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).
Bouncing test of the Kestrel valve operation with a harmonic camshaft.
| Identifier | ExFiles\Box 179b\3\ img181 | |
| Date | 10th February 1933 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/Aln. c. to Sg.{Arthur F. Sidgreaves - MD} c. to Wor.{Arthur Wormald - General Works Manager} c. to Re. c. to E.{Mr Elliott - Chief Engineer} c. to By.{R.W. Bailey - Chief Engineer} Kestrel Valve Operation with Harmonic Camshaft. X2965. X4003. We have carried out a bouncing test on the Kestrel valve spring rig arranged to DES.1545. This embodies :- Harmonic camshaft to DES.1734. Exhaust Valve E.38330. Inlet Valve E.28651 (Standard). Rockers E.30792/3. Springs - Outer E.38324. Springs - Inner E.38325. The camshaft was run in the usual way from a 20/25 engine and bouncing speeds were observed with the rotoscope. These were found to be, (in terms of equivalent crankshaft speeds) :- Inlets 3900 R.P.M. Exhausts 4100. It is not clear why the inlets should bounce at lower speeds; the mass of the inlet valve is slightly less than that of the exhaust, other reciprocating fitments being practically equal. The figures, however, represent the earliest stages of bouncing discernible in two or three of each kind of valve. A lift curve was taken on two of the valves, one inlet and one exhaust, the results of which are shown attached. A dotted curve is added shewing the lift specified on DES.1734. The exhaust lift taken agrees most nearly with this, but as the cams are all supposed to be the same the exhausts and inlets may vary equally between themselves as between one another. The calculated maximum operating speed for this layout is 4000 R.P.M. There was no sign of the valves flinging from the cams at full lift. The springs were very free from surging and no breakages occurred during the runs. As far as mechanical operation is concerned, this combination of cams and springs represents a considerable improvement over the previous types. Hs{Lord Ernest Hives - Chair}/F.J.Allen. Print attached. | ||