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).
Consumption test results for a Napier 16.9 HP 4-cylinder car at Brooklands.
| Identifier | ExFiles\Box 20\6\ Scan010 | |
| Date | 16th September 1909 | |
| R.R. 148 (20 H) (H.{Arthur M. Hanbury - Head Complaints} 360. 16.9.09) E.P. 4941. Consumption. Napier 16.9 H.P. 4 cylinder 1800. 2300 R.A.C. test on Brooklands. X985 3 1/2 bore x 5" stroke. 4 seater body windage 19.4 []' total weight (with passgs) 3,156. lbs. 26.004 miles per gallon. | ||