When a light aircraft points directly upwards during a loop-the-loop (which takes forever), what keeps it from falling out of the sky?

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When a light aircraft points directly upwards during a loop-the-loop (which takes forever), what keeps it from falling out of the sky?

In: Physics

Momentum.

If you were to stop it at that point and release it, it would fall. But, it has upward momentum, so it slows rather than falls.

Thrust from the engine/propeller. It’s in a vertical powered climb, not enough power and it will fall down backwards.

I use to work on a lower powered acrobatic plane, when the pilot and I would try to do a loop, it couldn’t do it, and the plane would fall and end up doing a hammerhead stall. With just the pilot on board it could usually do it.

Mostly just the momentum. Airplanes are usually flying very fast so when they turn and point upwards it will take some time to slow down. Especially when their engines are still running at full power. On the other hand since they are using momentum to stay in the air they do not need to have enough speed to get lift from the wings. So they can allow the airspeed to get pretty low towards the top of the loop. Of course at that point they do not have enough speed to generate lift to stay in the air so they will end up going downwards if they want it or not. But this also makes them pick up speed again as they head downwards.

You’re talking about the kind of loop where it goes upside down?

In any case, falling is completely different from flying. For an aircraft to start to fall, it needs its wings to stall, meaning that for whatever reasons, the wings are not producing meaningful lift any more, and won’t start to do so again easily. When the aircraft goes upside down, it is still going fast enough to produce lift, even if the lift might also be upside down. once it corrects it self to right side up it will still have enough speed to not stall and can continue flying without much additional effort.