History of Airplanes

Introduced in mid-1916. Designed along very similar lines to the Gotha, the Friedrichshafen bomber, is one of the principal heavy bombing machines turned out by the Germans. Its makers have long specialized in the manufacture of seaplanes of the single and the twin-engine type, and the bombing machine resembles the latter, except for the sweep back of the wings, which is apparently a reversion to former practice.

Top Speed: n.a.

Engine: Two Benz six-cylinder, at 225 h.p. each

Wingspan: 66.6 feet

Weight: 6,835 lb.

Armament: 3 Parabellum machine guns

Specifications from “Practical Aviation,” by Charles Hayward, 1919

Planes
The machine has a span of 66.6 feet on the upper wing, the lower wing being but slightly shorter, about 61.8 feet, so that there is very little overhang. A slight taper is given the planes from root to tip, the chord being 7.0 feet at the fuselage and f>.l feet at the wing tips. The gap is 6.39 feet at the body and increases slightly toward the ends of the wings. The machine stands 13.4 feet high over the top of the rudder and has an over-all length of 36 feet. Except at the central section, which is rectilinear, the wings are given a slight dihedral and also embody a slight sweep back and decalage, and the upper plane is st ‘l the machine is a pusher type, the trailing edges of the planes are deeply recessed to provide ample clearance for the propellers. Steel tubing is employed for the construction of the center section, while the wing framing is of laminated wood, the spacing of the spars being according to the usual German practice of placing the forward beam very close to the leading edge while the teas beam is disproportionately farther forward … The forward spar is about 15 inches from the leading edge and the rear spar is approximately one meter, or 3.28 feet, back of it. The wing ribs are parallel to the longitudinal axis of the machine, in contrast with the practice in the Gotha. Steel tubing is employed for the framing of the ailerons, which are of an irregular outline and ,are balanced at the wing tips. There is approximately 25 square feet of surface in each.

Tail Unit
Except for the unusual depth of the horizontal stabilizer, which is practically the same as its span, the dimensions being approximately 12 by 13 feet, the design of the tail unit is conventional. Steel tubing is employed for the framing of the elevators and the rudder and both are provided with balancing surfaces. The vertical stabilizing surface is the usual triangular fin.

Fuselage
In contrast with the monocoque type of body used on the Gotha, the Friedrichshafen is of the usual four-sided construction with wood cross members and wire bracing. Veneer is employed for the covering of the forward portion while canvas is used aft. The body is built as a unit and attached at a point flush with the trailing edge of the wings, keys being employed in assembling. The center section of the planes is fixed to the body by means of a cabane comprised of four vertical steel struts. Pilot and observer are seated tandem with the main fuel tank between them, the pilot being placed forward, while the bomb- dropping gear is disposed on either side of his seat. A passageway connects the seats so that the occupants may change positions if they so desire.

Power Plant
Two Benz six-cylinder vertical water-cooled engines comprise the power plant and develop a total of 450 h.p. They are spaced approximately 7 feet on either side of the center line of the machine and each is mounted on four V-shaped struts, the apexes of which bear on the vertical struts of the landing gear. Both engines are inclosed in a streamlined housing, of which the radiator forms the nose and which tapers back to a conical cap employed to streamline the propeller hub. The propellers have a diameter of 9.5 feet. The oil tanks are mounted below the radiators, while the main fuel tanks are located back of the pilot’s seat.

Landing Gear
By means of compression members, the chassis of the landing gear bears on the body as well as on the wings. This construction represents a departure from the usual German practice, as, in single-motor machines, the chassis bears on the body alone, and in twin-engine planes, on the wings alone. Two pairs of vertical steel tubing struts comprise the support of the landing gear, which is braced by tubular compression members leading from the body to the uprights. Each pair of struts bears on the base of the engine bed above it and carries twin wheels on a common axle in connection with rubber-strand shock absorbers. The tail skid is pivoted on a vertical steel tube member braced to heavy cross members inside the body, and the lower end of the skid is steel shod. No brake is employed on the landing gear.

Armament
The armament consists of three Parabellum machine guns, though the Friedrichshafen bomber is lacking in the after gun tunnel feature that distinguishes the Gotha. Each cockpit is surrounded by a gun-supporting ring around which the carriage of the piece may be slid by means of a lever which makes it possible to lock the gun at any point desired. The third machine gun is mounted on a pivot placed on the floor of the body and is designed to fire astern through a trap door. This gun is fired by the second gunner, who operates a lever to open the trap door. In addition to the machine guns, six bombs are carried in a vertical row in a self-feeding magazine, a fresh bomb dropping automatically into the place of the one that has been released. A spring jaw suspension is also provided under the center of the body for carrying an additional supply of bombs.

Weight
Fully equipped for flight, the total weight of the machine is 6835 pounds, comprising 4850 pounds as the gross weight of the machine, 951 pounds for crew, armament, and ammunition, and 1144 pounds for fuel and oil. This gives a lift loading of 9.9 pounds per square foot of surface and a power loading of 15 ½ pounds per horsepower.