The LFG Roland D.IV, later redesignated LFG Roland Dr.I was a German single engine, single seat

triplane A triplane is a fixed-wing aircraft equipped with three vertically stacked wing planes. Tailplanes and canard (aeronautics), canard foreplanes are not normally included in this count, although they occasionally are. Design principles The trip ...

fighter flown in mid-1917. It produced no performance or operational advantages over existing types and only one was built.

Design and development

The D.IV was a single bay

with equally spaced, staggered wings; only the lowest had dihedral. The central plane was mounted at mid-

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 ...

and the others passed above and below the fuselage, supported by centre section struts. The wings were two spar structures and decreased in chord from top to bottom, so the interplane struts were not parallel but leant longitudinally apart. In plan the fabric covered wings were almost rectangular, apart from angled tips; their span decreased a little from top to bottom but all carried externally interconnected, short span

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. There was a small circular cut-out in the

trailing edge The trailing edge of an aerodynamic surface such as a wing is its rear edge, where the airflow separated by the leading edge meets.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 521. Aviation Supplies & Academics, 1997. ...

of the upper wing above the cockpit to enhance the pilot's view. The fuselage of the D.IV, like those of their earlier fighter designs, was a wooden

monocoque Monocoque ( ), also called structural skin, is a structural system in which loads are supported by an object's external skin, in a manner similar to an egg shell. The word ''monocoque'' is a French term for "single shell". First used for boats, ...

but LFG abandoned their earlier ''Wickelrumpfe'' (wrapped fuselage) approach, which used thin bands of

spruce A spruce is a tree of the genus ''Picea'' ( ), a genus of about 40 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal ecosystem, boreal (taiga) regions of the Northern hemisphere. ''Picea'' ...

veneer reinforced with fabric, in favour of a cheaper ''Klinkerrumpf'' ( clinker fuselage) which followed boat building practice with overlapping spruce strips over a light wooden internal framework. It was oval in cross-section, though the six cylinder, water-cooled upright inline Mercedes D.III was mounted with its cylinders and exhaust exposed above it, driving a two blade

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 ...

with a large spinner. The fuselage tapered behind the open cockpit, where an unswept straight edged, blunt angle tipped

tailplane A tailplane, also known as a horizontal stabilizer, is a small lift (force), lifting surface located on the tail (empennage) behind the main lifting surfaces of a fixed-wing aircraft as well as other non-fixed-wing aircraft such as helicopters ...

, mounted on top of the fuselage, carried separate, tapered

elevators An elevator (American English) or lift (English in the Commonwealth of Nations, Commonwealth English) is a machine that vertically transports people or freight between levels. They are typically powered by electric motors that drive tracti ...

. The vertical tail was rounded, with a

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium (usually air or water). On an airplane, the rudder is used primarily to counter adverse yaw ...

that extended below the tailplane to the keel. The conventional undercarriage had mainwheels on a single axle, supported by long V-struts to the lower fuselage, together with a short tailskid. The single prototype ordered by Idflieg was tested during the Summer of 1917 but was badly damaged at the end of September. LFG rebuilt it using a similar Klinkerrumf intended for a D.VI

biplane 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 ...

fighter and testing was soon resumed. It was decided that the Dr.I, as it was now known, showed no particular advantages over existing German fighters and development was abandoned.

Specifications

References

Bibliography

* {{Idflieg Dr-class designations Triplanes 1910s German fighter aircraft LFG Roland D.IV (Dr.I) Aircraft first flown in 1917