[ELI5] How did the auto-pilot in Charles Lingburgh and Amelia Earhart’s transcontinental planes work so they could sleep or use the bathroom?
In: Engineering
I can’t comment on these people’s planes in particular, but early versions of auto-pilot were mainly based on gyroscopes which are designed to keep themselves straight/level. They can’t really navigate and follow a route, but they’ll keep a plane level and more-or-less straight on their own. With a compass you can keep a straight heading more consistently.
Pretty much how modern ones work: with feedback control.
A specialized compass was invented in 1904 that allows to find the direction you’re flying including the change of height.
That information is compared to where you want to fly (spoiler: horizontally) and the difference is fed to the steering gear of the plane.
That technology was known from steam engines wich use the same technique to keep the RPM stable (with a centrifugal valve that opens more the faster it spins)
The only real difference is that today we do it in a microcontroller and not mechanically
Charles Lindbergh’s Spirit of St Louis had no autopilot. In fact, it was designed with intentional instability, to aid in keeping the pilot awake.
Earhart used a Sperry autopilot, which could maintain heading and pressure altitude.
Lindbergh wrote that he would have fallen asleep (his flight was 33.5 hours), except there was a fly inside the plane which irritated him enough to keep him awake. He nodded off for a few seconds more than once, and nearly flew into the Atlantic.
“Use the bathroom” would be a joke. He had an extra fuel tank fitted inside the cabin, and it had to be right in the middle to keep the plane balanced as it emptied. There wasn’t even room for him to stand up, and it was so cramped he borrowed a mirror from a woman’s handbag to help him see out of the side window. He did have two sandwiches and a bottle of milk, though.
Latest Answers