Re: airplane structural terms

Date:         22 Feb 99 03:30:32 
From:         "P. Wezeman" <pwezeman@blue.weeg.uiowa.edu>
Organization: The University of Iowa
References:   1 2
Followups:    1
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On 13 Feb 1999, Ken Ishiguro wrote:
> 3.  Wing incidence is the angle (viewed from the side) that the wing is
> attached to the fuselage.  In other words, if the leading edge were held
> in one place and the trailing edge were moved up or down, the angle of
> incidence would be changing.  Obviously, most wings are securely bolted
> to the fuselage, and the AI is fixed (except for the Boeing Tiltrotor).
> An "all flying" horizontal tail would be an example where angle of
> incidence is variable.

	On the Boeing Tiltrotor the wing incidence is fixed and the
engines with their rotors tilt. There were earlier designs, some
American, some Canadian, and perhaps one Japanese, where the entire
wing tilted. The Vought Crusader carrier based fighter, still used
with the French Navy until the naval version of the Rafale is
operational, has a variable incidence wing. This allows it
to increase wing incidence for landing and take-off while keeping
the fuselage horizontal for good pilot visibility over the nose.
The incidence changing mechanism was lighter than the longer landing
gear needed without it to accommodate landing with nose up. The
Martin XB-51 also had variable incidence. There is a homebuilt
aircraft design, called I believe the FreeWing, that uses wings
with variable incidence differentially for roll control, and collectively
for lift control (you can't really say that the wings control pitch
since the fuselage stays aligned with the relative wind).

                        Peter Wezeman, anti-social Darwinist

                             "Carpe Cyprinidae"