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).
Gearbox shaft whirling issues and clutch design improvements for the Peregrine model.
| Identifier | ExFiles\Box 179b\1\ img352 | |
| Date | 10th March 1933 | |
| HS.{Lord Ernest Hives - Chair} ) FROM R.{Sir Henry Royce} E-H ORIGINAL R4/M10.3.33. C- to SO. WOR.{Arthur Wormald - General Works Manager} BY.{R.W. Bailey - Chief Engineer} PEREGRINE. See me Sent off 14.3.33. H GEARBOX. You will remember I have written several times that I do not like the extension on the back of the Peregrine gearbox, as we have it at present. Since the necessity for this arose it has been discovered that if the shaft is in dynamic balance it will not whirl at the low speed that has been bothering us, but will wait until it gets to the real critical speed, when I anticipate that the whirling would be disastrous. What this critical speed is I should like HS{Lord Ernest Hives - Chair}/GRY.{Shadwell Grylls} to test experimentally, and report upon. It would appear that the whirling that has been troubling us occurs at the chief harmonic of the true whirling speed. This I think would seem to be at two thirds the true whirl. So that most of the shafts would, one thinks, be quite out of the danger zone if properly balanced, and the harmonic, which although irritating, is not dangerous. To make it safer however I suggested taking off the telescopic splines and putting them inside the gearbox extension. I made some sketches of this and it has been designed by D.A., but owing to some slight misunderstanding, and a thoroughness I did not think was necessary, the design he has made suggests extensive alterations to the gearbox. I had not seen the drawing (which was sent to Derby) principally owing to ill-health and other work, until yesterday, and on looking over the matter I think we can re-arrange it like I originally intended it to be, so that it would be easier to test because it will not affect the gearbox pattern. We want you therefore to stop work on the design we have sent you, and wait until Monday morning when we expect to send you a more simple scheme that we hope can be more quickly tested and introduced, if found good. CLUTCH. Regarding the clutch, when we looked into this the last time we got some information that the material and areas we were trying to work with were not the best, and we want the clutch fitted to a car that we last sent you of the 4 lever non-serrated type which has an increased surface of 31%, and so reduces the unit pressure to the figure which gives a smoother take up. It also has cast iron surfaces. This should considerably alter the behaviour of the clutch as regards jaggers, which seem to be a fairly consistent trouble with HS{Lord Ernest Hives - Chair}/GWH.{George W. Hancock - Head Chateauroux} in France. (1) | ||