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).
Clicking noise in the Wraith transmission, its cause, and potential solutions.
| Identifier | ExFiles\Box 156\4\ scan0077 | |
| Date | 2nd February 1938 | |
| 1330 By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} c. Hs.{Lord Ernest Hives - Chair} c. Da.{Bernard Day - Chassis Design} c. Hdy.{William Hardy} c. Mx.{John H Maddocks - Chief Proving Officer} c. HPS.{Horace Percy Smith - Experimental Factory Mgr} WRAITH TRANSMISSION Mx.{John H Maddocks - Chief Proving Officer} has complained of a series of clicks in the tranmission during torque reversals when shunting, such as changing from forward drive to reversing. We suspected the two tapers in the gearbox, and therefore assembled the car with no keys in the gearbox or axle tapers. In the first five yards the taper at the rear of the 3rd. motion shaft came loose and wound off the nut. It is very much easier to get the axle pinion nut tight than those on the gearbox due to the rigid fixture. The nut on the Wraith axle when hammered up by a tommy bar required 200 lbs.ft. to tighten it further. We therefore did up the gearbox nuts with this torque, noticing that the coupling on the 3rd. motion shaft moved some 10 thous. further up the taper than when done up in the usual manner. During gentle maneuvring on 2nd. and reverse gears the gearbox clicks had gone but full throttle in reverse slipped all the tapers including the axle. In Mx.{John H Maddocks - Chief Proving Officer}'s opinion, customers would complain of the noise, and therefore we must no rely on the keys to take the torque. In the opinion of RHC{R. H. Coverley - Production Engineer}/JRD. and HPS.{Horace Percy Smith - Experimental Factory Mgr} the Barker Colman hobbed taper spline would be a great improvement on Woodruff keys and would probably eliminate the noise. It is not possible to test this arrangement on Wraith without buying the necessary hob and broach. Our recommendations for the present are that more metal is added to the coupling flanges for which a scheme is required and that the nuts are done up with a spanner to give at least 200 lbs.ft. torque. Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} | ||