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).
Laboratory report detailing the examination of a failed Wraith spring pot bracket.
| Identifier | ExFiles\Box 119\1\ scan0092 | |
| Date | 3rd May 1938 | |
| 102/4 A.F.M. Bumper File Rm.{William Robotham - Chief Engineer} H1/EJW 1/SK 3.5.38. M 1592 LABORATORY. WRAITH-FAILED SPRING POT BRACKET. (YOUR Ref: Rm{William Robotham - Chief Engineer}/AFM{Anthony F. Martindale} 8/AP 13.4.38.) As requested we have examined the specimen which you sent to us, at the points indicated in your sketch. We could find no indication of weakness in the weld, where the structure was reasonably fine-grained --- see photomicrograph No.M 1592/1 positions "A" and "B". At "X" and "C", the coarse casting structure was still evident, as will be seen in the other three photomicrographs M 1592/2/3/and 4. At the edge of the specimen, the surface was decarburised and the surface oxide had penetrated the cell boundaries --- see M 1592/2. Hardness tests gave the results shown in the sketch below. [Hardness test sketch values] "X": 214, 224, 238, 249 "A": 239, 241 "B": 223 "C": 221, 217, 221, 217 A Tensometer tensile test piece cut from the region AX gave the following figures:- Ult. St.{Capt. P. R. Strong} Y.P. E.{Mr Elliott - Chief Engineer}% R.A.% 45.5 22.0 17.8 26.0 HL/EJW | ||