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).
With a diagram regarding modifications to the plunger notches on the Phantom Gearbox.
| Identifier | ExFiles\Box 66\4\ scan0229 | |
| Date | 14th December 1926 | |
| TO BY FROM AJS. Copy to - HS.{Lord Ernest Hives - Chair} X8310 AJS1/M14.12.26 PHANTOM GEARBOX. We have from time to time decreased the depth of the notches for plungers, in the slider guides on this gearbox. Now that the correct depth seems to have been arrived at we would ask you to drill out the inside of the two pieces carrying plunger notches, so that the thickness indicated below is .075 MINIMUM .075 AJS. | ||