Known to Allied aviators as the German “Spad,” the Albatros D.I, Appearing in 1916, is a high-speed type of machine, technically termed a destroyer and armed with two machine guns. The one shown in Fig. 48 was shot down in the British lines. It is a conglomerate copy of the French Nieuport and Moräne and the British Sopwith types, though equipped with a much heavier motor and lacking in the speed range of these machines.
Top Speed: 109 m.p.h.
Engine: 170 h.p. six-cylinder Mercedes inline
Wingspan: 27 feet 6 inches
Weight: 1,422 lb.
Armament: 2 machine guns
Specifications from “Practical Aviation,†by Charles Hayward, 1919
Planes
The Albatos D.I has a span of 27 feet 6 inches and the lower plane is one foot shorter than the upper. The planes have no sweep back nor dihedral but are so arranged that they may be given a variable stagger. The two main spars are quite close to the leading edge, the front being but ½ inch from the edge and the rear spar about 32 inches back of it. This gives a trailing edge with an overhang of over 2 feet, in which the ribs are linked together by a third spur of slightly more than ½ -inch square section which is introduced solely for the purpose of bracing the ribs as it is not connected in any way with the fuselage or the cabane. The angle of incidence varies from 2 degrees at the outside rib of the lower right wing to 5.3 degrees near the fuselage, increasing progressively, but being 4 degrees at the outside rib of the lower left wing. The upper plane is in one piece, while the lower wings are fixed to the fuselage by means of a bracket extending beyond the body.
Both wings and spars are finished with an outward slant and are beveled off sharply on the upper side. The ribs are spaced regularly on the upper plane, the spacing being slightly over 16 inches, while on the lower plani1 they are 14 inches apart except where the struts occur, at which [joints the rib is displaced though the total distance is 28 inches approximately. The wings are held apart by a single pair of parallel streamline struts on either side of the fuselage.
Variable Stagger. The lower planes are fixed in relation to the fuselage, but the position of the upper planes is variable by means of regularly spaced holes drilled in the horizontal tube which forms the upper member of the cabane. There are five of these holes at each end, the spacing between them being slightly less than 5 inches, and the two bolts holding the upper plane in position may be inserted at any of these points, so that the upper plane may be fixed directly over the lower or can be given considerable forward stagger. With the aid of this arrangement, the position of center of pressure can be shifted to allow for a variation in the weight of the motor employed or, possibly, for that of the pilot as well. arying the stagger moves the center of pressure longitudinally and permits the weights to be correctly adjusted. The usual method of doing this is merely to alter the angle of the tail, or horizontal st utilizer.
Transverse Control
Transverse control is effected by means of ailerons on the upper plane only, these surfaces having a span of about 7 feet 9 inches by a chord of approximately 1 foot 4 ½ inrlies to 1 foot 8 ½ inches and an area of 10.76 square feet (1 square meter) each. Including the ailerons, the total supporting surface is 267 square feet.
Tail Unit
A feature of the tail plane is that it is set perfectly flat, that is, without any angle of incidence, while both the horizontal and the vertical surfaces are of such heavy section (approximately 6 inches) IK« anchor bracing is employed. This type of construction is furthered by carrying the fuselage back with only a slight taper, so that it is unusually broad at its rear end, which terminates in a T serving as a support for the horizontal plane. Without including ilio part of the fuselage which contributes to the surface of the tail plane, the area of the latter is practically 15 square feet, while there is an additional 12 square feet in the elevator, which is a single unit balanced by a small triangular part projecting forward on the elevator hinge at either end. The balanced section represents about O.S.5 square foot, which is included in the total given. The framing of the tail plane and the vertical fin is of wood, but the elevator ami the rudder are built on steel tube frames. Tbe vertical fin has a surface of approximately 8J square feet, and the balamvd rudder, including the balanced portion, has an area of close to 6 square feet.
Fuselage and Landing Gear
The fuselage is built up on six longitudinal beams (longerons) two of which are smaller than thf others and are fixed halfway up the sides of the body, these upper Seams also being spread farther apart than the lower cms. The length of the fuselage is 21 feet 6 inches, with a maximum depth of about a feet and a maximum width of 3 feet 1/2 inch. With the exception of the forepart of the two lower beams, which are ash to serve as a support for the motor, all the longitudinals are of spruce and are wrapped spirally with fabric. Simple transverse … without cross struts are fixed to the longerons to form the body of the single-seated cockpit (monocoque), the body itself being inclosed with three-ply sheeting. These frames are of very thin laths, rounded on their inner faces and reinforced where attached to the- longerons, but heavier transverse beams are placed under the tail plane and the fin at the rear end. The landing gear is of conventional design and has a tread of about 6 feet 2 inches, cross-bracing cables being placed between the rear struts. No brakes are employed.
Power Plant
The motor is a six-cylinder Mercedes rated at 170 h.p. at 1450 r.p.m. and drives direct a propeller measuring 9.2 feet in diameter. A novel feature of the power plant it the disposition of tlic water-cooling system. The radiator is divid into two sections, one placed at each side of and on a level with the water jackets of the motor, the radiators being fed from a small aluminum gravity tank placed on top of the motor.