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).
Kestrel 27 engine bearing failure during testing.
| Identifier | ExFiles\Box 179b\3\ img150 | |
| Date | 6th February 1933 | |
| To R.{Sir Henry Royce} From Ha/Fmr. c. to Sg.{Arthur F. Sidgreaves - MD} Wor.{Arthur Wormald - General Works Manager} c. to Rg.{Mr Rowledge} Ry. c. to R.{Sir Henry Royce} Ha/Fmr.Y/MJ.6.2.33. KESTREL 27 ENGINE. BEARING FAILURE. The above engine which is fitted with short throw crankshaft in Vickers V.C.M. Steel, articulated rods, and Lead Bronze bearings, to Goshawk specification, was being used for testing modified slipper pads to the Goshawk supercharger in conjunction with bearing tests, under Kestrel 1025 Special Category type Tes Conditions which include Full Throttle Ground Level running using special fuel (Av./Ben./Meth.) 20/70/10 plus 4 cc's. TEL. Castor F.2 Oil, and K.L.G. 14 mm. Plugs Type 744. The tests consisting of a full throttle power curve from 3175 R.P.M. and endurance running at 891 BHP. 2750 RPM. were stopped after 15 mins. running owing to No. C lateral bolt (front) fracturing in the threaded section. A new lateral bolt was fitted and the tests restarted. The full throttle power curve was successfully carried out, with no trace of blower slip, preignition, or trouble of any description and no trace of detonation and the results are consistent with previous results. The next stage of the tests consisting of endurance running for two hours at 891 BHP. 2750 RPM. was commenced, and the engine ran perfectly steady and smoothly for a period of 30 minutes when the power output dropped slightly (about 15 BHP.) accompanied by excessive smoke from the breather, the oil pressure remaining constant at 60 lbs/sq.in. The engine was stopped and the oil filters dismantled and found to have collected a quantity of metal. Upon dismantling it was found that No.2 big end bearing had failed, the rod was blued considerably, also the journal was not damaged, but was found on testing to have reduced from 640 to 480 Brinell. The metal found in the filters was in the form of ribbons of spongy metal and was found on analysis to be 98% Lead, which had disintegrated from the bearing metal leaving the remainder of the constituents of the bearing metal intact on the rod. | ||