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).
Test report on detonation characteristics of a 7/1 compression engine using a 20/80 Benzol/Aviation fuel mix.
| Identifier | ExFiles\Box 36\2\ scan 159 | |
| Date | 10th March 1928 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/VH. c. to BJ. Wor.{Arthur Wormald - General Works Manager} c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to BY.{R.W. Bailey - Chief Engineer} Fl. c. to EP.{G. Eric Platford - Chief Quality Engineer} X2934 Hs{Lord Ernest Hives - Chair}/VH1/LG10.3.28. 7/1 COMPRESSION ENGINES ON STANDARD 20/80 FUEL. X1282 On examining the conditions which exist when a machine with a gate throttled high compression engine is taking off from sea-level, it will be seen that the reduced propeller speed involves higher M.E.P's than if the engine were able to rotate at normal r.p.m. The accompanying curves shew the variation of HP. and MEP. with the throttle set to give :- (a) 480 HP. at 2250 r.p.m. (b) 500 HP. at 2250 r.p.m. for speeds down to 1700 r.p.m. When using standard fuel (20/80 Benzol/Aviation) it is thus possible to reach a condition where a high compression engine might detonate badly on the ground, although free from detonations at the rated maximum permissible HP. at normal r.p.m. Tests were made on a 7/1 engine setting the throttle to give 480 HP. at 2250 r.p.m. on the brake and then braking down until the engine began to detonate. Detonations became distinctly audible at 1800 r.p.m. The test was repeated, setting the throttle to give 500 HP. 2250 r.p.m. Detonations became audible in the neighbourhood of 1900 r.p.m. and the engine was given an hrs. endurance at 1900 r.p.m., the engine ran quite well under these conditions, and no falling off in power Contd. | ||