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Topic: Supercritical wing


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In the News (Fri 31 Oct 14)

  
  X-29
On the forward-swept wing, ailerons remained unstalled at high angles of attack because the air over the forward swept wing tended to flow inward toward the root of the wing rather than outward toward the wing tip as on an aft-swept wing.
Phase 1 flights also demonstrated that the aeroelastic tailored wing did, in fact, prevent structural divergence of the wing within the flight envelope, and that the control laws and control surface effectiveness were adequate to provide artificial stability for this otherwise extremely unstable aircraft and provided good handling qualities for the pilots.
Wing trailing edge actuators controlling camber are mounted externally in streamlined fairings because of the thinness of the supercritical airfoil.
www.fas.org /man/dod-101/sys/ac/x-29.htm   (1960 words)

  
 Aerodynamics, Wings for All Speeds
As a general rule, a wing aft-sweep of less 30 degrees is required at subsonic speeds, and a sweep of 50 to 60 degrees is appropriate for supersonic cruise.
Wings with variable in-flight sweep have been proposed for a long time, sometimes they have also been developed (exclusively for fighter aircraft), but they pose challenging problems, such as the shift in the aerodynamic center, with consequences to the whole aircraft stability.
Wing thickness (or airfoil thickness) is strictly related to the drag characteristics at all speeds.
aerodyn.org /Wings   (908 words)

  
 Supercritical airfoil - Wikipedia, the free encyclopedia
Supercritical airfoils are characterized by their flattened upper surface, highly cambered (curved) aft section, and greater leading edge radius as compared to traditional airfoil shapes.
The supercritical wing is still the number one choice for high-speed subsonic and transonic aircraft from the Airbus A380 to the Boeing F-15 fighter.
Supercritical airfoils have four main benefits: they have a higher critical mach number, they develop shock waves further aft than traditional airfoils, they greatly reduce shock-induced boundary layer separation, and their geometry allows for more efficient wing design (e.g., a thicker wing and/or reduced wing sweep, both of which may allow for a lighter wing).
en.wikipedia.org /wiki/Supercritical_wing   (547 words)

  
 Concept to Reality   (Site not responding. Last check: 2007-10-26)
For example, if a supercritical wing of 17-percent thickness could be designed to have the cruise efficiency of a 12-percent-thick conventional wing, the internal fuel volume could be increased by about 40 percent and the amount of wing volume devoted to fuel could be increased by over 50 percent.
The industry-wide design approach to using supercritical wing technology was to increase the thickness ratio of the wing airfoil, reduce the wing sweep to reduce the structural weight, and increase the aspect ratio of the wing to reduce the drag due to lift.
The evolution of supercritical airfoil technology embodied in current jet transport aircraft is depicted in the accompanying sketch of typical airfoil shapes and camber distributions used by industry for conventional, intermediate, and aft-loaded airfoils.
oea.larc.nasa.gov /PAIS/Concept2Reality/supercritical.html   (3971 words)

  
 NASA - NASA Dryden Fact Sheet - F-8 Supercritical Wing
Compared to a conventional wing, the supercritical wing (SCW) is flatter on the top and rounder on the bottom with a downward curve at the trailing edge (see illustration).
The first flight of the supercritical wing at supersonic speeds was on May 26, 1971.
Flown as the SCW testbed by NASA from 1971 to 1973.
www.nasa.gov /centers/dryden/news/FactSheets/FS-044-DFRC.html   (681 words)

  
 Aeronautics - The Aerospace Age (1958 - Present)
For takeoff, landing, and low-speed cruise, the wing is perpendicular to the fuselage; at high speeds, the wing is pivoted to different oblique angles.
An aircraft using a joined wing would have its main wing swept upward and backward connected at the tips to the rearward wing which would be swept forward and downward, resembling the shape of a diamond.
The supercritical wing is designed to delay the point at which it reaches supersonic speeds, thus delaying the increased drag.
www.allstar.fiu.edu /aerojava/wings7.htm   (1764 words)

