Flight, June 1929

OLYMPIA AERO SHOW 1929

The Junkers "Junior"

   In view of the popularity attained in this country by the two-seater light 'plane and the modern tendency towards all-metal construction, it is interesting to see how a foreign aircraft constructor attacks the problem, especially when that constructor is one who has become world-famous as a constructor of larger aircraft. The Junkers "Junior," or A.50, to give it its official series number, follows closely previous Junkers practice in its design and construction. In spite of this, however, the tare weight of the machine is very low compared with British machines of similar class. In spite of the fact that it is a cantilever monoplane, the tare weight of the Junkers "Junior" is but 295 kg. (650 lbs.), a figure low enough to be rather startling, even making allowance for the low weight of the Armstrong Siddeley Genet engine with which the machine is fitted. The fuselage has an internal structure of duralumin tubing, and the bracing is entirely carried out by the covering, which is duralumin sheet with longitudinal corrugations. The wing is of typical Junkers construction, although the number of tubular spars has, in view, presumably, of the relatively small wing chord, been reduced to 4. The wing covering is also corrugated duralumin, and the corrugation run from leading to trailing edge. Exactly where all the structure weight is saved is difficult to see. One assumes, of course, that the machine is designed to the usual DVL load factors. As in other Junkers machines, the centre section of the wing is built integral with the fuselage, and the wing end pieces are attached to the end of it by four "pipe unions" in the usual Junkers fashion. The ailerons extend from near the wing tips to the joint with the centre section.
   The main petrol tanks, of a capacity of 80 litres (approximately 17 1/2 gallons) are built into the centre section of the wing, and a gravity tank holding 12-5 litres (2 3/4 gallons) is housed under the deck fairing.
   If the machine is intended for school work, dual controls can be quickly installed and one set again removed when the second occupant is merely a passenger.
   The undercarriage is of the divided type, with wide track. If desired float or ski undercarriages can be supplied.
   The overall dimensions etc. of the Junkers "Junior" are: Length o.a., 6-97 m. (22-9 ft.); wing span, 10 m. (32-8 ft.); wing area, 12-6 sq. m. (136 sq. ft.).
   With a tare weight of 295 kg. (650 lbs.), the gross weight of the Junkers "Junior" may either be 500 kg. (1,100 lbs.) or 550 kg. (1,210 lbs.) according to whether the machine is being used for school work or for touring. In the latter case more fuel is carried. The normal gross weight of 500 kg. (1,100 lbs.) may be made up as follows: Tare weight, 295 kg. (650 lbs.) pilot and passenger, 150 kg. (330 lbs.); petrol, 45 kg. (100 lbs.); oil, 10 kg. (22 lbs.); total loaded weight, 500 kg. (1,100 lbs). When used as a touring machine, the petrol load is increased to 65 kg. (143 lbs.) and the oil decreased to 8 kg. (18 lbs.), leaving a luggage, etc., weight of 32 kg. (70 lbs.) to make up the gross weight of 550 kg. (1,210 lbs).
   The estimated performance figures for the Junkers "Junior" are top speed near ground, 165 km./h. (102-5 m.p.h.); cruising speed, 135 km./h. (84 m.p.h.); landing speed approximately 75 km./h. (47 m.p.h.). The range is approximately 675 km. (420 miles) and the duration about 5 hours. Service ceiling, 4,500 m. (14,750 ft.). The following are the estimated climb times: To 1,000 m. (3,300 ft.) in 5-5 mins. To 6,600 ft. in 12 mins.; to 10,000 ft. in 21 mins.; to 4,500 m. (14,750 ft.) in 52 mins.

Flight, January 1930

THE JUNKERS "JUNIOR"

