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 comparing different types of pressed fan blades for Bentley and 25/30 HP cars.
| Identifier | ExFiles\Box 104\3\ scan0231 | |
| Date | 4th May 1937 | |
| To Da.{Bernard Day - Chassis Design} from Rm{William Robotham - Chief Engineer}/Std. c. RHC.{R. H. Coverley - Production Engineer} c. By.{R.W. Bailey - Chief Engineer} Handwritten: J 524 Rm{William Robotham - Chief Engineer}/Std.3/AP.4.5.37 Handwritten: see 324 REPORT ON TESTS ON PRESSED SETS OF FAN BLADES FOR BENTLEY AND 25/30.HP. CARS. Handwritten: See 224 We have previously suggested (Rm{William Robotham - Chief Engineer}/Std.7/AP.14.12.36) that we should use the 25/30. type of fan blades on both Bentley and 25/30.HP. cars. In view of the fact, however, that trouble was experienced with the fan blade rivets of this type of fan coming loose, spot welding was suggested as an alternative - this was decided to be impracticable since the two pressings which form the blade set do not fit together sufficiently well. RHC.{R. H. Coverley - Production Engineer} then suggested a fan made from a single pressings and made up two or three sets of blades in this manner. Also acting on this suggestion, the fan detailed for Wraith II. has a blade set made from a single pressing somewhat different in shape from those made by RHC.{R. H. Coverley - Production Engineer} We have therefore carried out the following tests on the three types of blades i.e. 25/30.HP, RHC.{R. H. Coverley - Production Engineer} pressed type, and Drawing Office pressed type to EW.947. (1) Cooling tests at Brooklands - Sheet (1) attached shows the results of these tests which were carried out on a Bentley car. (2) Cooling tests with car idling - Sheet (2) - carried out on a 25/30.HP. car. (3) The fans were compared for noise on a 25/30.HP. car. Conclusions from Tests. From Sheet (1) attached, it is seen that both the pressed construction fans are slightly inferior in performance to the 25/30. and Bentley fans, but thatmthe fan blades to EW.947 are the better of the two. From Sheet (2) it is seen that the pressed fan blade set to EW.947 is the best of the fans under idling conditions. From noise tests, there is little to choose between the fans on a Bentley car but on a 25/30 car the RHC.{R. H. Coverley - Production Engineer} pressed fan and the Bentley fan make far too much whine to be permissible - there is practically no difference between the standard 25/30.HP. fan and the fan to EW.947. continued | ||