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).
Comparison of engine efficiency using one versus two synchronized spark plugs under full and throttled load conditions.
| Identifier | WestWitteringFiles\P\October1926-November1926\ Scan018 | |
| Date | 5th October 1926 | |
| Top Graph: PINTS/B.H.P./HOUR B.M.E.P. ▲ TWO PLUGS SYNCHRONISED. ⊙ ONE PLUG. CARB. SIDE OF ENGINE. LIGHTER PHANTOM ENGINE. SPECIFIC CONSUMPTION WITH ONE & TWO IGNITIONS. 4.69 TO 1 COMP. RATIO. CURVE SHEWS NO APPRECIABLE DIFFERENCE IN EFFICIENCY WITH ONE OR TWO PLUGS. 1250 R.P.M. FULL LOAD. Bottom Graph: EFFECT OF IGNITION ON EFFCY WHEN THROTTLED. PTS/B.H.P./HR. %AGE OF FULL LOAD. ⊙ ONE PLUG AT 35° ADVANCE. ▲ SYNCHRONISED IGN. AT 27° ADV. 1000 R.P.M. SYN IGN ADJ. TO GIVE MAX TORQUE FOR EACH LOAD. CURVE SHEWS THAT NO APPRECIABLE DIFFCE EXISTS BETWEEN ONE OR TWO IGNS. UNDER LIGHT LOADS. ACLS 5/10/26. | ||