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).
Analysis of petrol flow restriction and pump delivery in relation to temperature for the Phantom III fuel system.
| Identifier | ExFiles\Box 149\4\ scan0111 | |
| Date | 18th November 1936 | |
| -2- Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}28/AP.18.11.36. The restriction through the carburetter needle valve was measured in terms of inches of petrol above the pump and the quantity passed through the valve plotted against pressure head for fully open, half open and 1/4 open. (Graph. No.2) This was done to get some indication of the level in the float chamber on max. consumption. For example, with the G.3. pump pumping in step, the float valve needle would have to be half open to pass the 112 pints per hour required by the engine. The restriction of the pipe between the block flexible pipe and small filter has not yet been allowed for in Graph No.2, and is equivalent to 4" head of petrol at 112 pints per hour. The total restriction and the pump delivery is given in Graph No.3. shewing that with the float valve fully open there is a margin of 44 pints per hour over the engines' maximum requirements. All these figures were obtained at ordinary temperatures but from the previous tests we know we can expect petrol temperatures up to and in excess of 50°C. that is on the suction side of the pump. We have also found that with the pump in its present position complete failure to lift petrol occurs above 55°C. independent of its capacity. The fitting of an extra single pump unit on the dash of the Phantom III. will not rule out the possibility of complete failure due to heat in hot weather. The only possible solution being a high lift pump situated in the frame where there is no lift and the hottest part of the petrol system is under pressure. Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems} | ||