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).
Proposal for simplified crankshaft oil drilling for Wraith III and Bentley 60 models.
| Identifier | ExFiles\Box 132\1\ scan0084 | |
| Date | 27th October 1938 | |
| 1116. BY/HS.{Lord Ernest Hives - Chair} c. Rm.{William Robotham - Chief Engineer} c. Pm/Swdl{Len H. Swindell} c. HPS{Horace Percy Smith - Experimental Factory Mgr} DA.{Bernard Day - Chassis Design}4/C.27.10.38. WRAITH 111 and BENTLEY 60. CRANKSHAFTS WITH INCLINED OIL HOLES BETWEEN PINS AND JOURNALS. Please receive herewith :- E.CD.977 Simplified Crankshaft Oil Drilling - Wraith lll and Bentley 60. This revised drilling of the crankshaft is suggested in order to delete the necessity for fitting the taper screwed plugs in the Bentley 60 Crankshaft with Packard type weights. The design follows aero engine practice as regards the arrangement of the inclined oil holes, and meets all the requirements of the jig designers for simplicity in manufacture. It will be noticed that in addition to reducing the number of communicating holes between journals and pins, a number of journal oil caps and studs are not required, as oil is not carried into the bores of the front, central and rear journals on the Bentley 60 shaft, nor into the central and rear journals of the Wraith lll shaft, oil is required in the front journal of the Wraith lll shaft to lubricate the crankshaft damper bearings. To prevent oil escaping from the rear end of the crankshaft into the clutch casing, a flat disc plug is fitted in both shafts. Additional radial holes are drilled in each of the intermediate journal bearings to bring the number of feed holes in each of these bearings to three equally spaced holes as shown in Sections BB. and CC. of E.CD.977. It will be seen that a considerable saving in cost will be made by this arrangement, although it remains to be tested whether the altered supply of oil to the crankpins is satisfactory under running conditions. This applies especially to the supply of oil from the two end intermediates, which have a through drilling. In order to try the scheme out, we suggest it should be included in the new Wraith lll crankshaft with the altered rear end to E.CD.924, which has recently been instructed, and if successful, afterwards applied to the Bentley 60 crankshaft. | ||