I’ve always wondered this. Why do gliders use a T-style tail, as opposed to a V-tail ie a swallow tail design? I think it would represent a significant reduction in weight over a conventional empennage, not to mention, offering a reduction in drag.
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5Because the swallows needed them and would not give them up :) – Mark Schultheiss Oct 02 '23 at 18:28
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The V-tail was a trend in glider design between the late Fifties and the early Sixties. High-performance gliders like the HKS-1, the Arlington Sisu 1A$^*$, the SB-5, the Standard Austria or the Schempp-Hirth SHK had them, as well as the aerobatic H-101 Salto.
However, eventually the T-tail became the preferred choice for these reasons:
- The endplate effect of the horizontal allows to make the vertical about 20% smaller.
- A T-tail will suffer the least damage in an outside landing.
- The effectiveness of a V-tail is lower for the same area, especially in damping.
- V-tails are not really better in terms of drag reduction.
$^*$ Added thanks to the helpful advice by Thomas Perry.
Peter Kämpf
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1A friend had an Austria glider with unusually large all-flying V tail surfaces and anti-servo tabs. He said it was actually deficient in rudder authority, making it a challenge in x winds. – John K Oct 02 '23 at 15:42
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@JohnK Name me one glider which isn't deficient in rudder authority at low speed. They all are, more or less. Fly fast enough and things become fine, though. – Peter Kämpf Oct 02 '23 at 19:21
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@PeterKämpf ...and I am going to add, the enigmatic Sisu 1A, if that is ok with you... – Thomas Perry Oct 03 '23 at 16:00
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@ThomasPerry ... and well deserved. I had no prior knowledge of the Sisu 1A. – Peter Kämpf Oct 06 '23 at 18:20