The 18-hour test bed endurance run of the Wraith Production Fan.
| Identifier | ExFiles\Box 8\9\ 09-page38 | |
| Date | 28th June 1938 | |
| 624 To By. {R.W. Bailey - Chief Engineer} from Rm {William Robotham - Chief Engineer} /Std. c. DA. {Bernard Day - Chassis Design} c. RHC. {R. H. Coverley - Production Engineer} c. By {R.W. Bailey - Chief Engineer} /Ald. {F. Allwood - Experimental Design} Rm {William Robotham - Chief Engineer} /Std.9/MH. {M. Huckerby} 28.6.38. WRAITH PRODUCTION FAN. We have just completed 18 hours test bed endurance at maximum speeds on the fan to the production Wraith scheme SCD. 510 which includes, of course, the latest form of adjustment and water outlet casting. No trouble was experienced during the running the belt required only slight tightening after initial settling down, and was not touched throughout the majority of the running. The percentage of slip at maximum speed was very slight, being only of the order of 2%, in fact, so little slipping of the belt on the pulley Vee occurred that the enamel in the Vee was still intact at the end of the running. When stripped the fan was in a satisfactory condition and no grease was lost from the fan during the running. In this respect this represents the best result we have obtained so far and justifies the inclusion of the felt seal which is part of SCD.510 scheme. No trouble from the adjusting locking bolts working loose was experienced, but it may be mentioned that the modified version of this adjustment used to permit the running of Ph.III fan on Wraith or B.III engine was run with the Phantom fan and belt and this did give trouble due to the adjustment locking nuts slackening and permitting the adjustment to slacken off. In view of this we think it would be advisable to split pin the adjustment locking nuts on the standard Wraith scheme, as if these nuts were to work loose and be lost the results would be serious. In all other respects this Wraith fan is satisfactory for production. We have found that in order to prevent loss of grease on the fan it is advantageous to pack the fan with the usual grease except for the back bearing which should be packed with high melting point grease, which is best done by immersing it in a bath of molten grease, allowing to cool and removing. The fan tested above was packed in this manner and the fan which ran 15,000 miles in France on 26.C.VI was also packed in the same manner. We recommend, therefore that production should be instructed to pack all Wraith fans, and also Phantom fans in this manner in future. 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).