Flight, February 1922

THE "J.L.-12" ATTACK 'PLANE

   AN all-metal, armoured attack monoplane has just been built in America by the J.L. (John Larsen) Aircraft Corp., of New York. This machine is known as the "J.L.-12," and, as will be seen from the accompanying illustration, bears a strong resemblance to the Junker all-metal monoplane. It is reported that a "J.L.-12" made a remarkable flight on October 21 last, when, piloted by Capt. B. H. Pearson, it left the J.L. aerodrome at Central Park, Long Island, at 9.15 a.m., and flying against a 60 m.p.h. headwind at 2,500 ft., arrived at Washington at 11.45 a.m., thus covering the distance of about 200 miles in 2 1/2 hours, or at a speed of 80 m.p.h.
   The principal feature of the "J.L.-12" consists of its armament of 30 Thompson machine guns. These are arranged in a main battery of 28 guns in two sections. The first section is of 12 guns, located directly behind the pilot's seat, and the second, of 16 guns, is mounted at the rear. Firing is operated by three levers, one firing the 12-battery, the other firing the 16-battery, whilst the third lever puts all 28 guns into action. The two remaining guns are operated independently by the pilot, or gunner, from the cockpit.
   The main battery is located in the floor of the fuselage, the first section of 12 being set at a slight forward angle, and six of the second section fire directly downwards, the remainder being trained slightly aft. The circular drums for the guns contain 100 cartridges, and the ammunition equipment for the machine in battle trim consists of three drums for each of the thirty guns. The replacement of fresh magazines for all the guns requires only four minutes.
   It is claimed that by operating the ailerons so as to rock the machine laterally, an effective side rake fire is obtained. The proposed functions of the "J.L.-12" are to provide a machine having high speed, quick climb and controllability, which can be used against infantry, convoys, etc. It will dive down on the enemy, and flying low over him, open fire and then climb rapidly to a safer altitude in order to give the gunner an opportunity to renew the magazines before another similar attack.
   As regards the construction of the machine, this is, we believe, a modification of the Junker, already described in FLIGHT. American-made aluminium alloy is employed in its construction, the metal sheets being 25/1000 of an inch thick. The armour, presumably on the lower portion of the fuselage, is 9/64 in. armour-plate. The machine is braced throughout with steel.
   The principal characteristics of the "J.L.-12" are :-
   Span 49 ft.
   Over-all length 32 ft.
   Engine 400 h.p. Liberty
   Weight (empty) 2,900 lbs.
   Weight (fully loaded) 5,000 lbs.
   Weight of armour, armament and magazines 3,848 lbs.
   Weight of fuel (5 hrs.) 800 lbs.
   Weight of pilot and gunner 352 lbs.
   Speed range 55-145 m.p.h.
   Climb 1,000 ft./45 s., 10,000 ft./11 mins.
   Range of action 400 miles.

   In discussing the machine Mr. Larsen stated that "It has been put through the most severe tests already, and the flying and the battery performance have been perfect.
   "One marked feature of the machine is its climbing ability. During a recent test it climbed the first 1,000 feet in forty-five seconds, and rose to 10,000 feet in less than twelve minutes. It is as fast as a scout 'plane, and has high qualities of manoeuvring at speed."
   It was a similar but smaller machine to the J.L.-12 - the J-L.-6 - that created an endurance record (26 hrs. 19 mins. 35 secs.) recently.

