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).
The running experience and tests of Vandervell bearings on Merlin engines.
| Identifier | ExFiles\Box 115\4\ scan0110 | |
| Date | 14th October 1940 guessed | |
| VANDERVELL BEARINGS. RUNNING EXPERIENCE ON MERLIN ENGINES. Confirmation of the results obtained on rig test of Vandervell bearings has been given by tests on Merlin 2433. This engine was fitted with the following bearings of Vandervell manufacture. (a) Main bearings - in tri-metal and fitted in steel housings machined from our standard bearings and line reamed in the crankcase, the centre housing being arranged to take the thrust on the normal thrust flange with LTI lining (b) Connecting Rod bearings - inner in tri-metal blade rod in lead bronze - of the strip type without flanges. (c) Camshaft bushes - in white-metal. steel backed. The main bearing liners were oval and barrel shaped to an extent determined from rig tests on the Single Panel Rig. i.e. were broached to give .002" extra clearance at the joint face and were barrelled .0004" to relieve edge loading. The remaining bearings were produced with parrallel bores. Strip after 2 Hours. Main Bearings. - in good condition generally but careful examination revealed points at which break up would be expected to commence with further running. Connecting Rod Bearings.- inner bearings all showed slight signs of break up near the joint face opposite to the tang. blade rod bearings in good condition Camshaft bushes - in good condition. Strip after 30 hours endurance at maximum cruising conditions (2650 RPM + 7 lbs/sq.in. boost) Main Bearings. (see attached photograph) All bearings show signs of break up but this is especially noticeable on Nos. 3 and 6 cap half bearings the break up similar in every respect to that shown by bearings run on the rig. Break up generally was more marked near the oil groove, but bedding on the whole was uneven some bearings appeared to have been beeding only over half their area. P.T.O. | ||