Plane on conveyor belt

[expat]

Firstly this could be the video forum, real aviation or general, so as required MODS....anyway

Plane on conveyor belt, the cause of many threads and conversation web wide and quite a few at Simv. Well, Mythbusters have done the plane on conveyor belt full size. I still see some holes in this test, but..........

The theory

Plane on conveyor belt

Matt

[C]

Mods, someone lock this thread. NOW!

I can't take another one!

[expat]

Mods, someone lock this thread. NOW!

I can't take another one!

But Mythbusters are the answers to all our questions

Matt

[patchz]

Mods, someone lock this thread. NOW!

I can't take another one!

[color=#000000]You don't wanna try it with the VC10 Charlie?

[DaveSims]

As much as I usually like the mythbusters, I think they completely missed the whole point of that myth.

[patchz]

As much as I usually like the mythbusters, I think they completely missed the whole point of that myth.

Which was?

[DaveSims]

The original myth is that if the aircraft was on a conveyor belt going X mph, and its forward speed on the conveyor belt was equal to X, would it fly?  Now any pilot would know the difference between airspeed and groundspeed, and their relationship to lift.  When the mythbusters conducted the myth however, the aircraft actually moved faster than the conveyor belt, which gave it a forward airspeed, and it flew.  Since the plane actually took off, they claimed the myth was true.

[Jeff.Guo]

Urm, I think you missed the point of about the physics...

...aircraft wheels are free rolling. It doesn't matter how fast the conveyor belt is moving, an unpowered aircraft will ALWAYS be stationary, minus static friction between the rubber on the tire and the belt.

...of course, this also means that any thrust would propel the aircraft forward.

[Cobra]

I am really confused as to how there is any confusion over this? Lift is generated by airflow over the wing and thus airspeed is the only thing of relevance? If the belt is moving at the exactly same speed as the aircraft, then airspeed and the lift produced is null.

Are they saying that because the wheels are spinning it should fly

[B-Valvs]

I was about to post this (http://www.youtube.com/watch?v=S377HwOthjo), but then I saw that it was already posted.

I don't see why this is hard to understand either. They expain it very well. The conveyor belt does not affect the plane.

8-)

[Jeff.Guo]

The stationary aircraft over on a conveyor belt is a straw man point...

...with an airworthy undercarriage, the aircraft throttle would be somewhere around idle for it to accomplish that.

...the point is that the conveyor have virtually no effect on the performance of the aircraft. I.e. there is little difference between a conveyor and a regular runway.

[DaveSims]

Urm, I think you missed the point of about the physics...

...aircraft wheels are free rolling. It doesn't matter how fast the conveyor belt is moving, an unpowered aircraft will ALWAYS be stationary, minus static friction between the rubber on the tire and the belt.

...of course, this also means that any thrust would propel the aircraft forward.

So was the point of the myth that the friction of the undercarriage having to spin twice as fast as normal would be sufficient to prevent takeoff?  It happens anytime an aircraft takes off downwind.

[Jeff.Guo]

[quote]So was the point of the myth that the friction of the undercarriage having to spin twice as fast as normal would be sufficient to prevent takeoff?

[B-Valvs]

[quote][quote]So was the point of the myth that the friction of the undercarriage having to spin twice as fast as normal would be sufficient to prevent takeoff?

[BAW0343]

[quote][quote]So was the point of the myth that the friction of the undercarriage having to spin twice as fast as normal would be sufficient to prevent takeoff?