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).
The investigation of cracks in the R engine cylinder block and proposed remedies.
| Identifier | WestWitteringFiles\T\March1929-December1929\ Scan142 | |
| Date | 28th May 1929 | |
| BG. ) FROM R.{Sir Henry Royce} RG.{Mr Rowledge} ) C. to HS.{Lord Ernest Hives - Chair} HL. P-F.{Mr Friese} re. RG{Mr Rowledge}'s VISIT TO WW. ON TUESDAY, MAY 28th. The R.{Sir Henry Royce} engine cyl block occupied most of the time. It is not very manifest what is the cause of the cracks between the cyls. It was concluded on the last occasion to be due to faulty metal in the casting, which also shewed itself on the 'H' engine, where the metal is proportionately much thicker. The situation is a very difficult one because we cannot get more metal between the cyls. on present engines. We decided however to try two methods of strengthening the parts. E.{Mr Elliott - Chief Engineer} has just finished a design where we fit a steel bolt right across the cyl. jacket so as to put the aluminium in compression, anticipating any tension that may occur at this point. The patterns will have to be altered to suit this arrangement. The second scheme is to replace about 3" of the lower part of the jacket with an aluminium alloy forging. E.{Mr Elliott - Chief Engineer} has also nearly finished the design for this, which will also require alterations to the patterns. In the meantime we hope that better castings can be made in Hall's metal, which is much stronger, especially when hot, and the use of the rubber ring with expansion spaces will result in the present design giving satisfaction without either of these drastic changes. Naturally the RR. Co. will take the responsibility of making this doubtful part quite satisfactory at their own cost, such a promise may help to give the Ministry confidence to give us an order. The R.{Sir Henry Royce} engine started life with another design of cyl. liner which was not found efficiently cooled, though it followed closely other makes which were thought to be satisfactory, namely, the 'Hispano', and the 'Wright'. The cracks between the valves have only just shewn themselves, and we are very surprised that it has happened. We do not know the cause, nor are we able to suggest a remedy, except to increase the thickness, and it is very certain that we must get better aluminium alloy, possibly improved by heat treatment. BY.{R.W. Bailey - Chief Engineer} with HL. will I hope report on the castings which failed, and HS.{Lord Ernest Hives - Chair} will reproduce the fault on test bed or hangar. All the examinations and evidence shew no better reasons than want of uniformity of strength of metal, or uniformity of stress, from some unknown cause. SH R.{Sir Henry Royce} | ||