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).
Shock damper tests investigating the relationship between external pressure and ball pin load.
| Identifier | ExFiles\Box 151\2\ scan0142 | |
| Date | 11th January 1934 | |
| HS {Lord Ernest Hives - Chair} / RH {R. Hollingworth} SHOCK DAMPER TESTS. RELATION BETWEEN EXTERNAL PRESSURE AND BALL PIN LOAD. PII FRONT & REAR F85733 & 2. RRS469 VALVE CHAMBER ETC. Each damper was set to a definite initial ball pin load, then, with the external pressure applied in increments of 5 LB/sq" up to 30 LB/sq", the damper loads were measured by means of an extended lever, the readings being then corrected to normal ball pin leverage. The results showed that there was practically no variation in static load due to valve damping disc - "hat" - diametral clearance, between .010" and .040", although some variation is anticipated in the dynamic loads. The "triple area" valve - GL {G. Linnett} 638, as used on 27EX independent front springing scheme - was tested on a standard front damper, and by comparison with the standard valve readings - see TEST DAMPER 'graph' - gave a load ratio of 1 : 2.96, or 33.8%, at 30 LB/sq" external pressure. Also, the small diameter bellows F85875 (the effective area of which was 50% of the standard bellows F85395) gave a load ratio of 1 : 1.83 or 54.6% at 30 LB/sq" external pressure. Two front, and two rear production dampers, when checked up, showed a rather large variation between the fronts at 30 LB/sq", whilst the rears varied slightly throughout the range. Although not investigated at the time, presumably the variation between the fronts was due to restricted bellows movement, whilst the small difference between the rears may have been due to differences of friction load, or bellows rating. MBell | ||