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).
Specifications for the adjustment range of gun mountings in two and four-gun turrets.
| Identifier | ExFiles\Box 176\1\ img113 | |
| Date | 1st January 1940 | |
| S E C R E T PART II - TURRET GUNS. January, 1940. 1. In turrets equipped with two guns, the gun mountings must be provided with means of adjustment in both horizontal and vertical planes, so that the gun barrel centre lines can be diverged either horizontally or vertically at any angle from the parallel position up to at least 2º included angle. 2. In turrets equipped with four guns, the gun mountings must be provided with means of adjustment so that the gun barrel centre lines can be diverged at angles ranging from the "all parallel" position up to the corners of a square pattern of at least 2º side, the horizontal and vertical adjustments being obtained independently. 3. The actual range of adjustment provided must exceed the above range by the amount necessary to cover manufacturing tolerances in the positions of the mountings. If preferred, this excess may be provided by some form of semi-permanent adjustment (e.g. shims), whereby the guns can be aligned parallel while the normal working adjustments remain set at their appropriate inner limits. 4. In allowing for this range of movement, adequate clearance of the guns from possible obstructions must be taken into consideration. 5. If provision of the full range of adjustment specified above involves serious design difficulty, the matter should be referred to Air Ministry for further consideration of the minimum acceptable range of adjustment. | ||