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 inconsistent results of chromium plating tests on aero engine cylinder bores.
| Identifier | ExFiles\Box 127\3\ scan0105 | |
| Date | 2nd July 1936 guessed | |
| Chromium Plating. We have not done a great deal of work on chromium plating cylinder bores, the process having been carried out only on two single cylinder aero units. We find in these cases, however, that results are so far rather inconsistent. On one unit after a 50 hours endurance run the plating - carried out by Durion - had begun to come off and adhere to the pistons, causing three partial seizures. Wear was rather disguised by distortion, but figures are shown on the accompanying print. Piston rings, however, were in remarkably good condition, wear figures being as under, closed gaps before and after running being given. 1 2 3 4 5 Gap New .012 .012 .012 .014 .014 Gap after 53 hrs. .015 .014 .014 .018 .015 The other unit so treated has run intermittently for just over 100 hours, and is still in very good condition, though no figures are as yet available. | ||