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Old 01-20-2021, 04:08 PM   #1 (permalink)
aerohead
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historical origin of some rules of thumb

* Delta-10% Cd = delta- 4.2% mpg @ 70-mph. Re: SAE Paper 730790
* Delta- 10% Cd = delta - 2% EPA Combined mpg Re: SAE Paper 740969
* Delta- 10% Cd = delta- 4.28% mpg, EPA Combined, Re: SAE Paper 760187
* Delta- 10% Cd = delta- 4.236 % mpg @ a constant 55-mph for a fully-warmed test vehicle as per SAE J-1082 Road Test Procedure, Re: SAE
* Delta- 10% Cd = delta-5% mpg, @ a constant 55-mph, as otherwise tested to SAE J-1082 protocols, Re: General Motors Aerodynamics Laboratory, Warren, Michigan, USA.
* Delta 10% Cd = delta- 3.5% mpg, Re: Ford Motor Company, 1982
* Delta 10% Cd = delta- 8.82% mpg, Re: Robert Stempel, Manager, Chevrolet Motor Division, General Motors Corporation, Re: GM, Chevrolet Citation-IV concept car, 1984.
* ' If, in the given example, the drag coefficient Cd was reduced from 0.46 to 0.30 ( 34.782% ), a fuel consumption reduction for a petrol-engined vehicle of 14 percent would be returned ( delta-10% = delta 4.025% ). For a diesel-engined variant, a reduction of 17 percent would result ( delta-10% = delta- 4.887% ).' Wolf Heinrich Hucho, page 104, 2nd-Edition, December, 1986.
* A delta- Cd 0.01 = delta- 0.01 mpg, Re: GM Sierra / Silverado pickups, Frank Meinert, G.M. Pickups, to Edmunds.com, 2012.
* ' With an increase of 10 per cent in top speed, which results from approximately a 30 per cent reduction in aerodynamic drag,.............', Wolf Heinrich Hucho, page-92, 2nd-Edition, December, 1986.

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Last edited by aerohead; 01-20-2021 at 04:32 PM.. Reason: add data
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