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).
Test results on gearbox, steering, and induction roar issues for the Goshawk 11.
| Identifier | Morton\M1.1\ img076 | |
| Date | 13th October 1921 | |
| To R.{Sir Henry Royce} From Hs.{Lord Ernest Hives - Chair} c.c. to CJ. c.c. to K.{Mr Kilner} c.c. to Da.{Bernard Day - Chassis Design} c.c. to BY.{R.W. Bailey - Chief Engineer} c.c. to Wor.{Arthur Wormald - General Works Manager} c.c. to EP.{G. Eric Platford - Chief Quality Engineer} INDUCTION ROAR GOSHAWK 11. X4219 GEAR BOX. We have had the long retaining bolt which holds the collars for retaining the ball bearings on the side shaft, break. This occurred on the Test Bench. We were running with the gear box fitted with 14d angle gears. We had these gears cut specially on the black side. On the Test Bench we cannot tell any improvement in the silence with the 14d compared with the 20d angle gears. One would imagine the only reason for the retaining bolt breaking is that the side shaft must be vibrating or deflecting. STEERING. We have fitted up a bare chassis which is to go on the bumping rig. On there we have "B" and "C" steering fixed to the solid dashboard. The thick dashboard makes all the difference to the rigidity of the steering. With this type of steering we certainly think no other stays are necessary. INDUCTION ROAR. We have carried out further tests in connection with this and feel fairly convinced that the noise does not come from the induction passages. We have made all kinds of temporary alterations to the passages which have not made the least difference to the noise. The noise comes from the air or gases passing through the valve. We have carried out tests by altering the shape of the valve, making it tulip shape instead of mushroom shape. We found that this did make a definite reduction in the amount of noise. We have also tried reducing the diameter of the head of the valve, leaving a very narrow seating of about .030". We found that this also made an improvement. These tests show that the critical point is the gas passing the valve. So far our tests have only been carried out on one cylinder. We are now making a set of inlet valves to see the effect. If we have discovered the root of the noise, it would be worth while persevering to obtain the minimum amount of noise at this point because there is no doubt that all cars make this noise more or less. Hs.{Lord Ernest Hives - Chair} | ||