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Originally Posted by Scissors
Reading is fundamental.
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Originally Posted by Scissors
Nobody said anything about calculating the aircraft's velocity by wheelspeed. RIF.
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Since you love to cite the term, perhaps you should utilize it more yourself.
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Originally Posted by Scissors
(post# 671)....if the treadmill is moving at the same rate as the wheels....
(post# 674)....the rate at which the wheels spin versus the rate of the treadmill.
(post# 674)....the surface is moving in a direction opposite the plane's and at the same speed as its wheels.
Etc, etc, etc....
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These would
all involve measuring velocity via wheel speed....
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Originally Posted by Scissors
The original version of this thought experiment refers to the rate at which the wheels spin versus the rate of the treadmill. If these match, then the axis of the of the wheels does not move. They stay in one place. If the wheels are staying in one place, this means the plane's ground speed is zero--which means that its air speed is zero.
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Regardless of the velocity the treadmill achieves, it is impossible for it to impart enough resistance, via an aircraft's free-rolling wheels, to overcome an aircraft engine's forward thrust. Simple fact. There is nothing which states that this magical treadmill cannot achieve instantaneous speed matching, meaning that the belt would simply be "chasing it's tail" with continuous acceleration (If we continue with this theory of measuring of wheel-speed, that
isn't a measurement of wheel-speed as you contend.)
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Originally Posted by Scissors
....or because the drag from the treadmill against the wheels equals the thrust....
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Originally Posted by Scissors
Contrary to the apparently popular opinion, the wheels of a plane and their contact patch with the ground is not perfectly free of drag.
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They don't need to be, as thousands upon thousands of aircraft prove, every single day. The level of friction generated by the rolling wheels
cannot prevent the aircraft from achieving lift-off. The fact that an aircraft's engines are capable of dragging it's locked wheels (which produce an exponentially greater friction) across the tarmac, only demonstrates the engines capability.
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Originally Posted by Scissors
Scenario 3:
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Despite your panning of this theory, this seems to be the most appropriate description of how it
would work. Your assumptions seem based on the idea that this treadmill isn't capable of matching speeds by any reasonable reaction time. However, the treadmill would simply have to maintain a continuous rate of acceleration, as it works to match a speed which it is in itself accelerating. This rate of acceleration, by both the aircraft and treadmill, would be only slightly reduced by the rolling resistance between the wheels on the landing gear and the treadmill surface. At any rate, even if the wheels and treadmill
were absolutely condemned to maintain an
absolute equal speed, the aircraft would simply drag the tires in a rolling skid....
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