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).
Blower design, comparing Roots type, drive mechanisms, and gear configurations.
| Identifier | ExFiles\Box 3\4\ 04-page104 | |
| Date | 24th October 1932 guessed | |
| (2) Roots type has been neglected by us, and suffers from the disadvantage of being difficult to obtain. We still think however that if we went to David Brown's with out requirements they might be able to do something for us. The short time that I had to examine the Derby design for blower of the flight dimension one made me think that we had not been thorough enough to expect any better results than have been obtained by the Allison Co. For instance, I think that the rotors must have some special provision to prevent them altering the shape with the centrifugal force. I have thought of building them up in sections, but something still better might be suggested. In addition, the single helical gears with the single end control would appear to be not permanent enough for timing the two rotors and I think we should be obliged to use either straight gears or double helical, and make other provision of a more permanent nature for adjusting the timing. Regarding the drive from the engine I think the spring drive and the solid drive would have to be carried out rather differently. Personally I should like to see the spring drive work on serrations at each end, and the solid drive might be of the Oldham type because the range of movement need only be small and it is not carrying any load except when the starting handle is used, in fact, one could imagine that it would be made of some light material like fibre, or bakelite, as was used in the Silver Ghost pump. As far as I am concerned, it would be better still if the spring drive to the blower could be at the engine end of the blower, and no permanent drive, the starting handle reaching through a hole in the hollow shaft of the blower. R.{Sir Henry Royce} | ||