Fig. 5. Sopwith Speed Scout or "Chaser."
Fig. 6. Nieuport Biplane Scout with Machine Gun Pivoted Above the Upper Wing. This Gun Fires Above the Propeller.
Night flying in squadrons always introduces the danger of collision, and to minimize this danger, by decreasing the number of machines, the size and carrying capacity of the bombers has been continually increased. Again, bombing requires the steady platform that only a large machine can give, and for accuracy the span and area must be greater than that of the reconnaissance type. In night flying a large machine is safer to handle owing to its lower landing speed and ability to come to rest quickly after landing, and this is of the greatest importance when landing outside of the aerodrome. For daylight work at comparatively short distances the smaller bomb carrier used at the beginning of the war is probably preferable as it has better maneuvering qualities, and as the bombs are divided among a greater number of machines they are not so likely to be defeated before accomplishing their object. Because of their great size, these bombing aeroplanes are nearly always of the "twin motor" type with two, or even three, independent power plants. The use of a twin power plant is an added insurance against forced landings in hostile country, or over unsuitable ground, and even with one dead engine the machine can be flown home at a fair speed.
Fig. 8. Fokker Synchronized Machine Gun. The Gun Is Driven by the Motor in Such a Way That the Bullets Pass Between the Propeller Blades. "L’Aerophile."
"Spotting" for the guidance of the artillery is a duty usually performed by the reconnaissance type, or small bombing type, and is usually done under the escort of chasers. Their duty is to direct the battery as to the placing of shots. The ideal machine for such a purpose would be the direct lift type similar to a helicopter which could hover over one particular spot until its object had been accomplished in making measurements, and plotting enemy positions. Since no such machine is at present available, the duty must be performed by a low speed aeroplane, that is large enough to provide a fairly steady platform and at the same time has sufficient speed for a quick getaway. A dirigible has the necessary hovering qualities but lacks the speed necessary for avoiding attack from even the slowest of aeroplanes, and in addition is a magnificent target for anti-craft guns if kept at an altitude low enough for accurate observation. A large speed range is a desirable characteristic in such service.
Photography is of the greatest importance in reconnaissance, since the camera distinctly records objects on the terrain, so small and obscure that they may entirely escape the eye of the observer. Again, the photograph is a permanent record that may be studied at leisure in headquarters, or may be used in comparisons with photographs taken at an earlier date in the same territory. Thus changes in the disposition of enemy batteries, trenches, and troops can be quickly identified. With modern aeroplane photographic equipment, a vast territory may be investigated and mapped out by a single machine in a few hours. Camouflage has but few terrors for the camera, and the photographs often clearly reveal that which has been passed over time and time again by the observers. When sent out on a specific mission, the aeroplane returns the films in an amazingly short length of time, and within a few minutes they are developed and are ready for the inspection of the officers in charge. The analysis of these photographs has rapidly developed into a science well worthy of a Sherlock Holmes. Changes in the position of shadows, suspiciously sudden growths of underbrush, changes in the direction of paths, and fresh mounds of earth all have a definite meaning to the photographic expert.
