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Originally Posted by fleaofsc
You guys don't understand what Mainerunr is trying to say. Both he and I understand what all you are trying to say. Someone else said "Can a plane take of if its wheel speed equals the speed of the treadmill." The answer to that question is NO.  |
This is an incorrect statement. The plane will take off.
The incorrect theories that abound in this thread have three types of errors.
First is reading comprehension. The statement: "Will the plane take off" implies that the pilot has engaged the engines at take-off thrust. No half throttle, no partial throttle; full take-off power.
The second error is basic physics. The propulsion system on an airplane is by momentum balance. The momentum of high velocity gases exiting the engines is counterbalance by forward momentum. The observed motion of a balloon caused by a sudden release of air is but one example of this principle. You can put wheels on the balloon and put it on a moving conveyor. But the balloon acts on the expulsion of air and will ignore the wheels.
The third error is assuming the conveyor can move the plane. There is only a frictional coupling to work with. This is poor at best. We can compare this with an open differential. In a situation where one wheel has no traction, how much torque is delivered to the other wheel? Not much. The internal friction in the open diff is not sufficient to transmit torque. This is why we have lockers.
If the pilot applies full take-off power to the plane, it will take off. The conveyor can go backwards, forwards, same speed, half speed, twice speed, or any speed, and the plane will take off. There is nothing the conveyor can do to prevent take off because the plane is driven by the forward momentum created by the engines.
