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).
Continued discussion on fan design, suggestions for stability, and analysis of test failures.
| Identifier | ExFiles\Box 135\4\ scan0054 | |
| Date | 14th March 1940 | |
| - 2 - Continued:- An extra amount of lateral stability could also be obtained by copper brazing two flanges at the top and bottom of the cylindrical blade root and making this a fairly close fit inside the pressed flange. Whilst we agree that the design you have submitted is probably considerable superior to anything we could evolve by following the above suggestions, we feel that price considerations will force us to utilise pressings for almost the entire construction of the fan. As regards your other queries we have no definite information on the amount of noise we should get from a symmetrical fan with very much reduced blade pitch, but from tests that have been carried out we consider it extremely probable that a symmetrical fan would be satisfactory. The fan SCD.866 has been tried and was rig tested where it failed after 40 hours due to cracking of one of the blades. The idea certainly appears promising and was reasaonably quiet at high speeds. When the particularfan was tried, however, a considerable amount of blade flutter was evident. Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} | ||