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).
Test log documenting various modifications to a car to solve a 'jellyING' or vibration issue.
| Identifier | ExFiles\Box 28\5\ Scan045 | |
| Date | 30th April 1930 | |
| CONDITION OF CAR FOR TEST RESULTS OF TEST 1. 22.1.30 | 22 Ex. | STANDARD S.S. ENCLOSED LIMOUSINE | CONSIDERABLE AMOUNT OF JELLYING. ROAD SHOCKS EXCESSIVE. WINGS FLAP TOO MUCH. 2. 22.1.30 | 22 Ex. | 2 CWTS: ADDED CENTRALLY IMMEDIATELY IN FRONT OF RADIATOR. | STEERING HEAVIER. NO APPRECIABLE IMPROVEMENT IN JELLYING, IF ANYTHING THE REVERSE. 3. 22.1.30 | 22 Ex. | 1 CWT: ADDED AS DUMBEL IN MANNER INDICATED 4 WTS. IN LINE WITH WHEEL CENTRES. BAR ACROSS DUMB IRONS. | THIS IS 100% CURE OF THE TROUBLE. 4. 23.1.30 | 22 Ex. | WING STAYS STIFFENED UP. | WING FLAPPING LARGELY ELIMINATED. 5. 23.1.30 | 22 Ex. | CROSS MEMBER IN FRAME CENTRE SLACKED OFF. | NO APPRECIABLE RESULT. 6. 23.1.30 | 1 W.T. | NORMAL CONDITION THIS CAR JELLIES EXCEEDINGLY BADLY. VIOLENCE 75% GREATER THAN 22 EX. (BODYS. | THE FEATURE OF THIS CAR IS THAT IT JELLIES ON GOOD ROADS TO QUITE AN EXCESSIVE EXTENT. 7. 23.1.30 | 1 W.T. | 20" WHEELS COMPARED WITH 21" | NO APPRECIABLE DIFFERENCE. THE TYRES ARE APPROXIMATELY THE SAME RUNNING DIA. SO WE SHOULD NOT EXPECT MUCH DIFFERENCE. WITH 40 LBS TYRE PRESSURE JELLYING 70% LESS THAN WITH 35 LBS/SQ IN". 8. 23.1.30 | 1 W.T. | RADIATOR WT. REDUCED BY 1/3. | NO APPRECIABLE DIFFERENCE. 9. 24.1.30 | 1 W.T. | CROSS STEERING TUBE LOADED UP. SOLID. SIDE STEERING TUBE MADE SOLID. | ROAD SHOCKS REDUCED, BUT NO APPRECIABLE EFFECT ON JELLYING. ROAD SHOCKS NOT MUCH ON A GOOD ROAD BUT COME UP BADLY ON A BAD ROAD. JELLYING NOT APPRECIABLY ALTERED TO ANY EXTENT. 11. 25.1.30 | 1 W.T. | WHEELS TRIED GIVING 7'50 WIDER TRACK | 20% IMPROVEMENT IN ROAD SHOCKS ON A BAD ROAD. STEERING NIBBLES SOMEWHAT ON A GOOD ROAD. SELECTIVITY IMPROVED. JELLYING NOT MUCH IMPROVED. 12. 27.1.30 | 1 W.T. | PHANTOM I AXLE FITTED. 7'50 WIDER TRACK WHEELS WITH THIS AXLE. | SLIGHT IMPROVEMENT IN JELLYING AND ROAD SHOCKS. SAME IMPROVEMENT WITH WHEELS AS PREVIOUSLY FOUND. 13. 28.1.30 | 1 W.T. | TORQUE ARM BALL END ALLOWED A CERTAIN AMOUNT OF MOVEMENT. SO AS NOT TO INTERFERE WITH GEOMETRY. | SLIGHT IMPROVEMENT IN JELLYING (5%) 14. 28.1.30 | 1 W.T. | ONE WAY FRONT SHOCK ABSORBERS TRIED. DOWNWARD LOAD ONLY. | LITTLE DIFFERENCE TO JELLYING. PERHAPS SLIGHTLY WORSE. 15. 31.1.30 | 20 EX. DIABOLO RUBBER FT. | SHOCK DAMPERS CONTROLLED FROM DRIVING SEAT VARIOUS LOADING TRIED. | 150 UP TO 0 DOWN. RIDES VERY HARSHLY. 150 DOWN TO 0 UP. NO JELLYING IMPROVEMENT OVER STANDARD WITH ANY LOAD. 16. 21.1.30 | 1 W.T. | ENGINE FEET TIGHTENED UP. | SLIGHT IMPROVEMENT IN JELLYING, BUT ONLY SLIGHT. 17. 21.1.30 | 1 W.T. | PIVOT LEAN ALTERED FROM 3 1/2 TO 2 3/4 DEGREES. | SLIGHT IMPROVEMENT IN ROAD SHOCKS. 18. 31.1.30 | 22 EX. | TUBULAR CROSS MEMBER IN FRONT OF RADIATOR | 25% JELLYING IMPROVEMENT. 19. 6.2.30 | 20 EX. DIABOLO RUBBER FT. | BALL PIN ON STEERING ARM RAISED 1.75". | JOGGLES ON A GOOD ROAD WORSE. NO IMPROVEMENT IN JELLYING. 20. 11.2.30 | 20 EX. | SCUTTLE TIGHTENED UP. SOLID WASHERS. | JELLYING SLIGHTLY REDUCED (5%). ENGINE VIBRATIONS WORSE. EXHAUST BOOMS INCREASED. 21. 