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).
Graph comparing piston inertia torque curves for various engine cylinder configurations.
| Identifier | ExFiles\Box 137\4\ scan0213 | |
| Date | 17th February 1931 guessed | |
| PISTON INERTIA TORQUE, Rd. OF COUPLE, Acc., Ω'l, Ω²l, ω²r, ω, α, IO, 25°, 60°, 3000 R.P.M., 1 CYL., TWICE FULL SIZE., 6 CYL., 4 CYL., 12 CYL. 90°, 12 CYL. 45°, 8 CYL. OR, 12 CYL. 60°, 1" = 82 LBS. FT. FOR, RECIPROCATING MASS, OF 1LB. PER CYL., 0, 90, 180, 270, 360 | ||