DESCRIPTION

The Vickers aircraft machine gun differs from the water cooled type in that the water-cooling system has been displaced by a skeletonized steel tube and a device has been attached to permit of the gun being used with a synchronizing gear. The guns are installed on fixed mounts either singly or in pairs. In many cases the American water-cooled type guns shipped abroad for.ground work were remodeled in France to fit them for use in aircraft. This was accomplished by skeletonizing the water jacket and water jacket cap to permit the free circulation of air for cooling. The front and rear covers were then milled out to permit the mounting of different types of trigger motors.

FEED

The gun is fed from a metallic link belt similar to that used in the Marlin aircraft machine gun, the links being of slightly different design to adapt them for use in the feed box. The method of loading the belt is described. (See p,. 44.)

POINTS TO BE OBSERVED BEFORE A FLIGHT

The gun should be in perfect operating condition, all parts clean and properly oiled. The parts which require particular care in oiling are:

• Rear bearing of barrel (in trunnion block).
• Front bearing of barrel.
• Side plate cams.
• Guides for lock on recoil plates.
• Guides for lock on rear cover.
• Feed box slide. Carrier (where it slides on lock frame).
• Crank pin.

Test the engagement of the safety sear with the firing pin by pulling back slowly on the roller handle, and listening for the click.

Adjust the tension on the recoil spring so that it weighs from 7 to 9 pounds.

Weight of the friction of the recoiling parts - this should be less than 4 pounds.

Make sure that the barrel disk, front disk, and follower where used are screwed up tight.

Always keep the adjusting nut tight.

Work the mechanism slowly several times to see, that it operates smooothly and remove any cause of friction..

Inspect the loaded belt for correct alignment of cartridges.

See that the gun is firmly fixed on its mount.

Make sure that the synchronizing device will release the hand sear.

Wipe all oil off face of lock.



ELECTRIC HEATER FOR VICKERS GUN

In order to prevent the oil from gumming due to the low temperature at high altitudes, the lock of the Vickers un is kept warm by two small electric heating elements attached to the inside of the side plates. The heaters consist of a grid of resistance wire contained between two copper plates and insulated from them by mica.

The heaters are superimposed on the side cams and attached by binding posts through the side plates, providing terminals for lead connections. Each heater consumes 18 watts, at 12 volts, and is fed from the generator which supplies the lighting system.

U. S. 30 CAL. VICKERS LOADING HANDLE

Description
The U. S. loading handle for the 30 Calibre Vickers gun consists of a handle arm and an operating cam which are joined together by means of three bolts. Several bolt holes in the operating cam permit the adjustment of the handle arm to suit the type of machine on which the gun is mounted. The loading handle is attached to the gun by means of a bolt which replaces the handle block pin.

Operation
In loading the gun the belt is inserted in the feed box and the handle arm is depressed twice. When the handle arm is depressed the operating cam rotates the roller handle and also recoils the barrel, thereby operating the feed mechanism. This is very convenient in the case of a misfire in that it obviates the necessity of pulling in the belt while the roller handle is being rotated.

"SPEEDED-UP" VICKERS AIRCRAFT MACHINE GUN, CAL. .30

In order to provide an increased rate of fire of the Vickers aircraft machine gun to meet the requirements of active service conditions certain attachments are provided which bring up the rate of fire to between 950 and 1,000 shots per minute. These consist of a special muzzle attachment and a redesigned back plate, embodying a buffer which causes a quicker return of the action of the gun.

The Vickers gun in figure 17 is fitted with the " speedingup " attachments.

11 m/m VICKERS AIRCRAFT MACHINE GUN

The 11 m/m Vickers aircraft machine gun differs from the .30 caliber gun onlv in the 'size of some of its parts. It is designed for the use of incendiary and tracer ammunition in attacking observation balloons.

11 m/m ammunition is somewhat lower than that of the service ammunition, but it is sufficient to enable attack on observation balloons at relatively long ranges, beyond the barrage set up in their defense.

This gun operates in exactly the same manner as the .30caliber gun, and the same precautions regarding care apply to both.

DISINTEGRATING METALLIC LINK BELT

DESCRIPTION

The metallic link belt is made up of individual links held together by the cartridges which it contains. The metallic belt is fed into the machine gun in the same manner as a web belt, but as the cartridges are extracted the links are no longer held together and drop out of the gun one at a time.

LOADING

The. method of loading is as follows: Twenty links are placed in the corrugations of the base of the loading machine so joined together as to form a section of the belt. Twenty cartridges are then placed in the corrugations behind the links and the pushing bar is pushed forward by means of the handle. This forces the cartridges the proper distance into the links, thereby joining a section of the belt. This section is then moved to the left or right so that the last cartridges rest in the support provided, allowing the unoccupied loop of the last link to line up with the first link of, the next section. (See figures 19, 20, 21.)





PACKING

Metallic links are packed in cardboard containers (see figs. 20-21) holding 10 lnks in each. These containers are designed to facilitate laying out the links on the loading machine.

Twenty-five containers, one of which, marked with a red stripe, contains a link fastened to a brass strip 6 inches long, are packed in a carton. This strip is for threading the belt through the gun.

Forty cartons, containing 10,000 links, are packed in a wooden box ready for snipment and marked "For aircraft use.)"