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).
Comparison test results for a 3-bladed fan versus a standard 6-bladed fan on a 40/50 chassis.
| Identifier | ExFiles\Box 75\3\ scan0164 | |
| Date | 26th November 1919 | |
| X.3976 H.R. 253 x 100(?) (S.T. 575. 16-4-19) C. 2354. To R.{Sir Henry Royce} from EH. Copy to CJ. " " BN.{W.O. Bentley / Mr Barrington} " " E.{Mr Elliott - Chief Engineer} " " DA.{Bernard Day - Chassis Design} EH2/LG26.11.19. X.3438. TESTS ON 40/50 CHASSIS COMPARING FAN FITTED WITH X.3576. 3 BLADES WITH THE STANDARD FAN WHICH HAS 6 BLADES. This test was instructed in Mr. Elliott's memo E8/G5.16.19. The idea of the test was to see how much efficiency we dropped when using only 3 blades instead of 6, as it was desired on the new chassis to use a 3-bladed fan. TEST 1. We measured the amount of air passing through the radiator at a certain spot by means of a wind gauge which measured feet per minute. This test was taken on a complete Car with the bonnet closed. | R.P.M. Of the engine. | Ft. per min. 6-bladed fan. | ft. per min. 3-bladed fan. | |-----------------------|--------------------------|--------------------------| | 500 | 400 | 395 | | 1000 | 908 | 850 | | 1500 | 1400 | 1300 | TEST 2. A test was made on the dynamometer. The engine was run at 1000 R.P.M. full power and the difference in time to heat the water a certain number of degrees with 3 bladed fan and with 6-bladed fan, was measured. | R.P.M. of the engine. | Time to raise water temp: 80°C. | |-----------------------|---------------------------------| | | 3-bladed fan. | 6-bladed fan. | | 1000 | 8 mins. | 9 mins. | TEST 3. Comparative tests were run on the road. Contd | ||