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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).
Final tests conducted on Lead Bronze bearings.

Identifier  ExFiles\Box 173\2\  img226
Date  27th February 1934
  
SEATON (crossed out signature)
C Hero (signature)
U S A
February 27, 1934
Indianapolis, Indiana

HS{Lord Ernest Hives - Chair} from RHC{R. H. Coverley - Production Engineer}

BEARING TESTS

Enclosed are particulars of final tests conducted here on Lead Bronze bearings copy of which has been handed to Allison Engineering Company.

No. 7 Test was completed at 4250 R.P.M. for 20 minute duration, during preliminary run at this speed considerable oil pressure drop occurred, it was therefore decided to install an auxiliary oil pump driven by an independent electric motor to maintain a pressure of 70 lbs. per sq. in.

This speed produces a rubbing velocity of 56 ft/sec. all previous tests at 3750 R.P.M. being 49.5 ft/sec. The limit has not been reached on these bearings although for speeds in this region judging by the movement of bearing in crankcase balancing of crankshaft would be necessary.

It will be observed there was a decided bearing temperature rise when speeds were increased which may be accounted for by clearance for such speeds .0045 clearance may not be sufficient.

Bearings were however sized on Horizontal Bores and finish would normally be considered most unsatisfactory which made conditions of test more severe and may account for temperature rise, therefore results are more convincing.

It will be necessary to increase running in period for New Bearings which in earlier stages should be carried out by motoring engine for period of 5 hours before running under its own power, when this stage is reached it is considered necessary to run light for two hours.

In order to eliminate scored bearings, Allison recommended the introduction of Auto Klean filter. Particular care is exercised in U.S.A. regarding oil filtration with use of Lead Bronze bearing.Filters of this type are permanently arranged in oil system.

Enclosed also are photographs of equipment used for bearing tests in Stutz factory. Whilst it would have been possible to run up to 4500 R.P.M., Stutz representative would
  
  


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