The Collins X-112 was an experimental two-seat ground-effect vehicle, designed by

Alexander Lippisch Alexander Martin Lippisch (November 2, 1894 – February 11, 1976) was a German aeronautical engineer, a pioneer of aerodynamics who made important contributions to the understanding of tailless aircraft, delta wings and the ground effect, and a ...

in the United States in the early 1960s to test his thick reverse

delta wing A delta wing is a wing shaped in the form of a triangle. It is named for its similarity in shape to the Greek uppercase letter delta (Δ). Although long studied, it did not find significant applications until the Jet Age, when it proved suitabl ...

concept.

Design and development

Lippisch's development of his Aerofoil Boat, a ground-effect vehicle for use over water, began whilst he was working in the aviation division of the Collins Radio Company in

Cedar Rapids, Iowa Cedar Rapids () is the second-largest city in Iowa, United States and is the county seat of Linn County, Iowa, Linn County. The city lies on both banks of the Cedar River (Iowa River), Cedar River, north of Iowa City, Iowa, Iowa City and north ...

, US. The Collins X-112 was built to test the concept. The Airfoil Boat was an inverse-delta aircraft, that is, it had a wing which was triangular in plan but with a straight, unswept

leading edge The leading edge of an airfoil surface such as a wing is its foremost edge and is therefore the part which first meets the oncoming air.Crane, Dale: ''Dictionary of Aeronautical Terms, third edition'', page 305. Aviation Supplies & Academics, ...

. Combined with strong anhedral, this layout produces stable flight in ground effect. Specifically, it is claimed that it is stable in pitch and also that it can fly in ground effect at altitudes up to about 50% of its span, allowing it to operate over rough water. This contrasts with the lower- aspect-ratio square wing of the ekranoplans, which leaves ground effect at only 10% of span, limiting them to the calmer waters of lakes and rivers. Its

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 ...

was conventional, with flat sides and rounded decking. The nose-mounted single engine was of very low power, only . Two open cockpits were arranged in tandem, both over the wing. Aft of the trailing edge

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

the bottom of the fuselage rose strongly to carry a tall, broad

fin A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fin ...

and

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 ...

. The X-112 had a T-tail, carrying elevators. Its thick

airfoil An airfoil (American English) or aerofoil (British English) is the cross-sectional shape of an object whose motion through a gas is capable of generating significant lift, such as a wing, a sail, or the blades of propeller, rotor, or turbine. ...

wings were low-mounted, each with a

tip Tip commonly refers to: * Tip (gambling) * Tip (gratuity) * Tip (law enforcement) * another term for Advice (opinion), Advice Tip or TIP may also refer to: Science and technology * Tank phone, a device allowing infantry to communicate with the oc ...

float or "pontoon", which in combination with the strong anhedral kept the fuselage well clear of the water surface. Each float carried a winglet fitted with an

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 ...

for

roll control Roll or Rolls may refer to: Movement about the longitudinal axis * Roll angle (or roll rotation), one of the 3 angular degrees of freedom of any stiff body (for example a vehicle), describing motion about the longitudinal axis ** Roll (aviation), ...

. A retractable water-rudder, fuselage-mounted at the point at which the lower fuselage rose upwards, provided directional control on the water surface. Tests made during 1963 began with the Airfoil Boat operated like any fast motor boat, planing on the surface. With speeds increased to around the X-112 rose clear of the surface as a ram-air

air cushion The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing for ...

or ground-effect vehicle. Solo free flights at up to were made; tests with two occupants were also conducted. "Entirely satisfactory" stability and control characteristics were reported under all these conditions. With the Airfoil Boat proved, the X-112's mission was completed, and Lippisch, suffering from cancer, left Collins Radio. He recovered sufficiently to design and build its successor, the fibreglass, more powerful X-113 with Rhein-Flugzeugbau GmbH in Germany.

Specifications

Sources

*"The aerodynamics of the unconventional air vehicles of A. Lippisch", Henry V. Borst and Associates, 1980 *US Patent 3190582 Ground Effect Aircraft with some X-112 characteristics rchive*"The Aerofoil Boat X-112", Collins Video (https://www.youtube.com/watch?v=wlIK-xViG_4 rchive

References

External links

* (, the embedded video is not available in this archived copy of the article). {{Lippisch aircraft Ground effect vehicles Low-wing aircraft Single-engined tractor aircraft Aircraft first flown in 1963 1960s United States experimental aircraft T-tail aircraft