Unsatisfactory performance of the Wraith fan and proposing modifications using a Cadillac fan and new pulleys.
| Identifier | ExFiles\Box 8\9\ 09-page01 | |
| Date | 25th June 1937 | |
| To HPS. {Horace Percy Smith - Experimental Factory Mgr} from Rm {William Robotham - Chief Engineer} /Std. 624 Rm {William Robotham - Chief Engineer} /Std.17/AP.25.6.37 WRAITH FAN. As a result of tests on 25.G.V1. we find that the Wraith fan is not satisfactory from the point of view of noise, and that if we drop the speed the cooling is inadequate. We have therefore tried the five blade Cadillac fan (as per that which we propose to standardise on Ph.III.) and think that it will be satisfactory if its speed is dropped to approx .8 X engine speed. At the same time, we wish to make the fan drive more satisfactory - will you therefore detail and make a Wraith fan hub to suit a 5 blade Cadillac fan with the pulley dimensions as shewn on attached sheet. Will you also please detail and make two driving pulleys for this fan to the particulars given on attached Sheet,- they give alternative speed ratios of .8/1 and .85/1. We shall fit this fan to the Wraith which is to run 15,000 miles in France. Rm {William Robotham - Chief Engineer} /Std. | ||
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).