The Aviatik is one type of machine which has been used to a large extent by the Germans for their bombing raids. It is equipped with two bomb-launching tubes having a diameter of 8 1/2 inches and placed at either side of the body forward of the pilot’s seat. The bombs are released from these tubes by means of spring triggers operated by pulling a lanyard held by the observer. In addition to the bomb-dropping tubes, the machine is also equipped with two machine guns mounted on tubes which are brazed to the fuselage and which curve upward and outward from it so that the guns have an effective range of fire in practically every direction exclusive of the zone traversed by the propeller.
Top Speed: 80 m.p.h.
Engine: 160 h.p. six-cylinder D II Mercedes
Wingspan: 41 feet
Weight: 2,732 lb.
Armament: 1 machine gun
Specifications from “Practical Aviation,” by Charles Hayward, 1919
Planes
The wing span is 40 feet 8 inches for the upper plane and 35 feet 5 inches for the lower plane, the chord is 6 feet 1 inch, the gap is 6 feet 4 inches, and the total supporting surface aggregates 430,56 square feet. Of this area, the ailerons, which are fitted to the upper wing only, comprise 17.22 square feet. With the exception of a slight sweep back, approximately 1 degree 10 minutes, and the recess in the upper wing just over the observer’s seat, the planes are practically rectangular. They are set at a dihedral of about 5 degree and their angle of incidence is 4 degrees 38 minutes.
Tail Unit
The machine has what is termed a longitudinal dihedral, that is, the rear horizontal stabilizing plane is set an angle of incidence of —58 minutes to the wings. The area of this stabilizing plane including that portion of the body embraced by it is 35.52 square feet. Compared with this, the vertical fin is very small, having an area of but little over 3 square feet, which fact is doubtless accounted for by the great amount of vertical surface presented by the sides of the fuselage.
Two semi-oval surfaces form the elevators, which have an area of 12.07 square feet. Steel tubing is employed for framing all the surfaces of .the tail unit, but it is supplemented by wood ribs in the stabilizer. The rudder is of the balanced type and has an area of 6.45 square feet.
Fuselage
Steel tubing forms the foundation of the cockpit, But the remainder of the body is built almost completely of wood. the engine supports as well us the forward ends of the other two in longerons are of ash and arc fabric-wrapped as far back as the rear end of the after seat. From that point on they are of pine and are not covered with fabric. The top of the body is enclosed by arched aluminum plates. Controls of the Deperdussin type, with the control cables passing inside the lower planes, are used.
Power Plant
A Mercedes six-cylinder vertical water-cooled motor drives a two-blade propeller direct. The radiator is placed just over the motor and a special extension is attached to the exhaust manifold to discharge the exhaust gases above the upper plane. The motor dimensions are 140 millimeters bore by 160 millimeters stroke, or about 5 ½ by 6 ½ inches. At 1300 r.p.m. it is estimated that this motor develops about 170 h.p. With the propeller but without oil or water, it weighs 715 pounds. The necessary cooling water weighs 55 pounds, while the fuel for a flight of four and one-half hours duration adds 418 pounds. The weight of the complete machine, empty, is 1831 pounds and that of its useful load 908 pounds. It is said to have a speed range at sea level of 82^19 m.p.h.
German pilots claimed to have succeeded in climbing 15,570 feet with an observer and 180 gallons of fuel in the tanks, though the recognized maximum climb for this type of machine is approximately 11,500 feet with a useful load of 750 pounds. Aviatik machines captured by the French and subjected to tests showed horizontal speeds of 79 m.p.h. at 1000 meters, 74 m.p.h. at 2000 meters, and 66 m.p.h. at 3000 meters, while their climbing ability was 500 meters in 4 ½ minutes, 1000 meters, in 9 ½ minutes, 2000 meters in 21 ½ minutes, and 3000 meters in 47 minutes.
The machine described here is similar to both the Rumpler and the Albatross biplanes and is one of the earlier models. Later models of practically the same construction and design were fitted with much more powerful motors, such as the Benz and Mercedes which develop 220 h.p. They differed only in their dimensions and chiefly in the bore so as to adapt them to the same engine beds. These higher-powered machines are said to be capable of developing a speed of 93 m.p.h. at an altitude of 2000 meters.