RCU Forums - View Single Post - Sweepback = Dihedral Effect?

01-13-2003 | 01:28 AM

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MJohnny78

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From: Kill Devil Hills, NC

Sweepback = Dihedral Effect?

Back in the early 50's I read in some mag that about 5 deg.'s of sweepback is equivalent to 1 deg. of dihedral. This is why sweptback jets don't need dihedral, and why some with extreme sweepback actually have NEGATIVE dihedral (or "anhedral", with wings that slope downward).

What about this, Aeronautical Engineers, do you agree, and if so, could you provide the EXACT no. of degrees of sweepback in my stated "formula" above?

FOR NON-BELIEVERS: Imagine a sweptback jet "falling off" to the left - the airstream does little for the right wing panel as it is somewhat in the "shadow" of the fuselage - the left wing panel, however, is highly affected since the plane is "FALLING" somewhat in THAT DIRECTION - the result is that the left panel is generating MORE LIFT now than the other one, tending to raise the left side again ---- THE SAME EFFECT AS DIHEDRAL.

Everyone agree?

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