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).
Potential weight savings in lbs for various vehicle components.
| Identifier | ExFiles\Box 4\1\ 01-page008 | |
| Date | 6th October 1932 | |
| - 2 - E.1/HP.6.10.32. --------------- twice this amount in using the same method of construction on the SpectreCodename for Phantom III, not counting anything for the reduction in the size of the cylinder blocks from J.III. Another source of saving should be in the flywheel. This unit, including the clutch scales 140 lbs on Phantom and we might reasonably expect to reduce this by 50 lbs. We should also expect to shorten the bonnet and chassis, retaining the present body base, and this, together with some lightening of the front axle and road springs consequent on reduced front end weight might save 40 lbs. Our present P.II radiator filled with water reaches the colossal figure of 160 lbs and we understand that 40 lbs out of this might be saved as soon as a certain type of matrix becomes available. As there should be more heat to water from the 12 cylinder engine demanding possibly a larger matrix, we put this saving at 40 lbs. The brake operating gear on Phantom II we believe adds up to quite a respectable weight, and with the adoption of a scheme such as is now being discussed for the Bensport using pipe lines instead of levers, shafts and differentials much of this weight could be written off. We might put this saving at 20 lbs. Totalling the items indicated we get: Engine................ 170 Flywheel and clutch.... 50 Shortening chassis, etc. 40 Radiator.............. 40 Brake Gear............ 20 ----- 320 lbs. Taking the total weight of the P.II car with passengers as 52.5 cwts or 5900 lbs. this saving represents 5.5%, and if the engine B.M.E.P. were 110, would be equivalent to a gain of 6 to 7 lbs per sq. in. on this figure. No allowance has been included in the aforegoing for saving on bodywork, but the wider chassis frame should permit of some reduction in the body sills and with the usual extremely heavy movable cushions replaced by the type used on J.III, and with other developments which time may bring, the figure given should be improved on. With regard to the question of windage, the 12 | ||