I'm thinking this question had to been asked before, but I did a search and couldn't find anything on it. It's really bugging me, because I never could find out the right answer.

Suppose you have a jet airplane sitting on a runway. But this runway acts like a treadmill. The jet starts it's thrusters and for every mile an hour the Jet's wheels move forward, the treadmill moves a mile an hour in the opposite direction.

Will this jet eventually take off? Thanks.

Rob

Stratmando

I come back hoping we all understand, the faster the treadmill goes, it still has no effect on freewheeling wheels, whether jet or prop, Aircraft will move forward, jump off treadmill, or if hypothetically speaking, a 10 mile long treadmill, craft will move forward and take off.

lobrobster

I believe this is incorrect and it's the key to the question. The treadmill doesn't match the velocity of the jet, it matches the velocity of its wheels. All the difference in the world.




Right, I understand that. The scenario would work with either a jet or a powerful enough propeller driven plane. A jet plane is 'pushed', a propeller driven plane is 'pulled'.

Stratmando

Heres another way,
Any plane will take off of the treadmill, the movement of the treadmill is to spin the wheels, spins only the wheels, Prop or jet will push against the Air, and take off.
I'll try not to respond a couple of times.
I used to think the World was Round, Now I know It is Square.

Flying Blue Eagle

HAY SYRATMANDO - IF this old world is square, then what happens when we go over the edge and start down hill will we be able to make the next turn? And if we do will gravety hold us up while we are upside down .?? I think IM in trouble BYBYBYhbhbh;;

IM still IN yhe same thinking as you are on the way we read and understood the question at first< AND ON THOSE TERMS IT WOULD BE THE WAY THAT YOU AND I STILL THINK< THE WAY THEY ARE SAYING THE PORE A?C WOULD NOT STAND A CHANCH <SINCE HE CAN't GIVE THE A/C FULL THROTTLE IN ORDER TO MOVE IN THE OPPSIT DIRECTION. HAY TAT TAINT FAIR!!! F.B.E. GODBLESS

Sitkadiver

Thank You "MYTHUSTERS", from he Discovery Channel. They tested this myth and found that the treadmill speed had no effect on the ability of an aircraft to take off. Since the thrust produced by the prop is independent of the wheel speed, the plane still takes off like normal.

lobrobster

Are you serious? I would have loved to have seen that! When did that show air? I wonder if there's any way to get a copy of it.

Stratmando

I missed the episode too, but here it is:
http://mythbustersresults.com/episode97

Flying Blue Eagle

Lobrobster - Boy ,I have heard a really good one on how to describe something, and I think you have done a very Good job of describing the problem, Good goin . I just wish that I could take a ( B-47 jet bomber and try this problem, Just to find out wjhat would happen. O f corse I want to use water alcacol , for wet thurst and put 32 bottles of ( ATO 0 on the rear behind the aft wheel well, A 1000 lbs. of thrust per bottle, ha ha ,good by conveyr belt , If I couldnt take off from it ,THen good by belt ( BECAUSE I WOULD MELT IT AND GO AHEAD AND TAKE OFF, _ NOTICE THE WORD ( HEAT & MELT )

I DO NOT SEE how the belt could move as fast as the a/c would move forward, I says that for every mile an hour the a/c moves forward, the belt moves BACKWARD< causeing the a/c to go no where. ( THE wheels are free weeling ,there is little friction , that will cause the a/c to just sit there. the power of the thrust from the engines has nothing to do with the wheels of the a/c, they have not one thing to do with the power of the a/c , moveing forward, IT IS THE THRUST OF THE ENGINES THAT IS AND WILL MOVE THE A?C FORWARD< AND TO REACH ROTATION POINT ) I can see that IF it was a car , truck , or any type of vehicle, that has a drive train from the engine to the drive wheels that this would happen, the more gas you give the engine the faster the wheels are going to turn and then the belt is going to counter react and travel in the oppsite direction, WHICH MEANS YOU HAVE THE QUESTION IN VIEW.

THE HEAT FROM THE JET ENGINES WOULD MELT THE BELT REAL QUICK ANY WAY< AND YOU COULD THEN WAVE GOODD BY TO THE A/C. YOU al have a good day and safe flying, keep her between the clouds, GOD BLESS ::: F.B.E.