Here’s what I’ve done lately. I’ve read in Edgar’s book that an EBLA of 10-12 degrees is quoted as being best by Adrian Gaylord. I guesstimated that angle and took a hardwood flooring sander to a laminated stack of foam sections. The way the trunk is setup, I can actually get the front edge of my “wing” pretty close the rear glass. I sanded the leading edge more than I really needed to, but it seems to work very well. Flow is cleanly attached, so far as I can tell.
I used a very long tuft to try and measure the proper EBLA of the car, and got confused. It was evenly spaced 2” or so above the surface of the “wing”, and did that consistently.
I cut/taped another piece, adding more height with the same angle. Yet again, it looks like the tuft is 1-2” above the “wing”. Even if adding a bit more height is a better idea, I don’t think I want to as I can’t see much of anything with the extra 1-2”. It’s much more practical without.
Am I simply looking at the boundary layer? I hope that’s the case, but I’m not too sure. If anybody could explain this to me I would greatly appreciate it.
