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).
Issues with the Bendix Pinion for the Goshawk 11 engine, specifically thread angle and gear noise.
| Identifier | ExFiles\Box 40\6\ Scan014 | |
| Date | 8th October 1921 | |
| X 8692 X.4384 To Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to CJ. c. to Wor.{Arthur Wormald - General Works Manager} c. to Da.{Bernard Day - Chassis Design} c. to EY. R2/G1 8.10.21. RE. BENDIX PINION FOR GOSHAWK 11. X.4384. With reference to the Bendix Pinion for Goshawk 11, we cannot find having sent any instructions as to the angle of the thread. It is true that there is a section of the thread shewn on Lec.1371 but it does not give any pitch (i.e. number of threads) or any indication of the pitch of the thread, except that it is drawn as a double or quadruple thread only. We presume, however, that the Works have made it as a single pitch screw, in which case we should conclude from your letter that it is much too slow, and should be altered to at least a double thread of twice the angle, or even three or four pitch thread to considerably greater angle. As regards whether our gearing is noisier than others, we think this is a question of getting the gearing correct, and it would be a question you should take up with the Works. There must be something wrong with the cutters, or the cutting. A few trials of slightly different allowances might make this very much more satisfactory. For instance, one might allow the pinion to be slightly larger. We notice the cutting has to be done on the Fellows system on the pinion, it would therefore be necessary to cut the flywheel also with the Fellows system. Fellows gears are generally more noisy than B and S. until they have been well run in. As regards the pitch and number of teeth, we think it will be found that our pinion is larger and therefore the contd:- | ||