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 testing, focusing on fuel mixtures and variations in compression ratios.
| Identifier | WestWitteringFiles\N\July1925-September1925\ Scan160 | |
| Date | 1st August 1925 | |
| R.R. 493A (50H) (D.B. 175 25-9-24) J.H.D. -7- Expl. No. REF: Hs{Lord Ernest Hives - Chair}/TAG/LG26. 8. 25. EXPERIMENTAL REPORT. observed at all speeds. The engine ran quite comfortable at 2400 r.p.m. full throttle. GENERAL. For the tests a spirit of 50% aviation and 50% Benzol was used, having a specific gravity of .775 at 15°C temp. A 25% Aviation and 75% Benzol mixture was tried but made no difference either way, so that 50/50 was used for all the tests recorded on this report. K.L.G. F.10 sparking plugs were used and gave us no trouble. Castrol oil was used. Standard pistons. The compression ratio was checked on several cylinders with standard pistons taken from stock (production), which are supposed to give 5.3 to 1 ratio. We did not find one cylinder and piston which gave the nominal 5.3 to 1 compression ratio, in fact, in one case the ratio was 5.17 to 1 but with the same piston in another cylinder the ratio was 5.27 to 1 and this figure was the average of those tested i.e., omitting the 5.17 to 1 case. The limits allowed in machining the combustion chamber of the cylinders are rather generous and these would cause the differences (coupled with the probable variation in the seating of the valves) obtained in the compression ratio figures of which 5.27 to 1 is the average. Appended are the theoretical findings on the foregoing tests. Hs{Lord Ernest Hives - Chair}/TAG. | ||