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 crankshaft bearing loads and pressures for Wraith III and B.III engines under various conditions.
| Identifier | ExFiles\Box 115\2\ scan0373 | |
| Date | 5th December 1938 | |
| BY/B.6/C.5.12.38. [Diagram showing crankshaft journals A-G and crank throws 1-6 with force vectors] Handwritten notes on diagram: small small 583 large 292 292 rotating 1312 + recipg 1014 =Total inertia =2326 2326 inertia + 591 gas 3203 brg. reaction in vertical plane Wraith III | B.III A.{Mr Adams} Due to rotating masses only (at 3500 r.p.m. Resultant load on each outer bearing A or G.{Mr Griffiths - Chief Accountant / Mr Gnapp} | 337 lbs. | 485 lbs. " " " " inter " B or F | 1373 " | 1524 " " " " " inner " C or E | 1195 " | 1363 " " " " " middle bearing D | 1383 " | 1802 " B. Maximum resultant load on inter.brg. F or B. due to rotating and reciprocating parts together; (inertia only). Occurs when cranks 3 and 4 are at T.D.C. | 2812 " | 3049 " C. Maximum load on inter. brg. F.{Mr Friese} due to explosion pressure (600 lbs/sq.in.) acting on Crank 6 when speed so low that inertia negligible. (Max^m occurs when Crank 6 at T.D.C) | 4200 " | 4200 " D.{John DeLooze - Company Secretary} Maximum resultant load on inter.brg. F.{Mr Friese} due to inertia forces and explosion press. (on No.6) combined. (Maximum occurs when cranks 3 and 4 at T.D.C. | 3255 " | 3430 " Peripheral speed of journals at 3500 R.P.M. v (ft/sec.) | 38.22 | 38.22 Projected area of brg. F.{Mr Friese} after deducting radii (sq.ins.) | 3.035 | 3.035 Max. press intensity on brg. F.{Mr Friese} due to gas and inertia (Case D) = p (lbs/sq.in) | 1072 | 1130 p.v. due to gas and inertia at 3500 r.p.m. | 41,000 | 43,200 BY/B. | ||