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).
Modifications to the 20 HP side steering tube following failures during testing.
| Identifier | ExFiles\Box 56\4\ Scan022 | |
| Date | 18th November 1926 | |
| X.5450 To BY.{R.W. Bailey - Chief Engineer} from EHR. To Hs.{Lord Ernest Hives - Chair} c. to BJ. DA.{Bernard Day - Chassis Design} R1/M18.1126. 20 HP. SIDE STEERING TUBE. (71-A-8) In reply to your memo. BY12/H16.11.26. Since these tubes have stood 10,000 miles tasts several times, and bumping, one can only think they have been broken by rough handling during shunting, with under-inflated tyres - (let us rehearse this.) I think the .062 tubing is too thin, and .092 should be used, by increasing the outside dia. 1/16". Provide sufficient safety clearance - .2 per side per ball, or .4 if all at one end, that is, a total of .8 before choc-a-bloc. The force to take out this clearance not to exceed 500 lbs., and the flexibility to be at the rate of 1250 lbs. per inch. To damp the steering it is preferable to put pressure on the balls on the axle of the cross steering tube joints as adopted on the 40/50. The pressure on the pendulum ball cannot be effective as this should have very little angular movement. The work should be put in hand to change all the tubes as quickly as possible. DA{Bernard Day - Chassis Design}+ will send particulars for the joint, and the work must proceed simultaneously with the testing. R.{Sir Henry Royce} | ||