From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Comparative table of aerodynamic resistance data for various competitor cars.
| Identifier | ExFiles\Box 161\1\ scan0196 | |
| Date | 20th September 1938 | |
| AERODYNAMIC RESISTANCE. OTHER CARS CAR :- CAPACITY IN C.C.M.S H.P. AT LAP SPEEDS LAP SPEEDS MPH FRONTAL AREA SQ.FT. WGT TONS ACTUAL "K" ACTUAL Cx{Major Len W. Cox - Advertising Manager} K TUNNEL FLAT PLATE K TUNNEL REFLEX REMARKS. PACKARD 6 LIGHT SALOON | 4620 | 72.0 | 81.0 | 26.40 | 1.72 | .00178 | .695 OLDSMOBILE 6 LIGH SALOON | 3760 | 57.5 | 77.0 | 25.60 | 1.70 | .00168 | .656 FORD V8. SALOON | 3620 | 58.0 | 81.6 | 23.80 | 1.51 | .00150 | .586 JAGUAR SALOON 3 1/2L | 3485 | 77.0 | 84.0 | 23.60 | 1.75 | .00187 | .730 DELAGE (LABORDETTE) | | | | | | .000562 | .220 PEUGEOT CARÉNÉ (ANDREAU) | | | | | | .000716 | .280 ROLLS-ROYCE, LTD PRINT ROOM SEP 22 1938 DERBY. | ||