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).
Bench experiments to determine the optimal blade shape for 20 HP radiator fans made from sheet material.
| Identifier | ExFiles\Box 75\3\ scan0208 | |
| Date | 1st February 1925 guessed | |
| X4234 To R.{Sir Henry Royce} from EFC. c. CJ. E.{Mr Elliott - Chief Engineer} Da.{Bernard Day - Chassis Design} c. By.{R.W. Bailey - Chief Engineer} Rg.{Mr Rowledge} EFCl/T9.B.25. X.1017. BENCH EXPERIMENTS ON 20 HP. RADIATOR FANS. X4234 In our EFCl/T17.12.24, it was mentioned at the end that an experimental 20 HP. fan would be made with four blades, with the full possible tip diameter and starting with the blades very wide. Progressive alteration to the blades would then be made to find out the best shape of fan which could be produced from sheet material. This has now been completed to our satisfaction for the 20 HP. fan. In the case of the EAC. fan, though we have previously arrived at one which was a good deal better than the standard, and have two of these running, one on chassis 44-PK and another on chassis 98-NK for the 10,000 mile test, we may, on applying a similar process in the case of this fan, be able to produce some further improvement. Returning, however, to the case of the 20 HP. fan, please find attached photostat copy of sheet of curves labelled I, for fans of suitable size for 20 HP., this group of curves corresponding to group W of the previous report, i.e. they are curves which give, on an axial thrust base, the power absorbed in driving the various fans and the speeds at which those fans have to be driven. As before, these curves are independent of the drive ratio, except in so far that since the power includes power to slip and flex the belt, slight alterations in the power curves might be expected with different sizes of pulleys (driving or driven). Contd. | ||