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).
History of lubrication and modifications for the Kestrel and Merlin engines' main pressure systems.
| Identifier | ExFiles\Box 115\2\ scan0583 | |
| Date | 10th July 1941 | |
| KESTREL, MERLIN MAIN PRESSURE LUBRICATION HISTORY. LUBRICATION AND MODIFICATION DETAILS | ARRANGEMENT DRAWINGS AND MODIFICATIONS. --- ROW 1: KESTREL LEFT COLUMN (Diagrams and Description): Diagrams: Nº 7, Nº 1,2,3,4,5,6 Text: WHITEMETAL MAIN AND BIG END BEARINGS. EVERY MAIN BEARING EXCEPT THE REAR FEEDS A BIG END. THREE HOLES IN EACH JOURNAL EXCEPT THE REAR, ONE HOLE IN EACH CRANKPIN. NO GROOVES IN THE MAIN BEARINGS. MIDDLE COLUMN (Lubrication and Modification Details): KESTREL. SPECIFIED OIL - SUMMER 'P's'. WINTER 'P's'. OIL PRESSURE - 50-65 LB/SQ IN. MINIMUM OIL PRESSURE CHANGED FROM 50 LB/SQ IN. ON EARLY TYPES TO 30 LB/SQ IN. (1) WHITEMETAL ON STEEL SHELLS FOR BIG END AND MAIN BEARINGS. (2) THE CENTRE MAIN BEARING HAS DEEP WHITEMETALLED END FLANGES RESORTED TO TAKE THRUST. (3) OIL DISTRIBUTED THROUGH GROOVES IN THE BEARING CAPS IS FED THROUGH TWO 3/16" DIA. TRANSFER HOLES IN EACH MAIN BEARING, SUBTENDING AN ANGLE OF 60°. (4) NONE OF THE MAIN BEARINGS ARE GROOVED. (5) EVERY JOURNAL EXCEPT THE REAR IS AN OIL RESERVOIR FED THROUGH THREE .201 DIA. HOLES AND IS USED TO FEED A BIG END. (6) ONE .201" DIA. HOLE IS DRILLED IN EACH CRANKPIN. (7) BIG END BEARING BLOCKS HAVE FOUR 1/8" DIA. HOLES AND THE EXTERNAL WHITEMETAL FACING IS GROOVED (210° WIDE x .020 DEEP) THROUGH 240° TO ASSIST LUBRICATION OF THE PLAIN RODS. (8) ONE PRESSURE OIL PUMP IS USED AND TWO SCAVENGE PUMPS, THE LATTER MOUNTED ONE ABOVE THE OTHER AND OPERATING IN TANDEM. RIGHT COLUMN (Arrangement Drawings and Modifications): SERIES I AND EARLY SERIES II & II MS. II S AND IV MS. CRANKSHAFT E.{Mr Elliott - Chief Engineer} 33837 CONNECTING RODS E.{Mr Elliott - Chief Engineer} 44184 CRANKCASE AND BEARINGS E.{Mr Elliott - Chief Engineer} 45245 --- ROW 2: KESTREL LEFT COLUMN (Diagrams and Description): Diagrams: Nº 7, Nº 1,2,3,4,5,6 Text: CHANGE FROM WHITEMETAL TO 2% TIN BZ/L FOR THE BIG ENDS AND 1/2% SILVER BZ/L FOR THE MAINS. PART ANNULAR GROOVES IN ALL EXCEPT THE REAR MAIN BEARING. MIDDLE COLUMN (Lubrication and Modification Details): KESTREL. SPECIFIED OIL - D.T.D. 109. OIL PRESSURE - 60-65 LB / SQ. IN. (1) LEAD BRONZE ON STEEL SHELLS USED FOR MAIN AND BIG END BEARINGS - FOR BIG END A 2% TIN ALLOY AND FOR MAINS A 1/2% SILVER ALLOY. BIG END BEARINGS MADE BY THE CENTRICAST PROCESS, MAIN BEARINGS BY THE ALLISON STATIC CAST PROCESS, THE LATTER PROVED GOOD ANTI-SEIZURE CHARACTERISTICS AND THE DOUBLE LATTER DEPENDED ON MERLIN DUE TO CRACKING AND BREAKING UP OF THE BEARING FACES. DID NOT OCCUR OWING TO LOWER P.V. VALUES. ATTEMPTS WERE MADE TO USE CENTRICAST LEAD BRONZE MAIN BEARINGS IN 1933 PRODUCTION BUT THESE FAILED DUE TO REPEATED