  
 Aerospaceweb.org | Ask Us - Supercritical Airfoils   (Site not responding. Last check: 2007-10-26)
The basic design approach behind these shapes is to flatten the upper surface of the airfoil to reduce flow acceleration and to use a highly cambered aft section to generate the majority of the lift.
The disadvantage of this approach is that aft-loaded wings shift the center of lift back which necessitates moving the wings forward.
To give some idea of the practical benefit of the supercritical airfoil, Air Force and NASA researchers under the auspices of the Transonic Aircraft Technology (TACT) program modified a basic F-111 bomber and replaced the existing NACA 64-210 wing airfoil with a supercritical shape of equal thickness.
www.aerospaceweb.org /question/airfoils/q0003.shtml   (843 words)

  
 Langley TACT Development
Wing sweep on the X-5 could be continuously varied from 20 deg to 60 deg through the use of a translating wing-pivot mechanism.
Subsequent tests of the isolated wing and horizontal tail in the Blowdown Tunnel revealed that the horizontal-tail design had an inadequate margin of safety for flutter at low supersonic speeds, and the geometry of the F-111 tail configuration was changed.
A high-lift section was used for low-speed landing conditions, and the wing was recontoured to a supercritical shape for transonic flight and adjusted to a symmetrical section for supersonic flight.
www.f-111.net /articles/Langley-TACT-Developmnt.htm   (8561 words)

  
 The Vought F8U-1(F-8A) Crusader
During takeoff or landing, the angle of incidence could be increased by seven degrees, which enabled the wing to retain a high-angle of attack during takeoff and landing, and yet enabled the fuselage to remain fairly level for better forward visibility.
The ailerons and the entire wing leading edge surfaces were interconnected and were automatically lowered to 25 degrees when the wing was raised to increase the camber and thus the lift.
When the wing was lowered after takeoff, all the surfaces returned to their normal in-flight positions, with the leading edge going to the position selected for the cruise droop.
www.plane-crazy.net /links/f8.htm   (2519 words)

  
 ON THE WING: A BUSINESS--CLASS JET
Starting with use of supercritical wing technology developed by NASA in the 1970s, Cessna has repeatedly called upon NASA's know-how and use of its test facilities.
On this latest venture into business-class jet aircraft building, a highly swept, second-generation supercritical wing was designed, capable of Mach.92 and supporting the aircraft to a maximum altitude of 51,000 feet.
Supercritical wings change the shape of the airflow by flattening the upper surface of the wing, which minimizes the effect of the shock wave.
www.sti.nasa.gov /tto/spinoff1998/t1.htm   (783 words)

  
 Aerospaceweb.org | Ask Us - Mach Trim and Boeing 757 / 767
Is the Boeing 757 wing a supercritical wing?
Yes, the Boeing 757 uses a supercritical airfoil, the Boeing TR-51 series to be exact.
Cp travel is usually associated with the wing airfoil section, but I believe that both aircraft use the same airfoils, or ones similar enough that their Cp movement should be similar.
www.aerospaceweb.org /question/dynamics/q0137.shtml   (549 words)

  
 AMST Prototypes: Boeing YC-14 and McDonnell Douglas YC-15   (Site not responding. Last check: 2007-10-26)
The Boeing Model 953 design for STOL performance was based on the use of a supercritical wing, developed by NASA from the wind-tunnel research of Dr. Richard Whitcomb, which provides highly efficient performance from the wing at high subsonic speeds.
To this wing Boeing added an advanced wing upper-surface blowing concept, mounting the twin turbofan engines forward and above the wing so that their efflux was exhausted over the wing (this location also gave the airplane a quieter noise footprint.).
With the wing's leading-edge flaps and Coanda-type trailing-edge flaps extended, the high-speed airflow from the engines tended to cling to the upper surface of the wing/flap system and was thus directed downward to provide powered lift.
www.theaviationzone.com /factsheets/amst.asp   (708 words)

  
 F-8 Supercritical Wing (SCW) in flight
The F-8 Supercritical Wing was a flight research project designed to test a new wing concept designed by Dr. Richard Whitcomb, chief of the Transonic Aerodynamics Branch, Langley Research Center, Hampton, Virginia.
Compared to a conventional wing, the supercritical wing (SCW) is flatter on the top and rounder on the bottom with a downward curve at the trailing edge.
The last flight of the Supercritical wing was on May 23, 1973, with Ron Gerdes at the controls.
www.dfrc.nasa.gov /Gallery/Movie/F-8SCW/HTML/EM-0085-01.html   (372 words)

