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).
Frontal area calculation diagram for the Bentley I.
| Identifier | ExFiles\Box 160\2\ scan0138 | |
| Date | 5th July 1933 guessed | |
| BENTLEY I UNSHADED AREA 28.38 □ FT. K = .00165 2.22 □ FT. SHADED AREA. 10 FT. BETWEEN GREEN & BLUE CAR. | ||