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 foreplanes are not normally included in this count, although they occasionally are. Design principles The triplane arrangement may ...

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 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 ...

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

fuselage The fuselage (; from the French ''fuselé'' "spindle-shaped") is an aircraft's main body section. It holds crew, passengers, or cargo. In single-engine aircraft, it will usually contain an engine as well, although in some amphibious aircraft t ...

and the others passed above and below the fuselage, supported by centre section struts. The wings were two

spar SPAR, originally DESPAR, styled as DE SPAR, is a Dutch multinational that provides branding, supplies and support services for independently owned and operated food retail stores. It was founded in the Netherlands in 1932, by Adriaan van Well, ...

structures and decreased in chord from top to bottom, so the

interplane strut In aeronautics, bracing comprises additional structural members which stiffen the functional airframe to give it rigidity and strength under load. Bracing may be applied both internally and externally, and may take the form of strut, which act in ...

s 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 around ...

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 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

veneer Veneer may refer to: Materials * Veneer (dentistry), a cosmetic treatment for teeth * Masonry veneer, a thin facing layer of brick * Stone veneer, a thin facing layer of stone * Wood veneer, a thin facing layer of wood Arts and entertainment * ' ...

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 A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an infin ...

, water-cooled upright inline Mercedes D.III was mounted with its cylinders and exhaust exposed above it, driving a two blade

propeller A propeller (colloquially 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 ...

with a large

spinner Technology *Spinner (aeronautics), the aerodynamic cone at the hub of an aircraft propeller * Spinner (cell culture), laboratory equipment for cultivating plant or mammalian cells * Spinner (computing), a graphical widget in a GUI * Spinner (MIT Med ...

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

tailplane A tailplane, also known as a horizontal stabiliser, is a small 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 and gyroplane ...

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

elevators An elevator or lift is a cable-assisted, hydraulic cylinder-assisted, or roller-track assisted machine that vertically transports people or freight between floors, levels, or decks of a building, vessel, or other structure. They are ...

. The vertical tail was rounded, with a

rudder A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, aircraft, or other vehicle that moves through a fluid medium (generally aircraft, air or watercraft, water). On an aircraft the rudder is used primarily to ...

that extended below the tailplane to the keel. The

conventional undercarriage Conventional landing gear, or tailwheel-type landing gear, is an aircraft undercarriage consisting of two main wheels forward of the center of gravity and a small wheel or skid to support the tail.Crane, Dale: ''Dictionary of Aeronautical Term ...

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