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 of a Phantom engine's power curve, showing the increase resulting from using larger chokes in the carburettor.
| Identifier | ExFiles\Box 66a\1\ scan0193 | |
| Date | 13th September 1927 | |
| STANDARD PHANTOM POWER CURVE (SHEWING INCREASE DUE TO LARGER CHOKES IN CARBURRETTOR) ENGINE No RE.25. COMPRESSION RATIO = 4.12 TO 1 STANDARD INDUCTION PIPE. BED EXHAUST SYSTEM (WITH SILENCER) CURVES CORRECTED TO N.T.P. CARBURETTOR HAVING 1.250 DIA. H.S. & .850 DIA L.S. CHOKES. AIR PORTS LARGER IN SAME PROPORTION. INLET AREA 12.6% GREATER THAN STD. BRAKE HORSE POWER R.P.M. OF ENGINE. AIR VALVE PISTON REMOVED (LARGER CHOKES) STANDARD CARB. DEPRESSION IN INDN PIPE:- STD CARB. LARGER CHOKES. AIR VALVE REMOVED. INDN PIPE DEPN (INS OF HG) AHP 13-9-27 | ||