Frederick William Lanchester

“ An aeroplane armoured in all its vitals with 3 mm, steel, and otherwise designed on the lines indicated, flying at not less than 2000 ft, altitude, will be extremely difficult to bring down; so much so, that unless its exposed structural members be literally riddled and shattered by rifle and machine-gun, or unless a gun of larger calibre be brought to bear, it will be virtually impossible to effect its capture by gun-fire alone. ”

“ The obvious disadvantages, however, of artillery, in place of a light automatic or machine gun, lie in its want of portability and its unhandiness, difficulties which may, in course of time, be overcome. ”

“ The independent cavalry may be engaged in operations of strategic import, as in the conduct of a reconnaissance in force, or in the execution of a wide turning or out-flanking movement, or in the countering of such a movement on the part of the enemy. Alternatively it may be employed in its tactical capacity, its full weight being thrown at some critical moment into the fighting line, it may be to attack and destroy the cavalry of the enemy, to raid and capture or put out of action his artillery, to harass him in retreat, or to convert a retreat into a rout. ”

“ It is important to understand clearly that any intermediate course is fatal. Either the bullet must be definitely resisted and stopped, or it must be let through with the least possible resistance; it is for the designer to decide in respect of each component which policy he will adopt. The thickness of the armour required will depend very much upon the minimum altitude at which, in the presence of the enemy, it is desired to fly; also upon the particular type of rifle and ammunition brought to bear. ”

“ It is evidently not impossible for a strategic scout (as we may term the machine under discussion) to descend to low altitude in pursuit of more accurate and precise information; but it is always to be remembered that any such manoeuvre is dangerous to an unarmoured machine ”

“ If we take the case of a 1-pounder having the same velocity, its effective vertical range is well over 12,000 ft., and from that calibre upwards the range will, in practice, be more a question of the shell being properly directed than whether it will attain the height. At the best, firing from the ground at an aeroplane at high altitude, will require skilful gunnery, and when near the limit of the trajectory nothing but sheer good luck will render a hit effective. ”

“ It is manifestly not possible for an aeroplane to perform all the duties required of it, in connection with tactical operations at high altitude, [2] and whenever it descends below 5,000 ft., or thereabouts, it is liable to attack from beneath; in fact, at such moderate altitudes it must be considered as being under fire—mainly from machine-gun and rifle—the whole time it is over or within range of the enemy's lines. Protection from the rifle bullet may be obtained in either of two ways ”

“ All things considered, it would appear probable that attack on aeroplanes at high altitude from the ground will be found impracticable, or at least uncommercial. Not only have we to reckon with the various considerations above discussed, but also with the fact that, in our climate at least, not more than one day in four is sufficiently clear to render high-altitude shooting possible, and though it is true that an aeroplane, to make observation, cannot remain above or in the clouds, it presents but a poor mark under bad weather conditions. ”

“ The height to which aircraft artillery will carry is by no means subject to the same limitation as that of the small-bore machine-gun or rifle, the resistance of the air being many times greater than that due to gravity. Thus the ordinary rifle bullet, at 2,000 foot-seconds muzzle velocity, would carry to a height of over 60,000 ft. ”

“ Anything serious in the direction of armour or armament will be entirely out of place, since under no circum1 stances will such a machine be required to act in a combative capacity; its defence lies in its speed. It appears from all reports that the duties in question are such as to require an observer (probably a staff officer) of mature knowledge from a military standpoint, with considerable flying experience, possessing something of an intuition for reading the meaning of the incomplete and fragmentary indications which are obtainable from high altitude observation. ”

“ It is well understood that the determination of the distance of an aeroplane of known size with approximate accuracy is a matter of perfect simplicity. Thus, if the aeroplane be flying fairly overhead, or directly towards or away from the observer, and the span be a known dimension, then by measuring the optical angle presented by the span, the distance or range is given by simple proportion. ”

“ It has comparatively little to fear from field artillery owing to the want of handiness of the ordinary field-gun. The "laying" of a field-piece is far too clumsy a business to permit of its effective use on so small and rapidly moving a target as presented by an aeroplane in flight, though it may be effective when used against a dirigible. With regard to rifle or machine-gun (small bore) fire, calculation shows that aircraft is absolutely safe at an altitude of somewhat over 7000 ft. ”

“ Parenthetically, it may be pointed out that the same method will enable the range of a hostile aeroplane to be determined, provided the type be identified, and its leading dimensions are known; it also suggests the importance of not flying exactly towards or away from, or exactly broadside to, any position of the enemy guarded by counter-aircraft artillery; flying end on to the enemy is also to be deprecated on the ground of fixity of direction. ”

“ When all has been said, differentiation of type must, from the Service standpoint, be looked upon as an evil, only to be justified when, and to the extent that, service conditions prove it to be necessary. So far even the broad distinction between machines for strategic reconnaissance and for tactical operations has scarcely been drawn or received recognition. ”

“ The duties of a strategic scout on long-distance work would, without doubt, permit of flying at such a high altitude, and it may be added that, although absolute immunity is not reached at less than about 7000 ft., a solitary aeroplane can only present a very unprofitable target at far lower altitudes. ”

“ In fact, it may be taken that at, say, 5000 ft, or 6000 ft., the amount of small-arm ammunition required to bring down an aeroplane would be enormous. Not only has the velocity become so reduced as to render a "hit" capable of but little mischief, but the time of flight of the bullet, rising vertically to this altitude, would be about 8 or 9 seconds and the distance moved by the aeroplane 1000 ft., more or less. ”

“ If it were not for the consideration of the weight of armour, there is no doubt that an altitude of about 1000 ft, would be found very well suited to most of the ordinary tactical duties of the aeroplane. At such an altitude, however, the thickness of steel plate necessary becomes too serious an item for the present-day machine, even allowing for the very excellent and highly efiicient bullet-proof treated steel which is now available ”

“ Firstly, the flight range or radius, as determined by petrol capacity, is a far more important factor in its design, since it will require to operate over a large area, and to cover long distances over the enemy's territory, where any renewal of fuel supply is impossible ”