Breakthrough Laminar Aircraft Demonstrator in Europe

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The Breakthrough Laminar Aircraft Demonstrator in Europe (BLADE) is an Airbus project within the European Clean Sky framework to flight-test experimental laminar-flow wing sections on an A340 from September 2017. [1]

Contents

Design

The left laminar flow wing section BLADE, ILA 2018, Schonefeld (1X7A5551).jpg
The left laminar flow wing section

Natural laminar flow is opposed to hybrid laminar flow artificially induced through hardware. It is difficult to industrialise a wing smooth enough to sustain the laminar flow in operation, due to having very low design and manufacturing tolerances, leading-edge retractable slats, and fasteners, that is aerodynamically robust enough, and can withstand surface deformations and dirt, de-icing fluid, and rain-droplet contamination.

The 9 m (30 ft) metallic outboard section with a carbon fiber reinforced plastic upper laminar flow surface is isolated from the rest of the wing and has two ailerons on each side. Its wing sweep is around 20° for a Mach 0.75 cruise, instead of 30° for a Mach 0.82–0.84 cruise. Laminar flow is expected along 50% of chord length instead of just aft of the leading edge, halving the wing friction drag, reducing the overall aircraft drag by 8% and saving up to 5% in fuel on an 800 nm (1,480 km) sector. [1]

Development

The A340 flight demonstrator ILA 2018, Schonefeld (1X7A5479).jpg
The A340 flight demonstrator

The demonstrator took off on 26 September, 2017. [2]

In April 2018, after 66 flight hours, drag reduction is better than expected at 10% and laminar flow is more stable than anticipated, including when the wing twists and flexes. Both wings with their carbon fibre upper sustainably generate the desired effect, while the carbon fibre left wing leading edge and metallic right wing leading edge have small differences in aerodynamic effects. The aerodynamic benefits could be sustained at Mach 0.78 up from Mach 0.75 and next-generation single-aisles could use from the late 2020s.

Tests will continue until 2019 and will include wing contamination and a fixed Krüger flap. [3]

Morphing flaps should be flight tested from May 2020. [4]

Related Research Articles

Wing Surface used for flight, for example by insects, birds, bats and airplanes

A wing is a type of fin that produces lift while moving through air or some other fluid. Accordingly, wings have streamlined cross-sections that are subject to aerodynamic forces and act as airfoils. A wing's aerodynamic efficiency is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift.

Airbus A330 Wide-body twin-engine jet airliner

The Airbus A330 is a wide-body aircraft developed and produced by Airbus. Airbus conceived several derivatives of the A300, its first airliner in the mid-1970s. Then the company began development on the A330 twinjet in parallel with the A340 quadjet and launched both designs with their first orders in June 1987. The A330-300, the first variant, took its maiden flight in November 1992 and entered service with Air Inter in January 1994. The slightly shorter A330-200 variant followed in 1998.

Vortex generator Aerodynamic device

A vortex generator (VG) is an aerodynamic device, consisting of a small vane usually attached to a lifting surface or a rotor blade of a wind turbine. VGs may also be attached to some part of an aerodynamic vehicle such as an aircraft fuselage or a car. When the airfoil or the body is in motion relative to the air, the VG creates a vortex, which, by removing some part of the slow-moving boundary layer in contact with the airfoil surface, delays local flow separation and aerodynamic stalling, thereby improving the effectiveness of wings and control surfaces, such as flaps, elevators, ailerons, and rudders.

Swept wing Plane wing that angles backwards or forwards

A swept wing is a wing that angles either backward or occasionally forward from its root rather than in a straight sideways direction.

Transonic

Transonic flow is air flowing around an object at a speed that generates regions of both subsonic and supersonic airflow around that object. The exact range of speeds depends on the object's critical Mach number, but transonic flow is seen at flight speeds close to the speed of sound, typically between Mach 0.8 and 1.2.

Airfoil Cross-sectional shape of a wing, blade of a propeller, rotor, or turbine, or sail

An airfoil or aerofoil 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.

Wingtip device Aircraft component fixed to the end of the wings to improve performance

Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft's drag by partial recovery of the tip vortex energy. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without greatly increasing the wingspan. Extending the span would lower lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan.

Rolls-Royce Trent Family of turbofan aircraft engines

The Rolls-Royce Trent is a family of high-bypass turbofans produced by Rolls-Royce. It continues the three spool architecture of the RB211 with a maximum thrust ranging from 61,900 to 97,000 lbf . Launched as the RB-211-524L in June 1988, the prototype first ran in August 1990. Its first variant is the Trent 700 introduced on the Airbus A330 in March 1995, then the Trent 800 for the Boeing 777 (1996), the Trent 500 for the A340 (2002), the Trent 900 for the A380 (2007), the Trent 1000 for the Boeing 787 (2011), the Trent XWB for the A350 (2015), and the Trent 7000 for the A330neo (2018). It has also marine and industrial variants.

