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).
Letter discussing developments in spark advance mechanisms, particularly automatic systems.
| Identifier | ExFiles\Box 37\1\ scan 240 | |
| Date | 3rd August 1923 | |
| Oy5-W-8823 [STAMP: RECEIVED 15 AUG 1923 H2] August 3, 1923. Mr. Claude Johnson, Rolls-Royce, Limited, London, England. (Copy for attention of Mr. Royce) Mr. Hives) ✓ Dear Sir: Re Spark Advance Mechanism We attach herewith for Mr. Royce's attention an article by Professor George B. Upton on experiments in spark advance. [STAMPED IN RED: COPY] We think these are interesting as representing the direction in which the industry is working in this country, to take the operation of the spark advance entirely out of the hands of the driver. While the paper contains a great deal of matter which is scarcely of practical value, it establishes the possibility of representing correct spark advance by a correction for speed plus a correction for intake vacuum We know that the Connecticut Ignition Company have worked out a similar scheme successfully, and that the Franklin Company have used the device practically as suggested by Professor Upton, namely, a centrifugal advance of ordinary type with an advance by vacuum bellows replacing the hand advance. The Connecticut Company have attempted to get the same result by a direct operation of the advance by intake vacuum coupled with an attachment to the accelerator pedal which cuts down the vacuum (and therefore the advance) by introducing a leakage of air into the bellows at the greater throttle openings. Oy. | ||