The final Euler fighting triplane (Type 5) is seen here in its original form

The final Euler fighting triplane (Type 5) after the application of increased gap and deeper cabane.

The most successful of the Euler-Hromadnik triplanes was the Type 4.

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.)

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.)

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.

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.

The Dr.I series however was largely an experimental triplane fighter. The first Euler triplane, powered with 160 h.p. Oberursel U III, the designation was not official, neither is it completely certain.

The Euler Dr 1 apparently stayed at prototype stage, designed by Julius Hromadnik, the first being under test in the summer of 1917, competing with the Hansa-Brandenburg Dr.I and DFW Dr I. It was not accepted for service.