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).
Comparison of engine component loads and pressures for the Wraith, Bentley, and Kestrel VI engines.
| Identifier | ExFiles\Box 114\2\ scan0075 | |
| Date | 1st October 1934 guessed | |
| -3- The maximum inertia load at T.D.C. on the Wraith is 5615 lbs. and the unit pressure 1815 lbs./sq.in. Figures on the Bentley which has a heavier piston are 5645 lbs. and 1882 lbs/sq.inch. On the Kestrel VI the maximum unit pressures are 920 lbs/sq.inch at 2600 R.P.M. and 1765 lbs. at 3600 R.P.M. The average inertia loading on the Wraith big-end at 5000 R.P.M. is 1155 lbs/sq.inch, on the Bentley 1175 lbs/sq.inch and on the Kestrel VI 810 and 1550 lbs/sq.inch at 2600 and 3600 R.P.M. respectively. The maximum unit pressure under the maximum gas load of 5000 lbs. on the Wraith big-end is 1615 lbs/sq.inch.,on the Bentley 1800 lbs/sq.inch, and on the Kestrel VI 2,920 lbs/sq.inch. Balance Weights. The percentage balanced on the crankshaft on the scheme so far completed is 86% of the rotating weight including the big-end, or more correctly 72% including half the piston in as well. The figure of 96% was obtained by reckoning the balance in lbs/inches2. From the comparative bearing loads the amount of balance provided is sufficient. Main Bearings. The average unbalanced inertia load per crank is 2275 lbs. at 5000 R.P.M. and the resultant main bearing loads are 1140 on the end bearings, 2275 on the centre, and 1610 lbs. on the intermediates. The maximum gas loads on the main bearings are 3750 lbs. on all of them. The areas, loads and unit pressures on the bearings as shown on the scheme are:- End. Inter. Centre. Areas. 4.00 3.375 4.00 sq.ins. Average Inertia load 1140 1610 2275 lbs. " " press 284 477 570 lbs/sq.in. Max.gas load. 3750 3750 3750 lbs. " " pressure. 940 1110 940 lbs/sq.in. Contd: | ||