Quote:
Originally Posted by Mighty Mira
Very good point. I think the key is to make the bottom as curved as the top, or at least, to angle the end upwards (slightly). I think the latter is the better solution, to be honest.
It makes sense if you realize that Bernoulli's explanation is not really the proper explanation for why lift is generated. See here. The reason lift is generated is that air sticks to the surface, and momentum is conserved. Hence whatever direction the air tends to go after it leaves the vehicle is opposite to the direction the vehicle will be propelled. And provided that the slope the air is attempting to stick to is not steeper than a certain grade, you can direct it in any direction you choose.
In fact, now that I know about it, teaching the Bernoulli effect as the primary cause for lift is really doing a disservice to aerodynamics understanding.
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The essay referenced above does not properly address lift.
I do not have a text handy, do not remember the equations off the top of my head and could not reasonably represent them in ASCII even if I did.
However, as I recall, lift is produced
both by pressure differential (which can be directly measured)
and by downflow (which can be observed but is much harder to quantify). For a specific airfoil, the relative contribution of each is determined by the aspect ratio of the wing
So a short stubby wing like a typical rudder will primarily generate lift from downflow, but long skinny wings like the main wing on a high performance sailplane will primarily generate lift from the Bernoulli effect.
An infinite wing (meaning infinite span) has infinite lift and no downflow.
Modern jetliners and sailplanes typically have winglets on their wingtips. These are designed to improve the lift to drag ratio of the wing by reducing the wingtip vortices, which also reduces the downflow.
Considered as a wing, the typical autobody has a pretty low aspect ratio so you might suppose that downflow dominates. However automobiles generally do their flying close to the ground so you may want to research wing in ground effect (WIG) vehicles, instead of airplanes.
http://en.wikipedia.org/wiki/Wing_In_Ground_Effect
Linear Mode
