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 the compression pressure of Aluminium vs. Cast Iron cylinder heads on a Bentley B.A.A. unit.
| Identifier | ExFiles\Box 86\1\ scan0057 | |
| Date | 10th March 1938 guessed | |
| COMPARISON OF CYLINDER HEADS (BENTLEY). UNIT. - B.A.A. ① ALUMINIUM CYLINDER HEAD (COMPRESSION RATIO 7.38:1) ② CAST IRON " " ( " " ) FOR VALVE TIMING SEE BV.21 COMPLETE AIR SILENCER & TEST BED EXHAUST SYSTEM COMPRESSION PRESSURE (LB/D") 160 150 140 R.P.M. 500 1000 1500 2000 2500 3000 3500 4000 4500 BV.23 R.M 193 3A | ||