Flight, January 1923

THE JUNKERS ALL-METAL MONOPLANE
180 H.P. B.M.W. Low-Compression Engine

   IN our issue of last week we published a brief resume of the paper on "Metal Aeroplanes" read before the Royal Aeronautical Society by Mr. Stern on behalf of Professor Junkers, who was prevented by illness from being present. At the conclusion of the lecture it was announced that permission had been obtained for one of the Junkers machines to fly to this country in order to give members of the R.Ae. Soc. An opportunity of examining Professor Junkers' method of metal construction.
   The machine arrived on Thursday of last week (January 11), and by permission of the Junkers representatives (and greatly assisted by Mr. Stern, of the Air Ministry Laboratory, South Kensington, who acted as interpreter), our representatives were allowed to examine the machine in detail for the purpose of compiling the following notes, and in order to obtain the accompanying sketches and photographs.
   The particular machine which visited Croydon was one taken from the regular service. So far as could be ascertained it was built in 1921, but had not been in constant use all the time since, having, apparently, spent some of the time as one of many "confiscated" by the Inter-Allied Commission. Certainly the metal showed no signs whatever of corrosion externally, but as the length of time during which the machine has been in actual service is not known, this fact does not really enable one to form an opinion. We were informed by the pilot that one of these machines which had been in service in Sweden for over a year had been left out in the open habitually, had been in the sea (it was a seaplane), and generally had been very far from receiving careful treatment, yet the metal nowhere appeared to have suffered from corrosion, in spite of the fact that it was built of Duralumin throughout. The exact treatment of the metal is not known, but it appears that some form of aluminium paint is coated on all the parts before they are assembled, and the whole structure then given one or two coats of varnish.
   In type the Junkers monoplane which visited Croydon is not new, a considerable number having been in use in Germany, while others were purchased for America by Mr. John Larsen, and were used in that country for various purposes. We have always understood that the experience with these machines was not a very happy one, but we were informed by the Junkers representatives that the original makers had nothing to do with the machines after they left the Dessau works, and that alterations were made to them, so that the Junkers firm feel that they should not be blamed for anything that went wrong. They stated that of the machines used in Germany, under the supervision of the original makers, not a single one gave any trouble.
   Fundamentally the Junkers monoplane is a cantilever wing machine, with the wing placed low on the fuselage ("tiefdecker" is the German name) in the place usually occupied by the lower plane of a biplane. The reasons for this arrangement were outlined in Professor Junkers' paper, the wing roots, fuselage, etc., forming one solid unit to which all the heavy loads and the wings themselves are attached. Aerodynamically this arrangement has been found to be slightly inferior to the more usual arrangement in which the wing is placed above or on the top of the fuselage, but Professor Junkers considers that the slight loss is more than made up for by the rigid structure resulting from the low position.
   During the War a few all-metal Junkers machines were captured, and one or two were, at one time, on view at the exhibition of enemy aircraft at the Agricultural Hall, Islington. The armoured biplane was briefly described and illustrated in FLIGHT of November 28, 1918. The monoplane, the Junkers D.I, was described and illustrated in our issues of April 1 and April 8, 1920, while a commercial machine, very similar to the present specimen, was illustrated in FLIGHT of October 30, 1919. The latter machine was the one which reached an altitude of 6,750 metres with eight people on board, as mentioned in Professor Junkers' lecture. The engine used on that occasion was one of the 185 h.p. B.M.W. overdimensioned, high-compression engines, which maintain their power up to a height of about 15,000 ft. The machine at present under review is fitted with one of the low-compression B.M.W. engines, as the high-compression type was not permitted by the Inter-Allied Commission.
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   But few particulars of the Junkers monoplane are available, but following are a few which are thought to be approximately correct :- Span,. 17-1 metres (56 ft. 1 in.); wing area, approximately 350 sq. ft.; weight of machine empty, but with cooling water, 1,155 kg. (2,540 lb.); useful load, 645 kg. (1,200 lb.); maximum permissible total weight, 1,800 kg. (3,635 lb.); power loading (180 h.p.) 20-2 lbs./h.p.; wing loading 10-7 lb./sq. ft.; maximum speed, about 160 km. (100 miles) per hour; cruising speed, 140 km. (87 m.p.h.); landing speed, 80 km. (50 m.p.h.); duration, 8 hours at cruising speed, corresponding to a range of about 700 miles.

   Herr Patze, one of the directors of the Junkers air lines, visited this country in order to try to arrange with the Daimler and Instone lines for an extension of their services into Germany, Junkers machines picking up the passengers and goods at Amsterdam and Cologne. Owing to the French occupation of the Ruhr the arrangements have had to be postponed, but it is to be hoped that later on the suggested connection will come into being.

Flight, August 1923

GOTHENBURG International Aero Exhibition 1923

   Junkers Flugzeugwerk A. G., Dessau, exhibited three different types, one of which was the "Annelise" or "F" model, which is already well known to readers of FLIGHT, an illustrated description having appeared in P'LIGHT of January 18, 1923, when the machine paid a visit to Croydon aerodrome in connection with Professor Junkers' paper before the Royal Aeronautical Society. The cabin has seating accommodation for four passengers. The type F, like all other Junkers machines, is built entirely of metal, practically all Duralumin. The main characteristics of the machine are as follows: Engine, 185 h.p. B.M.W.; length o.a., 9.6 m. (31 ft. 6 ins.); span, 17.8 m. (58 ft. 5 ins.); height, 3.3 m. (10 ft. 10 ins.); useful load, 650 kg. (1,430 lbs.); speed, 165 km. (102 m.p.h.). The machine can also be supplied as a seaplane, fitted with twin floats, or with skis for use on snow. In that case the overall dimensions are slightly altered, and, in the case of the seaplane, the useful load reduced to 550 kg. (1,210 lbs.).
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Flight, April 1930

AIRCRAFT FOR THE PRIVATE OWNER

JUNKERS F13

   THE Junkers F.13, though in the luxury class as a private owner's machine, has already found one owner in this country, as the Hon. F. E. Guest, the chairman of N.F.S., maintains one for his own use.
   Junkers machines are really too well known to need much description and, structurally, the F.13 is just the same as the Junkers Junior, which has already been described. The same all-metal cantilever principles are adhered to and also all the other Junkers details which have gone so far in building up this form of machine. The F.13 is a cabin machine with ample accommodation for four passengers, and in front of the cabin is the pilot's cockpit, with two seats side by side and with dual controls fitted.
   A similar version to this machine, but with the cabin stripped, is used for freight, and it was in a machine of this type which Herr Kohl, Baron von Hunefeld and Major Fitzmaurice flew from Dublin to Labrador in April, 1928.
   The pilot's cockpit is not enclosed, but so carefully has the design of the nose of the machine been carried out that there is no draught at all, and one has the added advantage of being able to dispense with windows, which might possibly become fogged in bad weather.
   The passengers' cockpit is extremely comfortable, and this, added to the inherent advantages of the low wing type of machine, make the F. 13 certainly one of the most comfortable machines we have ever flown in.
   Large luggage accommodation is arranged behind the cabin in a compartment which has its own door on the side of the fuselage.
   The engines fitted are either the Junkers 280-310 h.p. L5 water-cooled or the Jupiter 425 h.p. air-cooled radial. The former is an exceptionally quiet running engine, and when travelling in this machine so fitted there is no difficulty experienced in conversation between the passengers. Trost Bros., of Victoria Street, London, are the agents for these machines over here, and they keep one or two at Croydon for taxi work, where they have been doing quite a lot of work during the last year.
   The general equipment of the Junkers is very thorough indeed, and many extra instruments are fitted as standard. There is a centralised fire-extinguisher system which has nozzles directed to vital parts of the machines, so that a fire can be extinguished immediately.