Chart detailing piston development and failure analysis for a 3½ Litre Bentley engine.
| Identifier | ExFiles\Box 86\2\ scan0147 | |
| Date | 2nd November 1933 guessed | |
| FEBRUARY TO NOVEMBER 1933 PISTON DEVELOPMENT. 3½ Litre. BENTLEY. (FRANCE) H.S. 1198 TABLE COLUMNS: PISTON, UNIT, MILES RUN (1000 to 10,000), FAILURE ROW A: PISTON: PIECE No E.56610 C'CASE ALLOY. SHRUNK-ON GUD. PINS. CHASSIS 1.B.III DESPATCHED TO FRANCE 8-2-'33. UNIT: SPEC: C.XIII, RHC {R. H. Coverley - Production Engineer} /WSC {W. S. Cassel} 4/AP 9-3-'33, CYL. BLOCK. SHORT TYPE BARRELS. MILES RUN EVENTS: At ~2800 miles: No. 6 PISTON BROKEN ABOVE GUDGEON PIN. At ~3200 miles: No. 5 PISTON CROWN ADRIFT. FAILURE DIAGRAM: Shows a FRACTURE across the top of the piston below the rings. ROW B: PISTON: PIECE No E.57122. SHRUNK-ON GUD. PINS. UNIT: SPEC: AS ABOVE. MILES RUN EVENTS: At ~4800 miles: No. 3 PISTON SKIRT FAILURE. FAILURE DIAGRAM: Shows a fracture on the piston skirt. ROW C: PISTON: PIECE No. E.B.495 T/O 404 DIE CAST Mx. {John H Maddocks - Chief Proving Officer} BEDDING SHRUNK-ON GUD. PINS. CHASSIS. 1.B.IV. UNIT: SPEC: B.IV(A), RHC {R. H. Coverley - Production Engineer} /WSC {W. S. Cassel} 7/AP 17-7-33, CYL. BLOCK, LONG TYPE BARRELS. MILES RUN EVENTS: At ~8800 miles: No. 5 PISTON SKIRT FAILURE, Nos 3, 4 & 6 CRACKS STARTING FROM HOLES AT THE END OF THE HORIZONTAL SLOT. FAILURE DIAGRAM: Shows a sectioned piston with a large portion of the skirt broken away. ROW D: PISTON: PIECE No E.B.495 F {Mr Friese} /F 404 DIE CAST GRINDING Ex 11480 SPECIAL HEAT TREATMENT (CHILLED FROM THE DIE) SHRUNK-ON GUD. PINS. CHASSIS 1.B.IV. UNIT: SPEC: B.II(B), RHC {R. H. Coverley - Production Engineer} /WSC {W. S. Cassel} 1/AP 23-9-33, CYL. BLOCK, SHORT TYPE BARRELS. MILES RUN EVENTS: At ~5500 miles: PISTONS COLLAPSING Nos 4, 5 & 6 SPLIT CLOSING UP. At ~8800 miles: No. 6 PISTON CROWN ADRIFT, FAILURE ABOVE GUD. PIN BOSS. FAILURE DIAGRAM: Shows a sectioned piston with CRACKS indicated at the gudgeon pin boss. | ||
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).