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 performance graph and a comparison of M.E.P. between water-cooled and air-cooled engines.
| Identifier | ExFiles\Box 173\2\ img091 | |
| Date | 23th February 1934 | |
| -7- 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/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] Vertical Axis: B.M.E.P, SP.{Mr Spinney} FUEL, LBS:, .43 Horizontal Axis: TOTAL FUEL LB / HR. Graph Labels: 10%, 99% POWER, NON DETONATING FUEL, DETONATING Graph Stamp: ROLLS-ROYCE, LTD, TEST 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. | ||