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 report on 40/50 Bump Dampers, detailing wear and performance after 30 and 38 hours.
| Identifier | ExFiles\Box 16\4\ Scan295 | |
| Date | 7th May 1931 | |
| FILES. X7520 7.5.31. 40/50 BUMP DAMPERS. FRONT :- AFTER 30 HRS. LOADS 70/80 LBS NO LEAK N.SCH.3244. The condition of the hardened S/ZN bushes (F.82195 with .005" case) was excellent. The maximum wear measurable on the pivot pins was .0001" The actual dimensions of the pivot pins and bushes after test were :- Offside:- Pin 4.997" Lever .5003" Clnce .0006" Nearside:- " 4.9955" " .5000" " .0005" The actual dimensions before test are not known but the bushes were ground to suit the pins to give a good floating fit. The general condition of the dampers was good (these same dampers have been previously used for other tests) except for the N.S. large main ball race which had excessive side play. These dampers also incorporated a special oil feed for the pivot pins, leading from the air vent holes, and on account of this the stand-pipes were not shortened to the present standard length, so that the full effect of the extra feed could be determined. The oil levels after test were extremely low. The loads were not checked. REAR :- AFTER 38 HRS. LOADS 100/100. NO LEAK. ARRGT DRG. F.83611. Hs{Lord Ernest Hives - Chair}/Rm{William Robotham - Chief Engineer} The oil level was good, the loads were within limits except for the N.S. H.P. which was 10 lb, also the main levers and bearings were good. The ball pins were badly discoloured, especially the off side (one oil hole of the latter being completely blocked up) due to failure of the oiling system. These were incorrectly lubricated, wrong scheme fitted. The piston pads and grooves worn in them, in each case the depth of groove measured .002" L.P. and .0005" H.P. The pistons were good except for slight "picking up" marks in each case at the H.P. end. The ball ends of the inter levers were worn approx .003" O.S. and .001" N.S. | ||