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 Merlin crankshaft bending test, with comparisons to the Wraith crankshaft.
| Identifier | ExFiles\Box 132\1\ scan0065 | |
| Date | 6th October 1938 | |
| 1116 To Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} from HPS{Horace Percy Smith - Experimental Factory Mgr}/W.Bell. HPS{Horace Percy Smith - Experimental Factory Mgr}/WB.{Mr Brazier/Mr Bell}3/CB.6.10.38. MERLIN CRANKSHAFT BENDING TEST. Crankshaft Details D.4475 (VCM.3250, R.R.D.8). Further to HPS{Horace Percy Smith - Experimental Factory Mgr}/WB.{Mr Brazier/Mr Bell}2/CB.22.9.38. The test was carried out in exactly the same way as for the Wraith Crankshaft. From BL.2211, sheet 2, it was found that the displacement at the centre journal with loads of 200 lb. applied simultaneously at all crankpins was .024" in a direction between crankpins 3 and 4 and 2 & 5, making an angle of 30° with the direction of 3 & 4. It will be seen from Table II that the restoring load is 373 lb. From BL.2211, sheet 3, it will be seen that the restoring load reduces the displacement at journal 3 in the ratio of 11:1, that at 4 in the ratio of 17:1, that at 6 in the ratio of 9:1 and that at 2 in the ratio of 6:1. Finally, the displacements at the centre journal for loads of 200 lb. and 300 lb. hung at the centre journal in various directions were plotted as polar curves (BL.2211, sheet 5) which approximate to a family of ellipses of equation r = .0853 W / {1 + 1.48 cos²(θ+19)}^(1/2) where θ is measured from 1 & 6 direction towards 2 & 5, W is the load in lb. at the centre journal, r is the displacement at the centre journal in 1/1000" HPS{Horace Percy Smith - Experimental Factory Mgr}/W. Bell. J.{Mr Johnson W.M.} Bromilow H.F. Payne (Handwritten) Please return to GRY{Shadwell Grylls} | ||