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).
Aero engine design choices for a new model, including bore/stroke ratios, cylinder construction, and liners.
| Identifier | ExFiles\Box 179b\1\ img181 | |
| Date | 19th November 1932 | |
| RO.{C. C. Rose - Export Manager}) FROM R.{Sir Henry Royce} HS.{Lord Ernest Hives - Chair}) BY.{R.W. Bailey - Chief Engineer}) C__ to BG. WOR.{Arthur Wormald - General Works Manager} E.{Mr Elliott - Chief Engineer} H2/M19.11.32. (X2917) AERO ENGINES. My last memo. stated^in wor{Arthur Wormald - General Works Manager} that the 5.5"x 6" engine was the correct intermediate position. This has come about through some slight errors in the figures possibly due to approximations. It is not a serious matter, but the intermediate sizes would be a little further from Kestrel and a little nearer the Griffon, which may be thought the wrong way about. The stroke/bore ratio too is not quite correct. I therefore suggest that instead of adopting 5.5" for the bore we adopt 5.4", keeping the 6" stroke, which will bring it to the proper position, although the stroke/bore ratio will still be slightly different, but these are the best round figures that I can suggest. With reference to the cylinder construction, I think in these new model engines we should definitely avoid a 6 bolter of the type used on the 'R' engine, that we should make the cylinder block for those of our present Kestrel sizes of the two piece pattern, and the new size of engine shall be^of the combined jacket and crankchamber new type. I say this after due consideration since RG{Mr Rowledge}'s visit, and the reason is we know that the 2 piece block design is extremely practical, and will make a satisfactory engine, whereas the combined jacket and crankchamber may give us trouble, and take a long time to get over. RG.{Mr Rowledge} says that the new type is favourable to the reduction gear casing, and that we can better attach it to the crankchamber in this, than our present type. I think we shall have to make the best of this disadvantage, and still let the Kestrel proceed with a 2 piece block until we have proved that the combined construction is preferable. It will be seen that this is keeping the knowledge and conditions that we have already, and only venturing on the new ^work on the new size of engine. Regarding the liners I understand from RG.{Mr Rowledge} that we have not succeeded in making the hardened austenitic liner that the Bristol people found so good, but we can make liners of the ordinary nitro-hardening alloy, satisfactorily hardened, so that we can avail (1) | ||