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).
The investigation of front wheel movement on a Packard to determine the desired movement for the B.III bumper chassis.
| Identifier | ExFiles\Box 159\7\ scan0199 | |
| Date | 9th March 1938 | |
| To By. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /Clapham. c. Da. {Bernard Day - Chassis Design} c. Mx. {John H Maddocks - Chief Proving Officer} c. Da {Bernard Day - Chassis Design} /Ev. {Ivan Evernden - coachwork} 1375 REPORT ON WHEEL MOVEMENT INVESTIGATION. We have investigated the front wheel movement on the Packard, both on the road and on the drums, in order to ascertain the desired wheel movement to be used on the B.III bumper chassis. By using 3" high cams we have had a good many failures of rubber bushes in the front suspension levers, rubber buffers, and the frame. Although is is a great advantage to accelerate failures for quick developement, it is necessary to attain a state which can be comparable with road conditions. In this case it appears that 3" cams are rather too large for B.III restricted wheel movement. As soon as we are satisfied with the frame and buffers we intend to return to 2" cams. In order to hasten failures we shall double the number of cams on the drums. | | Wheel Movement. | Wheel Acceleration. | | :--- | :--- | :--- | | Good road 30 m.p.h. | 1" | | | Bad road 30 m.p.h. | 3" | 6g | | Hump back 30 m.p.h. | 4.3" | | | 3" cams 100 r.p.m. | 6.3" | 17g | | 2" cams 100 r.p.m. | 4" | 13g | | 0.75" cams 100 r.p.m. | 1" | 4g | The good road used was a portion of the Ashbourne Road. The bad road was a bit of Ambaston Lane, and the hump back was near Longford. Rm {William Robotham - Chief Engineer} /Clapham. | ||