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).
Agreeing on valve sizes and materials for the 20 HP and Phantom models.
| Identifier | ExFiles\Box 106\5\ scan0017 | |
| Date | 9th March 1928 | |
| E.{Mr Elliott - Chief Engineer} Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} BY.{R.W. Bailey - Chief Engineer} c. to BJ. Wor.{Arthur Wormald - General Works Manager} X5060 R1/M9.3.28. 20 HP. & PHANTOM VALVE SIZES. X.5060 X.8060 I agree to LeC.2523 : Phanton. Exhaust 1.700 ) Bore of seat. Inlet 1.900 ) 20 HP. Exhaust 1.250 ) " " " Inlet 1.350 ) Material of valves may be different for exhaust and inlet as may be advantageous for hardening the ends, ease of forgings, and machinery and cost. R.{Sir Henry Royce} | ||