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).
The adjustment and clearance requirements for fixed aircraft gun mountings.
| Identifier | ExFiles\Box 176\1\ img112 | |
| Date | 1st January 1940 guessed | |
| 2. 5. In the case of aircraft equipped with two or more fixed guns, the mountings are to be provided with means of adjustment of the gun alignment. The dispersion requirement of para. 1(b) is that each gun shall be capable of adjustment over a range of at least 1º in all directions from the datum alignment. 6. The actual range of adjustment provided in the gun mountings must exceed that specified in para. 5 by the amount necessary to cover manufacturing tolerances in the positions of the mountings. 7. In allowing for this range of movement, adequate clearance of the guns from possible obstructions, (e.g. blast tubes, and proper relationship of associated equipment (e.g. ammunition boxes), must be taken into account. 8. Fulfilment of the above requirements will meet the essential need of provision for obtaining a dispersion pattern of the gun barrel centre lines of any diameter up to 2º at 400 yards range. Where the provision of the full range of 2º for each gun involves serious difficulty, however, consideration will be given to alternative proposals for obtaining the required dispersion, e.g. by arranging for some of the guns to cover only a selected portion of the total dispersion, thereby reducing the range of adjustment necessary on these guns. | ||