   AMONG the foreign light 'planes exhibited at the Olympia Aero Show last July was the experimental model of the new Junkers "Junior." Since that time exhaustive flying tests have been carried out, and certain minor modifications have been made and incorporated in the production type, which will be put on the market very shortly. The changes are not great, but it is of interest to note that the tare weight figure has been increased from that of 295 kg. (650 lbs.) quoted for the machine at Olympia, to 340 kg. (750 lbs.). In our Olympia Show issue of July 18 we said: "In spite of the fact that it is a cantilever monoplane, the tare weight of the Junkers “Junior” is but 295 kg. (650 lbs), a figure low enough to be rather startling, even making allowance for the low weight of the Armstrong Siddeley “Genet” engine with which the machine is fitted. ... Exactly where all the structure weight is saved is difficult to see. One assumes, of course, that the machine is designed to the usual D.V.L. load factors."
   The fact that the tare weight has gone up to 750 lbs. in the production machine appears to indicate that a strengthening-up process has been gone through, and also possibly some extra weight may have been added in the way of extra comfort for the occupants. It is usual for the production type to be heavier than the experimental model, and no undue significance need be attached to the fact in this case.
   The tare weight is still very low compared with British light aeroplanes, and as German aircraft generally is not usually known for lightness, it would be interesting to know how such a low structure weight has been attained.
   The vexed question, monoplane or biplane, has not by any means been settled yet, nor has the question of whether the high-wing or the low-wing type is likely best to meet the private owner's requirements. It is of interest to recall, however, that in his lecture to the Royal Aeronautical Society, Sqdn.-Ldr. Probyn expressed himself in favour of the low-wing monoplane, voicing rather a preference for one with a cabin. To this extent the Junkers "Junior" does not meet the requirements of this well-known touring private owner-pilot, as it is of the usual open type. With effective windscreens, however, many might prefer the unobstructed view which the Junkers arrangement does undoubtedly give.
   With the arrangement of the Junkers "Junior" there is little fault to find. The front cockpit is placed well forward, so that the occupant can look straight down (as, indeed, he is seen doing in the aerial view). The rear cockpit is well aft, and also affords a vertical view of the ground. Between the two cockpits is a luggage locker.
   As the machine is of all-metal construction (with the usual Junkers corrugated Duralumin covering of wings and fuselage) the "Junior" does not, it is claimed, need a hangar but can quite well spend most of its time on the ground pegged-out in the open.
   Canvas covers for the two cockpits and for the engine are provided, as are also the necessary pegs, etc. One of the photographs shows the machine so pegged out, and with the cockpit and engine covers in place. In this connection it should be recollected that the machine is not provided with folding wings, and that therefore it occupies a fairly large space, so that the machine may well require to be left in the open where a machine with folding wings would be housed.
   Having gone into production, it appears likely that the Junkers "Junior" will be taking part in considerable numbers in the round-Europe contest which Germany is organising this coming summer as a result of a German pilot having won first place in the contest last year. There will then be an opportunity to see how it compares with British light 'planes of somewhat the same power, and of which it is hoped that a fairly large number will take part.

   Length, o.a. 7-15 m. (23 ft. 5 in.)
   Wing Span 10 m. (32 ft. 9 1/2 in.)
   Wing Area 12-6 sq. m. (136 sq.ft.)
   Wheel Track 1-83m. (6 ft.)
   Tare Weight 340 kg. (750 lbs.)
   Pilot 75 kg. (165 lbs.)
   Passenger 75 kg. (165 lbs.)
   Petrol and Oil 70 kg. (154 lbs.)
   Luggage 30 kg. (66 lbs.)
   Gross Weight 590 kg. (1,300 lbs.)
   Wing Loading 46-5 kg./m.2 (9-55 lbs./sq.ft.)
   Power Loading 6-7 kg./h.p. (14-8 lbs./h.p.)
   "Wing Power" 6-98 h.p./m.2 (0-647 h.p./sq.ft.)
   Maximum Speed 165 km./h. (102 1/2 m.p.h.)
   Cruising Speed 140 km./h. (87 m.p.h.)
   Initial Bate of Climb 3-3 m./sec. (650 ft. min.)
   Ceiling 4,200 m. (13,800 ft.)
   Range 650 km. (400 miles)
   Endurance 5 hours.

Flight, April 1930

AIRCRAFT FOR THE PRIVATE OWNER

JUNKERS JUNIOR

   IN as much as it is the only entirely metal machine at present on sale, the Junkers junior stands in a unique position in the light aircraft world. By entirely metal we mean that both the fuselage and lifting surfaces are constructed of, and covered with, metal. This form of construction eliminates a very large proportion of the difficulties and disadvantages which go hand in hand with most other forms of construction. Further, it is a full cantilever monoplane so that besides the advantages of metal construction, it can claim the added advantages of having no bracing wires or struts which may require adjusting or truing up in any way. When suitably protected with varnish or other anti-corrosive substance, it is certainly one of the most weatherproof forms of aircraft construction, and should give the private owner no trouble on this score.
   The low wing design has very distinct advantages from the point of view of the pilot, as his outlook is unrestricted in all directions.
   The metal used is mainly duralumin, so that though the wing coverings are thin and light they are perfectly strong, and will stand all the usual reasonable amount of knocking about that such parts are subject to.
   The wing construction is on the four-spar principle with easily detachable screw couplings connecting the wings to the fuselage. The fuselage is of the monocoque type, with tubular frames, and a corrugated dural skin covering. The seats are arranged in tandem with the pilot behind, and there are two luggage lockers, one between the cockpits, and one behind the pilot. The tail plane is adjustable, and all control surfaces are mounted on ball bearings. The elevators and ailerons are controlled by push rods and the rudder by cables. The engine fitted as standard is the Armstrong-Siddeley Genet, while an engine driven pump looks after the fuel supply from the two main fuel tanks, which are in the centre-section of the wing either side of the fuselage with an emergency tank of 2 1/2 gallons in the fuselage, which will feed the engine by gravity, and can be filled from the main tanks by a hand pump. The total fuel capacity is 18 gallons.
   The sole concessionnaires for the British Isles are Trost, Bros., of 104, Victoria Street, London, S.W.I.
   Two main models are marketed, the Touring Model, which is delivered at London ready to fly away for L840, and the Club Model, which is the same, with the addition of dual controls and an extra set of instruments in the front cockpit, this latters cost ?885.
   Like all Junkers machines, the Junior is fairly heavily loaded, so that it is a very comfortable machine to fly in bumpy weather, and in landing it "stays put” in a very satisfactory manner, and for those who are prepared to pay for the advantages of metal construction there is no doubt that it should prove eminently suitable as a private owners' machine