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).
Comparison table of camshaft acceleration, deceleration, and tappet velocity data for various engines.
| Identifier | ExFiles\Box 124\2\ scan0312 | |
| Date | 26th May 1941 | |
| To Rm.{William Robotham - Chief Engineer} from Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} Copy to Jnr.{Charles L. Jenner} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation} B.60 file 104f. Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden}6/ST.26.5.41. GENERAL INFORMATION ON CAMSHAFTS A - MAX. ACCELERATION AND DECELERATION. in feet/sec^2 @ 1000 R.P.M. ======================================================================================== Engine Unit | Rocker Ratio | Max. + u2 accel. of inlet VALVE | Max. + u2 accel. of inlet CAM | Max.decel. of inlet VALVE | Max.decel. of inlet CAM | Max.accel. of.inter. VALVE at max.engine speed ------------|--------------|---------------------------------|-------------------------------|-----------------------------|---------------------------|------------------------------------------------- Bentley II | 1.245 | 2952 | 2370 | 960 | 770 | 59600 @4500 REM. Bentley V | 1.31 | 3180 | 2430 | 906 | 692 | 64300 @4500 RPM. Bentley 60 | 1.28 | 4043 | 3160 | 1071 | 837 | 81500 @4500 RPM. Myth | 1.3 | 3000 | 2310 | 651 | 500 | 67800 @4750 RPM. Merlin | 1.5 | 3870 | 2580 | 1104 | 737 | 50400 @3600 RPM. ======================================================================================== B - TAPPET VELOCITY WHEN MEETING AND LEAVING THE TOE OF THE CAM. in feet/sec. @ 250 R.P.M. ======================================================================================== | I N L E T | E X H A U S T Engine Unit | OPENING Cam strikes tappet. | CLOSING Cam leaves tappet. | OPENING Cam strikes tappet. | CLOSING Cam leaves tappet. ----------------|-----------------------------|----------------------------|-----------------------------|---------------------------- Bentley II | at .083 ft/sec. | at .06 ft/sec. | at.083 ft/sec. | at .06 ft/sec Bentley V | .114 | .057 | .114 | .057 Bentley 60 | .081 | .059 | .103 | .075 Myth | .103 | .058 | .103 | .075 Merlin | .146 | .146 | .146 | .146 ======================================================================================== | ||