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).
Braking and servo capacity issues for the Peregrine and Bensport models.
| Identifier | ExFiles\Box 1\10\ B001_X106 TO X 110-page020 | |
| Date | 19th November 1932 | |
| HS.{Lord Ernest Hives - Chair} } FROM R.{Sir Henry Royce} DA.{Bernard Day - Chassis Design} } HDY.{William Hardy} } X106 RL/M19.11.32. X.4027 X.4553 X.1559 C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer} BRAKES - (ESPECIALLY REFERRING TO PEREGRINE & BENSPORT). We are agreed that these have got somewhat wrong due to being scaled down like the rest of the chassis, though the weight of the complete car has not been reduced in the same proportion, and the average speed at which the cars will be driven will be faster than we anticipated. One can look upon this problem as a question of pulling up within a certain distance when it might be considered that it was weight, multiplied by (average speed, squared). The brakes themselves should we think we increased in capacity either in diameter or in axial xxxxxxxx length. The nearest way to do this on Peregrine is to convert the back brakes to one pair of wide shoes per drum, and to increase the front brakes in width for which I understand there is ample room. If this does not meet the views of DA.{Bernard Day - Chassis Design} and Derby, there is nothing for it but to increase the diameter of the drums from 12" to 14", in the same way that it is suggested we do on Bensport, which latter will be still more exacting owing to its higher speed and probably greater weight. (You will see here one of the reasons why I wish to get the weight of the Bensport engine reduced.) With reference to servos, it appears that these have become alarmingly small to look at, and are proving to be wanting in capacity. If it were only a question of heat I have faith that this would be reduced by the decreased speed. Whether we shall be satisfied with half speed I have some doubt, and I think we shall have to be contented with a reduction of one third, that is, two thirds its present speed. I understand however that half speed will be the easiest to test, and should be tried out before deciding upon the best ratio. I now understand that both for clutches and this servo problem we ought to reduce the intensity of pressure on the friction surfaces, and to make a sufficient change it is necessary to go quite a long way. We are hoping to get some benefit from asking the servo to do less in proportion than it does on the larger cars. (1) | ||