AIR GUNNERY

Dominion, Volume 11, Issue 214, 29 May 1918, Page 5

AIR GUNNERY

DIFFICULT WAR PROBLEMS FOR AIRMEN THE BEST TYPE OF WAR AEROPLANE (By a Eoyal .Flying Corps Officer.) (Published by authority 'of the War Office, per favour of tho Royal Colonial Institute.) 'Aerial, like naval gunnery, introduces features not met-with in the work of land artillery, in that it is carried out from vnriablo motion platforms, and directed at moving targets. Aeroplanes pitch, roll, yaw, and vibrato as do ships driven at high speed, all four being eeparato movements which handicap the gunner in his aim. At present the elevation of sights does not enter into tho calculations of tlie airmail, as tho bullets projected from his machine-guns have practically a flat trajectory up to tho maximum effective range at which fire is opened. With tho coining of larger aircraft mounting heavier guns, aerial gunnery will perhaps become still moro like naval gunnery. Even at the present, time aeroplanes ..mount low velocity quick-firing suns about the size of the old one-pounder pom-poms, but these aro used as a weapon against balloons nnd ground targets and rarely in aerial fighting. Judging Distance.

• Distance judging is as difficult in the air as it is at sea. Sighting devices, dependent on a knowledge of the himof the "enemy aircraft, assist the airman to reservo_ fire until approaching crnft come within the effective range. Visibility, of course, varies with the conditions of the atmosphere, but riiachines of average she are rarely visible at over four miles, inlr?* the glint of the sun is reflected from I'lie underside of a wing as it banks steeply on a tun:. At this distance it 19 impossible to tell wlin'hrr the machine be friend or foe. owing to tho similarity in appearance of the many machines used on both sides; should the Machine be approaching from tho direction of the sun it is hidden in the glare and will be unseen without the aid of Bmoked glasses. This means that the time between sighting an enemy and coming within range is very short, for at the speed at which fighting aeroplanes Bow fly two machines approaching one another from a distance of four, mi'es will meet in less than a minute. Xhe use of telescopes or prismatic glasses <!o not solve this problem. Such a smell object in the sky as an aeroplane would never be picked un in the narrow of view off°''ed by a telescope, and the vibration of the machine confines fm use of prismatic glasses, witli their wider .ingle of view, to those, of low power. These points can be proved on the ground; very few wnnle • can hn'd prismatic glasses of s 12 power steadily.

' Difficulties of "Spotting." . A machine at the same altitude, as oneself, unless viewed broadside, presents none of its usual distinctive identification marks; these are painted 011 the. top of the upper planes and underneath the lower-planes near the wing-tips, and on tho rudder and side of the body, and are therefore visible only from above, below or one side. A machine flying below is more easily spotted, despite the use of camouflage, as it will sooner or later pass over some ground or a cloud of a colour that will contrast with its own. The machine above, and below, will be quickly identified by its markings on thewings. The enemy have adopted a special schemc of colouring for some of their faster machines, flown by their best fighters,' perhuns that they may be quicker recognised by their own airman or, as is suggested, in a rather foolish effort to intimidate their opponents. • In aerial combat machine-gun. fire is Hot effective at ranges.over four hundred yards. Some gunners claim that it is a waste 'of ammunition—aiid the amount carried is nwessarily limited—to open firo nt over three hundred yards. At tho close'range at which fighting now takes place it is surprising that instances of collision.'are so few. There is so much movement of the machine, due to engine vibration and the inequalities of the air, especially at low altitudes and in the region of clouds, that at two hundred yards range tho shots cannot be contained within a circle of less than from_ twenty to fifty feet diameter, depending upon atmospheric . conditions. This, when fired |it an object which does not change ils position relative to the gunner's machine. "When the gun has (0 Iks traversed to follow (he path of a crossing aeroplane,, the grouping of the shots is proportionately larger. , These minimum groupings enlarge its the range increases.

The Pilot the Target. Although fire is confined to Mich short Tango tho speed of the machine is so great that under some conditions (such as two fast machines (lying from opposite directions), the barrel'-of the gun has to be aligned us much t.sone hundred feet ahead of the target to allow for the <ljstunco covered by the two machines during the timo tho bullet (ravels 200 yards. The use of "tracer" bullets, whoso path can be traced 'through the air, does not entirely solve this problem of speed allowance; their "trail" may die out before reaching the mark, and so mislead the gunner into thinking it was extinguished as a result of striking (lie enemy machino. They cannot be easily •followed when fired across tho line of flight of a fast machine. Tho vitals of an aeroplane form unite a small target and may bo partially armoured. Frayed wires, and struts and wings picrecd with bullets will not bring a machine, down. A bullet in the engine, tanks, or controls will send it down out of action, but the occupants, if they descend behind their own lines, will probably escape uninjured and tho machine be repaired. The only target that counts is the enemy pilot. If he'is killed tho result will bo that tho machino will spin down finally to crash, generally .with results fatal to any other occupants.,. Hitting the <mcmy pilot mortally may be likened trt •holing a ship on tho water-liuc. All these problems have determined that; all offensive lighting shall be done forward, and havo resulted in the development of the fast single-seater ''handy" machines OS tho best form of fighter, having as its Biain armament two or moro fixed guns, mounted to fire ahead, and aimed by steering the machine. These machines, with climbing powers unhampered by weight, can out-manoeuvre any slower craft, and select a "blind" spot in the enemy's defences, i.e., a position covered from tho enemy's fire by some part of tho aeroplane, generally Ihe tail. Tho usual tactics employed is to keep behind, slightly above ol- below, tho rnemy machino, and follow his movements—equivalent to finding and keeping the range—thus ensuring continuous fire bo long as both machines movo in the name direction. These are tho tactics employed by tho British airmen when tlicy locate a raider over London at night. Tho fight usually resolves itself into a running one, a condition which the faster machines can always dictate. 'From the foregoing it is evident that the small fastVichiue, aptly named by the French "avions-de-chas.se," will prove t9 be tho best fighters until larger machines, mounting heavier guns, arc evolved, and the problem of aim is solved.