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

Euler D I
   Provided as a Nieuport copy at the request of the German authorities, only comparatively few Euler D Is were built, and they were used for training. Type Tested December 1916. Engine, 80 or 100 h.p. Oberursel U O or U I rotary. Span, 8.1 m. (26 ft. 7 in.). Length, 7.12 m. (23 ft. 4 3/8 in.). Height, 2.66 m. (8 ft. 8 3/4 in.). Weights: Empty, 380 kg. (836 lb.). Loaded, 600 kg. (1,320 lb.). Climb, 2,000 m. (6,560 ft.) in 12.5 min.


Euler D II
   A development of D I, with parallel-chord wings having single spars. Type Tested December 1916. Only one example built. Engine, 100 h.p. Oberursel U I rotary. Span, 7.47 m. (24 ft. 6 1/8 in.). Length, 5.94 m. (19 ft. 5 7/8 in.). Height, 2.75 m. (9 ft. 0 1/4 in.). Weights: Empty, 380 kg. (836 lb.). Loaded, 615 kg. (1,353 lb.). Speed, 145 km.hr. (90.625 m.p.h.). Climb, 2,000 m. (6,560 ft.) 9.5 min. Duration, 1 1/2 hr.


Euler D
   Obviously a 160 h.p. Mercedes D III development of the Euler D II, but the D III designation has not been confirmed. No details.

W.Green, G.Swanborough The Complete Book of Fighters

EULER D I Germany
  
   The success at the front of the Nieuport 11 prompted the German authorities to request several manufacturers to design aircraft based on the French fighter, that produced by the Euler-Werke as the company’s D I probably adhering most closely to the original. Powered by an 80 hp Oberursel U O seven-cylinder rotary and mounting a single 7,92-mm machine gun, the DI prototype was flown in the autumn of 1916, and an initial series of 50 was ordered in October of that year, despite the fact that type testing at Adlershof was not to be completed until January 1917. Two Euler D Is (presumably prototypes) were recorded as being at the front at the end of October 1916, but the production aircraft was to be employed primarily as a fighter trainer. A further 50 were ordered with the completion of the Adlershof trials, but part of this order was later transferred to the D II (which see).

Max speed, 87 mph (140 km/h).
Time to 6,560 ft (2 000 m), 12.5 min.
Empty weight, 838 lb (380 kg).
Loaded weight, 1,323 lb (600 kg).
Span, 26 ft 6 7/8 in (8,10 m).
Length, 19 ft 0 1/4 in (5,80 m).
Height, 8 ft 8 3/4 in (2,66 m).
Wing area, 139.93 sq ft (13,00 m2).


EULER D II Germany

   The Euler D II was essentially a re-engined D I, the airframe being virtually unchanged and the power plant being a 100 hp Oberursel U I seven-cylinder rotary. A batch of 30 DII fighters was ordered in March 1917, but owing to tardiness on the part of the Euler-Werke in producing these, deliveries did not commence until the following December and, in consequence, the DII was relegated to the Jagdstaffelschulen with which it served until the end of hostilities.

Max speed 90 mph (145 km/h).
Time to 6,560 ft (2 000 m), 9.5 min.
Endurance, 1.5 hrs.
Empty weight, 838 lb (380 kg).
Loaded weight, 1,356 lb (615 kg).
Span, 24 ft 6 in (7,47m).
Length, 19 ft 5 7/8 in (5,94 m).
Height, 9 ft 0 in (2,75m).


EULER DOPPELDECKER (TYPE 1) Germany

   In April 1918, the Inspektion dei Fliegertruppen (Idflieg) reported that the Mercedes D III-powered triplane fighter (Type 3) had been rebuilt as a biplane and that altitude test flying was imminent. Official evaluation continued throughout May, during the course of which the I-type interplane struts were replaced by V-type struts and the inverted V-type struts of the cabane gave place to paired individual struts on each side. Testing appears to have been inconclusive, the prototype eventually being returned to the Euler-Werke. No specification is available.


EULER DOPPELDECKER (TYPE 2) Germany

   An extremely compact fighter biplane powered by the 160 hp Siemens und Halske Sh III counter-rotating engine driving a four-bladed propeller was flown for the first time in April 1918 by the Euler-Werke. This aircraft (which has been confused with the Euler DII) was a parallel-chord equi-span single-bay biplane and was reputed to possess an exceptional performance. It was scheduled to participate in the second D-type contest in May, but did not appear, and its subsequent testing was reportedly restricted. No specification is available.