Re: T-tail

Date:         25 Sep 97 01:39:42 
From:         k_ish <>
Organization: Netcom
References:   1 2
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JWizardC wrote:
> A note and a question:
> Note: (E-flat) - Most folkes don't take into account that the horizontal
> stabilizer also contributes lift to the aircraft. Granted, in most
> cases that lift is negligable, but it is there. <snip>

On an aircraft with conventional layout (i.e. not a canard design), the
stabilizer generates lift in the downward direction.  So it *increases*
the amount of lift the wing must generate; the stab has a negative
contribution to lift.

The reason for this is stability.  Visualize an aircraft in a dive.  As
airspeed increases, an increasing downforce is generated by the
stabilizer, which pitches the nose up and reduces airspeed.  If a
rear-mounted stabilizer generated upward lift, it would cause negative
pitch stability.

That's one advantage of canard designs- the canard is forward of the
center of pressure, and must generate upward lift to provide stability.
In this case, it does contribute to total lift.

Ken Ishiguro