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Old 12-22-2007, 06:41 PM   #9 (permalink)
newtonsfirstlaw
EcoModding Apprentice
 
Join Date: Dec 2007
Location: Melbourne
Posts: 152

The Mighty Mira - '92 Daihatsu Mira
90 day: 61.32 mpg (US)
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I was just thinking about velomobiles this morning, thinking to myself why even the best velomobiles like the Quest have relatively poor drag coefficients? The solution would be to raise the body of the vehicle so that the ground effect was minimal (this is the reason that cars used to be thought of as having a 0.11 theoretical minimum drag coefficient), and have two airfoil shaped spars with cowled front wheels. That way, stability would also be the same as a ground-hugging velomobiles. You might also increase driveline efficiency, because you might be able to have one long chain going from the front to the back (not sure how many chains there are in something like the quest, but looking at the front page it looks like there are several.

Everything close to the ground (only the wheels) is very narrow and cowled as a teardrop. And the "fuselage" is also an airfoil shape. Velos like the Quest are shaped like an airfoil, but being a groundhugger they'd be better off being shaped more like the Vector.

This page is darn cool, it lists most of the velomobile drag coefficients.

Quest:


Vector:


Doing all those things makes a vehicle surprisingly like the Aptera. Note also the relatively good crosswind performance, because the shape is streamlined from partly side on as well.

Anyway, back to the velomobile, if you did the things I was suggesting, you could reduce frontal area of the fuselage so it could be narrower than the Quest. And the cowled wheels would be fairly narrow and add little to the overall CdA.

Who knows, you might even end up with something that wouldn't slow up 60kph city traffic. With electric assist, it could be the ultimate commuting vehicle.
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