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).
Torque component vibration, engine speeds, and future design work for 6 and 12 cylinder engines.
| Identifier | ExFiles\Box 132\2\ scan0205 | |
| Date | 17th February 1941 | |
| Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}4/ET.17.2.41. - 5 - D.{John DeLooze - Company Secretary} It is correct to state that the torque component for the 3rd order vibration on the 6 cylinder will be greater than that for the 6th order on the 12 cylinder, although both are major orders. In our calculations we found the resultant torque component at any one crank on the 6 cylinder to be seventeen times that on the 12 cylinder for these orders. Actual figures were 3.6 lb/in² on the 12 cylinder and 61.6 lb/in² on the 6 cylinder. E.{Mr Elliott - Chief Engineer} We agree that there is little point in running much above 4000 R.P.M. with the engines at present in being. The conclusions drawn in the covering memo Rm.{William Robotham - Chief Engineer}16/ML.7.12.40 do serve as a warning, however, for future design work. Given similar breathing conditions the maximum speeds of any two engines will be approximately proportional to their piston speeds. Thus when we build smaller bore engines with smaller strokes, we expect them to run up to higher speeds. With a large rationalized programme, however, there is danger of the reciprocating parts on the engine at the bottom end of the scale being larger than necessary. It is against this danger that we should watch. Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} | ||