aerocap kamm back critique

[laack]

what would be the best way to maximize my aerocap. currently it is similar to what is drawn in black, but I have been recently thinking about the tail end of the Prius and insight. Their kamm spoiler represents more of the red line added to the slope of the rear window of the hatch.

Would it create a better separation or wake if i were to lift the trailing 6-8 inches to become parallel to the ground similar to the Prius? Is it purely aesthetics for the spoiler to be parallel rather than continue with the teardrop shape?

I'll try to get some pictures of my cap later, but I'm having trouble compressing the image to upload


Current mpg:
27.85
all highway trips if i maintain 65 =30-31.

previous best before cap 27.

[Frank Lee]

Spoilers are either added for fun or for correcting an aero deficiency.

If you don't have flow separation back there, a spoiler won't help and possibly could hurt.

You need to figure out if there is separation there. However, just by looking at the pics, the angle looks shallow enough to me that I'd say there isn't separation there.

[skyking]

That looks good as is, so do the results.

[laack]

i have done a bunch of tuft testing with it and there is no flow separation. The tufts do flap around a little bit, but they are all straight back with the flutter.

[Frank Lee]

Then why do you want a spoiler?

[skyl4rk]

Looks pretty good

If you want to redesign it, you could lower the tailgate build the cover to drop all the way down to tailgate level, possibly extending it past the tailgate.

[laack]

Originally Posted by Frank Lee

Then why do you want a spoiler?

its not that i necessarily want one, i am just curious why the prius has its parallel to the ground rather than following the teardrop. if there is an advantage to it that isnt specific to the prius/insight i would like to reap the benefits of a subtle change such as that.