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).
Cause of a steering 'joggle' in a 20HP car, comparing geometry issues versus gyroscopic action.
| Identifier | WestWitteringFiles\Q\April1927-June1927\ 53 | |
| Date | 30th April 1927 | |
| TO HS.{Lord Ernest Hives - Chair} FROM DA.{Bernard Day - Chassis Design} ORIGINAL DA{Bernard Day - Chassis Design}2/M30.4.27 20HP. STEERING GEOMETRY. X5430 R.{Sir Henry Royce} would like to know whether you are satisfied that the joggle which you complain of is due to the geometry, and not due to gyroscopic action on the part of the wheels. Obviously the treatment required to overcome it will be different in the two cases. As regards geometry you will remember that you had a 20HP. car - pre-front wheel brakes - fitted with radius rods which had absolutely perfect geometry over the whole range. R.{Sir Henry Royce} would like you to dig out the pieces of this, and repeat the experiment. If the steering ratios, angle of thread on the worm, etc, were the same, the absence of joggles with the radius rod control would seem to indicate that it is the geometry. If they do not disappear, on the other hand, it would seem to point towards gyroscopic action. There would still remain the possibility of side pressure on the wheel overcoming the friction of the steering gear. If it could be arranged that the axle were bumped up and down without side load, and joggles are still felt, this would certainly indicate gyroscopic action. Our recollection of the previous experiments in which perfect geometry was obtained is that though it was acknowledged there was a benefit, joggles were not eliminated, and the proposed radius rods were discarded as not being worth while. DA.{Bernard Day - Chassis Design} | ||