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).
Comparing the specifications and power output of Hispano and E.A.C. engines.
| Identifier | ExFiles\Box 180\M4\M4.1\ img038 | |
| Date | 11th March 1924 | |
| R.R. 493A (40 H) (EL 42 12-7-23). J.H. D.{John DeLooze - Company Secretary} EXPERIMENTAL REPORT. Expl. No. 4214 9770 REF: Hs{Lord Ernest Hives - Chair}/ACL/AV/10. 11.3.24. COMPARISON OF HISPANO AND EAC. ENGINES. HISPANO. E.A.C. Bore and stroke. 3.938 X 5.512 4.25 X 5.5 Swept Vol. (litres) 6.597 7.67 Compression ratio. 4.6 4.7 Connecting rod/crank. 4.2 3.6 Valve port diameter. 1.574 1.75 Ratio lift/port diameter. .39 .487 Induction pipe diameter. 1.575 2.00 Pre heating. Water jacketed. Hot spot. Throat area of carburetter. 2 X .911 * 1.822 Max. area throttle valve port - valve fully lifted. 1.532 sq.ins. 2.156 sq.ins. Valves. 45° flat. 45° tulip. E.A.C. capacity approximately 16% larger than Hispano. POWER OUTPUT. From the curves of B.M.E.P. against gas velocity, the Hispano curve starts falling at a 'conventional' gas velocity of approx. 183 ft./sec. The E.A.C. curve falls at a velocity of 155 ft./sec. Attached are displacement curves for Hispano and EAC. Inlet Valves. The ratio lift/port diam. is slightly greater for the EAC. contd:- | ||