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).
Page of valve spring calculations for a 40/50 model.
| Identifier | ExFiles\Box 56\2\ Scan113 | |
| Date | 18th December 1931 | |
| 4290. FILES. 18.12.31. 40/50 VALVE SPRING CALCULATIONS. we have - To make tappet follow the cam at 3700 R.P.M. Wt. of tappet .284 lbs. Accel. @ 3700 R.P.M. = 3800 ft/sec2. ∴ Load = (.284 X 3800) / 32 lbs = .284 X 120 lbs. = 33.7 lbs. To look after suction, push rod and valve. Wt. of push rod .158 @ 1.35 leverage spring required = .214 effective lbs. = .214 X 120 25.6 lbs. Wt. of valve .364 44 lbs. Suction @ 10 lbs/sq.in. 31.4 lbs. ------------------ 101.0 lbs. Max. acceleration of valve in valve spring taken as .0015"/div/div. VALUE OF ACCN. OF .001" per div per div. = .001 / 4 = .00025" per deg per deg (on cam) = .00025 X (360^2 X (3000)^2) / 60^2 = .00025 X 36 X 1500^2 = 20,250 ins/sec/sec. = 1687 ft/sec/sec. Rm.{William Robotham - Chief Engineer} | ||