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).
Data sheet listing specifications for P.II. and 25 HP engine components, focusing on crankshafts, balance, and flywheels.
| Identifier | ExFiles\Box 137\4\ scan0336 | |
| Date | 1st May 1931 | |
| 8634 May 1931. FILES. X.634. X.7010. X.5010. USEFUL DATA. P.II. Torsional period at 100 m.p.h. or 3900 r.p.m. standard crankshaft. Torsional period of chamfered shaft with 14EV{Ivan Evernden - coachwork} 12 weights to Lec.2616 begins 80 m.p.h. " " " 6 weights begins 86 m.p.h. Out of balance per crank standard shaft = 14.6 lb ins. chamfered 24-EX. = 11.74 lb ins. Out of balance of big end (2.531 lbs) = 6.95 lb. ins. 24-EX. shaft with 12 wts. balances shaft + 41% of big ends. Weight of con rod 3.341 lbs. Weight of piston 1.84 lbs. Reciprocating mass 2.65 lbs per crank. 25 HP. 2" pin crankshaft E.55619 torsional period 5000 r.p.m. standard " E.55127 " " 4700 r.p.m. Period of E.55619 with 12 wts. to Sch.1402 balancing shaft only = 4200 r.p.m. Out of balance per crank E.55619 = 6.20 lb ins. Wt. of big end for crankshaft E.55619 = 1.28 lbs. E.55127 = 1.27 lbs. Out of balance for 2" pin big end = 2.88 lb ins. Wt. of little end .384 lbs. Wt. of piston 1 lb approx. Standard flywheel weighs 95 lbs. - polar moment of inertia .691 Slugs ft2 Lightened " Lec.2830. 87 lbs. - " " " .555 " " | ||