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).
Efficiency comparison between a P.II. type steering worm and nut and a Marles-Weller type steering system.
| Identifier | ExFiles\Box 17\4\ Scan050 | |
| Date | 16th May 1933 | |
| X7430. from RHC.{R. H. Coverley - Production Engineer} c. Hs{Lord Ernest Hives - Chair}/Rm.{William Robotham - Chief Engineer} RHC.{R. H. Coverley - Production Engineer}3/BE16.5.33. MARLES-WELLER TYPE STEERING. EX.10037 We give below the efficiency of the P.II. type of steering worm and nut compared with the Marles-Weller type. It will be observed that the efficiency of the Marles-Weller is 60% of the P.II. type. There is a greater tendency on the Marles-Weller to stick, which is shewn by the fall in efficiency of approximately 6% in the initial loading as compared with 3½% on P.II. Tests were carried out on the standard steering rig, and load checked with spring balance on 20" lever. | | Std.P.II Nut & Worm. | | | Marles-Weller type. | | | |---|---|---|---|---|---|---| | Load Applied in lbs | Initial Effort | Effort req: to maintain movement. | Effy. | Initial Effort | Effort req: to maintain movement | Effy | | 150 | 1½ lbs | 1¼ lbs | 69% | 2½ lbs | 2¼ lbs | 38% | | 300 | 2½ " | 2¼ " | 76% | 5 " | 4 " | 43% | | 600 | 4½ " | 4¼ " | 81% | 8½ " | 7 " | 49% | | 900 | 6¾ " | 6¼ " | 83% | 11½ " | 10½ " | 49% | | 1200 | 9¾ " | 9 " | 76% | 15½ " | 14½ " | 47% | | | | AVERAGE | 77% | | AVERAGE | 45% | RHC.{R. H. Coverley - Production Engineer} | ||