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DF3VI > INFO 23.07.02 19:06l 61 Lines 2339 Bytes #999 (180) @ WW
BID : N7CDB0OVN00X
Read: DB0FHN GUEST
Subj: Re: VK5QX RE - BALLOONS
Path: DB0FHN<DB0ZWI<DB0HDF<DB0ERF<DB0ROF<DB0AIS<DB0NDK<DB0ACH<DB0OVN
Sent: 020723/1647z @:DB0OVN.#NRW.DEU.EU [BCM West<>Link - Neuss] bcm1.44l LT:18
from: DF3VI @DB0OVN.#NRW.DEU.EU (Patrick)
To: INFO @ WW
X-Info: Sent with login password
>From: VK5QX@VK5LZ.#ADL.#SA.AUS.OC
>To : INFO@WW
>
>
>
>SOME CLARIFICATION (? ?)
>
>Ray VK4LU said :-
>_______________
>
>" Just a few points I think are wrong. First on the plane wing. I seem
>to remember that about two thirds of the lift is provided by the
>differential pressure. The rest of the lift is provided by the wind
>straiking (sic) the underside of the wing.
>_______________
>
>I have never seen anything which suggests that lift is obtained by wind
>striking the underside of the wing.
>
>My understanding is that forward motion causes a flow of air to pass over
>both the top and bottom surfaces of the wing.
>
Of cource, MOST of the lifting force of a wing is produced by the bowed
shape of a wing, making the air run faster above the wing which results
in a pressure drop and this gives a lifting force.
But any solid material hold into the wind, even with no aerodynamic shape,
receives a lifting force depending on its angle in the wind.
Where dows this force come from? Imagine a vertical plate in the wind:
you need a lot of force to hold it against the wind. (Or look at a sail,
this force can move a big ship!)
When this plate is flipped gradually forward, more and more of this force
is redirected from horizontal to vertical force - most at 45 degrees.
Then the force decreases - because a horizontal plate has almost
zero area giving resistance to the wind.
Conclusion: If an aeroplane is starting, then a part of the lifting
force is added because of the angle of the plane's wings in the wind.
It goes to almost zero when the plane is flying straight...
(not really zero because of the shape of the wing, with the front being
higher than the back end.)
73
y
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: Patrick ! !__! DF 3 VI !__! @ DB0OVN !__! JO31FH !__! G21 !
/=o=O=O=O=o=' `O=O====O=O' `O=O====O=O' `O=O====O=O' `O===O'
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e-mail: df3vi@west-link.net
P.S. to Ian on TV-tube vacuum:
The topic was WEIGHT - not function - of a TV set.
Sorry to say, but you were off-topic.
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