Flight, May 1924

THE DIETRICH-GOBIET SPORT MONOPLANE
30-35 H.P. Haacke Engine
A GERMAN "FORD OF THE AIR"

   AMONG the newcomers into the German aircraft industry is the Dietrich-Gobiet Flugzeugwerk A.G., of Cassel, who commenced by building small biplanes, not unlike the Fokker D.VII in general lines. One such machine was exhibited at the Gothenburg Aero Show last year. This firm has now produced a small monoplane, intended to be a "Ford of the air," inasmuch as it can be built very cheaply in quantities and uses an engine of relatively low power, although the 30-35 h.p. two-cylinder opposed air-cooled Haacke engine fitted places the machine rather outside the light 'plane class. Incidentally, the Dietrich-Gobiet firm is believed to be exhibiting at Prague, and it seems probable that one of the machines to be shown will be the D.P. VII shown in the accompanying illustrations.
   The D.P. VII is a low-wing monoplane with high-lift wing section. In spite of the fact that the wing is in one piece and runs right through the fuselage, external bracing is employed, consisting of a pair of inverted Vee struts on each side, much after the manner of the de Havilland 53. Owing to the continuous spars, however, the stress distribution is of course, quite different in the Dietrich-Gobiet wing.
   The fuselage is, it will be seen, of rather unusual depth. This is probably a result of a desire on the part of the designers to obtain as good an angle as possible for the wing struts, and also comes in useful in allowing the wing to be pushed through the fuselage above the bottom longerons. A somewhat similar arrangement is employed in the Udet machines, but there the lower longerons have a hinged section which is opened to admit the wing. This necessitates raising the machine off the ground on trestles in order that the undercarriage may be swung out of the way. In the Dietrich-Gobiet, on the other hand, the opening in the sides of the fuselage is large enough to admit the wing section, and the wing can therefore be inserted or withdrawn without interfering with the undercarriage at all. It is stated that the wing can be removed by the crew of the machine without outside assistance in a few minutes, and for transport a couple of padded trestles, normally carried inside the fuselage, are placed above the fuselage and the wing secured to them by steel straps. The overall width of the machine is then only the width of the tail plane.
   Constructionally the Dietrich-Gobiet D.P. VII follows Fokker practice to some extent, in that the fuselage is built up of steel tubes braced with piano wire. The covering is the usual doped fabric. Welding is used as in the Fokker machines for joining struts to longerons. Apart from its depth, there is nothing unusual in the fuselage, which is of rectangular section. The cockpit has room for two occupants if necessary, the passenger straddling a box seat behind the pilot, after the fashion of the pre-War Morane-Saulnier monoplanes.
   The Haacke two-cylinder flat-twin engine is mounted in the nose of the fuselage, and it will be observed that a particularly "clean" entry is provided for the air, the upper part only of the cylinders projecting.
   The undercarriage is of the usual V-type, of streamline section steel tubes, but lateral bracing is by diagonal struts instead of wire.
   As distinct from the fuselage construction, the wing is an all-wood structure, with three-ply and spruce box spars, and wooden ribs. The ailerons are of considerable length, extending inward to the point of attachment of the wing-bracing struts. The controls are of usual type, and all control cables pass inside wing and fuselage respectively.
   It is understood that, the flying tests with the experimental machine having proved satisfactory in every way, the machine will now be put into quantity production. In this respect the Germans appear to have advanced farther than we, inasmuch as several makes have been, or are being, put into quantity production. Thus the Mark Monoplane, which resembles the D.P.VII in that it has a steel tube fuselage, but differs from it in being a parasol monoplane, has been produced in fairly large numbers for some time.
   The main characteristics of the Dietrich-Gobiet D.P.VII are as follows: Length o.a. 5-4 m. (17 ft. 8 1/2 ins.); span 8 m (26 ft. 3 ins.); height 1-95 m. (6 ft. 5 ins.); area 10-625 sq. m. (114-5 sq. ft.). Weight empty 180 kg. (396 lbs.); useful load 160 kg. (352 lbs.) ; total loaded weight 340 kg. (748 lbs.). Power loading 9-6 kg./h.p. (21 -15 lbs./h.p.); wing loading 32 kg./sq. m. (6-52 lbs./sq. ft.). Speed 115 km./hour (71-5 m.p.h). Ceiling 2,400 m. (7,875 ft.). Range 350 km (217 miles). Fuel capacity sufficient for 3 hours. Petrol consumption for 100 km. (62 miles), 8 kg. (17-6 lbs.), oil consumption in three hours 2-5 kg. (5-5 lbs.). It will be noticed that the ratio of useful load to empty weight is very good.