  
 Modern Aircraft
To determine whether a supercritical aerofoil was actually feasible tests were performed by fitting an F-8U fighter with a supercritical aerofoil wing and then cruising in the transonic region.
However, when the data was presented in 1972 designers came up with the surprising conclusion that instead of using the supercritical wing to increase cruising speed it should instead be used to increase fuel economy at a speed of around Mach 0.8.
Furthermore the exact dimensions of the wing indicate that it is only 5.92% thick at the root whilst it is only 4.29% thick at the tip; this would make sense for a high speed aircraft where a thin wing is needed to achieve low drag.
www.bath.ac.uk /~en3gjh/aerofoil/modern_aircraft.htm   (927 words)

  
 The Airfoil Misconception in K-6 Textbooks
Because the air flowing above and below the wing must recombine at the trailing edge of the wing, and because the path along the upper surface is longer, the air on the upper surface must flow faster than the air below if both parts are to reach the trailing edge at the same time.
Wings create lift because they are curved on top and flat on the bottom.
Wings, rudders, propellors, oars; all these devices work by identical principles: they throw massive fluid one way, and are thrown the other way by action/reaction forces.
amasci.com /wing/airfoil.html   (7271 words)

  
 Partners in Freedom   (Site not responding. Last check: 2007-10-26)
The YC-15 was the first military transport to use supercritical wings, a major innovative technology conceived and developed through wind-tunnel research by Richard Whitcomb at Langley.
Whitcomb’s supercritical wings incorporate advanced airfoils that enhance the range, cruising speed, and fuel efficiency of aircraft by producing weaker upper-surface shock waves, thereby creating less drag and permitting higher efficiency.
The aerodynamic contribution of the winglets permits the C-17 to employ a shorter wing span while retaining the efficiency of a larger wing span.
oea.larc.nasa.gov /PAIS/Partners/C_17.html   (2742 words)

  
 Northrop B-2A Spirit
The length of the centerbody section was determined by the requirement that it had to be deep enough to accommodate the cockpit and the weapons bays, and this meant that it had to be a minimum length to avoid excessive drag at high subsonic speeds.
The brake-rudders are the primary means of yaw control, but because of the boundary layer over the wing the surfaces are ineffective until they have moved at least five degrees from their neutral positions.
The second supercritical section comprises the region from the inlet lip to the exhaust exist, where the flow is accelerated and recompressed once again.
home.att.net /~jbaugher2/newb2_1.html   (4814 words)

  
 Invent Now | Hall of Fame | Search | Inventor Profile
The solution, which subsequently came to be known as the "area rule," redirected the air over the wings through a more streamlined aircraft fuselage and eventually allowed for a supersonic Air Force.
Following the concept of the "area rule," Whitcomb designed a new aircraft wing that increased the range, speed and fuel efficiency of the jet.
This supercritical wing was successfully tested with the NASA Dryden TF-8A Crusader in 1971.
www.invent.org /hall_of_fame/1_1_6_detail.asp?vInventorID=199   (216 words)

  
 Richard Kline & Floyd Fogleman: Airfoil (US Patents 3,706,430 & 4,046,338)   (Site not responding. Last check: 2007-10-26)
As in the general case of airfoils that constitute aircraft wings, the relative air flow with respect to the airfoil is from the leading edge in direction generally parallel to the root section and rearwardly to the free trailing edge, and thence downstream in substantially the same general direction.
Although the upper wing surface and the under surface of the wedge portion are preferably slightly convex with respect to the generally linear leading edge, these surfaces for practical purposes may be considered planar.
The lateral edges of the wings converge toward the rear of the fuselage so that as viewed from the bottom, the composite area of the wings is of generally diamond configuration as illustrated in FIG.
www.rexresearch.com /klinfogl/klinfogl.htm   (9610 words)

