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).
Description of a test rig, test procedures, and results of tests on Vandervell bearings.
| Identifier | ExFiles\Box 115\4\ scan0113 | |
| Date | 10th September 1940 guessed | |
| - 2 - DESCRIPTION OF RIG. The rig consists of a main-shaft supported at one end by a spherical bearing and at the other end by the bearing under test and carrying an out of balance weight to provide the centrifugal loading. Mounted on ball and roller bearings and rotating concentrically with the main-shaft is a second shaft carrying balance weights to provide dynamic balance for the complete rig. The bearing under test is carried in a detachable crankcase panel (see photograph No.2.) fitted with main and cross-bolts in the normal manner. The construction is such that the panel can be removed at frequent intervals for examination of the bearing without disturbing the bearing in the panel. Deflection of the mainshaft is counteracted by use of a taper sleeve on which the bearing under test runs. A thermocouple pressing onto the back of the bearing records the temperature. Once the bearing has settled down (after 2 - 3 hours running) the bearing temperature remains sensibly constant but commencement of break up is invariably accompanied by a rise in bearing temperature of 2 - 3°C and thus forms a very reliable guide to the condition of the bearing. Details of Test. Incremental load running is carried out at a rate of 100 lbs/sq.in. increase in loading every 10 minutes, and experience has shown that when running endurance at a speed of 2580 RPM giving a mean loading of 2080 lbs/sq.in. which is rather less than that normally attained by the Merlin centre bearing under T.V. dive conditions, main engine break up can be reproduced. Throughout the series of tests DTD 109 oil was supplied at a temperature of 90°C and a pressure of 60 lbs/sq.in. Results of Tests on Vandervell Bearings. The results of the complete series of tests on Vandervell bearings are shown in the attached table in comparison with the RR standard alloy and the best RR alloy as developed from these and seizure tests. Summary of Results. It has often been claimed that one of the merits of the white-metal bearing is its ability to cope with excessive local loads during the running in period due to its inherent property | ||