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).
Calculations for bending moments, slope, and balance weight effects.
| Identifier | ExFiles\Box 115\2\ scan0380 | |
| Date | 10th January 1939 guessed | |
| - 2 - B.M. at x from one end -EI d²y/dx² = F/2 x - F[x - l/2] where [ ]=0 if x < l/2 -EI dy{F R Danby}/dx = Fx²/4 - F/2[x - l/2]² + A.{Mr Adams} so if x = l/2 ∴ A = - Fl²/16. -EI dy{F R Danby}/dx = Fx²/4 - F/2[x - l/2]² - Fl²/16. when x = 0 slope under this loading = Fl²/ 16EI. l = 5.625 - 2 x 0.6 = 4.425". Maximum slope at bearing = 1.224 F/EI. clearance at bearing { Maximum 0.00475" Minimum 0.0040" } width of bearing 1.20" Max.clearance 0.00388 Min. " 0.00333. Maximum slope before fouling occurs at { EI in line of webs 7.56 x 10⁶ " " " " " " " 14.35 x 10⁶ } Maximum slope in line of webs 1.62 x 10⁻⁷ F.{Mr Friese} " " " " " " 8.54 x 10⁻⁸ F.{Mr Friese} (B) Balance weights and their effect. Mass moment of large balance weights = 9.01 lbs. C.F. at 2600 RPM. = 1760 lbs. " " " 2850 RPM. = 2095 lbs. The balance weight is not placed symmetrically with respect to the bearings and so the reactions will not be the same. [Diagram of a beam with forces R, B, and S, and lengths a, b, and l] S(a+b) = B.a. R(a+b) = B.b. R = B.b / (a+b) The c.g. of the balance weights is taken to lie at the centre of the section through them parallel to the shaft, that is 0.450" from the crankpin face of the weight. it is 6.3125 - 3.250 + 0.450 + 0.825 = 4.338" from centre of No.6. main bearing. and 1.285" " " " No.7. main bearing. | ||