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 bearing loads and pressures for different balance weight schemes.
| Identifier | ExFiles\Box 8\5\ 05-page62 | |
| Date | 29th December 1938 | |
| - 2 - BY/B.8/G.29.12.38. Scheme of Balance Weights Used. | Load on each of bearings below due to rotating masses only. (lbs). | Max'm.load on each of bearings below due to rotating and reciprocating masses combined. (lbs). . | A.or G.B.or F.{Mr Friese} C.or E.{Mr Elliott - Chief Engineer} D.{John DeLooze - Company Secretary} | A.orG. B.or F.{Mr Friese} C.or E.{Mr Elliott - Chief Engineer} D.{John DeLooze - Company Secretary} No bal. weights. | 1140 1963 1960 3475 | 3430 6050 R.R. | 324 1445 1354 1355 | 2872 3892 Sch.(a). | 918 975 1138 2037 Sch.(b). | 928 1228 1185 1308 | 1790 2687 2630 3865 Sch.(c). | 923 1093 1116 1670 | 2568 4237 After deducting end radii and oil grooves :- Area of intermediate bearing B (or F) = 2.5 (1.325 - .2 - .125) = 2.5 sq.ins. Area of centre bearing D = 2.5 (1.825 - .2 - .175) = 3.625 sq.ins. .. With Scheme (b) of balance weights, the maximum bearing pressure intensity at 3500 R.P.M. due to rotating and reciprocating masses combined :- On bearing B or F = 2687 / 2.5 = 1075 lbs. sq.inch. " " D = 3865 / 3.625 = 1066 lbs. sq.inch. Again with Scheme (b) of balance weights it is of interest to note that the maximum loads (due to rotating and reciprocating masses combined) at the various bearings occur for the crank positions given below :- Maximum load at centre bearing D occurs when cranks 1 and 6 are at 120° to T.D.C. i.e. when cranks 3 and 4 on each side of D are at T.D.C. Maximum load at inner intermediate bearing E occurs when cranks 1 and 6 are vertical, i.e. when cranks 4 and 5 on each side of E are at 240° and 120° to T.D.C. respectively. Maximum load at outer intermediate bearing F occurs when cranks 1 and 6 are at 120° to T.D.C. i.e. when cranks 5 and 6 on each side of F are at 240° and 120° to T.D.C. respectively. Conclusions. Scheme (b) is the best of those considered. | ||