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That plane, and it taking off.

L

letdown427

Golden Member
You all know the question, conveyor belt etc etc, if not just search for it.

Let's see how AT is split on this. It'll be fun.

And as \/ \/ said, obviously it won't settle it, physics > democracy 🙂
 
I'm sorry, but physics > democracy. We could "democratically" vote to invent FTL travel, but it wouldn't suddenly appear as a result.
 
Originally posted by: jagec
I'm sorry, but physics > democracy. We could "democratically" vote to invent FTL travel, but it wouldn't suddenly appear as a result.
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True, I shouldn't have put 'settle' it. My mistake.Just curious as to the split of people with a grasp of physics and people who think it's a car! 😉
 
Then can someone explain this to me real quick? I don't feel like digging in the other thread :

If the plane and conveyor are moving at the exact same speed, meaning, the plane isn't moving, is air still being moved?
 
Originally posted by: LoKe
Then can someone explain this to me real quick? I don't feel like digging in the other thread :

If the plane and conveyor are moving at the exact same speed, meaning, the plane isn't moving, is air still being moved?
Click to expand...

Long story short: There are two interpretations to the control system discussed in that thread. The first interpretation is that as the plane moves forward at a velocity V (with regard to the stationary ground), the conveyor will move backwards at a velocity -V (with regard to the stationary ground). However, since the movement of the conveyor has a minimal effect on the movement of the plane, the plane will accelerate to takeoff speed Vto, with the wheels spinning at 2*Vto thanks to the conveyor matching that speed in reverse.

The second interpretation is that the conveyor will match the "ground speed" of the plane on the conveyor, in other words, if we hooked a speedometer to the plane's wheels, it would read that and match it in the other direction. This control system is impossible, because if the plane accelerates to any velocity V (even if it's really, really tiny), the conveyor needs to speed up to Vco=Vco+V. This leads to the conveyor going infinitely fast, even if the plane is only moving at 1MPH.
 
Originally posted by: JujuFish
Originally posted by: LoKe
If the plane ... moving ... meaning, the plane isn't moving
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Come again? 😕
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relative to the belt the plane IS NOT moveing, they are as one, to get the plane to take off it would have to be going at min take off speed + whatever its currently moveing at on the conveyor
 
Originally posted by: LoKe
Originally posted by: JujuFish
Originally posted by: LoKe
If the plane ... moving ... meaning, the plane isn't moving
Click to expand...

Come again? 😕
Click to expand...

I mean, the wheels are moving, but the actual plane isn't.
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Okay, plane is stationary, while the wheels are turning in one direction and the conveyor in the opposite? Well, then whether the air is moving relative to the plane all depends on whether there is wind or not.

Edit: Forgot the word 'air' in the last sentence. 😛
 
Originally posted by: LoKe
My answer of no was givne under the assumption that the plane was stationary with no influence from the wind.
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And that would be correct if that were the case. However, it is not.
 
Originally posted by: LoKe
Then can someone explain this to me real quick? I don't feel like digging in the other thread :

If the plane and conveyor are moving at the exact same speed, meaning, the plane isn't moving, is air still being moved?
Click to expand...

The plane still moves, despite the conveyor belt. A plane doesn't get its thrust through the wheels. The wheels will just be rotating at twice their normal speed.
 
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