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).
Comparison table of physical properties for materials RR.53 and Aerolite 122.
| Identifier | ExFiles\Box 86\2\ scan0134 | |
| Date | 3rd November 1933 guessed | |
| | | RR.53 | Aerolite 122. | |---|---|---| | Ultimate tons per sq.in. | 23 | 18 | | Elongation % | 1% | Less than 1% | | Brinell - normal temperature | 130 - 150 | 115 - 145 | | Brinell - @ 300° C. | 52 | 56 | | S.G. | 2.75 | 2.9 | | Thermal Conductivity (C.G.S) | .40 | .33 | | Exp. Coefficient | .000022 per °C. | .000023 per °C. | | ||