Discussion: How Stuff Works - Airplane / Conveyor Belt

"my understanding was"

"There's the issue... your understanding was incorrect. For the record, we all agree that if the plane doesn't move relative to the air, then it doesn't take off.

The riddle never explicitly says that the plane will not move relative to a fixed point - you, the reader, make that assumption or come to that conclusion based on the existence of the treadmill."

"The simple physics of the conveyer belt says that the requirement is zero relative ground speed. "

"Would you agree that the aircraft would NOT take off given a zero relative ground speed and conditions that excluded any significant head-wind ?
If so, then I believe we are on the "same page".
I would then propose the idea that the original myth is bogus rather than Jamie and Adam's efforts at (dis)proving it. Because the aircraft wheels to not provide any power or thrust, the aircraft's speed relative to the ground means nothing. The relative AIR-speed means everything.
If you had a head-wind that was faster than the aircraft's stall speed, you could, in theory, have the aircraft off the ground with a zero relative ground speed. I have seen trained birds do this: Fly into a big fan such that they are flapping away, but in one position relative to the audience.
My interpretation of the original myth statement says zero relative ground speed. We have seen that this is very difficult to achieve without actually tethering the aircraft to prevent forward motion.
I understand "speed". But it is all relative. There is relative air speed, which means everything to the wings for the purpose of lift, and there is relative ground speed which is aerodynamically meaningless, but very important to the airline's scheduling department."

"I believe that the INTENT of the myth was to create a zero-relative-ground-speed condition.
"

"Here's another way of a looking at this. Suppose that there is no wind. Then place the plane on the "simulated conveyor belt" (the thing that was pulled behind the truck in the show) and chock the wheels to the "conveyor belt" so the plane doesn't slip, but stays in the same place on the belt. Now get the truck up to the takeoff velocity of the plane. The plane should be able to take off without the engines even running.

Ok. Now turn the plane around. Get the "conveyor belt" going 70 mph. So now you have a plane going down the runway backwards being dragged on a tarp by a truck. This is where people can get the idea that the plane can't take off. In this situation, the plane would have to get up to 70 mph ground speed (on the conveyor belt) just to get back to 0 mph wind speed (and 0 mph ground speed).

This is the scenerio that was not tested on the show. If you can somehow get an airplane going backwards so that it's wind speed is, say, negative 70 mph, then can it overcome the intense tail wind and take off?"