Quote:
Originally Posted by brucepick
The car has no cruise control so I just had to do my best to start each coast at the same speed. I attempted to pass a particular speed limit sign at 40 mph, simultaneously putting the clutch in and going into a coast. I recorded the speed at start of coast at the same location each time, and recorded the end speed as I later crossed the same road each time, after about a half mile coast.
Northbound test runs, with spoiler:
START - - - END - - DELTA (MPH)
41.3 - - - - 33.8 - - 7.5
40.0 - - - - 32.4 - - 7.6
Northbound test runs, without spoiler:
START - - - END - - DELTA (MPH)
38.3 - - - - 32.9 - - 5.4
40.7 - - - - 35.5 - - 5.2
40.9 - - - - 34.8 - - 6.1
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That's disappointing alright, but I don't think it tells you much, at this speed, with only an "A" and a "B" run. Still, maybe you are making eddies worse right now. Here is what the tail of our car looks like with tufts pasted into a light mist of water at abt 45mph:
I'm thinking you could taper the sides more to reduce the eddies and smooth-out the down-wash coming from the roof and c-pillars. I wonder what of the aerocivic's dimensions you could just imitate:
Quote:
Originally Posted by brucepick
Next time I have an opportunity to test the spoiler I'll attach it with 3M's no-residue heavy duty duct tape and take it on the interstate. I found two places where I should be able to do a decent high speed coast.
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I think you need more complete testing too. Get as many runs as possible, not just ABA at higher speeds.
I feel you on the officer, and on the frustrated disappointment. I experienced the same process, as you no doubt recall. You'll improve my failure quite a lot if you get a cleaner and better designed shape that I managed.