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).
Engine bearing overspeed test, detailing temperature and torque load changes at various RPMs.
| Identifier | ExFiles\Box 173\2\ img237 | |
| Date | 23th February 1934 | |
| February 23, 1934 ROLLS ROYCE ENGINE BEARING TESTS (Continued) Overspeed Test This test was a continuation of Test #6 as the bearings were not inspected between tests. The engine was warmed up and brought up to speed in the usual manner and a run of 10 min. at 3500 R.P.M. was made, giving a total of 50 minutes at this speed, including #6 test. The bearings were then "broken-in" by two short periods at 3750 R.P.M. followed by a run of 10 minutes at this speed. The bearing temperature increased approximately 4° C. and the torque load about 1 3/4 lbs. as compared to 3500 R.P.M. Two short periods at 4000 R.P.M. followed by about a minute at 3750 R.P.M. was then followed by a 10 minute continuous run at 4000 R.P.M. The bearing temperature increased again about 4° C. and the torque load about 1 3/4 lbs. as compared to 3750 R.P.M. After breaking in to 4250 R.P.M. the continuous run was started. After 3 1/2 minutes at this speed the bearing temperature and torque load increased suddenly. The engine was slowed down to 4000 R.P.M. until temperatures steadied. The speed was then stepped up to 4250 R.P.M. and a continuous run of 20 minutes made with all temperature conditions steady. The average bearing temperature was only 1 or 2° C. higher than at 4000 R.P.M. and 12° C. higher than at 3500 R.P.M. At one time the temperature rose suddenly to 146° C. but fell back immediately without the engine speed being changed. Higher speeds were not attempted as the test rig vibration was fairly severe. No failure occurred. At all speeds above 3250 R.P.M. the auxiliary booster oil | ||