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).
Options for a combined car heater and defroster for a new Wraith chassis, recommending the Smith's 'HaDees' unit.
| Identifier | ExFiles\Box 109\5\ scan0104 | |
| Date | 29th December 1938 | |
| 664 also 1158 To By.{R.W. Bailey - Chief Engineer} from Rm{William Robotham - Chief Engineer}/Std. c. Da.{Bernard Day - Chassis Design} c. Da{Bernard Day - Chassis Design}/Ev.{Ivan Evernden - coachwork} c. By/Ald.{F. Allwood - Experimental Design} CAR HEATER AND DEFROSTER FOR SG{Arthur F. Sidgreaves - MD}'S NEW WRAITH CAR. We understand that Sg.{Arthur F. Sidgreaves - MD} is asking for a combined car heater and defroster to be fitted to his new Wraith chassis. We have done a fair amount of work on various heaters and heating systems and are shortly issuing a report on same - the only two practicable combined units, however, are the Smith 'HaDees' as modified for us for separate motor operation, and the R.R. designed Marston made heater to DCD.221 (with certain modifications). Both these units have separate motors located in the engine side of the dashboard to obviate motor noise. There is little to choose between these units from a performance point of view - the Smith's has a slightly greater heat output, while the R.R. design has a slightly better defroster air delivery - however, the R.R. design is about 3½ lbs. lighter than the Smith's and could be bought from John Marstons Ltd. at about 5/- less than the Smith's. However, since the adoption of the R.R. design would involve an expenditure of at least £150 in tool cost, and we are not contemplating supplying the heater as part of the chassis included in the chassis price, we think that it is advisable to adopt the Smith's 'HaDees' heater at present as our standard recommendation and accordingly recommend it for Sg{Arthur F. Sidgreaves - MD}'s car. We will order the necessary unit from Smiths and instruct the necessary fittings to be made in the Exp. Dept., if By.{R.W. Bailey - Chief Engineer} agrees to this. As regards the actual defrosting ducts, none of the arrangements fitted up by coachbuilders on B.V. and B.50 chassis so far have been satisfactory, partly due to the fact that the coachbuilders did not give us what we requested and partly because we were not sure what we wanted ourselves. However, we have now established that it is essential to minimise the hydraulic resistance to the defroster air flow by (a) using separate feed for each defroster (passenger and driver). (b) feeding to the defroster directly through the scuttle rail with a minimum of bends and restriction | ||