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).
Investigations into valve bounce and spring breakage on the Falcon engine, comparing double and triple spring types.
| Identifier | ExFiles\Box 43\3\ Scan113 | |
| Date | 13th January 1927 guessed | |
| Hs{Lord Ernest Hives - Chair}/ACLL/LG13.1.27. F.10. VALVE BOUNCE AND SPRING BREAKAGE. Further investigations have been made on the question of valve bounce and spring breakage on the Falcon engine and we have also had a good comparison of the endurance of two types of spring - the double and triple - during an endurance run on the engine. The engine in question was fitted with the triple springs LeC.2281, to an 'A' block and g five of these broke - the outer springs - during 34 hrs. running. The 'B' block was fitted with double springs LeC.2237 and not a single breakage occurred during a total of 202 hrs. running. The valves used were the heavy tulip type and the engine speed was 2100 r.p.m. except for short runs. We removed some of the intact springs from this engine and carried out some tests on the valve test rig in which the valve gear is belt driven. The apparatus described in a previous report was used which enabled a permanent record of the valve motion at various speeds to be obtained. Briefly the apparatus consists of a recording disc rotating with the camshaft and a scriber attached to the valve washer marks a polar diagram of the valve lift on the disc. By rotating the apparatus slowly the normal motion of the valve was scribed, and by increasing the speed the first signs of bounce could be detected by the deviation of the scribed track from the normal or datum line. The appended print shews the motion of the inlet valve under the action of both double and triple springs. contd :- | ||