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).
Intensive rough test of a clutch on car MX-4, resulting in its failure and fire.
| Identifier | ExFiles\Box 74\2\ scan0230 | |
| Date | 28th June 1929 | |
| OY-5 X H194 June 28th, 1929. TO: Mr. Bagnall cc - Mr. Beaver Mr. Burton Mr. Ainsworth Mr. Allen Experimental Dept. Mr. Bailey (England) Mr. Hives FROM: Mr. Olley CLUTCH - SECTION 6000 In an attempt to do some intensive rough-testing on a clutch to find approximately what owners are doing, MX{John H Maddocks - Chief Proving Officer}-4 was taken up Wilbraham Mountain first in high gear and then in second, slipping the clutch to ease the car up the steeper portions. Average speed 20 m.p.h. Total duration of climb about 3 minutes. This clutch has run 12,000 miles with satisfaction. It has ventilation holes cut in the clutch cover face, and rim, and four 3/4" slots through each Ferodo ring. A 3" hole was also cut through the large inspection cover on the clutch casing. The original idea of this was to try to keep the clutch parts cooler by the circulation of air through the interior of the clutch. This has not been any noticeable advantage, but the "ventilation" has allowed us to inspect the driven disc for proper setting and has also revealed the almost instant heating and smoking of the clutch under moderate slipping, like climbing on to the inspection ramp etc. On Wilbraham Mountain smoke issued from the clutch almost immediately when slipping commenced. And after three minutes, after changing into second gear, the driven disc "burst", and the oil in the coupling (apparently) caught fire, flames issuing from the casing. The engine was kept running slowly to avoid fire risk until the fire in the clutch died out. The clutch refused to drive at all and the car was towed home. -continued- | ||