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).
Continued report on Lepaz brake drums, detailing distortion, test procedures, and material comparisons.
| Identifier | ExFiles\Box 120\1\ scan0139 | |
| Date | 1st May 1934 | |
| (3). LEPAZ BRAKE DRUMS. CONTD. (6). COMMENTS ON (4) DISTORTION. The amount of distortion shown is usual for Cast Iron Drums under this severe test. (7). COMMENTS ON (5) TEST PROCEDURE. (a) The standard test is considered to be more severe than service conditions, because (1) the time of application is longer than the average service period, and (2) application is always at the maximum speed, whereas in service the application commences at the highest speed and finishes at a low speed, (3) the temperature reached is considerably higher than that obtained in service. (b) The special test is exceptionally severe and such conditions are never reached except perhaps on racing cars. N.B. Rolls-Royce find that in braking a Bentley from 80 m.p.h. to stop the temperature of the drum reaches 660 deg. F.{Mr Friese} (350 C) (8). GENERAL COMPARISON OF STEEL, HIGH GRADE CAST IRON & LEPAZ. Steel. Scores. Wears badly. Distorts. H.G. CAST IRON. Coefficient of friction diminishes considerably. Does not polish well in use. LEPAZ. Does not score. Wears as well as cast iron. Distorts no more than cast iron. Has a constant coefficient of friction. Polishes in use to a better surface than cast iron. -continued- | ||