SEIZURE BY THE CENTRE BEARING. WHITEMETAL WAS TRIED FOR THE CENTRE BEARING ONLY, BUT THE ENGINE WAS NOT FINALLY CLEARED FOR PRODUCTION UNTIL THE INTRODUCTION OF THE ALLISON BEARING. (2) ALL MAIN BEARINGS EXCEPT THE REAR WERE GROOVED INTERNALLY. (28° WIDE x .030" DEEP) THROUGH 180°. (3) A THREE GEAR SCAVENGE PUMP WAS TRIED IN PLACE OF THE TWO PUMPS IN TANDEM, THE OBJECT BEING TO REDUCE WEIGHT. THIS PROVED INADEQUATE AND WAS REPLACED BY A SIDE-BY-SIDE TWIN PUMP OF THE TYPE LATER USED ON MERLIN. (4) A LARGER CAPACITY PRESSURE OIL PUMP WAS INTRODUCED. RIGHT COLUMN (Arrangement Drawings and Modifications): ALL SUBSEQUENT KESTREL SERIES (THE VARIOUS ARRANGEMENTS SHEWN BELOW DO NOT DIFFER IN LUBRICATION DETAILS) CRANKSHAFT - SERIES V TO XXI - E.{Mr Elliott - Chief Engineer} 33837, SERIES XXX E.{Mr Elliott - Chief Engineer} 14948 CONNECTING RODS E.{Mr Elliott - Chief Engineer} 44184 OIL PUMPS E.{Mr Elliott - Chief Engineer} 45015 CRANKCASE AND BEARINGS: SERIES V TO IX E.{Mr Elliott - Chief Engineer} 45245 SERIES X E.{Mr Elliott - Chief Engineer} 46011 SERIES XXI E.{Mr Elliott - Chief Engineer} 49389 SERIES XXX A.{Mr Adams} 54069 MOD 216 - OIL GROOVES ADDED IN MAIN BEARING BUSHES. MOD 225 - LARGER CAPACITY OIL PUMPS. MOD 233 - CONNECTING ROD BEARING BLOCK LININGS CHANGED FROM WHITEMETAL TO 2% TIN LEAD BRONZE ALLOY. MOD 280 - CRANKCASE AND BEARING BLOCKS TO SUIT LEAD BRONZE BEARINGS. --- ROW 3: MERLIN LEFT COLUMN (Diagrams and Description): Diagrams: Nº 3, 5, Nº 1, 4, 7, Nº 2, 6. Box on diagram: 60° FOR BEARINGS Nº 1,7 HY{Tom Haldenby - Plant Engineer} - Nº 2,3,4,5,6 Text: 2% TIN BZ/L BIG END BEARINGS AND 1/2% SILVER BZ/L MAIN BEARINGS. EACH OUTER INTERMEDIATE MAIN BEARING FEEDS TWO BIG END BEARINGS. EACH INNER INTERMEDIATE MAIN BEARING FEEDS ONE BIG END BEARING. THREE HOLES IN EACH INTERMEDIATE JOURNAL AND ONE IN EACH CRANKPIN. PART ANNULAR GROOVES IN THE INTERMEDIATE MAIN BEARINGS. NO GROOVES IN THE CENTRE OR END MAIN BEARINGS. NO HOLES IN THEIR RESPECTIVE JOURNALS. MIDDLE COLUMN (Lubrication and Modification Details): MERLIN. SPECIFIED OIL - D.T.D. 109. OIL PRESSURE - 60 - 65 LB / SQ. IN. (1) LEAD BRONZE ON STEEL SHELLS USED FOR MAIN AND BIG END BEARINGS:- FOR BIG ENDS A 2% TIN ALLOY AND FOR MAINS A 1/2% SILVER ALLOY, BIG ENDS MADE BY THE CENTRICAST PROCESS, MAIN BEARINGS BY THE ALLISON STATIC CAST PROCESS. (2) TWO .218 DIA. TRANSFER HOLES IN EACH MAIN BEARING SUBTENDING AN ANGLE OF 60° FOR BEARINGS 1 AND 7, AND 80° FOR BEARINGS 2, 3, 4, 5, 6. (3) MAIN BEARINGS 3 AND 5 ARE EACH USED TO SUPPLY OIL TO TWO BIG END BEARINGS. BEARINGS 2 AND 6 EACH FEED OIL TO ONE BIG END BEARING. (4) MAIN BEARINGS 2, 3, 5, 6 ARE GROOVED INTERNALLY (.018" WIDE x .050 DEEP) THROUGH 140°. THE CORRESPONDING JOURNALS EACH HAVE THREE .201 DIA. HOLES. (5) BIG END BEARING BLOCKS HAVE FOUR 1/8 DIA. HOLES AND THE EXTERNAL LEAD BRONZE FACING