A plane is on a treadmill runway and matches the speed of the plane. Will the plane take off and fly?

Answer 1

No, because there's no air flowing over and under the wings to provide the lift that actually gets the plane up in the air.

Answer 2

Yes, the plane will take off.

First of all, the plane still needs the full runway length. In this case the runway happens to be a treadmill, but that's ok. The plane will have to accelerate along the treadmill before it can take off.

The question therefore is whether or not the plane can accelerate on the treadmill, which is moving in the opposite direction. This is also true. For a plane, the wheels just hold it off the ground. Sorta like a skateboard, with wings and an engine (the engines do not drive the wheels, the wheels just spin freely). Now, if you are on a skateboard and strap a rocket to your back and turn it on, then you will move forward.

Let's say the rocket pushes you at 100km/h. That means the wheels spin at 100km/h. The rocket will push you forward at 100km/h no matter what. If you jumped out of a plane and turned on that rocket, it would still push your forward at 100km/h... if you still had the skateboard when you jumped out, the wheels would spin at 0km/h, but you would be traveling forward at 100km/h.

Now, put the skateboard + rocket on a treadmill. In this case, you still will move forward at 100km/h. If the treadmill is turned off, the wheels also turn at 100km/h. Turn the treadmill on, and you will still move forward, but now the wheels gotta spin a little faster. Since the treadmill goes the same speed as you in the opposite direction, those wheels are gonna spin a lot more. In our example, the treadmill will spin at 100km/h, you will move forward at 100km/h, and your wheels will be underneath your skateboard moving at 200km/h. No matter how hard that treadmill works, it won't stop your forward motion, because the rocket is pushing you forward... the wheels are preventing the treadmill from pushing you back.

Thus, the plane + jet engine (or you on a skateboard + rocket) WILL move forward. Now that we know that the plane is moving forward, we trivially know that the plane will take off as per normal, except the wheels under it will be spinning a heck of a lot faster.

Marcel A.

Answer 3

Plane flies with the aid of airflow over the wings. If the treadmill runway has no matching airflow speed, the plane is still on the treadmill, not flying. It will just have the speed, not flight.

You can make the plane fly if you can generate equivalent airflow over the wings to fly. Just like you see people do in free-falling practice with airflow blown up at them keeping them suspended in the air.

Answer 4

I assume you meant the treadmill "matches the required speed for takeoff?

It's not only the speed of the plane - but also the required thrust from the engines, that is necessary to make it fly.

I was wondering if this plane would have wheels, or tennis shoes? Pretzels or peanuts?

Answer 5

no, why would it?