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).
Report comparing test bed and road results for Cast Iron Engine Units with various configurations.
| Identifier | ExFiles\Box 124\2\ scan0278 | |
| Date | 17th December 1940 | |
| To: EV.{Ivan Evernden - coachwork} c. JNR.{Charles L. Jenner} c. CTS.{C. Trot Salt - Carburation} c. Swal.Glasgow 1044 Rm{William Robotham - Chief Engineer}/Wym.{G. Harold Whyman - Experimental Manager}2/RH.{R. Hollingworth}17.12.40. Cast Iron Engine Units. We have been carrying out a series of tests with various cylinder heads, large and small throats, and different compression ratios, and induction systems with Twin S.U. carburettors and Duplex Stromberg carb. in the Cast Iron Engine Unit B.60 No.4, with the object of clarifying the whole position on the road. Test bed results do not always coincide with road results, because of the difficulty of working amidst the surrounding noise of machinery and the running of other engines, making detonation tests very difficult, and atmospheric and temperature conditions which vary between Test bed and road, and therefore we give in the following report, the natural road results obtained from out investigations to date in parallel with Test bed results. It should be borne in mind that the Test bed figures were obtained on B.60 No.3 Unit, fitted with flush top pistons and subsequent tests have shown us that flush top pistons are worth 2º for detonations and the first set of road figures on B.60 No.4 Unit in 3.B.50 car with standard .010" oversize pistons, .030" below the block face. We arranged to have a datum car, 2.B.50 with a similar engine - road wheel ratio namely 2,800 engine R.P.M. at 60 M.P.H. with the tyre pressures at 35 lbs. ", accurate and synchronized speedometers, and both cars weighted the same at 38 cwts. 3 qrs. 14 lbs. 2.B.50 car was fitted with a standard B.111 engine, Unit B.111 No.3 with a compression ratio of 6:2:1. All tests on both cars were done with clean cylinder heads. (Continued) | ||