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).
Series of proposed engine modifications for the Phantom model to increase power output.
| Identifier | WestWitteringFiles\R\October1927-December1927\ Scan109 | |
| Date | 28th November 1927 | |
| 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} C. PN.{Mr Northey} OWB. SG.{Arthur F. Sidgreaves - MD} PHANTOM - POWER DEVELOPMENT. Handwritten: X6830, X8771, X1725, X8774, X8060 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 - 105HP.) Maintaining double exhausts = two groups of threes. Cutout open plus 10% 115HP.) Comp. ratio plus 10% = 126HP. This is possible with turbulent head to reduce detonations and flexible mounting to reduce feeling of torque reaction. Carburetter plus 8% lower depression. 136HP. 4" to 1 1/2". This is possible with straight through carburetters. Valve area plus 18% = 10% gain. 149BHP. Slight economies and larger inlet than exhaust. Head 2" - large light inlet valve 1.9. Head 1.75" - slightly smaller exhaust 1 5/8. Valve timing long duration plus 4%. = 155BHP. Forego if necessary small percentage of low speed torque - for the loss we gain in less detonations and harshness. At speed of 2750 RPM. hope for 100 MEP. Should equal 157BHP. 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} Stamp: RECEIVED 29 NOV 1927 | ||