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).
Letter discussing gun installation, ejection, and feed mechanisms for aircraft cannons.
| Identifier | ExFiles\Box 176\1\ img110 | |
| Date | 31th October 1940 | |
| THE BRISTOL AEROPLANE COMPANY LTD. W. A.{Mr Adams} Robotham Esq. 31st October, 1940. - 2 - installations, by a cap over the end of the barrel which is blown off by the first shot. This does not prevent the gun from freezing up again if the flight is prolonged for another attack. We have, therefore, concocted a hinged cap over the end of the gun which is lifted clear each time a shot is fired, with sufficient advance and lag to prevent damage from the shells. I think it would pay you to consider something of this kind in the early stages of your firing mechanism design. Ejection. It is an advantage for both ejection and feed to take place close together, so that a pivot point can be chosen for the gun in a turret which will not give a large rise and fall to either the feed or ejection chutes. We have many more troubles with ejection chutes than we have with feeds, and I think that if it is possible in the gun design to ensure that the empty case is always ejected in the same direction by being, in some way, guided to the outside of the gun, this will greatly simplify our design. The chute has to be made large enough to pass an unfired round for purposes of clearing a jam, so that it is always liable to give trouble if a round comes out of the gun "head over heels". Feeds. For a cannon the size of yours, I do not suppose that belt feed is so attractive and you will probably be sticking to magazines for some time. To feed ½" guns, of course, a belt will be used. We have a sample of the ½" American Browning belt, and this is very lacking in the necessary flexibility; and we think that to get low drag turrets with ½" guns, some form of really flexible belt will be a great help, and if you can arrange your gun to operate with something that will twist like our 20 m.m. belt, I think that this will always give the turret designer much more scope. Excuse this being rather disjointed, but if there are any other points you wish to discuss, please let me know. Yours sincerely, L G Frise Enclosure. | ||