The Albatros D.XI was a German single-seat fighter

sesquiplane A biplane is a fixed-wing aircraft with two main wings stacked one above the other. The first powered, controlled aeroplane to fly, the Wright Flyer, used a biplane wing arrangement, as did many aircraft in the early years of aviation. While a ...

first flown in February 1918. It was the first Albatros fighter to use a

rotary engine The rotary engine is an early type of internal combustion engine, usually designed with an odd number of cylinders per row in a radial configuration. The engine's crankshaft remained stationary in operation, while the entire crankcase and its ...

, in the form of the 120 kW (160 hp)

Siemens-Halske Sh.III The Siemens-Halske Sh.III was an 11-cylinder, air-cooled counter rotary engine developed in Germany during World War I. The engine was a development of the earlier 9-cylinder Siemens-Halske Sh.I. Design The Siemens-Halske Sh.III was an 11-cyli ...

, and also featured a new wing construction with diagonal struts from the

fuselage The fuselage (; from the French language, French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds Aircrew, crew, passengers, or cargo. In single-engine aircraft, it will usually contain an Aircraft engine, engine as wel ...

replacing traditional wire bracing.

Design & development

The wings had unequal spans with the upper planes having greater span than the lower ones, and were braced by I-struts with an aerofoil cross-section, additional rigidity being provided by twinned diagonal struts from the base of these to the top of the fuselage, located where the "landing wires" of a normal wire-braced biplane would be. The use of a rotary engine necessitated a large-diameter

propeller A propeller (often called a screw if on a ship or an airscrew if on an aircraft) is a device with a rotating hub and radiating blades that are set at a pitch to form a helical spiral which, when rotated, exerts linear thrust upon a working flu ...

and a correspondingly tall

undercarriage Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include: *The landing gear of an aircraft. *The ch ...

. The D.XI was armed with the same twin 7.92 mm (.312 in) Spandau LMG 08/15 machine guns employed on other Albatros fighters. Two prototypes were built, the first having balanced, parallel-chord

aileron An aileron (French for "little wing" or "fin") is a hinged flight control surface usually forming part of the trailing edge of each wing of a fixed-wing aircraft. Ailerons are used in pairs to control the aircraft in roll (or movement aroun ...

s and a four-blade propeller; and the second with inversely tapered, unbalanced ailerons and a two-blade propeller. The D.XI was not put into production.

Specifications (D.XI)

References

*
Das Virtuelle Luftfahrtmuseum
{{Idflieg fighter designations Single-engined tractor aircraft Sesquiplanes 1910s German fighter aircraft D.11 Aircraft first flown in 1918