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).
Various schemes and tests for preventing water from entering a brake drum.
| Identifier | ExFiles\Box 84\2\ scan0281 | |
| Date | 30th January 1938 | |
| -2- In the two diagrams above, on the right is shown the method of collecting water from the brake drum. The plate is drilled 1/4" dia. flush with the working surface of the brake drum. On the left is a drum and wheel, the directions being those in which the hose was directed at the excluder, and refer to the table attached. In making the quantitative tests, the hose was directed at the excluder half way up the brake drum, or just above. The nozzle was 6 ft. distant from the point where the jet impinged. In each test the hose was played for 15 minutes and in each case every effort was made to get water into the drum, subject to the above limitations. The tests were made with the axles unloaded and carefully levelled when the wheels were straight, but when the wheels were on lock the axles were tilted to give the same drum angle with the vertical. Attached is a table of results. The figures are lbs. of water discharged in a 1/4 hour (average results) from the pipe into a sealed tin, in which there was a small vent hole. The results given in the table have been confirmed in three cases, in the following manner. With schemes 4 and 5 a hub pivot was mounted on two thin legs in the centre of a hole in a large metal sheet. The excluders were fixed to this plate and the drum placed in position. A hose was directed at the drum and the result watched from behind the screen. With scheme 7 a similar procedure was adopted, only the hub plate was removed. With scheme 4 the water came through in the form of a jet, much reduced. The small groove supposed to collect the water was filled up and could not drain the water away. The small opening supposed to restrict the entry of water was not effective against a hose. With scheme 6 the same thing occurred only not so badly. It was found that the amount of water entering was roughly proportional to the clearance, and by reducing this to unworkable limits all the water could be excluded. Under these conditions scheme 7 did not appear to permit any water to pass through. | ||