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).
Page of calculations for bearing pressures, inertia, and explosion loads, with a comparison to the Wraith III model.
| Identifier | ExFiles\Box 115\2\ scan0399 | |
| Date | 12th May 1939 | |
| - 2 - BY/B.1/G.12.5.39. Nett projected area after deducting radii and groove :- Of each of inter. and end bearings A, B, D or E = 2.5 x 1 = 2.5 sq/". Of centre bearing C = 2.5 x 1.5 = 3.75 sq/". Maximum inertia load on an inter. or end bearing is on B and D when cranks 1 & 4 at T.D.C (Case 2) and = 1290 lbs. Bearing pressure corresponding to this = 1290 / 2.5 = 516 lbs/sq.". Maximum inertia load on centre bearing is when cranks 1 and 4 are at B.D.C. (Case 3) and = 4282 lbs. Bearing pressure corresponding to this = 4282 / 3.75 = 1142 lbs/sq.". Maximum load, due to firing only, on any bearing, is on D when 4 is firing (Case 4) and = 4200 lbs. Bearing pressure corresponding to this = 4200 / 2.5 = 1680 lbs/sq.". Maximum combined inertia and explosion load on any bearing is on D when 3 is firing (Case 7) and = 3847 lbs. Bearing pressure corresponding to this = 3847 / 2.5 = 1539 lbs/sq.". For purposes of comparison, some of the corresponding figures for Wraith III when fitted with RR. system of balance weights are as follows :- Due to rotating and reciprocating masses at 3500 R.P.M. Bearing pressure on outer inter. bearing F = 2872 / 2.5 = 1148 lbs/sq.". Bearing pressure on centre bearing D.{John DeLooze - Company Secretary} = 3892 / 3.625 = 1074 lbs/sq.". | ||