I shot this pic last week at the RAAF Amberley Aviation Heritage Centre It's a UH-1 tail surface. Notice anything interesting? They screwed it on upside down! I've seen lots of helicopters, including H-1s, but I have never noticed this detail before. After a bit of Googling, it seems that the idea was to impart a nose up (tail down) force when the ship was moving forward because getting these things to move forward involves "pushing the nose down" and the designers wanted the tail surface to counteract this tenancy. The other interesting bit about this pic is that in this particular case, the surface is angled such that it would impart a nose down force. Is the tail surface on the H-1 movable? Can it be trimmed? If it is "trimmable", it seems they could have achieved the same effect with a "neutrally" shaped cross section, rather than an upside down airfoil. Very interesting.
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