conveyor belt and plane answered at last ??

[GasBod]

I've changed my mind,it wouldn't take off!It doesn't matter if it's a plane,car or a rocket on wheels.

 

[Deleted member 63160]

Just out of interest, to the folks that don't think it'll take off, what actually stops it moving forwards when the engines are given the beans?

 

[pred]

With a strong nose wind the aircraft would lift off, irrelevant to conveyor belt or the lack of engine power.

 

[doitall]

Mw Roofline and mitch66

We all know the plane can go forward, but read the question and Mw rooflines wonderful post.

As he/she rightly says the belt can go as fast as you like, and he can hold me in the same place with wheels whizzing round at the same speed as the belt I'm stood on.

Now the tricky bit, I need to go faster than the belt to get an air flow, but to do that the wheels must turn faster than the belt.

Same with the tread mill, it is running at 5 mph so to stay on it I have to walk or roller skate at 5 mph, if I do less I go backward, but if I go faster than 5mph I can go forward, but them I'm going faster then the belt

 

[doitall]

With a strong nose wind the aircraft would lift off, irrelevant to conveyor belt or the lack of engine power.

Hows it going to do that ??

If the plane was facing the same way the belt was travelling with everything switched off, at 85knots it would leave the ground for a short time.

 

[crank39]

Mw Roofline and mitch66

We all know the plane can go forward, but read the question and Mw rooflines wonderful post.

As he/she rightly says the belt can go as fast as you like, and he can hold me in the same place with wheels whizzing round at the same speed as the belt I'm stood on.

Now the tricky bit, I need to go faster than the belt to get an air flow, but to do that the wheels must turn faster than the belt.

Same with the tread mill, it is running at 5 mph so to stay on it I have to walk or roller skate at 5 mph, if I do less I go backward, but if I go faster than 5mph I can go forward, but them I'm going faster then the belt

By jingo i think they might start to get it now doitall

 

[doitall]

Not a problem Crank39 I know the answer and always have done.

The wheels are not allowed to go faster than the belt so the plane, roller skates or me walking very fast will not gain ground on the belt.

The plane therefore cannot take off, and the thrust, type of engine or whatever else you want to dream up will make no difference.

The plane is static with the wheels whizzing round driven by the belt, lets call it the starting line, to get to the 100m mark the wheels would have to make ground on the belt, or go faster than, and that dear friends is not allowed in the question.

 

[libby lou lou]

The End.

 

[securespark]

Ahhhhhhhh.......

I've just nipped out for another bag of popcorn...

 

[joe-90]

You are all wasting your time. If the question is interpretted that the wheels can't move faster than the conveyor then it must stay static. What you have to ask tourself is what the original question writer was getting at. Did he want to write a question that was invalid or did he simply ask about a plane on a moving runway/conveyor? Until that is decided there is no point discussing it.

 

[securespark]

I've done some digging.

The earliest internet reference to this question was posted on a Russian forum on August 4 2003.

Anyone care to translate?

http://forum.ixbt.com/topic.cgi?id=64:417

I didn't do the hard work, btw!

Andy Baio did: http://waxy.org/2008/02/origins_of_the/

When everyone's done with the plane, here's another, taken from Andy's webpage:

Q: two beer glasses 1 metre apart are the only things that exist in a universe - how long does it take for the beer glasses to clink (i.e. touch)?

 

[peterperfection]

Not a problem Crank39 I know the answer and always have done.

The wheels are not allowed to go faster than the belt so the plane, roller skates or me walking very fast will not gain ground on the belt.

The plane therefore cannot take off, and the thrust, type of engine or whatever else you want to dream up will make no difference.

The plane is static with the wheels whizzing round driven by the belt, lets call it the starting line, to get to the 100m mark the wheels would have to make ground on the belt, or go faster than, and that dear friends is not allowed in the question.

CLEVER BURGER.

All about air displacement .
Have to say- it got me though !!
Thanks .

 

[Deleted member 63160]

Take a treadmill running at 5mph, if you stand on it you'll go flying of the end at 5mph, now for the clever bit.

If you start walking at 5 mph you'll stay where you are, if you start walking faster the belt goes faster so you are walking on the spot, at no time can you walk off the end.

Correct because the drive is through your feet. What if you had roller skates on and a jet pack?

 

[matt1e]

This is the original question....

An aircraft is standing on a very long runway that can move (a conveyor belt). The aircraft moves in one direction, while the conveyor belt moves in the opposite direction. This conveyor belt has a control system that tracks the aircraft's wheels speed and tunes the speed of the conveyor belt to be exactly the same as the wheels, but in the opposite direction. There is no wind. The pilot begins to add thrust to the engines...

Will the plane ever take off?

I haven't lost the argument, just answer the question above, will the plane leave the ground or not.

It doesn't matter if it's nonsense, irrelevant or just plain stupid. yes or no.

Hi all
Right had a quick scan through and thaough I'd give my thoughts, and I"m on the side of joe90 and co
Sorry doitall but Based on the question in that context then yes realistically the plane will take off
You are presuming that the belt can hold the plane stationary in relation to the air around it which it, can't, you are also presuming that the planes wheels are going to be stationary which they are not, the belt would have to be rotating in the same direction as the wheels for that to happen ( which still wouldn't stop the plane taking off)
As others have said, the Plane is being subjected to forward thrust from its engine/prop (clue - "the pilot begins to add thrust" )
It's wheels are freewheeling they will spin faster but the plane will still take off no probs when its airspeed reaches takeoff velocity

 

[crank39]

Take a treadmill running at 5mph, if you stand on it you'll go flying of the end at 5mph, now for the clever bit.

If you start walking at 5 mph you'll stay where you are, if you start walking faster the belt goes faster so you are walking on the spot, at no time can you walk off the end.

Correct because the drive is through your feet. What if you had roller skates on and a jet pack?

Totally irrelevant, no ones disputing not being able to overcome to conveyor and move forward, but the wheels would need to turn faster forwards than the conveyor is turning backwards but that is not within the parameters of the question, see MW's very well put post for an explanation