Can A Plane Take Off On A Treadmill?
Registered User
Joined: Sep 2006
Posts: 205
Likes: 0
From: Winnipeg, MB
Originally Posted by duboseq,Feb 13 2008, 01:46 PM
Wow I feel stupid because it still does not make sense. 
I tell you what, lets take out the lift part of the equation and apply the equation with a plane on a quarter mile track.
If a plane at 1/2 throttle completes a qtr mile in 13 seconds @ 100 mph,
would it complete the same qtr mile @ the same speed if it was on a treadmill moving 100 mph in the other direction @ 1/2 throttle?
I tell you what, lets take out the lift part of the equation and apply the equation with a plane on a quarter mile track.
If a plane at 1/2 throttle completes a qtr mile in 13 seconds @ 100 mph,
would it complete the same qtr mile @ the same speed if it was on a treadmill moving 100 mph in the other direction @ 1/2 throttle?
Registered User
Joined: Jan 2006
Posts: 3,581
Likes: 0
From: Tampa Florida
Originally Posted by X4DLuvOfSpeedX,Feb 13 2008, 04:30 PM
STOP LOOKING SO MUCH INTO THIS STUPID RIDDLE!
Forget about friction loss, heat loss, wind resistance, etc. It's just a simple trick question to see who has enough common sense to understand a very basic concept of motion. If this was a Physics test questions, I assure you the instructor would've written "assume zero wind resistance, friction loss, etc" on the question.
If you're going to include friction, wind, heat, etc, then forget it. You'll need to know what kind of plane it is and its drag coefficient, the material of the tires, their coefficients of both kinetic and static friction, the barometic pressure and humidity and how the tires react to it, etc etc etc. It'll be a 100-page long formula that would take the world's top scientists one year to write. And then....... you would have to do the same thing all over FOR A FRIGGIN' GIGANTIC PLANE TREADMILL THAT DOESN'T EXIST.
Come on guys, have some common sense. It's a yes or no question.
Forget about friction loss, heat loss, wind resistance, etc. It's just a simple trick question to see who has enough common sense to understand a very basic concept of motion. If this was a Physics test questions, I assure you the instructor would've written "assume zero wind resistance, friction loss, etc" on the question.
If you're going to include friction, wind, heat, etc, then forget it. You'll need to know what kind of plane it is and its drag coefficient, the material of the tires, their coefficients of both kinetic and static friction, the barometic pressure and humidity and how the tires react to it, etc etc etc. It'll be a 100-page long formula that would take the world's top scientists one year to write. And then....... you would have to do the same thing all over FOR A FRIGGIN' GIGANTIC PLANE TREADMILL THAT DOESN'T EXIST.
Come on guys, have some common sense. It's a yes or no question.
Joined: Oct 2001
Posts: 5,729
Likes: 2
Originally Posted by duboseq,Feb 13 2008, 10:07 PM
Sorry man but I am analytical. I was the kid that took the VCR apart to see how it worked.
I kid, I kid.
It's just that the wheels of an airplane don't really play a roll in moving the plane. There's no drivetrain like in a car, so the wheels are designed to be free-spinning. Now there's no such thing as 100% efficiency, so there will be SOME loss to friction, but it will be close to constant and will have no effect on the airplane
It's like trying to turn yourself in a swiveling office chair without touching anything but the chair.
Registered User
Joined: Nov 2006
Posts: 2,316
Likes: 0
From: Goleta, CA
If you understand that forward momentum will allow the plane to gain altitude then you're almost there.
The biggest task to tackle is realizing that the treadmill has no effect on the plane.
Imagine this, a car is sitting in a large pool of oil. No matter how hard you step on the gas the car will not move due to the frictionless surface. Now if you apply an external force, (push the car with a stick or something) The car will move in that direction regardless of the speed of the wheels.
The plane and the treadmill are similar in that fashion. Assuming that the friction in the wheels are negligible, the moving treadmill will just freely spin the wheels.
It's hard to find a perfect real world example due to the fact that frictionless wheels do not exist but if you have a skateboard or roller blades you can try it.
Stand on the skateboard on the treadmill when it's stopped. Using your hands on the handle bars, move forward(External force). Try to remember how much force you used. Now turn on the treadmill while holding the handlebar (to compensate for the friction in the wheels). Try to move yourself forward like earlier. You should notice you're using the same amount of force to move the same speed. To further test it, turn up the speed some more and do it again.
The speed that the wheels are traveling is the speed of the treadmill going backwards + the speed of your forward movement, BUT the speed relative to ground is just your forward movement.
This works because the wheels are free spinning, like the plane. The wheels will spin at a speed to match the treadmill, with no more force than to cancel out the force of friction. Therefore, since the plane has free spinning wheels, the treadmill will just speed up the wheels.
The external force of the engines/propellers will make the plane move forward (like your arms from the skateboard experiment).
The wheels of the plane, like the skateboard, will be moving at the speed of the treadmill + the speed of the forward movement, but relative to ground only the speed of the forward movement.
Then the plane will move forward, and this will help create the lift to get it airborne.
The biggest task to tackle is realizing that the treadmill has no effect on the plane.
Imagine this, a car is sitting in a large pool of oil. No matter how hard you step on the gas the car will not move due to the frictionless surface. Now if you apply an external force, (push the car with a stick or something) The car will move in that direction regardless of the speed of the wheels.
The plane and the treadmill are similar in that fashion. Assuming that the friction in the wheels are negligible, the moving treadmill will just freely spin the wheels.
It's hard to find a perfect real world example due to the fact that frictionless wheels do not exist but if you have a skateboard or roller blades you can try it.
Stand on the skateboard on the treadmill when it's stopped. Using your hands on the handle bars, move forward(External force). Try to remember how much force you used. Now turn on the treadmill while holding the handlebar (to compensate for the friction in the wheels). Try to move yourself forward like earlier. You should notice you're using the same amount of force to move the same speed. To further test it, turn up the speed some more and do it again.
The speed that the wheels are traveling is the speed of the treadmill going backwards + the speed of your forward movement, BUT the speed relative to ground is just your forward movement.
This works because the wheels are free spinning, like the plane. The wheels will spin at a speed to match the treadmill, with no more force than to cancel out the force of friction. Therefore, since the plane has free spinning wheels, the treadmill will just speed up the wheels.
The external force of the engines/propellers will make the plane move forward (like your arms from the skateboard experiment).
The wheels of the plane, like the skateboard, will be moving at the speed of the treadmill + the speed of the forward movement, but relative to ground only the speed of the forward movement.
Then the plane will move forward, and this will help create the lift to get it airborne.
Registered User
Joined: Oct 2000
Posts: 15,323
Likes: 28
From: Longmont, CO
Originally Posted by duboseq,Feb 13 2008, 03:46 PM
Wow I feel stupid because it still does not make sense.
I tell you what, lets take out the lift part of the equation and apply the equation with a plane on a quarter mile track.
If a plane at 1/2 throttle completes a qtr mile in 13 seconds @ 100 mph,
would it complete the same qtr mile @ the same speed if it was on a treadmill moving 100 mph in the other direction @ 1/2 throttle?
I tell you what, lets take out the lift part of the equation and apply the equation with a plane on a quarter mile track.
If a plane at 1/2 throttle completes a qtr mile in 13 seconds @ 100 mph,
would it complete the same qtr mile @ the same speed if it was on a treadmill moving 100 mph in the other direction @ 1/2 throttle?
Registered User
Joined: Aug 2007
Posts: 695
Likes: 0
Originally Posted by Incubus,Feb 13 2008, 02:15 PM
It's like trying to turn yourself in a swiveling office chair without touching anything but the chair.
