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).
Design considerations for aero engines, including cylinder blocks, crankshafts, and balance weights.
| Identifier | ExFiles\Box 179b\1\ img159 | |
| Date | 15th November 1932 | |
| HS.{Lord Ernest Hives - Chair} FROM R.{Sir Henry Royce} HS{Lord Ernest Hives - Chair} R2/M15.11.32. C- to US. WOH. No. 1. re. AERO ENGINES. x-2717. HS{Lord Ernest Hives - Chair}' Naturally I am delighted with memo. on the aero engine technical situation, and especially with reference to the two piece cyl. block which agrees so closely with my own recommendations that have been standing for many years. Regarding the extra weight, I quite agree - as previously stated in several of my memos - that the extra weight is justified, but I also said I thought that we had not got to the minimum on that particular type, and it could be reduced, because, being stronger naturally, and the forces better distributed, the whole thing might be thinner, and the designs of the block might be gone over to see where economy of weight could be obtained. It is not necessary to repeat all the virtues of this type of block, but, as I think we all agreed that the pistons are a source of very great anxiety, the absence of distortion should so definitely help these as to alone justify the adoption of the two piece block, even without its other virtues. With reference to the con. rods, I have not very much to say about these but I should like both sorts tried out until one of them is proved easier in demand for skill and careful attention. With reference to the crankshaft, I think we can supply either type without much trouble, and we ourselves think that the nitro hardened shaft is quite equal in strength to the non-hardened shaft, and it probably has a very definite advantage in the case of poor or defective lubrication. For instance, if the British Govt. does not encourage the use of the hardened shaft, and we think it is better, and does not cost much more, it would be worth while our fitting it to engines going to other buyers because it does not need quite the same care. If however it costs more money it could be offered as an extra of say £20. per engine. At any rate I think we ought to give our customers the power to buy that which we think will give them the best service. You do not say anything about balance weights. One imagines that at the increased speeds suggested the balance weights would be a great boon, not only to save the crankshaft bearings but to avoid the ultimate breaking up of the crankchamber. If we make the engines without balance weights, then it is possible also to make them with balance weights at a small increase of cost and weight. (1) | ||