Frederick William Lanchester

“ The measure of the rapidity of gun-fire from an aeroplane or dirigible as an index of its fighting value depends upon the nature of the objective or target. It is evident that in some cases the mere number of projectiles per minute is the most important factor, as, for example, in attacking any object in which a hit is a hit whether the projectile be large or small. In other cases, where the mischief done is in any reasonable relation to the weight of the projectile, the total weight of projectiles discharged per second (or per minute) affords a better criterion. ”

“ The advantage of size and weight only becomes important when a single hit is sufficient to carry away an important strut or structural member which would have been penetrated without great injury by a bullet of ordinary size. Thus, so long as we are dealing with ordinary rifle, pistol, or machine-gun fire, we are concerned merely with the number of bullets that can be discharged per unit time, and this number—i.e., number per minute or second—fairly and properly expresses the value of the armament. ”

“ Obviously, rate of fire should be one of the last things to be sacrificed; but the alternative—a reduction in the load of ammunition—involves a curtailment of the period of activity, and, as a corollary, an increase in the number of machines required for a given combatant duty. Once admit the necessity for such additional machines, and we must estimate the sacrifice, or price paid for the armour, in terms of the loss of fighting strength due to the absence of a section of the air-fleet occupied in replenishing. ”

“ If we go further and endeavour to compare the relative value of armament of diverse type for aeroplanes, as, for example, in computing the relative merits of machine-guns and small artillery in any given case, we are inevitably thrown back on examining the service for which the armament is required ”

“ Similarly, we know that the initial need for armour is mainly to resist attack from below. These facts remain, and cannot be altered by the additional duties imposed when aeroplane attacks aeroplane. We may, and in fact shall, have to provide for a far wider range of fire; we shall need to make provision for training our gun or guns upward as well as downward; likewise we may find it expedient to provide protection against fire from above as well as beneath. But any extended scheme of armament or protection so developed takes essentially as its starting point the more elementary condition. ”

“ The question of employing armour as a protection against attack from above, or against dropping fire, is one which requires consideration on an entirely different basis from that of attack from below. ”

“ Protection by Armour and Shield Contrasted. It is, perhaps, opportune to draw attention here to the difference between shield and armour as a means of protection. The shield is essentially mobile, it is moved round and about to give the best protection possible, according to the direction of attack. A shield commonly forms part of a gun-mounting, but this is by way of being an accidental circumstance; the gun has to be trained on the enemy, and so the shield is made part and parcel of the gun, thus automatically taking the best position for the gunner's protection. ”

“ At present there are very few cases in which the automatic or semi-automatic 1-pounder could compete with the machine-gun as an aeroplane arm. If a percussion or impact-fuse were available sufficiently sensitive to explode with certainty on encountering balloon-cloth, the 1-pounder would be an excellent weapon for the destruction of the airship or dirigible. Every part of a shell exploding within the envelope is effective, and the fragments of a shell leave wounds in the envelope and give rise to loss of gas of a more serious character than that due to the rifle or machine-gun bullet. ”

“ In view of the comparatively flimsy and fragile nature of aircraft, it is doubtful whether the energy equivalent of the discharge will ever be of the importance which it is in the case of the battleship, where the destruction of the enemy depends to a very large extent upon the number of foot-tons with which he is assailed. ”

“ The effectiveness of shell fire depends entirely upon the conditions being present necessary to the correct timing of the fuse—that is to say, either the range must be known with great accuracy and the time-fuse mechanism correspondingly perfect, or the nature of the target must be such as to permit of the effective employment of an impact fuse of some description. ”

“ The machine which is able to attack from above is acting under the conditions for which its armour and armament were initially provided. Beyond this, the taking of the upper position at the start, or perhaps, we may say, before the start, gives the power to outmanœuvre an enemy, in spite even of inferior speed capacity in the ordinary acceptation of the term. The initial difference in altitude represents a store of potential energy which may be drawn upon when the opportunity occurs ”

“ If the only alternative were the cutting down of the speed of fire—tersely, if he were to substitute, say, 30 lb, of armour for 30 lb, of gun—and if this represent half his total gun capacity, and involve a reduction in his speed of fire by nearly one-half, then the change might be considered as nearly justified, since he would receive two shots for every one he could discharge, but would at the same time be proportionately less vulnerable. ”

“ This is evidently a serious matter under the best conditions—i.e., when fighting in the immediate vicinity of the base; if, however, an air-fleet be engaged far afield it becomes still more serious, and the sacrifice of rapidity of fire, rather than reserve of ammunition, might well prove to be the lesser of evils. ”

“ It is probable that in cases in which it may not pay to fit armour, it will still be found profitable, owing to the considerations already discussed, to provide shields to give partial protection both to gunner and pilot. ”