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).
Modifications and testing of a four-wheel brake system and steering lock.
| Identifier | ExFiles\Box 73\2\ scan0333 | |
| Date | 16th April 1924 | |
| R.{Sir Henry Royce} (at his convenience) Mr. [redacted] Mr. [redacted] Mr. [redacted] Mr. [redacted] c. Mr. c. Mr. 49940 SECRET FOUR WHEEL BRAKES. In my memo Rgl/W7.4.24 I said that I thought it would be a long time before we could give the customer the first car with four wheel brakes, and enumerated the various points that were holding us up. I am pleased to be able to say now that the position is very much better. Taking the points I mentioned in my memo, we now have a satisfactory fiat plate servo, which works with light pedal pressure etc. This has been attained by only slight modifications to your original design. The modifications are moving out the dogs to as large a radius as possible, reducing the width of the ferodo, increasing the leverage, and fitting thicker plates to stop distortion, as suggested in your recent memos. We started off to use the agreed scheme as a basis, as we said that if the agreed scheme were correct and working well, then H.DES.60 would also work equally well if we kept the same leverages, and that we could do all our experimenting on the agreed scheme, the difference in the parts being very small. We accordingly made the leverages on the agreed scheme the same as allowed on your design for H.DES.60, and with the modifications referred to, I consider that the effect is satisfactory, and as good as the Hispano. Altering the width of the ferodo is perhaps unnecessary, and we shall make further tests with regard to this. We are also trying to get the speed of the servo on the agreed scheme the same as on DES.60 to see what effect this has on the results. The thread with the 35° angle and the correct length of leverage works satisfactorily with the modified plates, and consequently I suppose you do not desire us to put through all the modifications that you have recently sent to us following our report of its unsatisfactory working with the original parts. The next point was with regard to steering lock. We find that we can, by making minor modifications to the levers, get 40° steering lock. It looks as though our model will give 42°, which is necessary if we are to have a commercial 40°. ( Contd. ) | ||