Flight, April 2, 1915.
ANOTHER GERMAN SEAPLANE.
THE B.F.W. (BRANDENBURGISCHEN FLUGZEUGWERKE).
SINCE giving a description of some of the seaplanes entered for the Warnemunde-Scandinavia Seaplane Race, which was postponed on account of the war, the following particulars are to hand of another machine designed specially for this contest - the B.F.W. seaplane. In its general lay-out, this machine follows the lines of other German biplanes of the tractor type, with which our readers are already familiar, having a rectangular section body, tapering almost to a point in the nose, where is housed the 150 h.p. Benz motor. The fuselage, however, is of somewhat unusual construction in that not only is it covered with three-ply wood, but it is strengthened internally with the usual diagonal cross-bracing. In the Albatros, it will be remembered, no internal cross-bracing of any sort is employed, the necessary stiffness being provided by the three-ply covering. In the B.F.W. seaplane the internal cross-bracing of the body has been employed to better prevent the fuselage from warping under the action of sea water. The resemblance to the Albatros biplanes will be easily understood when it is pointed out that this machine was built by Ingenieur Heinkel, who was formerly chief engineer to the Albatros firm. In the front portion the body is covered with a turtle-back of three-ply wood, finishing off behind the pilot's seat in a tapering shape somewhat similar to that found on the Deperdussin racing monoplanes, and evidently intended to form a streamline continuation of the pilot's head. Immediately behind the engine is placed the observer's seal, and between him and the pilot are mounted the fuel tanks. The radiators, which are of the usual type, are mounted one on each side of the body.
Carried on a structure of steel tubes are the two main floats, which are of large size and placed fairly close together. In front the floats are of the V-bottom type, flattening out gradually towards the step, which occurs approximately under the centre of gravity of the machine. Immediately behind the step the float bottom is perfectly flat, gradually running into a slight V-bottom at the stern.
The main planes, which are of large span, are of the usual plan form, that is to say, rectangular with rounded corners. They are connected by three pairs of spruce struts on each side of the fuselage, and the upper main plane is attached, in the centre, to a steel tube cabane resting on the upper longitudinals of the body. The attachment of the struts to the spars is very reminiscent of that employed in the Albatros biplanes, and consists of a bell-shaped piece of steel, secured by means of a bolt passing down through the spar, as shown in the accompanying illustration. The bracing cables are attached to this bell-shaped steel piece by passing the lower end of the wire strainer, which is fitted with an anchor-piece as shown in the sketch, through openings in the sides of the bell. This fitting does not impress us as being such a good piece of work as that of the Albatros machines, in which, if we remember rightly, the strainers were attached to a ring resting inside the steel bell.
Another of our sketches shows the trolley used for transporting the machine short distances overland. The two wooden cross-members, it will be seen, are partly channelled out to receive the two transverse steel tubes of the chassis, and for starting off from a shallow beach all that is necessary is to run the machine out until sufficiently deep water has been reached, when the trolley will automatically be left behind, and the machine free to proceed on its floats.
The subject of another of our sketches is the tail float and planes. The stabilising plane is semi circular, and to it are hinged the two elevator flaps. The rudder, which is partly balanced, is covered at the lower end with a copper skin to protect it against the action of sea water, and is used for steering on the water at low speeds. A small tail float of the form shown in the sketch takes the weight of the tail planes.