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).
Outlining design limitations for the Myth engine's inlet and exhaust system on the nearside, specifically when applying the Wisp arrangement.
| Identifier | ExFiles\Box 109\3\ scan0068 | |
| Date | 21th February 1941 | |
| Please, who shall do the designing? Jnr.{Charles L. Jenner} To Rm.{William Robotham - Chief Engineer} c. to Rm{William Robotham - Chief Engineer}/TAS.{T. Allan Swinden} c. to Rm{William Robotham - Chief Engineer}/HH. 700 SECRET. 1030 Jnr.{Charles L. Jenner}1/JH.21.2.41. Myth Inlet & Exhaust on the Nearside. The design work involved in applying the Wisp arrangement to the Myth sorts itself out under various limitations which can all be dealt with. The work Swinden has done has cleared the air. (1) The push rods and tappets need not be altered in any way, but the sparking plugs will not be in the middle of the combustion chamber; they will have offset about .450. We might skew them over to get them in the centre but I doubt if the middle plugs could be spannered owing to the central position of the distributor. (2) The cylinder head bolting on the nearside of the head requires respacing. This leaves us less room for the distributor tower, the bolting for this will not be ideal, but by providing a spigot twice as long as now it should be sufficiently rigid. (3) Owing to the width of this side of the engine the inlet pipe for the S.U. horizontal carburetter gets pushed out about 2.75 and in consequence the carburetter air intake will foul the bonnet side. Some hard work and ingenuity will be wanted to save about a ½" in overall width. (4) If we have the Stromberg carburetter the centre line of the induction pipe will be further out than shewn on PL.437 (Wisp) to make room for the Vacuum control on the distributor, the carburetter and distributor being side by side and closely together. (5) The introduction of 2 inlet ports in the head which run out between the sparking plug pockets, embarras the water spaces and this must be carefully set out, also the same ports force us to throw away 2 of the holding down studs or else have a flying boss through the ports. This limitation is serious and the whole project might fall down on its consideration. Jnr.{Charles L. Jenner} | ||