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).
Index card for Piston Ring Tests concerning W.3. No. 4. Unit.
| Identifier | ExFiles\Box 148\1\ scan0248 | |
| Date | 16th March 1940 | |
| 1256 HPS{Horace Percy Smith - Experimental Factory Mgr} | RH.{R. Hollingworth} Rm{William Robotham - Chief Engineer}/CTS.{C. Trot Salt - Carburation}1/ML.16.3.40 W.3. No. 4. Unit. Piston Ring Tests see file 636. | ||