Quote:
Originally Posted by 9racing
not true.. Myth busters did a show on this.. they used clay on the whole car, and dimpled the whole car.. both before the clay and after the clay and then after the dimples on the car.. The car with the clay and dimples actually got better gas mileage than the regular car minus all the weight from clay.. so if it is dimpled all over, you will get better gas mileage plain and simple.. so bring the hail, now im not sure how deep the dimples have to be before you start gaining anything.. it was a good amount they gained if memory serves right..
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I guess I should clarify. What I was trying to say is that you really don't need them over the entire car. Yes, MB did show an improvement with dimples over the entire car, but dimpling at certain spots on the car probably would have gotten the same result. Here's an excellent Air Force paper on some dimple research:
http://stinet.dtic.mil/cgi-bin/GetTR...c=GetTRDoc.pdf
Part of the background research for this particular paper cited previous dimple testing:
"James Lake [6] examined dimple location along with comparing dimples to v-grooves and trip wires in his investigation on reducing sparation on a Pak-B turbine blades. He found that dimple location had an effect on dimple effectiveness. Dimples were most effective when placed slightly upstream of the unmodifed blade separation point. As the dimple was moved further upstream of the separation point, its effectiveness decreased. His research shows that for maximum effect, dimples should be placed as closely as possible to the point of separation."
That's what I was trying to say originally. Although hail-damage could aid in fuel mileage, properly placed dimples would be most advantageous. Now, the paper I posted goes further, looking at the diameter/depth ratio of the dimples, and how that affects the flow characteristics.