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).
The method for conducting petrol consumption tests on a New Phantom touring car.
| Identifier | WestWitteringFiles\N\2October1925-December1925\ Scan152 | |
| Date | 12th June 1925 | |
| R.R. 493A (50 H) (D.D. 31, 12-6-25) J.H.D. EXPERIMENTAL REPORT. Expl. No. REF: Hs{Lord Ernest Hives - Chair}/Rhd/LG211125 NEW PHANTOMCodename for PHANTOM I - PETROL CONSUMPTION TESTS. METHOD EMPLOYED. These tests were carried out on an open touring car weighing 2.516 tons, fitted with Dunlop 33 X 5 straight sided cord tyres. The road surface for the most part was dry tar-macadam though occasionally this became wet. All the tests were carried out on a practically level stretch of road about 3/4 of a mile long and perfectly straight. The mean of three or four both way readings constituted a test for any one condition or speed. The method of carrying out the test was as follows :- The distance between two points on the road was accurately measured (about half a mile). A pipette which would just hold sufficient mixture to enable the car to cover this distance normally at 30 m.p.h. was then procured and rigged up as a flow-meter as in the illustration. Two stop watches were employed. The driver endeavoured to maintain the required speed by means of the speedometer. When passing the first point the carburetter was thrown into communication with the pipette and one stop watch started. The second stop watch was started as the level of the liquid fell past a pre-determined mark on the pipette. When the liquid fell past a second mark in the pipette the second stop watch was stopped. When the second point was passed the first stop watch was stopped. These two readings gave accurately the rate of fuel consumption and the average road speed contd :- | ||