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).
24-hour endurance test for Bentley piston development, detailing a piston seizure and planned modifications.
| Identifier | ExFiles\Box 86\2\ scan0083 | |
| Date | 18th October 1933 | |
| X236 To E.{Mr Elliott - Chief Engineer} from Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation} c. Wor.{Arthur Wormald - General Works Manager} By.{R.W. Bailey - Chief Engineer} c. MX.{John H Maddocks - Chief Proving Officer} Hs{Lord Ernest Hives - Chair}/CTS.{C. Trot Salt - Carburation}1/KT.18.10.33. BENTLEY - PISTON DEVELOPMENT. B.1 Unit. LeC.3493. LOP.EB.513. { EB.602 Piston. { EB.603 Piston Grinding. After the usual running in time of 4 hours pistons were still tightening up at 3000 R.P.M. Maximum power could not be maintained at this speed, until a total of 10 hours running in with gradually increasing load had been completed. After 5 hours endurance at 3000 R.P.M. the pistons were removed for inspection, but showed no signs of undue wear. However, further tightening up was experienced in an attempt to maintain power at 4000 R.P.M., so the engine was run just below this speed with occasional bursts at full throttle, until maximum power was maintained. This entailed a further 5 hours running in. 9 hours high speed endurance was then completed before No.4 piston seized, but they were still tightening up occasionally at 4250 during this period. Inspection showed the cylinder walls to be practically dry, and it was thought that the seizure was not entirely due to insufficient clearance. A new set of pistons will next be tried having increased clearance, and part of the cylinder barrel cut away to improve lubrication. These modifications are shown on LeC.3667. Light running 10 hours. At 3000 RPM. 5 hours. " 4000 " 6 hours 45 mins. " 4250 " 2 hours 15 mins. Total running = 24 hours. Hs{Lord Ernest Hives - Chair}/C.T. Salt. | ||