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).
The ignition timing range for a Goshawk engine on a 49-GB car.
| Identifier | ExFiles\Box 51\5\ Scan242 | |
| Date | 28th March 1923 | |
| Mr. Hives. from GWH. {George W. Hancock - Head Chateauroux} 4357 x40 28.3.23. GOSHAWK IGNITION ON 49-GB CAR. Range of ignition with .018" gap on contact = Retard 15° late Mech: advance 18.4° B.T.D.C. Auto: " 56° B.T.D.C. Average advance found on test bed for power is 44° B.T.D.C. GWH. {George W. Hancock - Head Chateauroux} | ||