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).
Bench test results for 25/30 HP ignition governors, comparing performance on standard and modified cylinder heads.
| Identifier | ExFiles\Box 82\4\ scan0322 | |
| Date | 9th June 1936 | |
| Hs{Lord Ernest Hives - Chair}/Swdl.{Len H. Swindell}21/Ks.9.6.36. 25/30 H.P. Ignition Governors. Bench tests have been carried out with regard to producing a governor characteristic that will match up with the ideal advance curves on both the standard production turbulent type of head and the same head deturbulated by machining away the turbulent lips to LeC.5002. The curve SP.{Mr Spinney}25 shows the various conditions of spark advance with the turbulent production head which has a compression ratio of 6 : 1. The ideal line (No.1) is that obtained with the minimum advance for maximum power with a range from 12° BTDC at 500 r.p.m. to 33° BTDC at 4000 r.p.m. No.2 curve is the advance line necessary to cut out detonations, this by listening close up to the head. At 900 r.p.m. this line goes further advance than what is necessary to obtain maximum power, and is therefore of no interest above this speed. The governor line (No.4) which has been produced by Hs{Lord Ernest Hives - Chair}/Wst. to our proposed requirements is arranged as follows - at 500 r.p.m. is midway between the advance necessary to obtain maximum power and that which cuts out detonations, the figure being 9° BTDC. This gradually comes up to the ideal line at 1000 r.p.m. and then follows the latter to within a degree up to 4000 r.p.m. This governor, for which we give a static setting of 9° BTDC (hand control advanced) has been submitted for test on the road, and the performance of which is being reported by Hs{Lord Ernest Hives - Chair}/wym.{G. Harold Whyman - Experimental Manager} In a similar manner to the previous description, the same governor but with a static setting of 13° BTDC is proposed for the deturbulated head LeC.5002, the complete curves being shown on SP.{Mr Spinney}26. | ||