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).
Gear ratio, clutch performance, and results from a hill climb test.
| Identifier | Morton\M21\ img077 | |
| Date | 27th June 1921 | |
| To R.{Sir Henry Royce} from DA.{Bernard Day - Chassis Design} -3- R5/G27/6/21 Contd. They agreed that this was probably so, but they pointed out that even with a head wind there appeared to be very little margin. It will perhaps be considered that the alteration to the gear ratio will cure this trouble also, but it might be dealt with by using a cowl over the fan. The third complaint is that the clutch will not stand abuse. For instance, in the sand test the driver slipped his clutch a good deal in order to keep his engine going. As a result it got very hot. As far as I know they have no instance of the clutch being spoilt, but they consider that the cotton fabric would very shortly have been destroyed. We pointed out that the improved gear ratio which would render the slipping of the clutch unnecessary would probably overcome this trouble, and they agreed, but said that there were other clutches which would stand punishment with which they thought ours compared unfavourably. No particular evidence was quoted, and this statement may be a little wild. They asked whether we would consider lining the clutch with ferodo instead of cotton fabric. The car started off with a total weight of 9688 lbs. In order to climb a hill of 1 in 5.9 they threw off ~~10~~ 8 cwts. leaving ~~8568~~ 8904 lbs. Then in order to climb 1 in ~~4~~ 3 they threw off another ~~1120~~ 1036 lbs, leaving ~~7392~~ 7864 lbs. There is some doubt about these weights, but I have gone into the question, and attach a summary of the result to this. The work they would like us to do is to suggest how the ratio may be increased, and what strengthening, if any, we should recommend on the back axle shafts, etc. to suit this ratio; also whether we can improve the clutch and overcome the boiling. DA.{Bernard Day - Chassis Design} | ||