Flight, February 1921
A NEW DUTCH COMMERCIAL AEROPLANE
The N.A.V..6 220 H.P. Benz Engine
ONE of the results of the prohibition imposed upon Germany by the Allies has been to force a number of German aircraft designers and skilled aircraft workers to go abroad,
in order to avoid leaving the industry altogether. Holland is one of the countries which German aircraft experts appear to favour as a temporary home until construction in Germany becomes permitted again. Thus it is natural if one finds, in practically all the Dutch machines, strong family resemblances to well-known German types of aeroplanes. One instance was the Fokker, which may or may not be a bonafide Dutch production. Lately a new addition to the "Dutch" aircraft industry is the "N.A.V." whose latest machine is the limousine shown in the accompanying general arrangement drawings, which we reproduce from the German aviation journal Illustnerte Flug-Woche. The initial letters N.A.V. refer to the name of the firm, which is Nederlandsche Automobiel en Vliegteuig Onderneming, with headquarters at Enykaaude, Maas, Holland.
The N.A.V. 6 has, it will be seen, a very strong resemblance to the German "Kondor" war machines, and it is understood that, as a matter of fact, German draughtsmen and workmen from the Kondor works are responsible for its production. The machine is, in many respects, similar to the Sablatnig as regards its general arrangement, with the cantilever thick-section wing and the pilot seated behind the passenger cabin.
In the N.A.V. 6, however, the wings are truly cantilever wings, whereas in the Sablatnig the load on the wings is relieved by a pair of lift struts on each side, an arrangement which, while adding a certain amount of resistance, adds enormously to the strength of a wing, which already has fairly deep spars. It is quite probable that this modification of the true cantilever wing will become popular in the future, especially for biplanes where a single pair of struts and single-bay bracing will then suffice for biplanes of comparatively large span. The cabin is meant to accommodate four passengers, but our German contemporary points out that the space is very cramped, which is not conducive to a feeling of security on the part of the passengers.
By a special form of construction the cantilever wings have been built for as light a weight as 1.64 lbs./sq. ft. (Nothing is said regarding factor of safety.) The span of the wing is 45 ft. 3 ins., and the maximum chord is 8 ft. 4 ins., diminished to 5 ft. 10 3/4 ins. at the tip. The maximum thickness of the wing section is 1 ft. 5 3/4 ins. The wing is supported on three struts on each side, two of which run to the lower longerons of the fuselage, the third being a drag tube running forward to the top longeron near the nose. These struts are streamline steel tubes. The wing appears to be built up in five sections. The centre section is, of course, in one piece, and each end section appears to be made up of two pieces, joined at the line where occurs the root of the aileron. Probably this has been done with a view to reduce the space required for crating the machine.
It appears that there are two radiators, one mounted on the leading edge of the plane and the other in the nose. Probably arrangements have been made for blanketing one of these, thus reducing the cooling surface to approximately half.
The engine is a 220 h.p. Benz, and the engine housing is arranged similar to the bonnet of a car, with two flaps which lift up for inspection of the engine.
The weight of the machine empty is given as 2,640 lbs., and the useful load as 1,100 lbs. It is expected that the speed will be about 100 m.p.h.
The area of the machine is 395 sq. ft., which therefore gives a wing loading of about 9 1/2 lbs./sq. ft. The power loading is 17 lbs. per h.p. Sufficient fuel is carried for a flight of five hours' duration (at cruising speed, probably), or a range of approximately 400 to 450 miles. It is possible that one of these machines may pay a visit to this country before long.