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).
Phantom power development, outlining proposed modifications to increase engine horsepower.
| Identifier | ExFiles\Box 69\4\ scan0373 | |
| Date | 28th November 1927 | |
| Hs.{Lord Ernest Hives - Chair} from R.{Sir Henry Royce} c. to BJ. Wor.{Arthur Wormald - General Works Manager} C. c. to PN.{Mr Northey} CWB. SG.{Arthur F. Sidgreaves - MD} 48771 R2/M28.11.27. PHANTOM - POWER DEVELOPMENT. X. 8830 X. 172 X. 8060 X. 87 X. 8771 For increased performance of acceleration, hills, and speed we are arranging for modifications as follow, to advance the power for sports and other chassis. Taking the present 4.1 to 1 comp. ratio under silent road conditions to give a maximum of Cutout open plus 10% 105 HP. 115 HP. } Maintaining double exhausts & two groups of threes. Comp. ratio plus 10% 126 HP. } This is possible with turbulent head to reduce detonations and flexible mounting to reduce feeling of torque reaction. Carb. plus 8% lower depression)4" to 1 1/4". This is possible with 136 HP. } straight through carburetters. Valve area plus 18% = 10% gain) Head 2" - large light inlet valve 1.9. 149 B.HP Head 1.75" slightly smaller exhaust 1 5/8". } Slight economies and larger inlet than exhaust. Valve timing long duration plus 4% 155 B.HP } Forego if necessary small percentage of low speed torque - for the loss we gain in less detonations and harshness. At speed of 2750 r.p.m. hope for 100 M.E.P. } Should equal 157 B.HP. The whole of these are some distance away but many should be possible on EAC.14., and all on EAC.10. In the meantime every effort should be made to reduce weight and windage of bodies etc. - lower and lighter. R.{Sir Henry Royce} | ||