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).
Power comparison graph for an Aluminium Phantom engine, testing large versus small diameter valves.
| Identifier | WestWitteringFiles\Q\December1926-January1927\ 48 | |
| Date | 16th December 1926 | |
| SHEET 3. BRAKE HORSE POWER B.M.E.P (LBS. PER SQ. IN.) R.P.M. OF ENGINE LARGE VALVES. B.H.P. " " B.M.E.P. SMALL VALVES. B.H.P. " " B.M.E.P. ALUM. PHANTOM POWER COMPARISON FOR 1.600 DIA. & 1.750 DIA. VALVES. COMP. RATIO = 4.69 : 1. CORRECTED N.T.P. Initials in stamp: WB{Mr Brazier/Mr Bell} Date in stamp: 16-12-26 | ||