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).
Alterations for a second synchromesh gearbox for the J.3 car.
| Identifier | ExFiles\Box 123\3\ scan0151 | |
| Date | 12th March 1934 | |
| ABRX X.4704 To BY.{R.W. Bailey - Chief Engineer} from HDY.{William Hardy} HDY.{William Hardy}1/HP.12.3.34. c.c. Hs.{Lord Ernest Hives - Chair} Da.{Bernard Day - Chassis Design} WHO. Gearbox for J.3. ---------------- The Experimental Department are about to build another gearbox of the J.3. synchromesh 2nd speed type which will be for the J.3. car, and as there have been a number of alterations since the first box was made we are giving below a list of the features we should like the box to have which are different from those on the first box. Gears. ------ As on N. Sch.3788 except for constant mesh gears which are to have the same tooth particulars as for the 20/25. This alteration was instructed in our Hdy.{William Hardy}2/HP.7.3.34. The outside diameter of the 1st speed pinion is to be reduced to give 15/1000" clearance between the pinion teeth and the sleeve. Synchromesh clutches and locking cam angles. --------------------- The top and 3rd speed clutches to be as on N. Sch.3809 i.e. as originally designed with 10° angle and standard type oil grooves. The 2nd speed clutch to be as on N. Sch.3997 except for the modification asked for in Hdy.{William Hardy}1/HP.2.3.34. The locking cam angles for top, 3rd and 2nd are to be increased and we will send a drawing of these. Sliders. -------- To have the interlock modification shown by N.Sch.3946. | ||