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Old March 21st 07, 02:29 AM posted to rec.aviation.homebuilt
Morgans[_2_]
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Default Whose airplane is it anyway?


"Peter Dohm" wrote

I don't know the reason, but every delta winged aircraft that I can recall
ever having seen pictured has had a pronounced nose high attitude while at
rest.

From that observation, it is easy to infer reasons--and, of course, to be
wrong!

If anyone here actually knows the real reason, please post it. (Inquiring
minds want to know.)


Delta wings don't really stall; they go into a "mushing flight" mode. That
is why they can land with the nose way up. To get slow, they need to get
the nose up. Also, the maximum lift coefficients are the highest with a
large angle of attack.

Taking off, the nose high attitude lets it "fly off" the runway when a
decent speed is reached. They would need to go very fast to bring the nose
up from a level attitude, because the elevons are not way back there on a
fuselage with a long moment, like standard wing plan forms. Without the
long moment, the elevons need all the help they can get, initiating
rotation, and the nose high attitude does just that.

You may have noticed that delta wings with a big canard (Mirage,
Eurofighter) do not have such a nose high attitude. The canard provides the
long lever (moment) needed to rotate the wing.
--
Jim in NC