Albatros D.IX was a German

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

 prototype single-seat fighter

Fighter aircraft

A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 built in early 1918. It differed from previous marks by using a simplified fuselage

Fuselage

The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

 with a flat bottom and slab sides. The wings and tail

Empennage

The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...

 were similar to those of the Albatros D.VII

Albatros D.VII

The Albatros D.VII was a German prototype single-seat fighter biplane flown in August 1917. It was powered by a water-cooled Benz Bz.IIIb V8 engine developing 145 kW and armed with two 7.92 mm machine guns...

. Power was provided by a 130 kW (180 hp) Mercedes D.III

Mercedes D.III

The Mercedes D.III, or F1466 as it was known internally, was a six-cylinder, liquid cooled inline aircraft engine built by Daimler and used on a wide variety of German aircraft during World War I. The initial versions were introduced in 1914 at 160 hp, but a series of changes improved this to...

a engine. The D.IX was armed with twin synchronised 7.92 mm (.312 in) LMG 08/15 machine gun

Machine gun

A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....

s.

The prototype exhibited disappointing performance and the project was discontinued.