Can the plane take off?

Scott215 said:
Look the guy will splat on the street.
The plane has no air coming over the wing . If planes just need thrust then why have a wing, ailerons and rutters.
Why not just put people on a jet engine with some plywood. Cheese and rice , let it go
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Scott - you are violating my engineering sense of order.....
 
Stee6043 said:
It doesn't actually matter how you phrase it, birds still aren't real. Somewhere in this thread there is an actual engineering type response to this riddle. The plane takes off but this is indeed the internet, nobody believes anything and everyone is an engineer, physicist, doctor or lawyer.

You have to acknowledge that the wheels are allowed to accelerate for a split second before the conveyor matches wheel speed or the actual answer to this riddle is "undefined" or, for those with liberal arts degrees, that's the "skip the next player" symbol from the card game Uno.
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And it's that statement that makes this a "divide by zero here" problem and ends the test. Do not pass go, do not collect $200.
 
It's winter...here's a picture of some accordion parts. Will it ever play again?
0945 Karpek, 41-120, S.N. 256 Bass Machine.JPG
 
km1125 said:
And it's that statement that makes this a "divide by zero here" problem and ends the test. Do not pass go, do not collect $200.
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So...sensitive. Your original post argued my answer was wrong because I didn't properly reference the original question. So below is my original conversation with chatGTP. Aside from this thread, which is 50% nonsense, I was really impressed that this AI model actually did change it's position as more questions were asked. Really kind of neat. And yeah...the plane still takes off (speed and acceleration are different and the original question only referenced one of those. There needs to realistically be a way for the conveyor belt to perceive a change in speed, acceleration, otherwise it can never match speed. So, inherent in the original question is the allowance for some level of acceleration) :)

You still won't believe this though, I get it. Nor would you believe the "real engineering model" that was presented somewhere in the mid-teens page count here. Shoot, there's even a Youtube link somewhere in here where the Mythbusters guys actually did it, in real life. But the resistance is real. I'm on an agonizingly long MS Teams call so this is helping me pass the time.


1704988375967.png


1704988408072.png

1704988424536.png
 
Yup, I guess it's Wintertime 'cause here I am reading through this AGAIN and responding AGAIN... just like you all! :)

First, the Mythbusters episode doesn't apply here because their test was different (see "In this case", below).

Second, these "can the plane takeoff" questions can, and have been, worded differently... which can change the answer.

In this case, the key wording is "exactly match the speed of the wheels". That's very exact phrasing. We CAN'T assume or infer that there is any delay between the treadmill and wheel rotation - we can only take the question verbatim. If we start to infer or assume, then... how MUCH do we infer or assume? And that becomes a very "grey" area.

So, if we take this question verbatim, then the plane cannot move forward since the treadmill will ALWAYS match the wheel speed and the plane would NOT takeoff.

Without that specific terminology... yes, the plane would take off.
 
Lazy Daze said:
Yup, I guess it's Wintertime 'cause here I am reading through this AGAIN and responding AGAIN... just like you all! :)

First, the Mythbusters episode doesn't apply here because their test was different (see "In this case", below).

Second, these "can the plane takeoff" questions can, and have been, worded differently... which can change the answer.

In this case, the key wording is "exactly match the speed of the wheels". That's very exact phrasing. We CAN'T assume or infer that there is any delay between the treadmill and wheel rotation - we can only take the question verbatim. If we start to infer or assume, then... how MUCH do we infer or assume? And that becomes a very "grey" area.

So, if we take this question verbatim, then the plane cannot move forward since the treadmill will ALWAYS match the wheel speed and the plane would NOT takeoff.

Without that specific terminology... yes, the plane would take off.
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If it were possible for a treadmill to be designed to exactly and instantaneously match the wheel speed, which it can't because it is an infinite feedback loop, I guess it wouldn't take off because both the wheels and treadmill would reach infinite speed and self destruct as soon as any forward motion relative to the ground begins (and initially there is no drag on the wheels so it would certainly move forward relative to the ground).

If wheels and a treadmill could be designed that defy physical limits (in the same way the treadmill with instantaneous response does), you would need to know the hypothetical drag of such imaginary wheels.

If the drag was less than the thrust, the plane will accelerate down the treadmill, and if the treadmill is long enough, it will take off. If not, it will fall off the back of the treadmill.
 
Lazy Daze said:
Yup, I guess it's Wintertime 'cause here I am reading through this AGAIN and responding AGAIN... just like you all! :)

First, the Mythbusters episode doesn't apply here because their test was different (see "In this case", below).

