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).
Calculation of torque for the Comet rear axle based on engine capacity and gear ratios.
| Identifier | ExFiles\Box 114\1\ scan0333 | |
| Date | 27th December 1940 | |
| To: Rm{William Robotham - Chief Engineer}/HH. From Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions} c. Ev{Ivan Evernden - coachwork}/JD.{J. Draper - Frames} Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions}1/EL.27.12.40. 1015 COMET REAR AXLE TORQUE Torque between centre casing and tubes is arrived at from the following assumptions :- Engine capacity 4883 c.c. Gearbox 1st speed ratio .335 Rear axle ratio 11/41 Assumed maxm. B.M.E.P. = 130 lb/in Then engine torque = (130 / 100) . (4.883 / 1) . (485.5 / 1) = 3085 lbs.ins. Rear axle torque = (3085 / .335) x (41 / 11) = 34,350 lb.ins. and torque between centre casing and tube each side = 17,175 lb.ins. This takes no account of wheel adhesion but appears to be a possible figure as it implies a laden weight/wheel of 1234 lbs. if coefficient of friction between tyre and road is unity. Ev{Ivan Evernden - coachwork}/DB.{Donald Bastow - Suspensions} | ||