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).
Experiments and conclusions regarding the setup and performance of a Peregrine servo brake lining.
| Identifier | ExFiles\Box 2\7\ B002_X 140 to 143-page13 | |
| Date | 25th January 1933 guessed | |
| -3- improvement in the case of the progressive braking from 150 direct to 350. The number of holes is rather small to have much useful effect. CONCLUSIONS From the foregoing experiments it will be seen that to get fairly good results from a Peregrine servo, it is not necessary to make any extensive alterations. The lining should first be scraped to give good bedding all over. Care should be taken that no glue is allowed to soak into the linings as the latter is very absorbent. After assembly the servo should be run for about 5 mins. whilst applying load of about 50 lbs. to the brake pedal intermittently until the servo becomes hot (100 - 200°C). The object of this running in until hot is not so much to obtain good bedding, as to burn away all traces of grease or oil which may be on the lining. It is important that the linings should be handled as little as possible during assembly as they absorb grease very rapidly, which reduces their efficiency considerably. The inner shaft should fit freely into the outer one. A clearance of .010 to .020 will be suitable as this will obviate any possibility of binding, and allow the linings to conform to any slight errors in alignment. The falling off in output, which is apparent when the load is increased without first releasing the pedal is due almost entirely to the rapid heating up of the driving plate. This heat builds up more rapidly than it can escape, as the plate is insulated on either side by the friction linings. Holes drilled about half-way through the lining have a beneficial effect, and if continued right through the driven plate to the atmosphere give even more improvement. (Curve B). The writer is of the opinion that if the linings were attached to the central plate and the two outer plates were of steel, the heat would have a greater chance of escaping. At present almost all heat escapes to the air via the rim of the central plate which has a comparatively small area, and to which it has to travel through the thin central plate. With an efficient servo of these dimensions on the road, however, severe work on Porlock etc. failed to cause loss of efficiency. E.A. Goodall. | ||