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).
Issues and solutions for common hand and foot brake shoes, focusing on thermal effects on different models.
| Identifier | ExFiles\Box 120\2\ scan0199 | |
| Date | 1st September 1937 | |
| 1029 To Da.{Bernard Day - Chassis Design} from Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} c. By.{R.W. Bailey - Chief Engineer} Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale}12/MH.{M. Huckerby}1.9.37. COMMON HAND AND FOOT BRAKE SHOES. With reference to Da.{Bernard Day - Chassis Design}5/G.{Mr Griffiths - Chief Accountant / Mr Gnapp} 28.8.37. The Wraith is the most satisfactory hand brake we have, even though it has not separate hand and foot brake shoes. On Wraith there is a slight tendency for the hand brake to release itself (about one notch) after standing parked some minutes; this was noticed once only in France in the recent test on 26.G.VI, after descending an Alpine pass. In normal conditions there is no trouble. By contrast the conventional R.R. separate aluminium shoe on 32.EX nearly resulted in the car running away in Paris, after the car had been driven a short distance with the hand brake dragging. This was because the shoe and drum were at the same temperature on parking, and the shoe contracted more than the drum. On Bentley IIA if we use an iron drum this effect will be noticeable at times. At other times the hand brake will tighten itself on, probably about 3 notches. We have been getting both these effects on I.B.IV. rigged up as requested in your note. The hand brake tightens if applied immediately after a sudden stop. It loosens if parked with a normally hot brake system. To reduce these effects we shall need :- (1) A heavy drum to prevent tightening on. (2) A heavily ribbed drum to prevent loosening. (3) As spongy as possible a hand brake. We already have made provision for (3); we suggest trying the standard drum to begin with to see if it is good enough in conjunction with the added sponge in the H.B. system. Rm{William Robotham - Chief Engineer}/AFM.{Anthony F. Martindale} | ||