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).
Data table showing coefficients of discharge for varying bore lengths and diameters.
| Identifier | ExFiles\Box 36\1\ scan 060 | |
| Date | 9th January 1917 guessed | |
| -5- (b) COEFFICIENTS OF DISCHARGE FOR HEAD 2. Length of Bore Diameter of Bore. ½" ¾" 1¼" 2" 3½" 3¾" 4½". 3/64 { Rad. in. .82 .74 .69 .615 X X X } A { Rad. out. .80 .74 .68 .61 X X X 3/32" { Rad. in. X .89 .88 .83 .80 X X } B { Rad. out. X .83 .83 .82 .715 X X ¼" { Rad. in. X X .92 .88 .865 .79 X } C { Rad. out. X X .835 .81 .76 .75 X 3/16" { Rad. in X X X .895 .865 .85 .845 } D { Rad. out. X X X .84 .83 .82 .805 | ||