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).
Troubles with gear noise and slow running on a supercharged Bentley.
| Identifier | ExFiles\Box 140\1\ scan0085 | |
| Date | 13th December 1934 | |
| x209 To RHC.{R. H. Coverley - Production Engineer} Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer}22/KW.13.12.34. Supercharging on the Bentley. We have been able to do very useful work on the existing set up on the Bentley. The outstanding troubles which we are having to work on are (1) gear noise and (2) slow running. (1) Gear Noise. We do not think the English gears are going to wear as well as the American gears, nor that they are as silent. The Graham-Paige has now run 10,000 miles, and we should like your opinion as to how these gears compare with those that have been running on the test bed. At the same time we believe that if we get a sufficiently flexible drive to the supercharger on our test bed unit it may quieten the gears down considerably. For this reason we should like you to replace the pressure couplings with very flexible Hardy couplings so that we can make a test. These couplings will only be required to run at idling speed. If they produce the necessary silence in the gears we shall have to develop a spring drive of some sort to give the same result in a durable manner. If they do not, we shall have to get some American cut gears and then try and get these reproduced in England. We now know from our running that the gear ratio required will be 4 to 1. (2) Slow Running. We think that the position of the blower in relation to the induction pipe has a large bearing on slow running. The attached sketches show three positions in which we should like to try the blower. These necessitate two facings on the crankcase in addition to the one we already have, and an alteration to the length of the blower drive. If the crankcase could be modified without a new casting to take the blower in these positions it would enable us to get the tests done in the minimum of time. We really only want to run the blower in these other positions at idling speed, if we find a great improvement we could then make the job more permanent. | ||