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 and diagrams comparing two-stroke engine valve opening areas for various valve designs.
| Identifier | ExFiles\Box 134\1\ scan0207 | |
| Date | 28th June 1940 | |
| TITLE: TWO STROKE VALVE OPENING AREAS Y-AXIS LABEL: AREA OF VALVE OPENING. []" X-AXIS LABEL: CRANKSHAFT DEG's. B.D.C GRAPH CURVES: - MR WOOD'S SLEEVE VALVE EXHAUST - KADENACY POPPET EX. - ENGINE SPEED ROTARY VALVE - G.M. TWO POPPETS EX - HALF SPEED ROTARY VALVE GRAPH ANNOTATION: - ASPIN'S BEST 14/6/40 - THIS IS BETTER THAN X SLEEVE VALVE NOTES BELOW GRAPH: THE CURVE FOR THE G.M. IS ACTUAL AND ALL THE OTHERS HAVE BEEN MADE TO THE SAME COMMON BASIS, THE AREAS BEING PROPORTIONAL TO THE PISTON AREA. THE SIZE OF THE KADENACY VALVE IS UNKNOWN, IT HAS PROBABLY A MASKED OPENING & OBVIOUSLY OF IMMENSE SIZE - A SLOW SPEED ENGINE. ASPIN'S 2 STROKE INLET VALVE RUNS AT HALF ENGINE SPEED, THE TWO INLET PORTS & TWO PLUGS PER C/L ARE USED ALTERNATELY. THE EX. PORTS ARE UNCOVERED BY THE PISTON. TO RUN THE ASPIN ROTARY VALVE AT ENGINE SPEED RESULTS IN DOUBLING THE PORT OPENING AREAS. NOW THIS MEANS DESIGN CONSIDERATION WHICH AT THE MOMENT I CANNOT SAY IF IT IS PRACTICAL. DIAGRAMS & LABELS (LEFT SIDE): - Top diagram: 4 Stroke Kadenacy, Dimensions: 4 1/16, 2 1/16, 4 1/4" - Middle diagram: Half Speed opening 33 3/4°, Engine Speed opening 67 1/2° - Bottom left diagram: MR WOOD'S ENGINE, EX, IN AIR - Bottom middle diagram: G.M. & KADENACY, EX, AIR - Bottom right diagram: ASPIN, IN, EX OTHER TEXT: E & C 28.VI.40 | ||