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).
Performance indicator diagram for a Hispano engine, plotting piston displacement against crank angles.
| Identifier | ExFiles\Box 72\4\ scan0150 | |
| Date | 12th March 1924 guessed | |
| 6.2 Spring Used—Rating 91.5° Diagram Area 10.3 □ Engine HISPANO Cyl. No. 6 Air Temp. 12°C Bar Temp. 765 m/m Cooling Water Temp. 80°C R.P.M. 2500 Lbs. Lift 108 H.P. 112.8 I.M.E.P. 118 Lbs/□" B.M.E.P. 88.2 Lbs/□" Max. Expln. Pr.{Percy H. Rose} 350 Av. Expln. Pr.{Percy H. Rose} 344 Mechanical Efficiency 74.5% Indicated Vol. Efficiency 88% DOTTED LINE SPRING RATING 0.2 LBS □" Graph Labels: FULL LINE 1" = 91.5 LBS/D" DOTTED LINE 1" = EC, TDC IO 5° AFTER ATMOS LINE IGNITION IC, EO PISTON DISPLACEMENT FOR CRANK ANGLES. | ||