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Old 07-14-2011, 10:46 AM   #14 (permalink)
t vago
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Quote:
Originally Posted by ChazInMT View Post
I only mention all this cause it sounds as if you project is a sort of prototype and you may make another version 2 of the same thing, I'd hope you consider making the Kamm shape less aggressive if you do.
I second that observation. You did make your taper too aggressive. I offer my own experiences to show.



Version 1 of my aerocap, as you can see above, had a pretty aggressive slope. With it, I saw an average of 3.6% improvement in FE.



Version 2 above, as you can see, is nowhere near as aggressive. While version 1 tapered down to about 2 inches at the back, version 2 tapers down to about 11 inches. Also notice the nice big 8 inch gap between the aerocap and the cab rear. Common sense would tell you that these things I pointed out would not work so well.

The incomplete form of version 2 netted me a 6% improvement in FE.



The complete form of version 2, with the 8 inch gap filled in, netted a 10% improvement over no cap.

Now, it's not to say that you did a bad job. One can't ignore an 18% improvement in FE like you saw with your camper extension here.

However, should you build a version 2 for some reason (I built my version 2 because my version 1 decided to fly away from my truck at speed and destroy itself), you should keep in mind our advice to build a less aggressively sloped version.

Quote:
Originally Posted by ChazInMT View Post
Again, Excellent Job!!
I second that, too.
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