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).
Test report on the performance of a cotton belting clutch under various loads and temperatures.
| Identifier | ExFiles\Box 74\2\ scan0115 | |
| Date | 1st April 1912 guessed | |
| Cotton belting clutch load in lbs on the lever | Equivalent gradient for chassis weighing 5,500 lbs | Temperature of clutch surface | Remarks 185 | 1 in 7.92 | - | Clutch started rear wheels satisfactorily. 231 | 1 in 6.35 | - | ditto. 280 | 1 in 5 | 110°F.{Mr Friese} | Clutch was allowed to slip a good deal before fully engaging and pedals rose to 3/8". 298 | 1 in 4.9 | 122°F | Clutch engaged satisfactorily. 310 | 1 in 4.7 | 170°F | Clutch allowed to slip a good deal but engaged satisfactorily. 320 | 1 in 4.6 | 200°F | Dressing in material commenced to swell and ooze out. Pedals rose to 7/8" but clutch engaged satisfactorily. 325 | 1 in 4.5 | 226°F | Clutch engaged satisfactorily. 330 | 1 in 4.44 | 300°F | Clutch slipped considerably but would pull up engine. Dynamometer weights were lifted but engine would not start road wheels. The temperature of the clutch faces at the start was 80°F After these tests the clutch was still quite satisfactory and the car could be comfortably driven. The only point to be observed was that the clutch had a slight tendency to stick. Nearly all the dressing was melted out but the clutch cone did not continue to bed more deeply into the flywheel, and the material had almost exactly the same appearance after test as before. Mr Platford regards these tests as being extremely satisfactory for the cotton belting. There is no doubt that this type of clutch will stand slipping to a very much greater extent than the leather cone. 12 sets are in course of | ||