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).
Technical memo comparing leverage fluctuations in different four-wheel brake cam designs.
| Identifier | WestWitteringFiles\M\October1924-December1924\ Scan14 | |
| Date | 10th October 1924 | |
| TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} DA{Bernard Day - Chassis Design}2/110.10.24. FOUR WHEEL BRAKES. X9940 X4214 X1559 Replying to your HS{Lord Ernest Hives - Chair}3/LG71024., the statement referred to is sufficiently true when compared with square cams and similar devices. The full range of the cam is 60° and if this were set out equally on either side of the centre line it would be found that the leverage increased 12½% from the initial position to the maximum, or if the average leverage is taken it may be said that the leverage fluctuates 6¼% on either side. This is so small a fluctuation compared with a square cam that it is reasonably true to say that it remains constant. In the case of the Hispano of course the cam has been curved in such a way as to keep the leverage fairly constant, but this is not directly aimed at the Hispano, but at the very square cams which were used on some Perrot systems. DA.{Bernard Day - Chassis Design} | ||