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Old Jul 15, 2013, 06:17 PM
FlyVA is offline
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United States, VA, Salem
Joined Oct 2002
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Above and below tails

Usually the bottom of a vertical stabilizer starts in the fuselage and extends upward. Mostly seen on DLGs, vertical stabilizers are equally 50% above and 50% below the fuselage so as to minimize the boom twist leverage generated when discus launched.

Here is an example of an “above and below” vertical stabilizer on a larger (actually 208”) sailplane which is this years AMA Nats XC winner “Frankenstein” by Peter Baumeler. What a beautiful sailplane.

Are there any aerodynamic disadvantages to an “above and below” vertical stabilizer?
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Last edited by FlyVA; Jul 18, 2013 at 02:51 PM.
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Old Jul 15, 2013, 06:41 PM
rrcdoug is offline
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With the very slender tailboom on this model, I can see the need to reduce torsional loads, hence the "balanced" vertical stabilizer.

As to aerodynamic advantages, a larger AR becomes possible but the fin/rudder is usually generating little lift compared to a wing (lifting surface) so I doubt a high aspect fin would make much difference.
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