Will it fly(don't answer too fast)?

[Woodlouse2002]

After reading eno's post I'm now really confused.

Infact, no I'm not. Imagine you're pushing a toy car against a conveyor belt. Not matter how fast the conveyor belt is going you can still push the car forwards, it's just the wheels will be going a lot faster. If you apply that to a plane and replace the force your hand puts on the car with the thrust of the engine then you will realise the plane will still go forwards.

However eventually the wheels will be going so fast that the bearings will probably melt, thereby jamming them and sending the plane backwards at 300mph. So although the plane would go forwards I doubt whether it could take off.

[Omag 2.0]

I see a loophole in your theory Woodlouse... It's stated that the belt will match the speed of the plane. If you ad thrust, the plane will move faster, but so will the belt... so, relatively, the speed won't change at all! But now we can discuss the fact of delay between the speed-measurement of the belt and the actual speedchange... still following?  ;D

[Ecko]

Helicopters are no differant to planes in that they need airflow over the wings to fly, the differance is their wings are smaller and rotate at god knows how many 1000 rpm.

Actually on most choppers they only rotate at a constant speed of 300-400 RPM.

[Woodlouse2002]

[quote]I see a loophole in your theory Woodlouse... It's stated that the belt will match the speed of the plane. If you ad thrust, the plane will move faster, but so will the belt... so, relatively, the speed won't change at all! But now we can discuss the fact of delay between the speed-measurement of the belt and the actual speedchange... still following?

[Hai Perso Coyone?]

It won't as it isn't generating airflow over the wings to give lift!

Exactly what I was going to say

It's like a plane on a treadmill....you don't actually feel the wind in your face when running on one do you...same goes here I suppose

[SilverFox441]

Take off.

Ask any seaplane pilot that's lifted out of a river headed upstream if it affected his takeoff speed. It does affect the length of the takepff run and the rate of acceleration...but the plane still lifts.

[SilverFox441]

Guys...wake up.

An airscrew (prop) provides thrust relative to the air mass...not the ground.

Assuming that the plane type chosen ahs sufficient thrust to overcome the rolling resistance of the wheels the plane will still move forward.

Some marginally powered typed might not be able to keep pace with the wheels rolling resistance, some types might suffer catastrophic wheel or tire failure before reaching takeoff speed...but the conveyor isn't going to inherently prevent the plane from moving forward int he airstream and lifting off.

Once that happens the conveyor has to instantly come to 0 mph. The shock rips the conveyor apart and we never have to deal with this question again.

[TSC.]

Posted by: SilverFox441 Posted on: Today at 7:23pm
Ask any seaplane pilot that's lifted out of a river headed upstream if it affected his takeoff speed. It does affect the length of the takepff run and the rate of acceleration...but the plane still lifts.

The seaplane lifts because of the air flowing past the wings - it has nothing do with the water at all. If it relied on the water it would be a boat.

In the question posted, the plane remains stationary relative to the rest of the world - which includes the vital air (& relative airspeed) around it.

Assuming that the plane type chosen has sufficient thrust to overcome the rolling resistance of the wheels the plane will still move forward.

In the question, we have to assume that no matter what speed the planes engine is revving - the conveyor belt will match that speed (produced by the thrust).

Once that happens the conveyor has to instantly come to 0 mph. The shock rips the conveyor apart and we never have to deal with this question again.  

LMAO - true!!

Cheers,

TSC.

[SilverFox441]

The assumption that the plane stays at rest relative to the world is false.

The plane accelerates at a slightly lower rate to the airmass around it due to wheel drag due to higher rolling velocities.

The seaplane lifts because of the air flowing past the wings - it has nothing do with the water at all. If it relied on the water it would be a boat.

The airplane lifts because of the air flowing past the wings - it has nothing do with the conveyor at all. If it relied on the conveyor it would be a car.

[TSC.]

Cars use roads.

But it is also the conveyor belt that is stopping the plane form accelerating anywhere. (hence no airflow).

Cheers,

TSC.

[Craig.]

You have all over analysed this, and Looking back at an old school work book where we did something simmilar, I see OTTOL, has actually written the question slightly wrong, I only post my answer from the past to stop the argument that appears ready to break out:)/
Yes the plane will take off, why? because the question doesn't say the conveyer belt is switched on, only set to the speed of the aircraft.

[Craig.]

Cars use roads.

But it is also the conveyor belt that is stopping the plane form accelerating anywhere. (hence no airflow).

Cheers,

TSC.

Here is another problem with this scenario, people can't seperate planes and cars in this situation. In a car the wheels are the direct driving force of the vehicle. That isn't the case with a plane. The thrust from the engines pushing it forward regardless, as there is no direct effect from the belt on the engines efficiency.

[TSC.]

I wasn't arguing - it was just some good banter.

Anyway now that Craig has solved the problem for us, how long would it take us lot in a boat on a conveyor belt to get to OTTOL's house & throw marmalade bombs at him (marmalade bombs that will somehow be subjected to the forces of giant fans equal to the force we can throw marmalade bombs at).



Cheers,

TSC.

[Craig.]

LOL I know you wern't
I might have completely the wrong scenario, like I said the question I had was slightly differant so untill Ottol comes back and confirms or deny's the answer. "carry on debating"

[TSC.]

I might have completely the wrong scenario, like I said the question I had was slightly differant so untill Ottol comes back and confirms or deny's the answer. "carry on debating"  

But i'm in my boat now



TSC.