O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
D.F.W. Dr I
Photographed at Adlershof in January 1918, at the first D types Competition, was this triplane variant of the D I. which stands behind it. Engine, 160 h.p. Mercedes D III. Armament, twin Spandau machine-guns.
W.Green, G.Swanborough The Complete Book of Fighters
DFW T 34-II Germany
Evolved in parallel with the T 34-I biplane, the T 34-II (sometimes referred to erroneously as the Dr I) single-seat triplane employed a similar fuselage, power plant (Mercedes D III), armament (twin synchronised LMG 08/15s) and undercarriage to those of the biplane fighter. Both top and bottom wings were one-piece units mounted well clear of the fuselage and sufficiently staggered to obviate the need for a pilot-vision cut-out. The central wing carried generous ailerons and possessed broad tips, and the tail surfaces were similar to those of the definitive T 34-I, but incorporating a somewhat larger rudder. Together with the T 34-I, the T 34-II triplane was submitted for evaluation in the first D-type contest, but was excluded from the competition flight testing for reasons of poor pilot visibility and "unsuitable design”. No data on the T 34-II are available.
J.Herris DFW Aircraft of WWI (A Centennial Perspective on Great War Airplanes 29)
Designed in 1917 during the height of Germany's 'Triplane Craze', the DFW T 34-II, was a triplane fighter developed in parallel with the T 34-I biplane fighter prototype. The triplane prototype shared everything but the wing cellule with its biplane counterpart.
Like its biplane sibling, the T 34-II was powered by a 160 hp Mercedes D.III engine and was armed with two machine-guns. Both the biplane and triplane were submitted to the First Fighter Competition but were excluded from flight testing due to poor field of view for the pilot. In addition, the triplane was condemned for "unsuitable design", although details are not available.
However, a look at the photographs gives rise to the suspicion that the "unsuitable design" comment might be related to the T 34-II's excessive number of struts. Unlike the biplane prototype, the triplane had a two-bay wing cellule, which created extra weight and drag and seems unnecessary for such a small aircraft. At least, if the aircraft's structural design was efficient, there would have been no need for the two-bay cellule. Moreover, N-struts were used in profusion, which seems redundant.
Furthermore, to achieve sufficient gap between the wings to avoid aerodynamic interference with the airflow between the wings, the bottom set of wings was suspended below the fuselage on struts. And these struts made little use of the strength of the separate undercarriage struts.
The Sopwith triplane came out well before DFW's triplane fighter arrived on the scene, and the Fokker triplane also appeared earlier, so the DFW design team certainly had examples of successful triplane fighters for inspiration. Certainly neither featured the complex array of heavy, drag-producing struts featured by the DFW Dr.I. All in all the excessive number of struts makes a poor impression and justified the "unsuitable design" comment on its own. Was there even more wrong with the design than this?
No performance or dimensional data is available.