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).
Instructing the development and testing of new cylinder and piston designs for a Bentley S/C unit.
| Identifier | ExFiles\Box 134\1\ scan0143 | |
| Date | 17th March 1939 | |
| 1129 To By/Ald.{F. Allwood - Experimental Design} from Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards}.1/MH.{M. Huckerby}17.3.39. BENTLEY S/C UNIT. Will you please detail and instruct one 3.500" bore cylinder which will be interchangeable with the existing blocks as far as valve gear etc. is concerned. The valve gear should be made adaptable to scheme SCD.1172, and we suggest new B.V cams and the interchange of the exhaust follower for an inlet follower. New push rods will, of course, be required. A Bentley III type cylinder head should be detailed to be used in conjunction with a raised crown piston formed to give a compression ratio of 12 : 1, with the standard head. Sufficient metal should then be left on the face of the head to give a compression ratio of 7 : 1 with this piston. Four pistons should be instructed. The idea of the above is to investigate thoroughly the potentialities and limitations of the "bump" pistons with regard to compression ratio and clearances. In addition to the above a 3.500" bore B.60 type cylinder should be detailed, two being instructed, together with a cylinder head of the latest type. The object of these bits is to investigate the effect of various shapes of piston bumps on the B.60 head performance and to establish a more correct standard of comparison with the existing 3.500" bore main engines. Pistons will be instructed later. Rm{William Robotham - Chief Engineer}/Ed.{J. L. Edwards} | ||