Flap (aeronautics) Anti-stalling high-lift device on aircraft

A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed.

Supercritical airfoil Airfoil designed primarily to delay the onset of wave drag in the transonic speed range

A supercritical airfoil is an airfoil designed primarily to delay the onset of wave drag in the transonic speed range.

An adaptive compliant wing is a wing which is flexible enough for aspects of its shape to be changed in flight. Flexible wings have a number of benefits. Conventional flight control mechanisms operate using hinges, resulting in disruptions to the airflow, vortices, and in some cases, separation of the airflow. These effects contribute to the drag of the aircraft, resulting in less efficiency and higher fuel costs. Flexible aerofoils can manipulate aerodynamic forces with less disruptions to the flow, resulting in less aerodynamic drag and improved fuel economy.

Formation flying

Formation flying is the flight of multiple objects in coordination.

BERP rotor

The BERP rotor blade design was developed under the British Experimental Rotor Programme. The initial BERP rotor blades were developed in the late 1970s to mid-1980s as a joint venture programme between Westland Helicopters and the Royal Aircraft Establishment (RAE), with Professor Martin Lowson as a co-patentee. The goal was to increase the helicopters lifting-capability and maximum speed using new designs and materials.

Leading-edge slat Device increasing the lift of the wing at low speed (take-off and landing)

Slats are aerodynamic surfaces on the leading edge of the wings of fixed-wing aircraft which, when deployed, allow the wing to operate at a higher angle of attack. A higher coefficient of lift is produced as a result of angle of attack and speed, so by deploying slats an aircraft can fly at slower speeds, or take off and land in shorter distances. They are usually used while landing or performing maneuvers which take the aircraft close to a stall, but are usually retracted in normal flight to minimize drag. They decrease stall speed.

Krueger flap

Krueger flaps, or Krüger flaps, are lift enhancement devices that may be fitted to the leading edge of an aircraft wing. Unlike slats or droop flaps, the main wing upper surface and its nose is not changed. Instead, a portion of the lower wing is rotated out in front of the main wing leading edge. Several modern aircraft use this design between the fuselage and closest engine, where the wing is thickest. Outboard of the engine, slats are used on the leading edge. The Boeing 727 also used a mix of inboard Krueger flaps and outboard slats, although it had no engine between them. Most early jet airliners, such as the Boeing 707 and Boeing 747, used Krueger flaps only.

Clean Sky

The Clean Sky Joint Undertaking (CSJU) is a public-private partnership between the European Commission and the European aeronautics industry that coordinates and funds research activities to deliver significantly quieter and more environmentally friendly aircraft. The CSJU manages the Clean Sky Programme (CS) and the Clean Sky 2 Programme (CS2), making it Europe’s foremost aeronautical research body.

Fuel economy in aircraft Aircraft fuel efficiency

The fuel economy in aircraft is the measure of the transport energy efficiency of aircraft. Efficiency is increased with better aerodynamics and by reducing weight, and with improved engine BSFC and propulsive efficiency or TSFC. Endurance and range can be maximized with the optimum airspeed, and economy is better at optimum altitudes, usually higher. An airline efficiency depends on its fleet fuel burn, seating density, air cargo and passenger load factor, while operational procedures like maintenance and routing can save fuel.

The term "smart structures" is commonly used for structures which have the ability to adapt to environmental conditions according to the design requirements. As a rule, the adjustments are designed and performed in order to increase the efficiency or safety of the structure. Combining "smart structures" with the "sophistication" achieved in materials science, information technology, measurement science, sensors, actuators, signal processing, nanotechnology, cybernetics, artificial intelligence, and biomimetics, one can talk about Smart Intelligent Structures. In other words, structures which are able to sense their environment, self-diagnose their condition and adapt in such a way so as to make the design more useful and efficient.

Aerion AS2

The Aerion AS2 was a proposed supersonic business jet that was being developed by Aerion Corporation. In May 2014, it was announced that the Aerion AS2 would be part of a larger Aerion SBJ redesign, which aimed for release after a seven-year developmental period. Aerion partnered with Airbus in September the same year. In December 2017, Airbus was replaced by Lockheed Martin. Its General Electric Affinity engine was unveiled in October 2018. In February 2019, Boeing replaced Lockheed Martin. Development stopped when Aerion ceased operations in May 2021.

References

  1. 1 2 Michael Gubisch (4 Sep 2017). "Airbus readies laminar-winged A340 for test flights". Flightglobal.
  2. "Airbus' "BLADE" laminar flow wing demonstrator makes first flight" (Press release). Airbus. 26 September 2017.
  3. Michael Gubisch (26 Apr 2018). "ILA: Airbus encouraged by laminar-winged A340 trial". Flightglobal.
  4. Thierry Dubois (Jan 8, 2018). "Researchers Combine Actuators, Smart Materials To Morph Wing". Aviation Week & Space Technology.

Further reading