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).
Table of results for clutch lining wear tests performed on a 25 HP & Bentley.
| Identifier | ExFiles\Box 103\1\ scan0095 | |
| Date | 3rd May 1934 | |
| -3- Hs{Lord Ernest Hives - Chair}/PHH.20/KW.3.5.34. Clutch Lining Wear Tests - 25 HP. & Bentley. Type of lining. | Wear due to 250 2000-3000 r.p.m. slips. | Additional slips 500-3000 to produce total wear of 0.100" | Remarks. ---|---|---|--- Standard 25 HP. and Bentley Clutch. RAD.13 Untreated | 0 | 85 | Very bad slipping and smoking throughout 500-3000 slips. RAD.5 Untreated -Ditto- repeat. | 0.004 | 270 | Very bad slipping and smoking throughout 2000-3000 slips and first 50 of 500-3000 slips. | 0.010 | 380 | RAD.11 Untreated X standard | 0 | 477 | Very bad slipping and smoking throughout 2000-3000 slips and first 10 of 500-3000 slips. RAD.11 1 1/2 hrs. at 600°F.{Mr Friese} | 0.006 | 310 | Clutch behaved perfectly throughout 2000-3000 slips. Had slipping and smoking during first 40 500-3000 slips. RAD.11 1 hr. at 700°F.{Mr Friese} | 0 | 350 | Clutch behaved perfectly throughout 2000-3000 slips and first 7 of 500-3000 slips. Slipped and smoked from 8th to 30th of 500-3000 slips. | ||