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).
Blueprint showing a cross-section of a machined component with various diameters and balance holes.
| Identifier | ExFiles\Box 179\3\ img117 | |
| Date | 31th January 1932 guessed | |
| D 1.888" DIA. Y RAD. 1.650" DIA RAD. 3.235" DIA. RAD. D .615" 55° 5 BALANCE HOLES .312 DIA X .625 DEEP 5 | ||