O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Friedrichshafen FF 39
   Some fourteen machines of FF 39 type, which was virtually a refined FF 33e, were supplied from December 1915 onwards. It was used for reconnaissance patrol duties and carried a radio transmitter. Engine, 200 h.p. Benz Bz IV. Span, 17.1 m. (56 ft. 1 3/8 in.). Length. 11.6 m. (38 ft. 0 3/4 in.). Height, 4.3 m. (14 ft. 1 3/8 in.). Area. 68.4 sq.m. (739 sq.ft.) Weights: Empty, 1,438 kg. (3,164 lb.). Loaded. 2.102 kg. (4.624lb.). Speed 137km.hr. (85.625 m.p.h.). Climb, 1,000 m. (3,280 ft.) in 9 min. Duration 5 hr. Armament, one manually operated Parabellum machine-gun in rear cockpit.

J.Herris Friedrichshafen Aircraft of WWI (A Centennial Perspective on Great War Airplanes 21)

Friedrichshafen FF39

   Powered by a 200 hp Benz Bz.IV, the FF39 was a larger, heavier, more powerful development of the Friedrichshafen FF33J that used the 150 hp Benz Bz.III. The additional power enabled the FF39 to be armed with a flexible machine gun, whereas the FF33J was not armed.
   A full year elapsed between the order for the FF39 prototype and its first flight, most likely due to delayed availability of the required 200 hp Benz engine. The FF39 gave good service but only 14 were built because it was soon replaced in production by the improved FF49C powered by the same engine. The first FF39 was delivered in late March 1917 and the first FF49 aircraft were ordered in May 1917.

Friedrichshafen FF39 Specifications
Engine: 200 hp Benz Bz.IV
Wing: Span Upper 17.10 m
Span Lower 16.60 m
Area 68.5 m2
General: Length 11.40 m
Height 4.20 m
Empty Weight 1,438 kg
Loaded Weight 2,102 kg
Maximum Speed: 137 km/h
Range: 600 km
Climb’: 800 m 7.4-9 min
1,000 m 7-12 min
1,500 m 11.5-18 min
2,000 m 17-27 min
Note: The variations in the climbing times given are due to variations in the flying weight due to different equipment and loads carried in the tests.


Friedrichshafen FF39 Production
Marine Numbers Quantity Date Ordered
587 1 December 1915
643-645 3 February 1916
1127-1136 10 December 1916

M.Dusing German Aviation Industry in WWI. Volume 2 (A Centennial Perspective on Great War Airplanes 85)

Flugzeugbau Friedrichshafen, Manzell near Friedrichshafen (Fdh)


Aircraft Development:

  As already mentioned, the company was primarily engaged in the construction of seaplanes. Of them, worth mentioning are:
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   FF 39, 200 hp Benz engine, with installation of bombs and a mobile machine gun;
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  Repeatedly, pilots could be rescued after engine failures, their planes sometimes floating around in capsized condition for days on the North Sea. The bombing flights over London and other cities and installations in England and Belgium also testified to the usefulness of these aircraft.
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Журнал Flight

Flight, October 16, 1919.


SOME FRIEDRICHSHAFEN "MILESTONES"

   PROBABLY no other German aircraft firm can show such a series of seaplanes as that produced by the Friedrichshafen Aircraft Works (Flugzeugbau Friedrichshafen) during the War, and for this reason a brief reference to the various types, illustrated by photographs, may not be without interest to readers of FLIGHT. The illustrations have been published in Flugsport, and the following is a translation of the descriptive matter accompanying the photographs :-
   "The Friedrichshafen Aircraft Works is the oldest German firm which has devoted its energies almost exclusively to the production of seaplanes. The firm was founded in 1912 and has produced a great number of seaplane types, under the efficient leadership of its founder and managing director, Dipl. Ing. Theodor Kober, who has been ably supported by his associates, in close co-operation with the Naval authorities and with various scientific institutions. The main sphere of activity of the firm was the construction, testing, and quantity production of seaworthy single-engined seaplanes of the types used by the German Navy for reconnaissance flights over the North Sea and the Baltic. That the firm was successful in this is proved by the fact that they have been able to supply practically all the requirements of the German Navy, and that a number of other firms have built their machines under licence. Among these may be mentioned the Luftfahrzeug Gesellschaft, the Sablatnig Aircraft Works, the Gothaer Waggonfabrik and the Warnemunde Aircraft Works. As the seaworthiness of a machine depends not only on the right shape of float, but also upon the strength of the floats and undercarriage, on the correct amount of buoyancy and on controllability when alighting, it will be seen what an abundance of experience has to be collected in order to fulfil the specifications for a seaworthy seaplane. A large proportion of the experiments was formed by tests on floats, of which over 100 types were produced. The F.F. machines, which have been well proved during the War, are all of the twin-float type, although before the War single-float machines and flying boats were also tried.
   "One object of the experiments was, among other things, to determine the number and placing of steps which best suited the different types of machines for starting and landing, and what float shape gave the best results for taxying. At the same time the floats should combine small air resistance and great rigidity with small weight, while the most suitable, strongest, and lightest construction of float details also required much work and very many experiments. The following are the most important types of seaplanes produced by the Friedrichshafen Aircraft Works :-

"The F.F. 39C.
   "As a result of the ever-increasing military demands, the reconnaissance machine type F.F. 33J, which was fitted with a 150 h.p. Benz engine, and which had already done extremely good work, had to be replaced by the F.F. 39C, which was fitted with a 200 h.p. Benz. Generally speaking the construction of the 39C was similar to that of the 33J, but on account of the larger engine, the dimensions were increased. Also the floats were of a different form (Fig. 19). The stagger was somewhat greater than that of the 33J, and various details were different so as to combine light weight with small resistance.