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).
Description of the rig used and general methods of working for air flow tests.
| Identifier | ExFiles\Box 17\6\ Scan146 | |
| Date | 24th August 1933 guessed | |
| -3- (3) Description of Rig used and general methods of working. For diagrammatic sketch of rig, see attached blueprint. The air flow for these tests was supplied by a Goshawk type blower, which could be run at any speed up to about 2600 R.P.M. and could be throttled at its outlet. This blower was by no means suitable for the work, its capacity was too large, necessitating considerable throttling with consequent tendency to surge - however it was the only blower available at the time. The air was passed from the blower through a specially machined and calibrated nozzle - and thence to an adaptor which would fit the port under test - through the port and valve and allowed to exhaust to the atmosphere. The pressure differences on either side of the nozzle and the pressure difference at the inlet to the cylinder head port were measured by means of water or mercury manometers. This temperature on the high pressure side of the metering nozzle and the temperature at inlet to port were also measured by means of thermometers inserted in pipe line. The general proceedure was to choose a suitable blower speed for the test in question and adjust throttle on blower outlet to give whatever pressure differences were required across valve. Valve was assumed to have atmospheric pressure on one side. A 1" bore metering nozzle was used for all the R.R. Bentley & Phantom tests, but owing to the large air flow required for the 8 litre Bentley head, a 2.5" diameter nozzle had to be used. | ||