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).
Modifications to the 'J. 3. Type' shock damper piston to reduce manufacturing costs.
| Identifier | ExFiles\Box 179b\1\ img013 | |
| Date | 19th August 1932 | |
| DY{F R Danby} FROM HDY.{William Hardy} HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} C. to GG. WOR.{Arthur Wormald - General Works Manager} B. C. to DA{Bernard Day - Chassis Design} ORIGINAL HDY{William Hardy}1/M19.8.32. SHOCK DAMPERS 'J.{Mr Johnson W.M.} 3. TYPE. MODIFIED PISTON. x5520. We send N. sch. 357 herewith which shews modifications to the damper piston to reduce the cost of manufacture. The halves of the piston do not now assist the alignment of each other as the spring bolts pass through clearance holes. This is, we believe, present Delco practice. The piston halves can be machined independently: they are identical, and there is only one reamed hole in each half. Compared with our present piston the loads on the cylinder walls due to cross winding forces are approximately doubled. R.{Sir Henry Royce} has remarked that for this reason this piston should be tested in an aluminium cylinder. We have reduced the distance between the rocking shaft and the cylinder by .075 in order to decrease the upward thrust of the pistons at their inner ends at large spring deflections. Three types of inlet valve are shewn - one similar to Delco, and one on the right as for Delco with an additional hole and groove to facilitate the escape of dirt from the valve seat. Derby should select the one found to be most satisfactory. HDY.{William Hardy} | ||