Construction details, part 1: Kammback transformation...
Before a tapered tail can do its drag-reducing aerodynamic magic
, we want to deliver clean, attached airflow to the back of the car. That's a problem with a notchback (a.k.a. 3-box) design, because airflow typically gets messy behind the rear glass:
Of course, the flow over the Civic's rear glass & trunk isn't as bad as this exaggerated image. How do I know? I
taped yarn tufts on the rear window and went for a drive.
Tuft testing result: I was slightly surprised to see separation/recirculation (red/orange area), but it's there. Even though the Civic's rear glass is laid way back and the deck is fairly high, it's obviously stil too "fast" to keep attached flow.
Solution: A MORE PRIUS-Y PROFILE, PLEASE!
HOW THE HECK DO I SEE OUT THE BACK?
It's got a rear plexiglass window. Also, I built in a high-center-mounted third brake light:
Looks neat, eh? No, the snow isn't sitting on cardboard. It's all wrapped in heat-shrunk plastic at this point.
And I gorilla taped the whole thing to the back of the car.
So, no, that means I can't open the trunk anymore. But I can still access it from the cabin, through the folding rear seatbacks. I can also get the spare & tools out that way if I need to.
(For full details of the Kammback construction start at
post #173 in the kitchen-sink-megathread.)