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).
The standardisation of thermometer units and radiator top tanks for the Wraith model.
| Identifier | ExFiles\Box 150\3\ scan0442 | |
| Date | 26th April 1938 | |
| To By. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /Std. c. Roy. {Sir Henry Royce} c. RHC. {R. H. Coverley - Production Engineer} c. By {R.W. Bailey - Chief Engineer} /NS. {Norman Scott} 1280. WRAITH OIL GAUGE AND THERMOMETER UNITS - ALSO RADIATOR TOP TANK. We find that the thermometer unit instructed for the first 100 Wraith production cars is of identical type used on Ph.III and B.III chassis, but that whereas Ph.III and B.III cars have steam valves fitted on their radiators, which raise boiling point from 100°C to 106°C, Wraith has no steam valve. This means that the thermometer on Wraith should have the old type dial reading up to 100°C and we have accordingly been in touch with Messrs. Smiths about the question of modified dials. Copies of the correspondence are attached and further, their Sales Director, Mr.Nicholls informed the writer over the telephone that the price increase, per Wraith thermometer, for the different dial, would be 2/-. Actually the steam valve of the type run for the last 5,000 miles of 20.G.VI car's mileage in France would only add approximately 1/- to the radiator cost, and it would therefore be economic to use it and keep the thermometer common to all cars. As, however, we do not consider that we have had sufficient experience with this valve, we recommend that the first 100 Wraith cars have thermometers with dials reading up to 100°C - will By. {R.W. Bailey - Chief Engineer} please instruct accordingly. As soon as we are satisfied with the steam valve we will standardise it and return to the thermometer common to all three cars. Accordingly, the radiator steam escape pipe and outlet flange should not be released for any Wraith chassis beyond the first 100 sets - if possible the radiator top tank and its fittings should be held up (for chassis beyond the first 100) pending the result of tests, which we are making shortly. It will be seen from Messrs. Smith's letter of 25th. inst., that a number of thermometers are completed against the Wraith order - we recommend that these are put on one side and utilised for either future Ph.III or B.III production. Rm {William Robotham - Chief Engineer} /Std. | ||