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).
Car 26-EX at 10,000 miles, detailing engine performance and acceleration data.
| Identifier | ExFiles\Box 182\M18\ img044 | |
| Date | 23th April 1934 | |
| W7741 To Sg.{Arthur F. Sidgreaves - MD} from G.W.H. c. Wor.{Arthur Wormald - General Works Manager} B. c. By.{R.W. Bailey - Chief Engineer} BP. c. Mx.{John H Maddocks - Chief Proving Officer} HS.{Lord Ernest Hives - Chair} Hotel de France, Chateauroux, Indre. FRANCE. 23.4.34. REPORT ON 26-EX. AT 10,000 MILES. ENGINE UNIT P.II. NO.28. Vulture Type Cylinder Head E.84904. Giving a compression ratio of 6.875 to 1. The engine has been free from half crankshaft period, has become smoother in running up to 70 M.P.H.; above this speed it is generally noisy and vibrations can be felt. There has been no sign of detonations. Carburation has been improved by fitting a weaker jet. Torque reaction period is passable. It has been free from over-oiling at low speeds. The breather from the rocker cover could not be used without excessive oil consumptions, owing to there being too much oil flung out of the rocker shaft bearings with the fitting of the automatic tappet adjustment and eccentric bearings. There has been no excessive speed used during the latter part of the mileage. The engine anchorage has given no trouble. Acceleration figures taken :- M.P.H. TIME (SECS) 10 - 20 4.57 20 - 30 3.97 30 - 40 5.1 40 - 50 5.9 50 - 60 7.65 60 - 70 10.95 Direct Drive. 3rd Speed Accelerations:- 10 - 20 3.8 20 - 30 2.95 30 - 40 4.15 40 - 50 4.00 (11 x 41 Axle Ratio. Dunlop Silent tread 7 x 19.0 type '90' tyres). | ||