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).
Table comparing the horsepower required to drive Bentley and Dubonnet cars, and the improved acceleration from streamlining.
| Identifier | ExFiles\Box 161\1\ scan0004 | |
| Date | 6th April 1936 | |
| -3- Ha/Rm.{William Robotham - Chief Engineer}16/KW.6.4.36. | Road Speed M.P.H. | H.P. Required to drive the car. | Improved Acceleration due to Streamlining. | |-------------------|---------|----------|--------------------------------------------| | | Bentley | Dubonnet | | | 40 | 20 | 12.5 | 7½% | | 60 | 47 | 24 | 28% | | 80 | 105 | 48 | 32½% | This assumes the weight of the two cars to be identical. | ||