Internal memorandum discussing a Wraith fan failure and investigating potential causes related to blade clearances.
| Identifier | ExFiles\Box 8\9\ 09-page44 | |
| Date | 15th November 1938 | |
| 624 To RHC. {R. H. Coverley - Production Engineer} from Rm {William Robotham - Chief Engineer} /Std. c. By. {R.W. Bailey - Chief Engineer} c. Hs. {Lord Ernest Hives - Chair} c. LA. {L. A. Archer} c. By {R.W. Bailey - Chief Engineer} /Ald. {F. Allwood - Experimental Design} Rm {William Robotham - Chief Engineer} /Std.5/MR.15.11.38. WRAITH FAN. We understand that a Wraith fan has failed on a customer's car and although we have not yet received any detailed information or damaged parts connected with this failure, we have been endeavouring to determine why such a failure should occur when we have run 15,000 miles on two fans satisfactorily and all our experimental cars are fitted with such fans. The only cause we can think of is the fan blade fouling some object and the only near objects are the radiator cross bracing stays. Reference to our experimental cars shows a clearance of .500 to .600 at these points (between blade leading edges and cross bracing stays) while reference to the scheme drawing for the Wraith fan shows a clearance of .475 at this point, the details having been produced in accordance with this. On examining chassis on production line, however, we noticed that in some cases the above clearance is only .250 approx., or even less. In view of the fact that the engine is mounted on rubber and that the fan blades move forward slightly at maximum revs - say up to .100, we do not regard .200 - .250" clearance as safe, and would like to know why it differs from the drawing office figure. Will RHC. {R. H. Coverley - Production Engineer} please check up on the production side of this and By. {R.W. Bailey - Chief Engineer} have the detail drawing checked so that the matter can be rectified as soon as possible. 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).