IS GROOVED (1/8" WIDE x .020 DEEP) THROUGH 240° TO ASSIST LUBRICATION OF THE PLAIN RODS. (6) ONE .201 DIA. HOLE IS DRILLED IN EACH CRANKPIN. (7) BIG END FAILURES WERE EXPERIENCED ON BEARINGS FED BY MAIN BEARINGS 2 AND 6, i.e. PART ANNULAR GROOVES GAVE AN INTERMITTENT FEED INADEQUATE FOR TWO SETS OF BIG END BEARINGS. RIGHT COLUMN (Arrangement Drawings and Modifications): THIS SCHEME WAS USED IN EARLY MERLIN DEVELOPMENT BUT DID NOT GO INTO PRODUCTION. CRANKSHAFT D.{John DeLooze - Company Secretary} 4518. CONNECTING RODS D.{John DeLooze - Company Secretary} 12846 OIL PUMPS D.{John DeLooze - Company Secretary} 11837. Box: DEVELOPMENT MOD ON "G" AND PRE-PRODUCTION. CRANKSHAFT D.{John DeLooze - Company Secretary} 2944 CONNECTING RODS D.{John DeLooze - Company Secretary} 4170 OIL PUMPS D.{John DeLooze - Company Secretary} 2912 --- ROW 4: MERLIN LEFT COLUMN (Diagrams and Description): Diagrams: Nº 3, 5, Nº 1, 4, 7, Nº 2, 6 Text: CHANGE FROM 1/2% SILVER BZ/L ON THE MAINS TO 1% TIN AND THEN BACK AGAIN TO 1/2% SILVER. COMPLETE ANNULAR GROOVES USED ON THE OUTER INTERMEDIATE MAIN BEARINGS. MIDDLE COLUMN (Lubrication and Modification Details): MERLIN. SPECIFIED OIL D.T.D. 109. OIL PRESSURE 60 - 65 LB/SQ IN. (1) COMPLETE ANNULAR GROOVES INCORPORATED ON MAIN BEARINGS 2 AND 6, THIS OVERCAME BIG END TROUBLE BUT THE IMPROVEMENT IN BIG ENDS PRODUCED MOST FAILURES REPORTED SINCE WW1 COMMENCED WERE ON BIG ENDS FED BY MAIN BEARINGS 3 AND 5, HAVING PART ANNULAR GROOVES. MOST FAILURES OCCUR IN SERVICE AND IT HAS BEEN SUGGESTED THAT THIS IS DUE TO AIR FINDING ITS WAY THROUGH THE PRESSURE PUMP DURING AEROBATICS. (2) 1/2% SILVER ALLOY USED ON ALL MAINS UP TO THE INTRODUCTION OF 1% TIN (L.T.I.). BEARINGS. THE TWO FACTORS CONTRIBUTING TO THE ABANDONMENT OF THE SILVER ALLOY WERE:- a.{Mr Adams} CRACKING OF THE LINING AT THE FLANGES OF THE CENTRE BEARING, THIS DEFECT WAS NOT SERIOUS, BEING CHIEFLY ONE OF APPEARANCE. b. BREAKING UP OF THE INTERMEDIATE BEARING FACES AFTER 300 HOURS, RESULTING IN OIL BEING BLED AWAY FROM THE BEARING GROOVES AND CONSEQUENT BIG END FAILURES. 1% TIN BEARINGS WERE USED SATISFACTORILY FOR 2,300 DEVELOPMENT HOURS AND 1500 SETS WERE PUT OUT. THEY THEN BEGAN SEIZING AND A RETURN WAS MADE TO 1/2% SILVER FOR ALL BUT THE CENTRE BEARING. IN GENERAL THE SILVER ALLOY PRESENTS A METALLURGICAL PROBLEM AND THE TIN ALLOY A LUBRICATION PROBLEM. RIGHT COLUMN (Arrangement Drawings and Modifications): CRANKSHAFT D.{John DeLooze - Company Secretary} 4518. CONNECTING RODS D.{John DeLooze - Company Secretary} 12846. OIL PUMPS D.{John DeLooze - Company Secretary} 11837. CRANKCASE AND BEARINGS D.{John DeLooze - Company Secretary} 1282. MECHANICAL HISTORY. THIS SCHEME WAS USED ON ALL MERLINS UP TO THE INTRODUCTION OF THIN SHELL BIG END BEARINGS ON MERLIN II AND X IN OCTOBER 1939. METALLURGICAL HISTORY. MERLIN I - 1/2% SILVER MAINS THROUGHOUT. MERLIN II - 1/2% SILVER UP TO Nº 5861. Nº 5861 TO 6028 { 1/2% TIN ON Nº 1,7. 