I think my design is flawed... help?

[Thenorm]

i think the radius in the corners of the Kamm is too large. looking from the side of the car looks fine, but looking from the top it looks like the side taper is too much, the flow separates and you get a snow acucmulation.
instead of one large curve, it should be a little closer to a box shaper (smaller radius in the corners, a little flatter on top)

[redpoint5]

I second the opinion of Thenorm. The snow pattern on the trunk really shows where the flow separates differently, and you want a uniform pattern and separation. The further back the snow accumulates on the trunk lid, the more effective your kamm is.

It generally looks good though. Did you do any before and after testing to quantify the gains of the kamm? I'd be curious to know how much of an improvement you saw.

[freebeard]

Your Kamm-back is trying to be more template-like (half-round) but you're up against the limitations of the template. It's dependent on the upstream conditions, and really needs to start at the stagnation point at the front.

That patch of clear glass. Was it caused by the airflow or was that an adjustment for visibility's sake? Otherwise the trident shape is way interesting and is going right into my 'snerodynamics' folder. The outer tips show the taper the roof wants and the center tip shows there are vortexes being generated. The buildup on top of the Kamm-back shows the influence of the upstream conditions.

I'm not sure I follow... do you mean cut the body of the car??

Two question marks?

"Anyone can restore a car, it takes a real man to cut one up."

"Cut. Weld. Drive."

...you get the idea. Cut a tall narrow C-shaped slit betwen the gas-cap/wheel well and the tailight. Push the back edge in and fill the corners. You have an air intake of maybe 24sq in.

Then skin the rear bumper and there should be a plastic egg-crate reinforcement, drill out the bottoms of all the cells. Cover it with used trampoline material.
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IMHO the best suggestion you've got was from kach22i:



The top is so close to right, stock; the only thing the Kamm-back is probably doing is causing concern among your neighbors. A thin aluminum Gurney flap affixed to the top of the backlight is probably the most you need.
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Remember half the drag is from underneath and the very rear. Think about a diffuser.

[aerohead]

There are:
*squarebacks
*notchbacks
*fastbacks
*'aerobacks'
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Your car is a notchback which has the most complicated flow of all body types.There's easily a dozen body criteria which will impact the flow of their aft-bodies.
I suspect that Honda has already 'optimized' everything you see in their wind tunnel and the introduction of the partial Kammback could compromise what they've accomplished.
If you had a hatchback,you could remove it altogether and construct an ideal Kamm roof profile of full length.More like what basjoos has done with his AeroCivic.
For you to do a proper Kamm roof as you've learned,will cost you access to the trunk.
Short of removing the trunklid,fabricating a overarching enclosure,you're kinda forced to do an articulated,hinged Kamm addition which can flip out of your way to get to the trunk.
The partial Kamm I'm afraid will never give you the performance you seek.

[whatmaycome14]

Thanks to everybody that responded. At this time, I've actually removed the whole set-up, but will be working on other designs. One of the biggest problems I have with it is that I can't test it! I ran out of duct tape and it's too cold and wet outside to really do anything. I may have to wait until spring to go any further with it.

I appreciate all the input though!