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).
Comparing the 'agreed' brake scheme with a 'Hispano' system.
| Identifier | ExFiles\Box 22\1\ Scan161 | |
| Date | 28th April 1924 | |
| B.R. 488A (20H) (D.A. 652 20-3-24) J.B.D. -4- EXPERIMENTAL REPORT. Expl. No. 9940 4214 REF: Hs{Lord Ernest Hives - Chair}1/LG28.4.24. resistance is suddenly overcome. The 'agreed' scheme has been improved by reducing the power of the servo by reducing the angle of the thread from 35 to 45°. We have been able to obtain jaggers with the 'agreed' type scheme of brakes. HISPANO. We have been carrying out further tests with the Hispano and find that the lag is appreciable on that car but not to the same degree as we had on our 'agreed' scheme. In the first place the effort required on the brake pedal to operate the pull off springs on the brakes is very much less on the Hispano than our brakes. This we suggest is due to the less number of bearings and mechanism to move. There is nothing to spare on the pull off springs they use: they only just keep the brakes clear of the drums. Also the ratchet on the Hispano is finer than the one we use on the 'agreed' scheme. Also, the angular movement of the servo is only 20°, compared with 60° on the 'agreed' scheme. The servo is also less powerful on the Hispano, i.e. it requires more pressure to lock the road wheels than with the 'agreed' scheme. If, however, the servo brakes are operated quickly with the car moving slowly, one is able to press the brake pedal until the brakes shoes are in contact with the drum before the servo comes into operation. The servo however, when it follows on does not come on with such a jerk. contd:- | ||