1% SILVER ON Nº 1,2,3,5,6,7. Nº 6029 TO 29421 - ALL 1% TIN. Nº 29421 ONWARDS { 1% TIN ON Nº4, 1/2% SILVER ON Nº 1,2,3,5,6,7. MERLIN X - 1/2% SILVER UP TO Nº 2001, ON MERLIN II AND X REVERTED TO 1/2% SILVER ON 30/10/40. ALL REPAIR ENGINES ARE SIMILARLY TREATED. N.B. THE ABOVE ENGINE NUMBERS DO NOT NECESSARILY REPRESENT ANY PARTICULAR CHANGEPOINT. THE LINING UP OF STOCK AND PRODUCTION IN TWO WORKS MAKE A CLEAN CUT CHANGEOVER ALMOST IMPOSSIBLE TO DEFINE. --- ROW 5: MERLIN LEFT COLUMN (Diagrams and Description): Diagrams: Nºs 3, 5, Nºs 1,7 AS ABOVE Nº4 SHEWN BELOW, Nºs 2, 6. Text on diagram: FLATS ARE GROUND ON THE SHAFT HERE. Text: COMPLETE ANNULAR GROOVES USED ON ALL THE INTERMEDIATE MAIN BEARINGS. PART ANNULAR GROOVES ON THE CENTRE MAIN BEARING AND TWO HOLES IN THE JOURNAL. A LARGER CAPACITY PRESSURE OIL PUMP. MODIFIED BIG END BEARINGS. MIDDLE COLUMN (Lubrication and Modification Details): IMPROVED LUBRICATION SYSTEM BY.{R.W. Bailey - Chief Engineer} (1) COMPLETE ANNULAR GROOVES INCORPORATED ON MAIN BEARINGS 3 AND 5. (2) ON THE CENTRE MAIN BEARING (Nº 4), THE TWO TRANSFER HOLES ARE MOVED ROUND TO SUBTEND AN ANGLE OF 110°. A GROOVE OF 110° IN THE BEARING IS PROVIDED (3/16" WIDE x .040 DEEP) THROUGH 80°. TWO .201" DIA. HOLES 180° APART ARE DRILLED IN THE JOURNAL AND FLATS ARE GROUND ON THE SHAFT AT THESE POINTS. THUS A RESERVOIR OF OIL IS OBTAINED WHICH SHOULD SAFEGUARD THE BEARING IN T.V. DIVES. (3) MAIN BEARINGS 1 AND 7 REMAIN UNALTERED. (4) A LARGER CAPACITY PRESSURE PUMP HAS PASSED TYPE AND FLIGHT TESTS AND WILL BE ON PRODUCTION ON MERLIN XX. THIS GIVES 25% INCREASE IN FLOW AND THE MIN. OIL PRESSURE IS RAISED FROM 60 TO 80 LB / SQ IN. ITEMS (1) AND (4) SHOULD EFFECTIVELY OVERCOME BIG END TROUBLES. RIGHT COLUMN (Arrangement Drawings and Modifications): THE LARGE CAPACITY OIL PUMP WILL BE ON MERLIN XX PRODUCTION. IT IS HOPED THAT THE MODIFIED BEARINGS WILL ALSO GO ON TO MERLIN XX. --- ROW 6: MERLIN MIDDLE COLUMN (Lubrication and Modification Details): THIN SHELL BIG END BEARINGS. BIG END BEARING BLOCKS WITH INTERNAL AND EXTERNAL LININGS WERE ABANDONED OWING TO UNSATISFACTORY ADHESION CAUSED BY DIFFERING COEFFICIENTS OF EXPANSION OF THE STEEL SHELL, BRONZE AND ITS LEAD BRONZE LINING. THIN SHELL INTERNAL LININGS FOR BOTH PLAIN AND FORKED RODS WERE ADOPTED, THE FORMER A 3% TIN LEAD BRONZE ALLOY, THE LATTER A 1% TIN ALLOY. A COMPLETE ANNULAR GROOVE (0.16" WIDE x .045" DEEP) IS PROVIDED IN THE PLAIN ROD BEARING. AT THE SAME TIME THE STATIC CAST HAS SUBSTITUTED FOR THE CENTRICAST PROCESS, THE LATTER PROCESS IS BAD FOR CRACKS AND A HIGH PROPORTION OF MANUFACTURING SCRAP IS OBTAINED. RIGHT COLUMN (Arrangement Drawings and Modifications): THIN SHELL BIG END BEARINGS CAME ON TO MERLIN II AND X PRODUCTION IN OCTOBER 1939. - MOD 112. | ||