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).
Cost and weight comparison between the Cub and Wraith engines.
| Identifier | ExFiles\Box 140\3\ scan0242 | |
| Date | 17th March 1939 | |
| 1175 & 1260 Typed. 17.3.39. Cub Engine (less clutch) 755 lbs. Wraith " (less clutch) 569 lbs. Material Cost. Cub (less clutch) £49 = 980/- Wraith( " " ) £35/10/- = 710/- Wraith Mat., Cost per lb. 710 / 569 = 1.25/- Cub " " " " 980 / 755 = 1.30/- Labour Cost. Cub (less clutch) = £16/6/3 = 326.25 Wraith (less clutch)= £33/13/4= 673.3 Wraith labour, Cost/lb. = 673.3 / 569 = 1.2/- Cub labour = 326.25 / 755 = .43/- | ||