  
 Boeing C-17 Globemaster III
McChord's 62nd Airlift Wing will receive 48 of the versatile airlifters, which will also be operated by McChord's reserve unit, the 446th Airlift Wing.
The C-17 incorporates many of the military jet transport standards — a high-set wing (swept 25 degrees), T-tail, rear cargo-loading assembly and heavy-duty retractable landing gear with fuselage blister fairings.
Each engine is rated at 40,440 pounds (180kN) of thrust and employ thrust reversers that direct the flow of air upward and forward to avoid ingestion of dust and debris.
www.theaviationzone.com /factsheets/c17.asp   (1685 words)

  
 Global Aircraft -- Question Board - Page 2
"Supercritical Wing" is a term used to describe a generation of wing designs which are flatter on the top, rounder on the bottom, and have a downward curve at the trailing edge.
The wing was designed to delay the formation of shock waves over the wing during transonic flight.
In other words, the wings were not being held together by some external wires like World War I aircraft had to have.
www.globalaircraft.org /qboard2.htm   (1798 words)

  
 GPN-2000-002001 - NASA F-8A Crusader Supercritical Wing Aircraft
The unique design of the Supercritical Wing reduces the effect of shock waves on the upper surface near Mach 1, which in turn reduces drag.
In this photograph a Vought F-8A Crusader is shown being used as a flying testbed for an experimental Supercritical Wing airfoil.
The smooth fairing of the fiberglass glove with the wing is illustrated in this view.
grin.hq.nasa.gov /ABSTRACTS/GPN-2000-002001.html   (95 words)

  
 NASA - F-111
The four dark bands on the right wing are the locations of pressure orifices used to measure surface pressures and shock locations on the MAW.
In the early 1980s the supercritical wing on the F-111A aircraft was replaced with a wing built by Boeing Aircraft Company System called a “mission adaptive wing” (MAW), and a joint NASA and Air Force program called Advanced Fighter Technology Integration (AFTI) was born.
Intense interest over the results coming from the NASA F-8 supercritical wing program spurred NASA and the Air Force to modify the General Dynamics-Convair F-111A to explore the application of supercritical wing technology to maneuverable military aircraft.
www.f-111.net /images/NASA/index.htm   (1161 words)

  
 YC-14 Advanced Medium STOL Transport (AMST)
In the 1950s, researchers explored employing the efflux of engines to augment wing lift using the jetflap concept to remove the limitations of conventional high-lift devices.
In particular, with the engines on top of the wing, they could be placed close to the centerline of the airplane without causing large aerodynamic inference with the fuselage.
After reviewing ongoing supercritical wing research at Langley led by Richard T. Whitcomb, they were impressed by the performance of a supercritical airfoil applied to a Navy T-2C aircraft in a research program by Langley.
www.globalsecurity.org /military/systems/aircraft/c-14.htm   (2457 words)

  
 Aeronautic Science and Wing Lift: what keep an airplane in the air?
The wing must deflect the horizontally-moving air downwards, as shown in the righthand diagram.
To determine whether an asymmetrical wing is REALLY set to zero angle of attack, we instead must inspect the trailing edge of the airfoil to see if it directs the air downwards more than the leading edge pulls the air upwards.
Note that the asymmetrical (cambered) wing at the top of the diagram has been adjusted to produce zero lifting force.
www.turnertoys.com /G1/aeroScience/default.htm   (660 words)

  
 TIME.com: The Upside-Down Wing -- Feb. 21, 1969 -- Page 1
The source of the trouble was the upper surface of the conventional wing, which has a convex curve to provide lift.* When the plane reaches about 80% of the speed of sound, however, the velocity of the air flowing over the upper side of the wing reaches the sonic barrier.
In his efforts to reduce turbulence, Whitcomb finally hit upon the design for what NASA now calls the "supercritical wing." To reduce the peak airflow speed and move the shock wave farther back on the wing, he drastically flattened the curvature of the upper wing surface.
To compensate for the loss of lift that resulted, he increased the curvature near the wing's trailing edge and put a concave contour on the underside.
www.time.com /time/magazine/article/0,9171,839005,00.html   (772 words)

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