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 the moment of inertia of a Bentley front brake toggle shaft and adjustment mechanism.
| Identifier | ExFiles\Box 85\1\ scan0114 | |
| Date | 18th June 1936 | |
| -2- Hs{Lord Ernest Hives - Chair}/AFM.{Anthony F. Martindale}15/KW.18.6.36. Moment of Inertia of Bentley Front Brake Toggle Shaft and Adjustment Mechanism. A pair of the above were fixed back to back by a 3/8" rod through the pin hole P in attached sketch. Allowing the mechanism to roll on knife edges on the shaft extremities gave a vertical line AB. CD is parallel to this and must pass through the C. of G.{Mr Griffiths - Chief Accountant / Mr Gnapp} Similarly the C. of G.{Mr Griffiths - Chief Accountant / Mr Gnapp} (G) lies on EF. This fixes G.{Mr Griffiths - Chief Accountant / Mr Gnapp} The mechanism was supported on a knife edge at F.{Mr Friese} and time of oscillation measured. Using formulae T = 2π √(k² + h² / hg) & I_axis = I_eg + Md² where T = 34.4 / 50 secs. h = GF = 3.9" k = rad. of gyration about G.{Mr Griffiths - Chief Accountant / Mr Gnapp} d = GD = .68" M = 1.836 lbs. (One adjuster etc. only). (Difference of weight of 3/8" rod mentioned above normal pin is 0.0255 lbs., and this has been neglected. Correction can easily be made if desired). 34.4 / 50 = 2π √(k² + 3.9² / 3.9 x 12 x 32.2) k² + 3.9² = (34.4² x 3.9 x 12 x 32.2) / (50² x 4π²) k² + 15.2 = 18.1 k² = 2.9 (k = 1.7) I_axis D = 1.836 (2.9 + .68²) = 6.17 lbs-ins² Hs{Lord Ernest Hives - Chair}/A.F.Martindale. | ||