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).
Gearbox schemes and comparing gear ratios for the B.S. and Peregrine models.
Identifier | ExFiles\Box 178\3\ img144 | |
Date | 15th April 1932 | |
FROM TA/HDY.{William Hardy} DA{Bernard Day - Chassis Design}/HDY{William Hardy}1/A/15.4.32. C. to SG.{Arthur F. Sidgreaves - MD} E.{Mr Elliott - Chief Engineer} HS.{Lord Ernest Hives - Chair} HY.{Tom Haldenby - Plant Engineer} B. S. GEARBOX. In connection with this gearbox we send herewith prints of N. schemes 34XX/59/60/65. Having no servo drive for B. S. and Peregrine we are not prevented from sliding the 1st. and 2nd. gears on the 3rd. motion shaft (N. sch. 3460,) but our impression is that the better compromise is obtained by our present arrangement of shafts and gears, as shown by N. schs. 34XX and 3459. N. sch. 3460. does not suit the R.H. change of Peregrine, as the 1st. and 2nd. fork has to pass over the sliders and will be fouled by the pendulum lever in reverse gear. GEAR RATIOS. We give below the ratios we suggest for B. S. and Peregrine. Those for B. S. are similar to the ratios of well known sports cars. It will be seen that, excepting the constant mesh, the gears are the same for the two cars. We have increased the size of the 1st. and 2nd. gear teeth from 10 D.P. on existing Peregrine design to 8 D.P., and have provided a 15 tooth 1st. speed pinion. With 160 BHP. the Lewis stress in the 1st. speed pinion is 110,000 lbs. per sq. in., against standard 25HP. 93,000 lbs. per sq. in. The shaft centres are slightly increased compared with the existing Peregrine design. B. S. Constant mesh.... 33/47 = .702 3rd............. .702 x 35/32 = .77 2nd............. x 20/26 = .54 1st............. x 15/31 = .34 R............... x 20/19 x 14/31 = .33 PEREGRINE. Constant mesh.... 30/47 = .638 3rd............. .638 x 35/32 = .70 2nd............. x 20/26 = .49 1st............. x 15/31 = .31 R............... x 20/19 x 14/31 = .30 (1) | ||