Quote:
Originally Posted by ConnClark
Some of the air tabs don' look exactly straight in the picture, but I don't think that is enough to make much of an improvement. Also of note moving the position of the air tabs fore or aft will have an effect on their performance.
Do you have the air tabs spaced as recommended by the mfg?
Potentially a better test would to be marking a starting point on a hill someplace with some chalk and doing a distance coast test from the same point each time.
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Sorry, I somehow missed this post.
In response to their straightness, that was the side of the van my friend did
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Yes, installed per manufacturers instructions, both the "on center" and the "from the trailing edge" distances. The taper on the van actually follows the aerodynamic streamlining template very well, so intuitively we saw no advantage to moving them fore or aft, and did not pursue that testing.
There are potentially more and better tests that could be done, including getting a wind tunnel for a day... but we are time and budget limited, so a set of GPS-data-acquisition coast down tests is all we get! Plus, our main goal was to test for drag reduction, and a roll down test like you described would more likely be used to test the rolling resistance of the tires.
Thanks for the input!