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).
Comparison of torque arm and suspension deflections between a B.III model and a Packard.
| Identifier | ExFiles\Box 127\1\ scan0356 | |
| Date | 9th May 1938 guessed | |
| -2- which is not machined like the cast steel torque arm on B.III. This allows a small amount of relative movement between the torque arm and lower lever, or possibly between the studs and the torque arm in the case of the Packard. In the case of the Bentley the torque arm is bending further back and there is practically no fidgeting. Some additional data have also been obtained. The inner end of the lower triangle lever moves backwards on both cars. .030" on B.III. (F) .063" on the Packard. The torque arm moves backwards in the direction of its C .004 for B.III (A) .002 for the Packard. All these deflections result from a load variation of 1200 lb. ranging from 300 lb. to 1500 lb. at the wheel. Item B1 is what would be expected from an end play of .008" and a diametral clearance of .001" in the needle bearings. The Packard is better in item B2 because of its much sturdier pivot pin. See Fig.III. In addition to this the needle bearings are further apart and are nearly twice as long. As a matter of interest the Packard has a large thrust bearing in its bottom pivot, apparently there to take braking loads. In obtaining this data the upper triangle and damper was dispensed with and in their place was fitted a single compression member this could be adjusted to make a variety of angles with the C/L of the frame. All the figures above are taken with this compression member in its normal position i.e. 6 1/2° and 69° from frame C/L for B.III and Packard respectively. | ||