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).
Comparison document detailing the specifications and weights of Aluminium versus Cast Iron (C.I.) engines.
| Identifier | ExFiles\Box 82\4\ scan0142 | |
| Date | 17th July 1935 | |
| x200 Hs{Lord Ernest Hives - Chair}/Gry.{Shadwell Grylls}24/KW.17.7.35. Aluminium Versus C.I. Engines. (1) Weight per inch of bonnet, wings and frame, 2¼ lbs. and therefore negligible. (2) Engine particulars. Bentley 26½" long 555 lbs. 460 without flywheel. (alum. head 505 lbs.) 390 Wraith 34" long J-3 28" long 480 lbs. 380 " " Tsn's 8-cyl. 3¼ bore 29.5 long (3) Max. possible bore of both J-3 and Bentley 3.6". (4) The J-3 crankshaft weighs 25 lbs. more than Bentley, chiefly due to longer stroke. (5) Increasing stroke of Bentley to 5" would probably increase weight 25 lbs. altogether. (6) The relative weights therefore of engines 3.6 + 5 in alum. and Bentley construction less flywheels are 380 and 415 lbs., the former being 1½" longer. (7) Tsn's engine in alum. construction of 3.0 bore, about 29" long and 400 lbs. and same capacity as 6 cyl. 3.6 + 5.0. | ||