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 comparison between Anglo Persian fuel and D.T.D.134 fuel, covering detonation, power, and consumption.
| Identifier | ExFiles\Box 179\2\ img069 | |
| Date | 18th December 1931 | |
| -2- (1) At the rated boost the power difference between the Anglo Persian fuel and D.T.D.134 is negligible. (2) That at 2000 r.p.m. the initial detonation point of the Anglo Persian fuel is at + 3" Hg. boost pressure as against + 1" Hg. of D.T.D.134. (3) That at boost pressures of the order of + 6" Hg. the Anglo Persian fuel shows a greater detonating tendency than D.T.D.134 with a consequent sharper power drop. (4) That the specific consumption of the Anglo Persian is higher than D.T.D.134. With regard to the last point (4), this is to be expected. The calorific value of D.T.D.134 is 143,000 BTU/gal. whereas that of Anglo Persian spirit (sp.{Mr Spinney}g. = .714) will probably be about 135,000 BTU/gal., which means that if an engine is tuned up to say .54 pts/bhp/hr. on D.T.D.134 it would be necessary to richen up to .572 pts/bhp/hr to obtain the same total heat value in the charge when running on Anglo Persian. To summarize, we may say that Anglo Persian spirit + 3 ccs TEL/gal is somewhat better from anti-detonating and power points over the range that we shall work than D.T.D.134 but that in order to obtain the best results, it will be necessary to run richer. Ha/H.R.Young. | ||