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).
Tests on a 40/50 chassis comparing a fan fitted with 3 blades against the standard 6-bladed fan.
| Identifier | ExFiles\Box 75\3\ scan0088 | |
| Date | 26th November 1919 | |
| X3438 R R.{Sir Henry Royce} 235 A (100 T) (S.P. 575. 16-4-19) (j.{Mr Johnson W.M.} 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} ------------------------- 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 suing 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 | ||