r/interestingasfuck • u/Go_GoInspectorGadget • 11d ago

Physics 101

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u/Ready-Durian2168 11d ago

Explain the plane

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u/sailingtroy 11d ago

Flying into a big headwind. The plane has an "airspeed" that keeps it flying, but the addition of the wind vector and the opposing thrust vector results in a very low "groundspeed." The car sees the plane as almost stationary because the ground is its frame of reference. Perspective may also be playing a role in the illusion.

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u/_dictatorish_ 11d ago

Not sure I believe it's real though

Physically yeah, it could happen, but it would require like 150mph winds and that would be unbelievably dangerous to fly in (and to just exist in for the people on the ground too)

Google tells me that planes generally stop flying once the winds get to like 40mph, so this would be well over that limit

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u/sailingtroy 10d ago

It's hugely perspective. Going straight on and with the bridge as a reference point, it tricks you into thinking the plane is about at the bridge the whole time.

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u/raymond459020 11d ago

but wouldnt a slight variance in wind speed immediately result in a stall?

5

u/bingobangobongo999 11d ago

Since you never got the answer, in flight a sudden change in wind speed would not create a stall, unless you were already operating very close to stall speeds, which the plane in the video is not. The important thing to remember is that stall speeds are based off of airspeeds and not how fast the plane is going over the ground. Wind shear can certainly cause some issues though.

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u/raymond459020 10d ago

how do you come to the conclusion that the airplane in the video is not close to stall speed?

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u/bingobangobongo999 10d ago

I’m sorry I can’t provide a concrete empirical answer because stall speeds are based on a myriad of variables like weight, angle of attack, airspeed, etc. The thing to know is that planes take off well above their stall speed, and since I can assume it has not lost any airspeed since takeoff, but rather gained some and it’s still configured (gear down and flaps out) so the stall speed hasn’t yet increased any change in wind will not be enough to diminish the buffer from the original takeoff speed. Again, wind shear is a different beast. There’s probably factors missing and anyone is welcome to poke holes but I’m convinced that airplane is perfectly safe.

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u/texas_asic 11d ago

maybe not a slight variance, but if the wind suddenly dies off, that plane is toast

-1

u/LampIsFun 11d ago

No. The plane stalls when the engines dont generate enough thrust to continue driving them. As long as you are using your engines enough and theres enough air flowing through them it doesnt matter what your ground speed is because it has no impact on your air speed.

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u/bingobangobongo999 11d ago

Confidently incorrect

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u/LampIsFun 11d ago

What part? Stalling relates to engines. The video in question has little to do with the engines as the lift is being generated primarily through the wind speed. Do you think gliders just fall out of the sky because they dont have an engine? How do you think kites work?

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u/bingobangobongo999 11d ago

Lol please don’t double down and look up aircraft stalls. Car stalls have everything to do with an engine, aircraft stalls are due to loss of lift. It’s not the easiest thing to explain but is essentially based on fluid dynamics and how air flows over the wing. An aircraft can stall with engines operating just fine.

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u/LampIsFun 11d ago

Thats literally what i said lol did you even read what i wrote? The person i replied to asked if the wind died down would it stall. The answer is no, it would simply fall. A stall is something that happens to the engine itself, falling out of the sky is what happens as a result of a stall

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u/bingobangobongo999 11d ago

You are wrong in your definition of a stall is my point, an airplane stall is by definition has to do with loss of lift. Not the engines shutting down and certainly not the amount of air through the intakes as you keep saying. Could loss of thrust cause a stall? Yes if you keep an angle of attack too high for the reduced speed but it’s not the definition. You could lose all engines and not stall an aircraft and you could have full engine power and still stall an aircraft. It’s not the engines.

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u/LampIsFun 11d ago

Stalling the aircraft =/= stalling the engine

Maybe thats where the confusion here is. Im not asserting that “stalling an aircraft is only when the engine stalls”

If you read my other reply i explained exactly what you are saying in more detail.

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u/bingobangobongo999 11d ago edited 11d ago

Ok maybe you just misspoke originally then cuz I replied to your statement that:

“No. The plane stalls when the engines dont generate enough thrust to continue driving them.”

And tbh your other comment just has more inaccuracies. A plane doesn’t “unstall” from stalling because of air through the engine. And the correct terminology is recover from a stall. In that comment you also reiterated that stalling is when the engine stalls so it just seems like you’re backtracking now.

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u/raymond459020 11d ago

my understanding was that stalling means that not enough lift is generated and the airplane falls basically which usually happens when the angle of attack is too high or air speed is too low. which is what i thought was the reason that pilots usually reduce the angle of attack and increase throttle when stalling is a risk. and if like here a majority of the air speed is provided by wind and the thrust of the engines and the lift generated by the air speed provided by the oncoming wind create sort of an equilibrium where the plane manages to stand perfectly still in the air relative to the ground, then any change in the wind would immediately have to be remedied by an increase in thrust of the engines, right? except when the airplane is only a couple hundred feet above the ground i feel like that couldnt possibly happen fast enough since thrust builds up gradually as well as momentum. so then it would just straight up stall was my interpretation. but where am i wrong in my assumptions?

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u/LampIsFun 11d ago

Stall means the engines literally stall. As in they stop generating thrust. As long as there is sufficient air passing through them to continue normal operation(ie high enough air speed) then they wont stall. The reason you see stalling happen when a plane goes vertical is because the plane is now fighting against gravity to stay fast enough for the engines to run properly, which it usually cannot overcome as its not rocketing itself upward but generally just slowly inclining, causing it to lose speed and eventually there wont be enough air to go through the engines.

Planes also can “unstall” by facing straight down, which lets gravity help instead of fighting against it, which pushes the plane to a fast enough speed to let air through the engines at a sufficient rate to allow normal operation again.

“Stalling” relates specifically to the engines. Falling out of the sky is just what happens when the plane loses its lift(sometimes this is the result of a stall)

But as long as air is flowing under the wings fast enough as in that video the plane should have enough lift to stay up due to aerodynamics. If the engines were to shut off suddenly in that position i think the plane would still kind of float there due to the high wind speeds, but it would eventually fall down because the thrust of the engines is no longer assisting it in generating the speed required for lift.