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).
Breakages in steering and spring components and proposed solutions.
| Identifier | WestWitteringFiles\L\Jan1924-March1924\ Scan24 | |
| Date | 16th January 1924 | |
| TO R.{Sir Henry Royce} FROM DA.{Bernard Day - Chassis Design} SECRET DA{Bernard Day - Chassis Design}1/M16.1.24. Copy to - CJ. HS.{Lord Ernest Hives - Chair} RG.{Mr Rowledge} E.{Mr Elliott - Chief Engineer} A.{Mr Adams} C. X9770 X9410 X9420 X943 Referring to R2/M16124., I am sorry that we did not realise that you were expecting us to send our remarks along to you. We did send some remarks to HS.{Lord Ernest Hives - Chair} on the subject of the broken steering and the broken springs. The increase in the breakages in the steering with the use of radius rods and shorter pendulum lever we suggest is due probably entirely to the use of set up springs in the side steering tube and a straight tube, and these breakages will probably go back to normal now that we are using the standard side steering tube with balanced springs and a set. The question will arise again when we begin to bump EAC.2. with the new steering box and straight side steering tube. We expected that we should wish to try balanced springs in conjunction with this box, and another test would be to reduce the force of the set up springs. But we do not yet know how the new steering box stands up on the bumping rig. With reference to front springs we attributed the increase in breakage to the use of a longer spring pad and increased centres for the spring clips with the new axle. This has the effect especially on the bump of shortening the 2 halves of the spring, and since the bump is the same one supposes that the amount of work being done per cubic inch of metal is greater with the new axle than with the old one. We have known of course for a long time that the front springs are very near the mark as regards liability to break. The slight increase of stress due to the new width of spring pad would probably immediately shew. We consider that this trouble will be completely cured and the front springs better than they have ever been before by the use of 45" centres and a 25% drop in deflection. The stress in the top plate for instance is dropped about 10,000 lbs per sq. in. compared with springs on existing 40/50 cars without front brakes, and the stress in the other plates a somewhat similar amount. This improvement in strength will also occur to a slightly less degree even if we used the eccentric springs which it is now suggested should be adopted for the first RAC. 3s. In these the corresponding drop in stress is about 9,500 lbs. per sq. in. DA.{Bernard Day - Chassis Design} | ||