Oblique Wing.

Posted: Wed Oct 17, 2012 12:35 am
by rjaypeters
What's wrong with an oblique wing?

Posted: Wed Oct 17, 2012 5:20 pm
by DeltaV
rjaypeters wrote:What's wrong with an oblique wing?
http://en.wikipedia.org/wiki/Oblique_wing

Image

That's a question best answered by having you pilot the vehicle while encountering wake turbulence behind, say, a 747.

Image

I just prefer bilateral symmetry.

All this gives you over a conventional swing-wing is one less pivot.

Big deal. The flight control disadvantages are not worth it. The asymmetrical control problems in non-smooth air become worse with speed.

Posted: Wed Oct 17, 2012 5:29 pm
by GIThruster
DeltaV wrote:All this gives you over a conventional swing-wing is one less pivot. Big deal.
It is a big deal. The box that links swing wings to the rest of an aircraft is the heaviest part of the aircraft. The Oblique wing avoids this.

I would agree though that Oblique and star-shaped wings make little sense for other reasons. NIAC has made some very poor choices this last year.

Posted: Wed Oct 17, 2012 5:44 pm
by DeltaV
Problems of High Speed and Altitude

Page 6:
NASA Oblique Wing Test Vehicles

Stability and control issues
abound: The fact that birds and
insects are symmetric should give
us a clue (though they use huge
asymmetry for control)

– Strong aerodynamic and inertial
longitudinal-lateral-directional
coupling

– High side force at zero sideslip
angle

– Torsional divergence of the
leading wing
So you'll need bigger control surfaces, heftier actuators and stronger structure on the leading wing half. There goes your weight advantage.

The only desirable asymmetry is the transient kind, for control.

Posted: Wed Oct 17, 2012 6:12 pm
by GIThruster
DeltaV wrote:The only desirable asymmetry is the transient kind, for control.
Agreed. This bi-directional configuration loses the mass for a variable geometry wing, but gains the mass for twisting the engine location/direction, the cockpit, even the seats. There are so many needless complications here one fails to see how anyone could fund it. yeah, you can do a study with an RC aircraft for $10,000 but after that it should be obvious this is not a good idea.

I'm very disappointed with what NIAC II has come up with. The technologists at NASA seem to lack common sense.

Posted: Fri Oct 19, 2012 1:58 am
by rjaypeters
Thanks for the enlightenment re: "what's wrong with an oblique wing?" In my experience, those who insist upon bilateral symmetry for its own sake tend to be limited in flexibility of thought.

Not liking oblique wings because of the raft of problems they bring is another situation...