11.2.30 | 1 W.T. | SPARE WHEELS FITTED AT THE SIDE. | 30% IMPROVEMENT IN JELLYING. APPRECIABLE IMPROVEMENT - SAY 30% REDUCTION. 22. 17.3.30 | 1 W.T. | SANDWICH FEET FITTED TO THE FRONT AND DAMPERS ON THE ENGINE. SCUTTLE TIGHTENED UP. FRONT OF FRAME STANDARD. | IMPROVEMENT OVER DIABOLO RUBBERS & STANDARD SHOCK DAMPER MOUNTING APPEARS TO BE APPRECIABLE BUT JELLYING STILL QUITE NOTICEABLE. 23. 17.3.30 | 1 W.T. | TWO 3 1/2 TUBULAR CROSS MEMBERS FITTED IN FRONT OF THE RADIATOR AS WELL AS LARGE CROSS ENGINE FEET AS ABOVE & SCUTTLE. | IMPROVEMENT NOT VERY GREAT. APPEARS TO BE 10%. 24. 17.3.30 | 1 W.T. | AS 23 BUT TUBULAR CHASSIS MEMBERS SLACKED OFF, ONE BEHIND GEAR BOX AND LARGE ONE BEHIND THAT. | IMPROVEMENT APPEARS TO BE DETECTABLE - SAY 10% OVER 23. 25. 18.3.30 | 22 Ex. | 25% STIFFER FRONT SPRINGS FITTED. | RADIATOR JELLYING FREQUENCY HIGHER. STEERING MUCH IMPROVED FOR SHOCKS & DIRECTIONAL STABILITY. 26. 18.3.30 | 22 Ex. | 25% WEAKER FRONT SPRINGS. | RADIATOR JELLYING FREQUENCY LOWERED. STEERING WANDERS & IS MORE INCLINED TO HIGH SPEED WOBBLES. 27. 6.4.30 | 20 EX. | SINGLE POINT RAD. MOUNTING FITTED. | RADIATOR CAP MOVEMENT REDUCED 50%. 28. 6.4.30 | 20 EX. | SINGLE POINT ENGINE MOUNTING IN FRONT WITH ONE TUBULAR MEMBER BEHIND RAD & TWO IN FRONT. DIABOLO REAR FEET. | JELLYING SLIGHTLY WORSE THAN 14 EX. JELLYING IS NOT IN EVIDENCE ON A GOOD ROAD. STEERING POOR FOR WANDERING. JELLYING AMPLITUDE GREATER FREQUENCY LOWER ON A BAD ROAD. 29. 7.4.30 | 20 EX. | AS 28 BUT SHOCK DAMPERS MOUNTED ON THE ENGINE. | JELLYING MUCH THE SAME. STEERING WANDERS CONSIDERABLY MORE & KICKS BACK. JELLYING PRACTICALLY NON EXISTENT EVEN WITH SPARE WHEELS REMOVED FROM THE SIDES. 30. 8.4.30 | 20 EX. | AMERICAN P.I. CHASSIS. BODY NOT MOUNTED ON SUBFRAME. | RADIATOR WILL MOVE ON A BAD ROAD BUT NOT PERIODICALLY. SLACKING OFF TORQUE REACTION VIBRATION DAMPERS INCREASES RADIATOR MOVEMENT SLIGHTLY. 31. 22.1.30 | 19 Ex. | STANDARD CONDITION. CABRIOLET DE VILLE. FRONT OF BODY IS VERY FLABBY AND MOVES WITH THE DASH. | THIS CAR IS FOR ALL PRACTICAL PURPOSES IMMUNE FROM JELLYING SHEWING UP THE INCONSISTENCY OF THE TROUBLE. THE WHOLE FRONT OF THE BODY OSCILLATES INSTEAD OF THE RADIATOR JELLYING. 32. 16.4.30 | SEAGRAVES CAR 80W.T. | STANDARD CONDITION. JELLYING BAD FOUND TO BE DUE TO OUT OF BALANCED WHEELS. | THIS CAR IS NOT NEARLY AS BAD AS 1 W.T. FOR JELLYING WHEN THE WHEELS ARE PROPERLY IN BALANCE. 33. 16.4.30 | 20 Ex. CAR 80W.T. | CENTRE POINT RADIATOR MOUNTING. TEMPORARY SCHEME. | 60% JELLYING CURE ON THIS CAR AS FAR AS THE RADIATOR CAP IS CONCERNED. 34. 17.4.30 | 1 W.T. | CENTRE POINT RADIATOR MOUNTING. W.W. DESIGN. | DISAPPOINTING. NOT MORE THAN A 30% CURE ON THIS CAR. 35. 20.4.30 | 1 W.T. | CENTRE POINT MOUNTING TRIED WITH VARIOUS RATING OF RUBBERS AND INCREASED FRICTION ON CENTRAL SUPPORT. | WEAKEST RUBBERS GIVE BEST RESULTS. SCHEME VERY SENSITIVE TO RUBBER RATING AND INITIAL COMPRESSION. BEST PROPORTIONS 60% CURE. 36. 25.4.30 | 1 W.T. | SPRINGS TRIED OF VARIOUS RATING IN PLACE OF DIABOLO RUBBERS. | BEST PROPORTIONS OF SINGLE ACTING SPRINGS AND CENTRAL FRICTION GIVE 90% CURE OF RADIATOR MOVEMENT. 37. 27.4.30 | 80 W.T. | AS ABOVE | SIMILAR RESULTS TO 36 BUT JELLYING SCUTTLE AND HIGH LAMPS SPOIL THE EFFECT OF THE CURE. STAMP: ROLLS-ROYCE LIMITED MINT ROOM. 30 APR 1930 DERBY. | ||