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).
Report on 'Ramp Head No.2', its promising performance, and suggestions for further modifications and testing.
| Identifier | ExFiles\Box 133\2\ scan0096 | |
| Date | 13th November 1934 | |
| To HS{Lord Ernest Hives - Chair}/Wd{Mr Wood/Mr Whitehead}, from HS{Lord Ernest Hives - Chair}/Smth. c. to WOP. c. to E.{Mr Elliott - Chief Engineer} c. to MS. C. to Hy.{Tom Haldenby - Plant Engineer} Re HS{Lord Ernest Hives - Chair}/Wd{Mr Wood/Mr Whitehead}/CHP.1/GB.1.11.34. We have read this report with great interest and note that the Ramp Head No.2 appears to be promising. It would seem that this head owes its superiority almost entirely to its more efficient induction. From the detonation point of view the differences between the two heads are negligible. It occurs to us that before proceeding further with the Ramp head we could with advantage concentrate for the time being on the possibility of improving the volumetric efficiency of the standard head. We are committed to this head for some time, and any modifications to it which you find to be advantageous will be of immediate use. We note that a small improvement was obtained with the ramp head by cutting away the inlet valve guide boss, and suggest that a similar modification is made to the standard head, accompanied, if possible, by an enlargement of the inlet passage so that it is as big as that on the ramp. We feel that this enlargement will probably be necessary if we are to get any advantage out of the 1.550 dia. inlet valve head which you are testing. With regard to the effect of trepanning the ramp head, this is very puzzling and emphasizes the need for more knowledge of the influence of design on the orifice coefficient than we possess at the moment. It would appear that the orifice coefficient is very sensitive to the shape of the walls in the vicinity of the valves, and we should suggest that the effect of this be tested by building up two modified standard heads (Lec.4100) with trepanning round the inlet valve as shown below (Figs. 1 & 2). A comparison of these with Lec.4100 (Fig.3) should give us some useful information which could be checked by air blowing tests. | ||