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).
Engine detonation, including a consumption loop graph and M.E.P. limits for air-cooled versus water-cooled engines.
| Identifier | ExFiles\Box 178\2\ img206 | |
| Date | 24th February 1934 | |
| -7- He/Rm.{William Robotham - Chief Engineer}14/KW.23.2.34. DETONATION. Heron says one of the best indications of detonation is to switch off momentarily, if all cyls. will cut out dead for about ten revs., no detonation. The other way is to take a consumption loop and if the engine will hold 99% full power on .43 lbs/B.H.P. hr. there is no detonation and the distribution is very good. Or run on a fuel that you know will not detonate and then compare this curve with the fuel where detonation is suspected. If detonation is taking place, the curve will fall away as shewn. [Graph] B.M.E.P 10% 99% POWER NON DETONATING FUEL DETONATING Sp.{Mr Spinney} FUEL LBS: .43 TOTAL FUEL LB/HR. ROLLS-ROYCE, PRINT ROOM 24 FEB 1934 With regard to the respective limit of M.E.P. on water cooled and air cooled engines, he has had no case on a multi-cylinder engine where the design was at all comparable. On a single cylinder, however, where he surrounded an air cooled cylinder with water, he found that the water cooled could stand 50% additional M.E.P. The figures he gave on one particular fuel were - Air cooled 200 M.E.P. Water cooled 300 M.E.P. | ||