![X-18 tilting its wing bw](https://upload.wikimedia.org/wikipedia/commons/6/6c/X-18_tilting_its_wing_bw.jpg)
A tiltwing
aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines ...
features a wing that is horizontal for conventional forward flight and rotates up for vertical takeoff and landing. It is similar to the
tiltrotor
A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a trans ...
design where only the
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 ...
and engine rotate. Tiltwing aircraft are typically fully capable of
VTOL
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
operations.
[Markman, Steve and Bill Holder. "Tilt-Wing VTOL Systems". ''Straight Up: A History of Vertical Flight''. Schiffer Publishing, 2000. .]
![VTOL DiscLoad-LiftEfficiency](https://upload.wikimedia.org/wikipedia/commons/e/e5/VTOL_DiscLoad-LiftEfficiency.svg)
The tiltwing design offers certain advantages in vertical flight relative to a tiltrotor. Because the slipstream from the rotor strikes the wing on its smallest dimension, the tiltwing is able to apply more of its engine power to lifting the aircraft. For comparison, the
V-22 Osprey
The Bell Boeing V-22 Osprey is an American multi-mission, tiltrotor military aircraft with both vertical takeoff and landing (VTOL) and short takeoff and landing (STOL) capabilities. It is designed to combine the functionality of a convention ...
tiltrotor loses about 10% of its thrust to interference from the wings.
Another advantage of tiltwing aircraft is the ease of transition between VTOL and horizontal flight modes. A tiltrotor must first fly forwards like a helicopter, building airspeed until wing lift is sufficient to allow the nacelles to begin tilting down. As a note, the MV-22 Osprey's stall speed in airplane mode is . Conversely, a tiltwing aircraft can begin the transition from helicopter to airplane at zero forward airspeed. Because of this, the
Canadair CL-84 Dynavert
The Canadair CL-84 "Dynavert", designated by the Canadian Forces as the CX-131, was a V/STOL turbine tiltwing monoplane designed and manufactured by Canadair between 1964 and 1972. Only four of these experimental aircraft were built with three ...
was able to take off vertically, then accelerate from zero airspeed to in 8 seconds.
However, the fixed wing of a tiltrotor aircraft offers a superior
angle of attack
In fluid dynamics, angle of attack (AOA, α, or \alpha) is the angle between a reference line on a body (often the chord line of an airfoil) and the vector representing the relative motion between the body and the fluid through which it is m ...
—thus more lift and a shorter takeoff roll—when performing
STOL
A short takeoff and landing (STOL) aircraft is a conventional fixed-wing aircraft that has short runway requirements for takeoff and landing. Many STOL-designed aircraft also feature various arrangements for use on airstrips with harsh conditio ...
/
STOVL
A short take-off and vertical landing aircraft (STOVL aircraft) is a fixed-wing aircraft that is able to take off from a short runway (or take off vertically if it does not have a heavy payload) and land vertically (i.e. with no runway). The ...
operations.
The main drawbacks of tiltwing aircraft are susceptibility to wind gusts in VTOL mode and lower hover efficiency. The wing tilted vertically represents a large surface area for crosswinds to push against.
[ Tiltrotors generally have better hover efficiency than tiltwings, but less than helicopters. This is due to the difference in rotor disk loading.
As of 2014, ]NASA
The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research.
NASA was established in 1958, succeeding t ...
is testing a diesel-electric hybrid 10-foot 10-rotor tiltwing called the GL-10 Greased Lightning, with most propellers folding during horizontal flight.[Warwick, Graham. "Distributed power" '']Aviation Week & Space Technology
''Aviation Week & Space Technology'', often abbreviated ''Aviation Week'' or ''AW&ST'', is the flagship magazine of the Aviation Week Network. The weekly magazine is available in print and online, reporting on the aerospace, defense and aviati ...
'' page 31, 25 August 2014. Accessed: 26 August 2014.
List of tiltwing aircraft
Tiltwing designs with rocket, jet, or propeller propulsion
* Airbus A³ Vahana
The Airbus Vahana (Sanskrit: ''Vāhana'', or Vahanam literally means "vehicle") was an electric-powered eight-propeller VTOL personal air vehicle prototype financed by A³ (pronounced "A-cubed"), by Airbus and Airbus Urban Mobility. The Vahan ...
(2018)
* Canadair CL-84 Dynavert
The Canadair CL-84 "Dynavert", designated by the Canadian Forces as the CX-131, was a V/STOL turbine tiltwing monoplane designed and manufactured by Canadair between 1964 and 1972. Only four of these experimental aircraft were built with three ...
(1965)
* Hiller X-18
The Hiller X-18 was an experimental cargo transport aircraft designed to be the first testbed for tiltwing and V/STOL (vertical/short takeoff and landing) technology.
Development
Design work started in 1955 in aviation, 1955 by Stanley Hille ...
(1959)
* Kaman K-16B
The Kaman K-16B was an experimental vertical-takeoff-and-landing aircraft that was constructed by Kaman Aircraft for the United States Navy in 1959 to evaluate the tiltwing concept. Converted from a Grumman Goose amphibian, the K-16B underwent e ...
(1959)
* LTV XC-142
The Ling-Temco-Vought (LTV) XC-142 was a tri-service tiltwing experimental aircraft designed to investigate the operational suitability of vertical/short takeoff and landing (V/STOL) transports. An XC-142A first flew conventionally on 29 Septemb ...
(1964)
* NASA GL-10 Greased Lightning
The GL-10 Greased Lightning is a hybrid diesel-electric tiltwing unmanned aircraft.
Development
The wing has eight electric motor driven propellers while the horizontal stabilizer has two. In the future full-scale version, power will be genera ...
(2014)
* Vertol VZ-2
The Vertol VZ-2 (or Model 76) was a research aircraft built in the United States in 1957 to investigate the tiltwing approach to vertical take-off and landing.
Design and development
The aircraft had a fuselage of tubular framework (originally ...
(1957)
* Weserflug P.1003 (1938)
See also
* Thrust vectoring
Thrust vectoring, also known as thrust vector control (TVC), is the ability of an aircraft, rocket, or other vehicle to manipulate the direction of the thrust from its engine(s) or motor(s) to control the attitude or angular velocity of the v ...
* Tailsitter
A tail-sitter, or tailsitter, is a type of VTOL aircraft that takes off and lands on its empennage, tail, then tilts horizontally for forward flight.
Originating in the 1920s with the inventor Nikola Tesla, the first aircraft to adopt a tail-sitt ...
* Tiltrotor
A tiltrotor is an aircraft which generates lift and propulsion by way of one or more powered rotors (sometimes called ''proprotors'') mounted on rotating shafts or nacelles usually at the ends of a fixed wing. Almost all tiltrotors use a trans ...
* Tiltjet
A tiltjet is an aircraft propulsion configuration that was historically tested for proposed VTOL, Vertical Take-off and Landing (VTOL)-capable fighters.
The tiltjet arrangement is, in concept, broadly similar to that of the tiltrotor; whereas a t ...
* Coleopter
A coleopter is a type of VTOL aircraft design that uses a ducted fan as the primary fuselage of the entire aircraft. Generally they appear to be a large barrel-like extension at the rear, with a small cockpit area suspended above it. Coleopters ...
* VTOL
A vertical take-off and landing (VTOL) aircraft is one that can take off and land vertically without relying on a runway. This classification can include a variety of types of aircraft including helicopters as well as thrust-vectoring fixed-win ...
References
Aircraft configurations
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