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).
Report analyzing the efficiency of various mechanical components, such as toggles and Bowden cables, to diagnose performance loss.
| Identifier | ExFiles\Box 13\1\ 01-page69 | |
| Date | 21th December 1934 | |
| -2- HS{Lord Ernest Hives - Chair}/AFM.{Anthony F. Martindale}4/KW.21.12.34. DA.{Bernard Day - Chassis Design} has suggested that the trouble may be due to a large number of small distortions. His original suggestion that the carrier plate might distort under load can hardly account for the whole loss, as the deflection is only 6 thousandths. The following experiments have been made so far :- Measurement of efficiency of Bentley toggles. " " " Phantom torsion shaft. " " " Simple lever in 20/25 brake linkage system (G.63637). of efficiency of Bowden Cable. of coefficient of friction in a pin joint. It is proposed to collect information as soon as possible about the following :- Girling Cams. SpectreCodename for Phantom III Toggles. SpectreCodename for Phantom III Equaliser. The load-efficiency curves of all these components are attached to this report. The following information is obtained from them :- Toggles. The greatest individual loss occurs in the toggle mechanism. A Bentley toggle mechanism is most efficient during emergency braking, but then the efficiency is only 72% or less. The efficiency of SpectreCodename for Phantom III toggles is much lower. Bowden Cable. A Bowden cable is not an easy apparatus of which to obtain the efficiency, because the cable and sheath are not smooth and so behave erratically. Moreover, below 300 lbs. load (or so) an oil film can be maintained between cable and sheath for a short while, and the efficiency varies with the time of application of load. However, the four curves obtained show what efficiencies can be expected; the angle through which the cable is bent determining whether the cable is more efficient than any brake components it would replace. A graph of efficiency against angle will be prepared for the Design Dept. | ||