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).
Comparative table of crankshaft details for various engines, all with balance weights.
| Identifier | ExFiles\Box 138\1\ scan0019 | |
| Date | 1st April 1932 guessed | |
| CRANKSHAFT DETAILS. [IN EVERY CASE WITH BALANCE WEIGHTS.] TABLE HEADERS: ENGINE, J3, PEREGRINE, ALFA ROMEO, CHINA, P I ROW: BORE AND STROKE - J3: 3.4 X 5.0 - PEREGRINE: 2.725 X 4.125 - ALFA ROMEO: G5 X 88 - CHINA: 3.25 X 4.5 - P I: 4.25 X 5.5 ROW: RATIO STROKE : BORE - J3: 1.47 - PEREGRINE: 1.46 - ALFA ROMEO: 1.35 - CHINA: 1.38 - P I: 1.29 ROW: INERTIA OF CRANKSHAFT - LBS IN² - J3: 310 - PEREGRINE: 101 - ALFA ROMEO: 145 - CHINA: 240 - P I: 480 ROW: INERTIA OF BIG ENDS & PISTONS - LBS IN² - J3: 30.5 - PEREGRINE: - ALFA ROMEO: 25.9 - CHINA: 60 - P I: 210 ROW: INERTIA OF SPRING HUB OR SUPERCHARGER - LBS IN² - J3: - PEREGRINE: - ALFA ROMEO: 12.4 - CHINA: 10 - P I: 20 ROW GROUP: SPEED OF MASTER PERIOD - SUB-ROW: WITH HUB OR SUPERCHARGER R.P.M. - J3: - PEREGRINE: - ALFA ROMEO: 7200 - CHINA: 4200 - P I: 4000 - SUB-ROW: WITH NO DAMPER HUB - J3: 4550 - PEREGRINE: 5750 - ALFA ROMEO: - CHINA: - P I: ROW: CRANKSHAFT STIFFNESS - LBS FT/RADIAN - J3: 62500 E.57280 - PEREGRINE: 32000 E.100043 - ALFA ROMEO: 62000 - CHINA: 4200 E.57401 - P I: 90000 E.82572 ROW: JOURNAL DIA: - INS - J3: 2.500 - PEREGRINE: 2.000 - ALFA ROMEO: 1.888 - CHINA: 2.125 - P I: 2.800 ROW: CRANKPIN DIA: - INS - J3: 2.125 - PEREGRINE: 1.750 - ALFA ROMEO: 1.653 - CHINA: 2.000 - P I: 2.375 | ||