The most successful of the Euler-Hromadnik triplanes was the Type 4.
Euler Type 4
Piston
Euler Type 2
Confused erroneously with the DII, the Euler Type 2 biplane appeared in April 1918.
Euler Quadruplane
The Euler Vierdecker (Quadruplane) was a unique experimental quadriplane version fighter of 1918.
The designation of quadruplane (vierdecker) was something of a misnomer, for the top surfaces were, in fact, full-span ailerons, although the machine was later modified and normal ailerons fitted.
Euler Quadruplane
Engine: 100 h.p. Oberursel U I.
Wing area, 46.175 sq.m. (498.7 sq.ft.).
Empty weight: 883.5 kg. (1,844 lb.)
Loaded weight: 1,383.5 kg. (3,044 lb.)
Euler Dr.4
The Euler Dr 4 triplane emerged from the Euler-Werke in 1916 intended for training duties and featuring side-by-side seating. The designation was not official as it was not accepted for service.
Designed by Julius Hromadnik, it was powered by a 220 h.p. Mercedes D IV with reduction gears.
Engine: Mercedes D IV, 220 h.p.
Span: 10.0 m. (32 ft. 9 3/4 in.)
Length: 8.0 m. (26 ft. 3 in.)
Height: 3.1 m. (10 ft. 2 in.)
Wing area: 37.5 sq.m. (405 sq.ft.)
Euler Dr.III
A further experimental triplane, a development of Dr 2 fitted with 100 h.p. Oberursel U I engine.
Designed by Julius Hromadnik, the first being under test in the summer of 1917, the designation was not official since it was not accepted for service.
In its initial form, the D.III was, in fact, the Type 3 triplane rebuilt.
Euler Dr 2 / Type 3
Another experimental triplane powered with 160 h.p. Mercedes D III engine, the designation was not official.
The private-venture Type 3 triplane was the second Euler-Werke fighter of this configuration. Designed by Julius Hromadnik, it was not accepted for service.
Euler D
A fighter aircraft circa 1917 with a 160 hp Mercedes engine.
Euler Gelber Hund / Einsitzer
An experimental single-seat pusher design powered with 160 h.p. Mercedes D III engine. Known as the “Gelber Hund” (yellow hound), this single-seat pusher was the first Euler-Werke fighting scout.
The Euler “Gelber Hund” of 1915 featured a fixed forward-firing machine gun in the extreme nose of the fuselage pod.
Euler D.I / Euler D.II
After seeing the success of the French Nieuport 11 at the front, German designer August Euler set about to create a German aircraft based on the Nieuport 17 design. The Euler D.I single-seat fighter first flew in December 1916. It was powered by an 80 hp engine with the Euler patented machine gun on the front.
Two prototypes were recorded as being in service at the front in October 1916, and the German government ordered 50 in the same month. A further 50 were ordered in early 1917, but this order was largely transferred over to the D.I’s successor, the Euler D.II. About 75 were built. The D.I saw very little combat service with the German Empire, being largely used as a fighter trainer for the remainder of the war and retired around 1920.
The Euler D.II single-seat fighter successor to the Euler D.I was essentially a re-engined Euler D.I, the airframe being virtually unchanged and the power plant being a 100 hp Oberusel U I seven cylinder rotary.
Thirty D.II fighters were ordered by the German air force in March 1917, however due to slow production these were not delivered until December 1917. As a result, the D.II was relegated to the role of a trainer aircraft for the rest of the war and retired in 1918.
Euler D.I
Engine: 1 × Oberursel U.O, 60 kW (80 hp)
Wingspan: 8.10 m (26 ft 6⅞ in)
Length: 5.80 m (19 ft 0¼ in)
Height: 2.66 m (8 ft 8¾ in)
Wing area: 13.00 m² (139.93 ft²)
Empty weight: 380 kg (838 lb)
Loaded weight: 600 kg (1,323 lb)
Maximum speed: 140 km/h (87 mph)
Time to 2,000 m: 12.5 minutes
Crew: One
Armament: 1 x engine-mounted 7.92-mm machine gun
Euler D I
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.)
Empty weight: 380 kg. (836 lb.)
Loaded weight: 600 kg. (1,320 lb.).
Climb to 2,000 m: (6,560 ft.): 12.5 min.
Euler D.II
Engine: 1 × Oberursel U.I, 75 kW (100 hp)
Wingspan: 7.47 m (24 ft 6 in)
Length: 5.94m (19 ft 5⅞ in)
Height: 2.75 m (9 ft 0 in)
Empty weight: 380 kg (838 lb)
Loaded weight: 615 kg (1,356 lb)
Maximum speed: 145 km/h (90 mph)
Time to 2,000 m: 9.5 minutes
Endurance: 1.5 hours
Armament: 1 x engine-mounted 7.92mm machine gun
Crew: One
Euler-Voisin
In October 1908 August Euler founded the Euler-Werke in Frankfurt and managed to negotiate a license agreement with the Voisin brothers. In 1909 he created a factory at Griesheim Airport and started large scale aircraft production. The first few machines built were similar to Voisins, but Euler was not pleased with the original design and soon started to modify the construction, for example by lightening it, redesigning the landing gear and introducing ailerons.
Euler qualified for German pilot’s licence No. 1 on December 31st, 1909. Prince Heinrich of Prussia took his pilot’s certificate on an extensively modified example of the type. At least 30 other Germans learned to fly on this aircraft.
