Bicycle Bob:
I'm planning to hinge mine at the top, as you suggest and as basjoos did on his Civic:
Aerocivic - how to drop your Cd from 0.34 to 0.17
Though once I start construction, I'll probably wish I'd followed the "rubber membrane" method Newton used on his Mira:
DIY Rubber Front Wheel Skirts
I also like your idea of servos for hinge control (hadn't thought that there might be feedback if there were a direct link to the steering bits).
But I'm going to keep it simple and go with a low friction plastic stuck on the back side of the skirt which the tires will contact when they are steered. basjoos went with low profile metal rollers.
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For chuckles, some pics of the camera rig, or more technically, "web cam on a metal stick, secured with duct tape, a nylon strap, rope and a bungee":
The boom is an extruded aluminum U-shaped member (the track from a large vertical blind), secured to a roof rack. Between the "skirt off" and "skirt on" video sessions, I added the rope that goes from near the end of the boom to the bottom of the passenger door, tensioned with a bungee cord to the rear of the car. That put some pre-tension on the boom and reduced the camera bounce/wiggle compared to the runs without it.
It stuck out about 4 feet from the side of the car.
I was careful not to overtake cyclists or drive close to sidewalks or utility poles!
