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).
Petrol consumption test results for an AR.75 aluminium engine under different carburetion settings.
| Identifier | ExFiles\Box 147\5\ scan0099 | |
| Date | 11th October 1927 | |
| HS{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} X459 11-10-27 PETROL CONSUMPTION TESTS. 10EX. PARTICULARS OF CAR WHEN TESTS WERE MADE. ENGINE No AR.75 (Aluminium Engine). COMPRESSION RATIO. 4.95:1. DRILLED PISTONS WITH TWO TOP RINGS ONLY. (.0085" clearance) parallel. AXLE RATIO. 17/52 = 3.058:1. 33x6.75 Tyres at 35 lbs/sq" pressure. Water temp 75°- 80°C. Hood up. Roads dry, no appreciable wind. Tests were carried out at 30 m.p.h. with the carburettor lever at 1) Normal. 2) 3 notchs weak. 3) 3 notchs strong. Six tests were taken under each condition; the average figure for each condition being as below; 1) CARBURATION NORMAL. M.P.G = 17.48. 2) " " 3 WEAK. M.P.G = 21.28. 3) " " 3 STRONG. M.P.G = 16.99. AVERAGE OF THE ABOVE = 18.58 M.P.G. AHedley | ||