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).
Reliability of car weight data, the impact of coachbuilder fittings, and a call for more accurate weighing of experimental cars.
| Identifier | ExFiles\Box 18\1\ Scan050 | |
| Date | 17th February 1931 | |
| SG.{Arthur F. Sidgreaves - MD} FROM DA{Bernard Day - Chassis Design}/EV.{Ivan Evernden - coachwork} X7840 DA{Bernard Day - Chassis Design}/EV{Ivan Evernden - coachwork}1/17.2.31. C. to WOR.{Arthur Wormald - General Works Manager} HS.{Lord Ernest Hives - Chair} C. CAR WEIGHTS. SG{Arthur F. Sidgreaves - MD}6/C.6.2.31. X.7840. X.4538. X.226. It appears that our information regarding the weights of experimental cars is not wholly reliable. These weights were taken from Derby figures or from experimental 10,000 mile test reports. We would be glad if Derby would arrange to weigh such P. 2. and 20/25 cars as we possess, carefully stating the condition of the car when weighed - e.g. water, petrol, wheels, spares, and accessories. We feel that it is of vital importance that the weights of experimental cars should be carefully recorded and analysed so that the weight of the total car, contributed by the coachbuilder, can be accurately stated. We agree that the actual shells of our bodies today are very much lighter than they used to be, and that ironing has vastly improved. Most of the weight enters during the trimming and finishing, by the additions of the hardware and accessories. Customers cannot be prevented from demanding these fittings, many of which are to be found on cheaper cars, but we do feel that our leading coachbuilders have had the power in the past to have influenced hardware producers to make lighter and better fittings and accessories. Coachbuilders have admitted that the purchase of suitable hardware -(visors, screens, extra seats, door locks, suitable window lifts, handles, sliding and bucket seat mechanism,) has been one of their difficulties. Production cars such as the Humber score again on this point in that they are able to produce these on engineering lines to suit their needs. The body is not made and the fittings stuck on afterwards. They can use sheet steel whereas our bodies have similar fittings in forged iron and cast brass. Although the coachbuilder may "buy out" these fittings all that is not included in our complete chassis weight (chassis spares, and accessories,) must be regarded as coachwork. At the moment the position appears to be that while the part of the body made by the coachbuilder is reasonably light there is a chance that this advantage may be entirely cancelled by the coachwork accessories. It is encouraging to see how light the Maythorn bodies are and also those of Park Ward. We agree that the Parker Trials car C. T. R.{Sir Henry Royce} -78. is a bad example, and a special case, and unfortunately a leading trials car. | ||