PPRuNe Forums - View Single Post - Winglets, horizontal stabilizerlets and vertical stabilizerlets?
Old 18th Oct 2011, 03:44
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Mad (Flt) Scientist
 
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Originally Posted by rsiano
Hi,
If winglets are of any value, why has no one installed horizontal stabilizerlets? Or why has no one installed vertical stabilizerlets?
The easiest one first, the vertical.

The vertical stabilizer or fin generates zero sideforce under its most efficient overall configuration, zero sideslip/zero rudder. Therefore there is very little benefit in reducing the induced drag of the fin - the best way to make the fin efficient is to have a straight aircraft at zero sideslip/zero rudder.

Additionally, you dont know which way you'd want to bend the winglet because you cant (under most circumstaqnces) predict which way the fin might be lifting, because the ideal is ZERO.


The horizontal isnt quite as evident, but again the best solution for cruise drag for the tailplane is to minimize the load, through cg control etc., rather than to find a way to make the tail lift better. The critical cases for the tailplane are conditions where drag is a secondary consideration, where the max trim lift is required. So again, hard to justify wingletting the tail.
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