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).
Ignition setting test on an 18.G.IV 10,000 miles test car to determine optimum timing.
| Identifier | ExFiles\Box 165\4\ img114 | |
| Date | 26th October 1931 | |
| FILES. X6129 26.10.31. X5840, X5681 X6129 18.G.IV. 10,000 miles Test Car. The following test was carried out to determine the latest ignition setting that could be used without loss of power. It will be seen that 10° B.T.D.C. appears to be the optimum timing. Taken on Ticknall Hill. Figures are average of three tests each. Full advance = 13° B.T.D.C. at 63.1 secs. 4 notches retard = 11° " " 62.9 " 6 " " = 9° " " 63.4 " 8 " " = 7° " " 64.2 " Speedometer checked at 50 m.p.h. Time = 75 seconds, therefore 4% fast. 5.7 c/r.{Sir Henry Royce} camshaft to By/CS.2/EH22.9.31. Hs{Lord Ernest Hives - Chair}/Rn.{Mr Robinson} | ||