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).
Performance graph for a Hispano engine, plotting horsepower and mechanical efficiency against RPM.
| Identifier | ExFiles\Box 180\M4\M4.2\ img034 | |
| Date | 10th March 1924 guessed | |
| HISPANO MECH. EFF % 100 90 80 70 HORSE POWER. 160 140 120 100 80 60 40 20 0 500 1000 1500 2000 ENGINE R.P.M. FIGURES OBTAINED MECH EFF I.H.P. B.H.P. H.P. TO ROTATE ENGINE | ||