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 and criticisms of a hydraulic damper design.
| Identifier | WestWitteringFiles\V\October1930-February1931\ Scan360 | |
| Date | 20th February 1931 | |
| DA.{Bernard Day - Chassis Design} HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} (At Le CanadelHenry Royce's French residence.) [Text struck through: C. to SG.{Arthur F. Sidgreaves - MD} WOR.{Arthur Wormald - General Works Manager}] [Text struck through: C. to E.{Mr Elliott - Chief Engineer} BY.{R.W. Bailey - Chief Engineer}] re. HYDRAULIC DAMPERS. [Handwritten: X255.] [Stamp: ORIGINAL RECEIVED 25 FEB 1931] HS{Lord Ernest Hives - Chair}/RM.{William Robotham - Chief Engineer} sends suggestions for a design very like the Lovejoy but I think it could do with some modification and criticism. There are a few errors, as well as some alternative schemes which might be better. It is assumed that the horizontal type will be less costly to make and will give perhaps equally good results in use. We do not want ours to cost double that of our competitors though we cannot hope to compete with such a huge output, and if we make anything so nearly the same we might as well buy. So we must if possible get near their cost, but we would spend another 25% if it made a more lasting piece of work, unless we look upon these as scrap instead of repairable. The design RM.{William Robotham - Chief Engineer} suggested is not quite as stated - (1) One of the replenishing valves is not accessible unless the whole damper is taken apart. (2) "All the valves are vertical" should read 'valve faces' because we should call the valves horizontal. (3) The valve faces are shewn very wide: I thought it was suggested they should be 'knife-edge'. REPLENISHING VALVES. Unless care were taken not to use much spring pressure on these they would not open with atmospheric pressure because the ball seatings only have a very small area exposed to the intake pressure. It suggests larger balls and narrower faces. For accessibility I do not like these valves in piston and I much prefer all valves vertical (motion) - ie. horizontal seatings as is used in nearly all engineering work. Regarding RM{William Robotham - Chief Engineer}'s remarks about adjustable leak, for several reasons we must not have this. Find the best size round hole to make standard for the leak. If we gave an adjustment it would generally be wrongly set as well as a source of trouble and expense. My impression is that the leak should soften all speed of axle movements below the natural period of the car on its springs, which is perhaps 60 per min. It will be taken at some standard ball stroke of say 2" because the leak should only soften the ends of long stroke (4"). (1) | ||