• merc@sh.itjust.works
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    9 months ago

    My favourite story about aircraft design about some of the design mistakes on the F-16 fighter.

    The F-16 was the first fly-by-wire fighter. They didn’t have much experience with it, and tried out some new things. One was that instead of having a stick between the legs of the pilot they used a side stick. And, since everything was fly-by-wire they didn’t need the stick to mechanically move. They decided they’d just use a solid stick with pressure transducers, since it was simpler and more reliable than a stick that moved.

    The trouble was that the pilots couldn’t estimate how much pressure they were using. This led to the pilots over-rotating on take-off (pulling back too hard). Even funnier was that at early airshows, when the pilots were doing a high-speed roll, you could see the control surfaces twitching with the heartbeat of the pilots as they shoved the stick as hard as they could to get maximum roll.

    That led to them adding a small amount of give to the stick, essentially giving the pilots feedback on how hard they were pushing the control surfaces.

    Another more subtle issue with the design was that originally the stick was set up for forward, back, left and right aligned with the axes of the plane itself. But, they discovered that when pilots pulled back on the stick, they were pulling slightly towards themselves, causing the plane to also roll. So, they realigned it so that “pulling back” is slightly pulling towards the pilot’s body, rather than directly along the forward / backward axis of the plane.