"The episode, which airs in December, finds Savage and Hyneman tackling a question baffling everyone from bloggers to pilots: If a plane is traveling at takeoff speed on a conveyor belt, and that conveyor belt is matching the speed in reverse"
I will be so happy to put that damn plane/conveyor belt discussion to rest.
I've never heard the discussion. So I get to answer here. The question: If a plane is traveling at takeoff speed on a conveyor belt, and that conveyor belt is matching the speed in reverse, can the plane take off?
My answer: Duh, yes it can take off. Assuming the plane is a "normal" plane with a propeller or jets to create thrust. And assuming its wheels have a "normal" amount of friction (i.e. properly greased, inflated, brakes not engaged, etc.). And assuming the atmosphere is such that the plane would be able to take off if there were no conveyor belt.
The conveyor belt will only make the wheels of the plane roll twice as fast. The plane is going to do what it's going to do regardless of the conveyor belt. The only way the plane will fail to take off is if the wheels are so underdesigned that rotating twice as fast causes them to fall off before the plane leaves the ground.
I don't get it. Why is this even a discussion in blog land?
Also, the easier answer based on the faulty wording of the question in the Mercury's article: It's already taking off, since it's at "takeoff speed" as stated in the question.
It's discussed because for many non-aerospace engineers (or former, for that matter) it's non-obvious. Someone convinces everyone reading a blog that it's one way and then someone else makes an incorrect but convincing argument for being the opposite way. Most people are used to transportation being driven by wheels so it's unintuitive.
Comments
My answer: Duh, yes it can take off. Assuming the plane is a "normal" plane with a propeller or jets to create thrust. And assuming its wheels have a "normal" amount of friction (i.e. properly greased, inflated, brakes not engaged, etc.). And assuming the atmosphere is such that the plane would be able to take off if there were no conveyor belt.
The conveyor belt will only make the wheels of the plane roll twice as fast. The plane is going to do what it's going to do regardless of the conveyor belt. The only way the plane will fail to take off is if the wheels are so underdesigned that rotating twice as fast causes them to fall off before the plane leaves the ground.
I don't get it. Why is this even a discussion in blog land?
Also, the easier answer based on the faulty wording of the question in the Mercury's article: It's already taking off, since it's at "takeoff speed" as stated in the question.