Quote:
Originally Posted by j-c-c
I don't know what the relative air temp distribution is above a race track surface based on elevation. I suspect its mimical above 6" in all but the stillest of air for the first car, and likely nonexistent for every car thereafter in the pack. I also suspect because of drafting the lead car is the car producing the most power output in a pack over time and the one car most dependent on every single hp any cooler air or ram effect provides, and the car that aero slickness is most beneficial. My suspicion, cowl intake air location in NASCAR is more just a holdover from the 60's. On a slightly related note, I do know that rear center exhaust exit location (David Pearson) was banned in the 60's in NASCAR because it prevented anyone drafting the lead car due to engine overheating.
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1) from Chrysler's Romberg et al's reporting in 1971, the lead car receives a 30.1% drag reduction from the car behind them, while the trailing car picks up a 37.1% drag reduction.
2) From Gotz' commercial vehicle 'drafting' research we know that the car in a three-car draft would experience even lower drag ( 71% in the case of buses ).
3) rear exhaust outlets were banned because of carbon monoxide poisoning to the trailing drivers.
4) with respect to cooling, during the draft, the Cd of the second car has fallen from 0.315, to 0.198 ( in 1971), and because of the velocity-cubed power law of aerodynamics, the trailing car's engine is actually 'loafing', and it's heat rejection requirements extremely reduced. They could race 500-miles like that without event.