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).
Conclusions and recommendations drawn from observations of fan fractures to prevent future failures.
| Identifier | ExFiles\Box 86\5\ scan0048 | |
| Date | 29th May 1935 | |
| -3- Conclusions Drawn. (a) Observations of the fractures we obtained indicated that they were precisely similar to those obtained in production. (b) No breakage will take place if the fan is correctly balanced before being sent out. (c) If any unbalance is present, failure may occur at the adjusting trunnion housing shoulder (diagram 1), or at the spindle shoulder (diagram 1). Occasionally the bracket itself may fail. (d) Locking of the adjusting trunnion by means of a nut above and below it very much reduces the likelihood of failure owing to the obviation of shock loading on spindle. SUMMARY. We recommend that the fan spindle and trunnion housing (E.52866 & E.52864) should both be made in nickel steel, and should have the corners mentioned altered to generous radii. The trunnion housing should be locked by putting the lock nut E.52866 for the knurled adjusting nut E.52867 below the trunnion housing (diagram 2). We also think that the two rivets on each blade nearest the centre of the fan flange should be moved further from the edge of the flange and from the edge of the blade, as we have found signs of splitting of the metal due to rivetting at this point. Finally, and most important of all, the fan should be perfectly balanced before fitting to the car. This operation would be facilitated by using Dural blades instead of steel ones, besides saving weight. With these precautions we think that there is no possibility of further failures. HS{Lord Ernest Hives - Chair}/C.S.Steadman. | ||