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).
Lead bronze bearing test no. 3, detailing various test procedures, conditions, and results.
| Identifier | ExFiles\Box 173\2\ img118 | |
| Date | 9th February 1934 | |
| [handwritten] SGB.WOR.{Arthur Wormald - General Works Manager}RGE by / HS{Lord Ernest Hives - Chair} / RHC{R. H. Coverley - Production Engineer} [/handwritten] To HS{Lord Ernest Hives - Chair} from RHC{R. H. Coverley - Production Engineer} Copy sent to Allison Engineering Company Buffalo, N. Y. Feb. 9, 1934. LEAD BRONZE BEARING TEST NO. 3 Further tests were run Wednesday, Feb. 7th, in Stutz Factory, Indianapolis, on Allison Main Bearings 70/30 material specification having Kestrel Type oil grooves. [handwritten] Bearings being subject a total running time of 40 mins at 3500 R.P.M. [/handwritten] The object of running a further set of 70/30 was because Allison consider this composition is not entirely satisfactory for main bearing but quite suitable for connecting rods; therefore in view of successful test on first bearing [handwritten] wished [/handwritten] to confirm reliability of this composition. To enable tests to be conducted under exactly similar conditions at Derby more careful check of running condition torque loads are given, it will be observed from Test Data that <s>as speed stages were increased they were restored to previous speed</s> after one or two minutes duration; this was done because under certain conditions there was a jump in torque - bearing temperature, however, was not affected. At completion of a 15-minute test at 3500 R.P.M., it was decided, in view of cable which mentioned failure when attempting to carry out short duration tests at Derby, to run a similar test as it was thought perhaps this introduced some change in bearing conditions when suddenly increasing speed, particularly after [handwritten] observing [/handwritten] <s>serving torque increase during running in period.</s> [handwritten] later [/handwritten] The test is referred to as Diving Test to distinguish on data sheet for convenience of analysis, and consisted of running at 3500 R.P.M. for periods of 30 seconds, reducing speed to 2250 R.P.M. for one minute, and repeated 20 times.✓ It took 20 seconds to give increase in speed required on electrical dynamometer; this no doubt compares favorably with engine acceleration. The torque and bearing temperature having remained constant during diving test it was decided to repeat high speed test✓ of 15 minutes at 3500 R.P.M. During this test torque remained constant with slight decrease of bearing temperature compared with earlier figures, and appeared as though bearing would run indefinitely. Examination proved bearing condition to be better than Test No. 1 in which there was evidence of lead sweat. The next tests will be run on 60/40 Bearings having modified lubrication which will consist of holes instead of grooves, and will be subjected to same conditions of test as 70/30 bearing. If satisfactory I would then like to increase speed to | ||