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 failure of Condor valve spring washers during high-speed testing.
| Identifier | ExFiles\Box 36\1\ scan 144 | |
| Date | 23th November 1927 | |
| To R.{Sir Henry Royce} from Hs{Lord Ernest Hives - Chair}/VH. c. to BJ. RG.{Mr Rowledge} c. to E.{Mr Elliott - Chief Engineer} Wor.{Arthur Wormald - General Works Manager} c. to BY.{R.W. Bailey - Chief Engineer} X2925 Hs{Lord Ernest Hives - Chair}/VH1/LG23.11.27. CONDOR VALVE SPRING WASHERS. (Top E.30837). (2993) We have had a number of top spring washers (E.30837) fail whilst running at high speeds on the Condor valve spring testing rig. Up to the time the fractures occurred, a set of these collars had completed approx. 600 hrs. at the lower speeds, equivalent to 1900/2000/2100 r.p.m. When the fractures occurred the test rig was running at a speed equivalent to 2360/2400 r.p.m. This top spring washer (E.30837) was apparently drawn up to suit springs to LeC.2450 and LeC.2351. The dimension 'A' (see accompanying sketch) has been made .675" (-5) to suit the inner spring to LeC.2451 (internal dia. .716 (+10)), allowing the spring to seat properly without 'riding' on the .020" radius in the corner. Springs to LeC.2450 made from chrome vanadium steel and heat treated by RR. (RR "double quenched") represent the best we know for Condor springs. The inner springs to LeC.2450 have an internal dia. of .728" (+10) and if we accept these as the type we intend to use, this gives us an extra .012" to add to the dimension 'A' making it .687". We consider that we could safely increase 'A' to .700" (-5) without being seriously troubled by the spring 'riding' on the radius. contd :- | ||