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).
Secret memo discussing brake operation, comparing the RRM system to others, and outlining the advantages of a proposed new design.
| Identifier | ExFiles\Box 22\1\ Scan126 | |
| Date | 4th March 1924 | |
| X4214 To DA.{Bernard Day - Chassis Design} & BS.{A J. Barnes - Assistant Manager} from R.{Sir Henry Royce} c. to CJ. BJ. RG.{Mr Rowledge} PN.{Mr Northey} W.R. E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} Mr. Claremont. S E C R E T. E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. RE. BRAKE OPERATION. R1/M4.3.24. X.9940 X.4214 Referring to RRM. and other systems, I find I made an error in my last memo. in supposing that if we brake on 2 wheels (by foot pressure unassisted) we get nearly twice the braking we get on 4. On further consideration I find it is the same except for the effect of the friction of the extra mechanism and the effect of more pull off springs: the result is that instead of the leverage being much increased it can only be slightly increased, say 20% and this is the same amount as the extra braking. The follow up by the foot appears also to be about the same in each case. I have further concluded that there is very little difference in action between the latestmodified semi-servo (called RRM.) and the ratchet between the servo clutch and the lever going away to the brakes. Also RRM. could be arranged that the pulls of the 2 levers or rods could be joined in parallel before being divided between the 4 brakes. But for reasons given - i.e. 20% better braking, simplicity, and patents - the scheme is better as first described. It will be noticed that a brake system that requires the car to move an inch or two to put the brakes on cannot be considered quite satisfactory for exact shunting because one may be using the clutch and desiring the car to move up to the last inch, then on go the brakes to hold the car, and it is not usual for drivers to be forced to use the hand brake for such work. Except for the Hispano scheme there seems few systems which fulfil the requirements except the RR. semi-servo and its modifications, or something which seems subject to the Hispano patents if these are enforced. Even if we get a licence it would be a lot on so small a part of the car, (carrying it throughout the car would spoil our chance of profit) and has other disadvantages. So if we had a good scheme of our own it would be a great asset. I cannot still see why our's is not somewhat superior, as it has several advantages, thus - (1) Slightly better backward braking - 20% (2) Increased anugular movement of the servo, cooler and less stress and gentler action. (3) Suits the work in hand. (4) Avoids other people's patents, and is our own. R.{Sir Henry Royce} | ||