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Old 06 February 2008, 09:56   #81
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Quote:
Originally Posted by limeydal View Post
The propellor provides the "pull" to increase the wings speed relative to the air
around it. No forward movement " relative to the air " ,so no decrease in pressure above the wing ,so no increase in lift on the areofoil , hence no flight.
Think someones pulling our plonkers
Just for the record I'm with Nos on this - what happens with pusher props? What is actually stopping the plane moving forwards?

IT TAKES OFF!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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Old 06 February 2008, 20:07   #82
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Codders is partially right on lift to weight ratio.A model planes propeller thrust alone may increase the air flow across the wing enough to lift a light model.
Andy's original question posed a full size plane and no way is prop thrust alone going to lift it.
There's a reason we have long runways
You have to get that airflow moving fast over the wing and the differential in pressure between the top surface and bottom is what provides the lift.

So wheels/pusher props/conveyor belts etc are all obscuring the issue and basicaly irrelevant.

Lift = differential in pressure when the airflow splits at the wings leading edge .
The rest of the explanation is a little more complicated.
http://travel.howstuffworks.com/airplane.htm
But all boils down to fast moving air flow over the wing ,which you dont get with Andy's original scenario.
It aint' gonna fly;no way;no how

Imagine cookee's question about a pusher prop!(So no draft from a front mounted prop) If you stood alongside this plane in the test(remember speeds are matched ) could you stand a matchbox on the wing
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Old 06 February 2008, 20:15   #83
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You're missing the point by a mile.

For the conveyer to be matching the speed of the plane over the ground in the opposite direction, the plane has to be moving forwards over the ground. Therefore, you get airflow over the wings and it takes off.

It really is that simple.
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Old 06 February 2008, 23:37   #84
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It's NOT THE WHEELS THAT ARE POWERED ON A PLANE AND THATS WHY IT TAKES OFF!!!!!!!!!
Nail-on-the-head.


Myth..............BUSTED.
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Old 07 February 2008, 00:20   #85
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Wow!! I'm converted.
I will call the Navy tommorrow and tell them to scrap their carrier fleet.
Just instal a conveyor belt on a small deck and the fighters will just lift off !
Think we could make some money on this
Of course landing may be an issue
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Old 07 February 2008, 02:29   #86
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Originally Posted by limeydal View Post
Wow!! I'm converted.
I will call the Navy tommorrow and tell them to scrap their carrier fleet.
Just instal a conveyor belt on a small deck and the fighters will just lift off !
Think we could make some money on this
Of course landing may be an issue
I'd hang fire on that if I were you... even your Navy fleet ain't this long..



Quote:
Originally Posted by Andy Moore View Post
massive hypothetical conveyor belt, as wide and as long as a runway.
As my old teacher used to say "Make sure you read the whole question properly..." Actually what he used to say was " Clear off out of the class, Boy, and go and tell the Headmaster why you think it's funny to set fire to young Wilkes’ books".. but that's another story.
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Old 07 February 2008, 05:55   #87
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Quote:
Originally Posted by limeydal View Post
Wow!! I'm converted.
I will call the Navy tommorrow and tell them to scrap their carrier fleet.
Just instal a conveyor belt on a small deck and the fighters will just lift off !
Think we could make some money on this
Of course landing may be an issue
Errrrm....


Did you watch the whole of the video-the bit where the plane took off in normal distance over the ground?
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Old 07 February 2008, 11:26   #88
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When I was 42 I thought I had a brain the size of a planet, but nobody would listen.

After this thread I know my brain's the size of a planet, but if I say anything I know nobody will listen. So.........

I'm going to help Nos4r2 with his wall.

Nos Me
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Old 07 February 2008, 16:30   #89
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I gave up on this thread ages ago.

nos aystra me

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Old 07 February 2008, 22:40   #90
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