Quote:
Originally Posted by MetroMPG
That's a really interesting way to emphasize that point.
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Yes, it's a good way to think about it. Considering that an airfoil has a Cd of around 0.05, and good cars have a Cd of around 0.30, the airfoil has 1/6 the drag of the car and 1/20 the drag of a flat plate. It's as if the airfoil is almost invisible to the air.
Of course, being near the ground has issues, you can get to 0.11 or so but to get better you have to start approaching an airplane by having cowled wheels and hoisting a fuselage as high as you can without toppling in a corner. But still, a Cd of 0.11 is still 10 times better than a flat plate, which is what a motorcycle or upright cyclist is basically.
Another trick I learned from airplanes which the designers of the aptera seem to have learned is that you put the trailing edges of airfoils next to the leading edges of other aifoils. See this
plane. If you google the AR-5 you can find more about it - total CdA of 0.88 square feet. I think what happens is that the leading edge of an airfoil creates high pressure, the trailing edge creates low pressure, and you minimize pressure difference by doing this, and hence minimize drag.