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).
Supercharger rotor vane fractures during high-speed engine tests and a proposed design modification to strengthen them.
| Identifier | ExFiles\Box 36\2\ scan 197 | |
| Date | 1st November 1928 | |
| To R.{Sir Henry Royce} From Hs{Lord Ernest Hives - Chair}/VH. c. to BJ. Nor. c. to RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} c. to DY.{F R Danby} ORIGINAL Hs{Lord Ernest Hives - Chair}/VH1/LG15. 11.28. S/C. ROTOR FRACTURE. 44550 High speed running on F.{Mr Friese} XIV.S.27. Engine No.27 with .477/1 gear. S/C. to L.O.P. E.32291. Plugs - Champion R.11. Fuel - 100% Benzol. During some attempts at high speed running at 2750, 3000 and 3250 r.p.m., eleven of the vanes of the S/C. rotor (E.32276) were fractured close to the tip, where the radius to the shroud commences as shewn in the accompanying sketch. The fractures, which average about 1/4" in length, are attributed to back-fires experienced when running at 3250 r.p.m., pre-ignition due to a hot plug being the origin of the trouble. After the radius to the shroud, the rotor vanes do not vary in thickness, taking a plane parallel to the rotor axis. The vanes taper radially from the centre of the rotor; it is proposed to stiffen them up by increasing the thickness at the point of fracture, making it the same throughout the length of the vane. Tip of vane :- PRESENT SECTION. PROPOSED SECTION. [Image Text] FRACTURED ROTOR OFF F.XIV.S.27 FRACTURED VANES E.32276. ROTATION Hs{Lord Ernest Hives - Chair}/VH. | ||