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).
Failure analysis report on Phantom III fan blades due to fatigue cracks and incorrect material hardness.
| Identifier | ExFiles\Box 94\5\ scan0070 | |
| Date | 16th September 1938 guessed | |
| (2). No.2. Phantom III fan blades. All the five blades on this fan were found to have fatigue cracks starting from the top rivet hole. One of the blades had broken in two at this point. The material quoted on the drawing is half hard aluminium with minimum brinell of 40, specification 223A. The composition of the failed blade was within specification limits, but the hardness was only 29 brinell. Hardness tests on the other four blades gave results as follows, 36,37,37,37. These are all under the minimum figure. The blade which had completely broken in two and gave 29 brinell appears to be in the fully softened condition, and we consider that this is the cause of failure. Analysis. Cu. 0.07% Ni. 0.02% Mg. Nil. Mn. 0.02% Si. 0.17% Zn. Nil. Ti. Nil. Fe. 0.50% Fan, blades and blue prints returned herewith. HL/EJW. | ||