Quote:
Originally Posted by brucepick
And thanks to California8Civic!!
First, trim the fins so they don't exist at the tail end. Just a straight line from the current top forward corners, going down to the back to meet the spoiler rear edge.
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My bet, looking at the aerocivic is that this tail shape will be the winner even on our car, if any work well at all.
Quote:
Originally Posted by brucepick
I got the rear narrowing rate, and also the side slope of the side panels, by matching and following the contour of the body. I'm just trusting that the engineers did a pretty good job. So far it looks like that's the case - my first attempt likely increased the drag.
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Following their lead might suggest not having the fins at all. Seems possible that your fins are creating more turbulence, given how some of the air seems to travel down the back (my tuft images above). Some of the flow is spilling over and around and twisting, out back of the car, off those fins I suspect. In my tuft image, someone pointed out to me that you can see evidence of airflow sliding off the trunk lid at the sides, airflow that is probably spinning off the backend of the corners as a result. A kamm, a spoiler/kamm like this one, needs to eliminate that. I think the fins accomplish the opposite goal.
The kamm/spoiler wins if it reduces the turbulence off the c-pillar, and the subsequent eddies off the rear corners. Basjoos has the shape. Question is whether your spoiler version can accomplish it too. If you are keeping the fins, I like the suggestion of trimming them so they don't exist anylonger when you get to the end of the spoiler/kamm.
Just my untrained, hobbyist, opinion.