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).
Graph comparing the flywheel horsepower curves for the Phantom and Silver Ghost engines.
| Identifier | ExFiles\Box 69\4\ scan0389 | |
| Date | 24th July 1929 guessed | |
| B.H.P. R.P.M. 110 100 90 80 70 60 50 40 30 20 500 1000 1500 2000 PHANTOM SILVER GHOST FLYWHEEL H.P C.O. OPEN. COMPARATIVE HORSE POWER CURVES. SILVER GHOST & PHANTOM | ||