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 of material properties for 'Quickstep' and 'F.R.S.' variants after cooling.
| Identifier | ExFiles\Box 76\3\ scan0053 | |
| Date | 9th April 1918 guessed | |
| [Left Column] Cooled in open air from 900c 920 940 960 980 1000 1020 } approx 1030 1050 approx. [Center Column - Quickstep] Quickstep Br Fracture 321 good tough (n.d.) 402 " " 652 hard not brittle 720 " " Practically dead hard hard not brittle " " rather brittle " " brittle Extremely brittle Fracture bad [Right Column - F.R.S.] F.R.S. Br Fracture 287 good tough (n.d.) 340 " " 555 hard not brittle (slight short) 602 hard hot brittle 720 very hard & tough near dead hard more brittle 1030 brittle very brittle not bad - machine [Bottom Note] Q.S. took more blows than F.R.S [Signature] AH | ||