User talk:Proberts

Gravity
Sorry, but you have not explained how a vertical force can provide a horizontal acceleration. Without wings the glider falls vertically. It is therefore the wings that provide the horizontal force. The lift is always at right angles to the relative air flow. The airflow usually comes from below the line of zero lift of the wing and so there is a forward component. Just as there is a lateral component from the wings to turn the aircraft when it banks. Analogies with skate boards and bicycles do not apply because there is no rigid medium to transmit force. Much as I like Derek (he saved my life once), he is just plain wrong, though he can still beat me flying. Which particular element of drag do you think is reduced? Lift-induced drag or profile drag? If so, how? JMcC 23:45, 12 October 2006 (UTC)

Before you start resolving forces, try starting with the basic force diagram of a glider flying at a steady speed. There is drag acting at right angles to the lift, there is gravity acting downwards and there is a lift force. If the glider is flying at a steady speed, these forces cancel. If lift acts backwards as you say, your version of the diagram would have the drag acting backwards & slightly downwards to maintain equilibrium. What force increases to cause acceleration when the nose is lowered? You say that it accelerates because lift induced drag is reduced? However this lift induced drag falls towards zero as the glider passes min sink. Are you saying that if I am flying at 100 knots, there is no way I can speed up because there is no lift-induced drag left? I assure you that you can still speed up until the wings drop off. JMcC 09:41, 15 October 2006 (UTC)

Proposed deletion of File:Wing force diagram-png.png


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Proposed deletion of File:Gravity wing.png


The file File:Gravity wing.png has been proposed for deletion&#32;because of the following concern: "Unused, unclear use/purpose"

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