Quote:
Originally Posted by dcb
Is it safe to say the battery did not make any unusual contributions or detractions from any of the test?
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Yes:
- pre-test warm-up - by keeping the car at or above 46 mph, the battery soon reaches its nominal SOC. In this case, the warm-up area was at high speed, the Parkway at +50 mph, and the approach to the test runs on level ground, Governor's drive exit onto I-565.
- After 10 miles, the MPG does not significantly change - another key element is the vehicle achieves a steady state on a fairly level run. The local variations have been 'averaged' out of the final numbers.
- Proportionality between three West and three East runs - West: 53.0, 52.3, 52.9 and East: 54.2, 50.9, 53.7. Although the exact ratios vary, the order remains the same: A>C>B ... suggesting a valid data sample.
However, I agree a better procedure would be more randomized trials along the lines of an "A" "B" "A" series. Serendipity, the vehicle baseline runs without an air block were sandwiched between the two experimental configurations. Since I plan to do some wheel well cover tests and air dam and side skirts, I'll see if some of the combinational tests can mix it up a little better.
BTW, the results are consistent with what I had expected. The rear block should have some flow of air in that spills out the lips on either side. This should result in a loss of momentum and higher drag. The front, flush block would keep the air stream displaced but at velocity. The unblocked air inlet should cause significant energy loss as the air that enters is brought to near vehicle speeds and then dumped overboard.
I was lucky on Sunday. It was overcast which kept the temperatures fairly constant during the day. The last run was just at sunset and the temperatures were still what I'd seen earlier that afternoon.
Bob Wilson