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).
Engine performance data from Test 2 and Test 3, comparing magneto and battery ignition systems.
| Identifier | ExFiles\Box 54\5\ Scan244 | |
| Date | 16th June 1923 guessed | |
| Test 2. "Redline" No.1 spirit. Bar. 760 m {Mr Moon / Mr Moore} /m. Magneto. 25° B.T.D.C. fully advanced - centre plugs. Battery. 20° P.T.D.C. fully retarded - pocket plugs. 45° B.T.D.C. " advanced . Engine R.P.M. | MAGNETO. | BATTERY. Load. | H.P. | Notch. | Load. | H.P. | Notch. 1500 | 116 | 49.2 | - 6 | 112 | 47.5 | 0 1750 | 108 | 53.4 | - 3 | 103 | 50.9 | 0 2000 | 98 | 55.4 | 0 | 92 | 52.0 | 0 2250 | 86 | 54.6 | 0 | 86 | 54.6 | 0 2500 | 77 | 54.4 | 0 | 73 | 52.6 | 0 Test 3. "Redline" No.1 spirit. Bar. 760 m {Mr Moon / Mr Moore} /m. Magneto. 25° B.T.D.C. fully advanced. Centre plugs. Battery. 15° P.T.D.C. fully retarded. Pocket plugs. 50° B.T.D.C. " advanced. Engine R.P.M. | MAGNETO. | BATTERY. Load. | H.P. | Notch. | Load. | H.P. | Notch. 1500 | 118 | 50.2 | - 6 | 118 | 50.2 | - 2 1750 | 110 | 55.8 | - 3 | 110 | 55.8 | - 2 2000 | 101 | 57.1 | 0 | 99 | 56.0 | - 2 2250 | 89 | 56.6 | 0 | 86 | 54.6 | - 3 2500 | 75 | 51.6 | 0 | 72 | 50.9 | - 4 | ||