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).
Fitting of a 25/30 type electric pump and its effects on the carburettor.
| Identifier | ExFiles\Box 146\1\ scan0134 | |
| Date | 16th December 1937 | |
| W/P - Sr/VA. 1245 Rm{William Robotham - Chief Engineer}/JBD.{John B. Dixon - Fuel Systems}1/JH.16.12.37. In reply to your memo. Sr/VA.2/ET.13.12.37. We suggest that you fit a 25/30 type electric pump on the frame as near to the carburettor as possible. These pumps develop a max. pressure head of 30 to 36 inches of petrol with no delivery. At the engine consumption of 100 pints per hour the pressure head drops to 18 inches this fact makes it essential to mount the pump as near to and about the same level as the carburettor. With this consumption the condition should be similar to those existing when the carburettor is fed from the autovac. We regret we are unable to state what head the float needle of this carburettor will hold, but we do not think a pressure head of 36 inches would cause flooding, it would be advisable to temporarily couple up a pump at the same relative level to the carburettor as the position you intend to use to check for this before you complete the scheme. The high pressure pump generates a maximum pressure head of 7 ft. to 8 ft. head of petrol and we are afraid this would cause flooding. It would of course be possible to use the high pressure pump if the diameter of the float valve seat was reduced but it would then be too small to allow the autovac to be used as a stand by.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer}/J.B.Dixon. | ||