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Old 22 November 2007, 09:22   #21
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Originally Posted by kitten View Post
you said it
Ok kitten, instead of throwing bombs, why don.t you give us the wisdom of your brain?
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Old 22 November 2007, 09:26   #22
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Only if the speed created by the thrust EXCEEDS the reverse speed of the treadmill. The aircraft will then be moving forward and creating lift under the wings. It would then give a shorter take off run. Conversly, if the thrust is less the aircraft would reverse on the treadmill. Remember in the original question there was no mention of any simulated wind speed.

OK let me have a go at explaining it - if it was a car it would stay stationary as the wheels are turning against the treadmill. The thrust of the plane is acting against the air not the treadmill, therefore the plane will behave completely normally but the wheels will be going faster - that's all.
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When a boat looks that good who needs tubes!!!
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Old 22 November 2007, 09:43   #23
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Cookee, i accept your explanation. it made sense when you used the car / plane analogy. thats the beauty of an online arguement. We get there in the end
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Old 22 November 2007, 10:15   #24
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Originally Posted by Cookee View Post
OK let me have a go at explaining it - if it was a car it would stay stationary as the wheels are turning against the treadmill. The thrust of the plane is acting against the air not the treadmill, therefore the plane will behave completely normally but the wheels will be going faster - that's all.

Time for pedant's corner

You're assuming the wheelbearings and tyres are completely frictionless and that there's no gravity-so the plane is in fact providing a force that's acting on the conveyer-ie the engines aren't just acting against air.

In reality the wheel bearings and tyres would probably die before it got off the ground.
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Old 22 November 2007, 10:42   #25
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Time for pedant's corner

In reality the wheel bearings and tyres would probably die before it got off the ground.
I'm not sure we're talking about reality here - what about the bearings in the conveyor - while we're at it what about the conveyor itself!

Besides if the plane is capable of the sort of rough landings I've experienced over the years I think one double speed take off would be possible!
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Old 22 November 2007, 11:09   #26
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No airflow across the wings...No take off. This and that end of chat.....
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Old 22 November 2007, 11:10   #27
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No airflow across the wings...No take off. This and that end of chat.....
Have you read post number 22?
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Old 22 November 2007, 11:27   #28
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Have you read post number 22?
Did you read this part of the original question?
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The conveyor belt is designed to match the speed of the plane exactly but moves in the opposite direction.
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Old 22 November 2007, 11:38   #29
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Did you read this part of the original question?
Yes - I'm interested as to what effect you think that has!
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Old 22 November 2007, 11:52   #30
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No airflow across the wings...No take off. This and that end of chat.....
I agree! If you don't, please explain where the relative wind would come from that produces a negative pressure above the wings that exceeds the weight of the airplane.
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