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).
Fan belt tests for the British Goodyear N.8620B (No.2) belt.
| Identifier | ExFiles\Box 135\1\ scan0264 | |
| Date | 1st March 1938 guessed | |
| - 2 - REPORT ON FAN BELT TESTS FOR ROLLS ROYCE LTD., --------------------------------- BRITISH GOODYEAR N.8620B (No.2). Pulley diameter (base of vee) - 3-21/32") DAYTON COG Pulley Angle - 33°- 56') PULLEYS. Belt periphery External start - 50-1/4" finish - 46-11/16" Internal start - 51-1/4" finish - 47" Initial centres - 16-7/8" Fan Speed - 3700 - 4300 Driven Speed - 4200 - 4530 % slip Initial - 3.7 Average - 5.3 Minimum - 3.2 H.P. - 19 - 22 H.P. average (all test) - 21.3 Average HP x hours - 163.3 Temp. of running - 115°F Hours run - 7 hours 40 mins. The slip could not be kept down to 4% even with excessive tension. Consequently the slip varied around 4.5% till after 6 hours the belt was seen to be exhibiting signs of slackness. The centres were then increased by 3/16" to 17-1/16". This had the effect of reducing the slip for about 30 mins. when the centres were again increased by 3/16". This had no effect on the slip which gradually increased, rising suddenly to 16.9%. The test was suspended and the belt on examination disclosed a waist presumably due to cord fracture. On cutting and removing top cover, exposing cords, they were found to be all broken within an inch or so of length and slightly charred - 10 cords in this belt. Cords broken thus. S Longley | ||