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).
Three performance graphs for a J.III Rear component under varying pressure and temperature conditions.
| Identifier | ExFiles\Box 179b\2\ img096 | |
| Date | 18th October 1932 guessed | |
| Graph 1: J.III REAR. 90/90 LB. LOW PRESSURE 18.10.32 .250 HAT. .005" CLEARANCE PISTON VENTS .032" x .032" 4" STROKE 25 - 30 C R.P.M 250 180 135 90 45 22 308 LB/SQ" - 133 LB B.P 120 I.S ① Graph 2: J.III REAR. 90/90 LB. LOW PRESSURE 19.10.32 .250 HAT. .005" CLEARANCE PISTON VENTS .032 x .032 4" STROKE. AFTER RECOOLING R.P.M 250 180 135 90 45 22 308 LB/SQ" - 133 LB B.P 120 I.S ③ Graph 3: J III REAR. 90/90 LB. HIGH PRESSURE 18.10.32 .250 HAT. .005" CLEARANCE PISTON VENTS .032" x .032" 4 STROKE. 60° C R.P.M 250 180 135 90 45 22 308 LB/SQ" - 133 LB B.P 120 I.S ⑤ | ||