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).
Letter from the Experimental Department discussing Kestrel engine detonation tests in relation to jacket temperature and octane values.
| Identifier | ExFiles\Box 27a\4\ Scan145 | |
| Date | 7th July 1933 | |
| Y/1282. Expl. Dept. Hs{Lord Ernest Hives - Chair}/Lov.{Mr Lovesey}1/MJ. 7th. July 1933. F.R. Banks Esq., Ethyl Export Corporation, Abford House, Victoria, LONDON. S.W.1. Dear Banks, We have been carrying out some tests on our Single Cylinder Kestrel Unit to see to what extent the increase of cylinder jacket temperature increases detonation. We have in mind some tests which we shall be carrying out with the jacket temperature increased to 150°C. and want to know what increase in octane value would be necessary to limit the detonation to no more than obtained at the same power output but at 75° Jacket temp. A test we have made on the single cyl. unit running at 2500 R.P.M. +3 lbs. boost, 150 B.M.E.P. and 150° Jacket temperature appears to indicate that we shall want about 1 1/4 c.c. T.E.L. added to D.T.D.134 to prevent the detonation being any more severe than obtained at the same power on plain D.T.D.134 with jackets at 75°C. Do you think this appears about reasonable. The above test would indicate that raising the jackets to 150°C. has necessitated an increase in octane value from about 74 to 85 - very approximately. This shews that the advantage obtainable from a high octane fuel could be swallowed up by high temperature cooling instead of being used to permit increased power output. Hope you have a good trip in Denmark, and hoping to see you on your return, Kind regards, Yours sincerely, | ||