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).
Bearing endurance tests conducted on a single-cylinder test rig.
| Identifier | ExFiles\Box 115\1\ scan0320 | |
| Date | 23th April 1937 | |
| Wd.{Mr Wood/Mr Whitehead}5/RS.{Sir Henry Royce's Secretary}23.4.37. SINGLE CYLINDER DEPARTMENT. BEARING TEST RIG. Bearings in A.C.2, A.C.5.S, and A.C.6.S. have been tested on the above rig and compared with a standard BZ/L bearing. CONCLUSIONS. No material ran for as long as the BZ/L bearing without failure, although the A.C.6.S, after slight seizure and modification, concluded an endurance at a higher loading than the BZ/L. TEST METHOD. Bearings to be tested are bolted in an aluminium plate, resembling as near as possible, a section from a Kestrel crank-case. Load is applied by means of a revolving out of balance weight, the speed of rotation controlling the load pressure. Oil is fed to the bearings by means of a gear type pump, the pressure and temperature being kept constant, for all endurance running, at 40 lbs/sq.in. and 100°C. respectively. The approximate oil flow through the bearings was 7.5 secs/pt. i.e. 1 gall/min. though this figure ofcourse varied with the clearance and speed of rotation. The diametral clearance was maintained as near as possible to .004". Each bearing was incrementally loaded over a period of 3 hours from 50 to 1700 lbs/sq.in. a 13 hour endurance at 1700 lbs/sq.in. was then carried out at the end of which the bearings were removed and inspected. Following this, 4 hour endurance periods were carried out at an increase of 200 lbs/sq.in. at a time until failure occurred. Prior to each 4 hour endurance the bearings were given a standard incremental load warming up period. Warning of failure was indicated by means of a thermo-couple placed as near as possible to the bearing under test. A figure was obtained for a standard Kestrel Allison BZ/L centre main bearing and used as a basis of comparison for all tests. All the A.C. bearings were of the solid (i.e. unbacked) type and were low temperature treated for a total of 14 hours at 170°C; 7 hours in the rough casting stage and the remaining 7 hours prior to final machining. | ||