Second, these "can the plane takeoff" questions can, and have been, worded differently... which can change the answer.

In this case, the key wording is "exactly match the speed of the wheels". That's very exact phrasing. We CAN'T assume or infer that there is any delay between the treadmill and wheel rotation - we can only take the question verbatim. If we start to infer or assume, then... how MUCH do we infer or assume? And that becomes a very "grey" area.

So, if we take this question verbatim, then the plane cannot move forward since the treadmill will ALWAYS match the wheel speed and the plane would NOT takeoff.

Without that specific terminology... yes, the plane would take off.
Click to expand...

Agreed. But I think we can all agree that the spirit of this riddle is to think about "what if the treadmill is indeed moving backwards while the plane is trying to take off in a forward direction". That fun is fully lost if you go verbatim as nothing can happen. Neither the plane nor the treadmill will ever move. Pure silliness. We might as well have spent the last 29 pages debating politics or something even less worthwhile.

How about this variant: If, while on the conveyor that always matches wheel speed (verbatim, zero movement ever allowed) a wind coming directly on the nose of the plane were to increase to a velocity (wind speed) that exceeds the ground speed at which the airplane would normally take off, will it take off?

People will still say no...those wheels are still somehow involved in this whole thing...
 
@ttmott , I seriously thought we would never see that thread again. Let a dead horse lie. Lol
 
It's all irrelevant The wheels are not powering the plane if the plane can't move and gain ground speed it does not get any airspeed over the wings to create lift jets themselves do not create lift the wings and their design create lift I'm done beating this horse forever
 
Scott215 said:
It's all irrelevant The wheels are not powering the plane if the plane can't move and gain ground speed it does not get any airspeed over the wings to create lift jets themselves do not create lift the wings and their design create lift I'm done beating this horse forever
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The wheels don't have any impact on the plane moving forward other than some negative drag, which is typically much lower than the thrust. The thrust moves the plane forward, the wheels do whatever and create some amount of drag less than the thrust, forward airspeed results and creates lift.
 
bajturner said:
Haa! This is a great question to play with though! Healthy to work the brain...
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Ha. This has been fun. Though at times almost as silly as trying to convince my 8 year old that a bowling ball and feather will hit the ground at the same time in a vacuum, if dropped from the same height. That dude is stubborn...and I can't figure out where he gets that from :)
 
Stee6043 said:
Agreed. But I think we can all agree that the spirit of this riddle is to think about "what if the treadmill is indeed moving backwards while the plane is trying to take off in a forward direction". That fun is fully lost if you go verbatim as nothing can happen. Neither the plane nor the treadmill will ever move. Pure silliness. We might as well have spent the last 29 pages debating politics or something even less worthwhile.

How about this variant: If, while on the conveyor that always matches wheel speed (verbatim, zero movement ever allowed) a wind coming directly on the nose of the plane were to increase to a velocity (wind speed) that exceeds the ground speed at which the airplane would normally take off, will it take off?

People will still say no...those wheels are still somehow involved in this whole thing...
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It IS fun. It's good thinkin' stuff :)

Variant... yes, it would -- But that was an easy one ;)
 
Stee6043 said:
Agreed. But I think we can all agree that the spirit of this riddle is to think about "what if the treadmill is indeed moving backwards while the plane is trying to take off in a forward direction". That fun is fully lost if you go verbatim as nothing can happen. Neither the plane nor the treadmill will ever move. Pure silliness. We might as well have spent the last 29 pages debating politics or something even less worthwhile.

How about this variant: If, while on the conveyor that always matches wheel speed (verbatim, zero movement ever allowed) a wind coming directly on the nose of the plane were to increase to a velocity (wind speed) that exceeds the ground speed at which the airplane would normally take off, will it take off?

People will still say no...those wheels are still somehow involved in this whole thing...
Click to expand...
Now I agree with your variant. It’s the wind over the wings that would create lift and this along with the thrust be free from the conveyor. Take off. Finally. Shut the thread down
 
Great Lakes said:
But wait, does the guy hit the ground?
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Well, there are a few factors at play:
- is the car accelerating, decelerating, or at constant speed?
- does the diver propel himself forward, and if so, how hard?
- do determine the effect of air drag, what is the wind speed relative to the car/diver?

Looks like there could be a tailwind!

1704999204952.png
 
Great Lakes said:
Now I agree with your variant. It’s the wind over the wings that would create lift and this along with the thrust be free from the conveyor. Take off. Finally. Shut the thread down
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It's only January 11!!! We have much winter ahead of us yet.

In the variant I posted there is no need for thrust from the engines to make the plane take off...
 
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