Junkers patent drawing from March 1944.

The F-106 Delta Dart, a development of the F-102 Delta Dagger, clearly shows the "wasp-waisted" shaping due to area rule considerations.

NASA Convair 990 with antishock bodies on the rear of the wings.

Oilflow visualization of flow separation without and with antishock bodies.

This F-5E Tiger II, the Shaped Sonic Boom Demonstraton, was modified by NASA applying the areal rule at the fuselage below the wing to decrease the shock by the wings and produce negative lift. Note that the wings still produce a shock due to compression lift, so the nose-cone is widened to produce an even stronger shock, which therefor travels faster.

To generate lift a supersonic airplane has to produce at least two shock waves: One over-pressure downwards wave, and one under-pressure upwards wave. Whitcomb’s area rule states that air displacement can be reused without generating additional shock waves. In this case the fuselage reuses some displacement of the wings.

The Whitcomb area rule (sometimes just called the area rule) is a design technique used to reduce an aircraft's drag at transonic and supersonic speeds, particularly between Mach 0.8 and 1.2. This is the operating speed range of the vast majority of all commercial and military fixed-wing aircraft today. Image File history File links Patent_932410_Seite_5. ... Image File history File links Patent_932410_Seite_5. ... For the Prussian/German landowning classes, see junker. The name Junkers (IPA: /ˈjunkeɺs/) is well known in connection with aircraft, which were produced under this name for the Luftwaffe during World War II. In particular the Ju 87 Stuka and Ju 52 Tante Ju were common symbols of the... Image File history File linksMetadata Download high-resolution version (2400x3180, 8362 KB) Eclipse program QF-106 aircraft in flight, view from tanker Eine QF-106 des Eclipse Programmes während der Fluges, von einem Tankflugzeug aus, Fotografiert Orginal NASA relase to the picture: Eclipse program QF-106 aircraft in flight... Image File history File linksMetadata Download high-resolution version (2400x3180, 8362 KB) Eclipse program QF-106 aircraft in flight, view from tanker Eine QF-106 des Eclipse Programmes während der Fluges, von einem Tankflugzeug aus, Fotografiert Orginal NASA relase to the picture: Eclipse program QF-106 aircraft in flight... The Convair F-106A Delta Dart was the primary all-weather interceptor aircraft for the US Air Force from the 1960s through the late 1970s. ... The Convair F-102 Delta Dagger fighter aircraft was part of the backbone of the United States air defenses in the late 1950s. ... Image File history File links Download high-resolution version (1148x898, 194 KB) Convair CV 990, NASA Image Source: http://www1. ... Image File history File links Download high-resolution version (1148x898, 194 KB) Convair CV 990, NASA Image Source: http://www1. ... NASA Convair 990 The Convair 990 Coronado was a jet airliner produced by the Convair division of General Dynamics, a stretched version of their earlier Convair 880 produced in response to a request from American Airlines. ... Image File history File links Antishock_Bodies_Visualization. ... Image File history File links Antishock_Bodies_Visualization. ... Image File history File links 55051main_EC03-0210-1_F5E_2. ... Image File history File links 55051main_EC03-0210-1_F5E_2. ... The F-5 Freedom Fighter (or Tiger II) is a fighter aircraft, designed and built by Northrop in the USA, beginning in 1962. ... In aerodynamics, compression lift refers to an aircraft that uses shock waves generated by its own supersonic flight to generate lift. ... Image File history File links To generate lift a supersonic airplane has to produce at least two shock waves: One over-pressure downwards wave, and one under-pressure upwards wave. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... An object falling through a gas or liquid experiences a force in direction opposite to its motion. ... Transonic is an aeronautics term referring to a range of velocities just below and above the speed of sound. ... It has been suggested that hypersonic be merged into this article or section. ... An F/A-18 Hornet breaking the sound barrier. ...

Even at high subsonic speeds, local supersonic flow can develop in areas where the flow accelerates around the aircraft body and wings due to Bernoulli's principle. The speed at which this occurs varies from aircraft to aircraft, and is known as critical mach. The resulting shock waves formed at these points of supersonic flow bleed away a considerable amount of power, which is experienced by the aircraft as a sudden and very powerful form of drag, called wave drag. In order to reduce the number and power of these shock waves, the aircraft's shape should change in cross-sectional area as smoothly as possible. The design implications for standard "tube and wing" aircraft are that the body narrows beside the wings. This leads to a "perfect" aerodynamic shape known as the Sears-Haack body, roughly shaped like a cigar but pointed at both ends. Bernoullis principle states that in an ideal fluid (low speed air is a good approximation), with no work being performed on the fluid, an increase in velocity occurs simultaneously with decrease in pressure or gravitational energy. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... Wave drag is an aerodynamics term that refers to a sudden and very powerful form of drag that appears on aircraft flying at high-subsonic speeds. ... The Sears-Haack body is, generally speaking, the body least susceptible to wave drag. ... Four cigars of different brands (from top: H. Upmann, Montecristo, Macanudo, Romeo y Julieta) An airtight cigar storage tube and a double guillotine-style cutter A cigar is a tightly rolled bundle of dried and fermented tobacco, one end of which is ignited so that its smoke may be drawn...

The area rule was first discovered by a team including Heinrich Hertel and Otto Frenzl working on a transonic wind tunnel at Junkers works in Germany between 1943 and 1945; it is used in a patent filed in 1944. The design concept was applied to a variety of German wartime aircraft, including a rather odd Messerschmitt project, but their complex double-boom design was never built even to the extent of a model. Several other researchers came close to developing a similar theory, notably Dietrich Küchemann who designed a tapered fighter that was dubbed the Küchemann Coke Bottle when it was discovered by US forces in 1946. In this case Küchemann arrived at the solution by studying airflow, notably spanwise flow, over a swept wing. Heinrich Hertel (November 16, 1902 - 1982) was a German aircraft designer. ... For the Prussian/German landowning classes, see junker. The name Junkers (IPA: /ˈjunkeɺs/) is well known in connection with aircraft, which were produced under this name for the Luftwaffe during World War II. In particular the Ju 87 Stuka and Ju 52 Tante Ju were common symbols of the... Year 1943 (MCMXLIII) was a common year starting on Friday (the link is to a full 1943 calendar). ... Year 1945 (MCMXLV) was a common year starting on Monday (the link is to a full 1945 calendar). ... Year 1944 (MCMXLIV) was a leap year starting on Saturday (the link is to a full 1944 calendar). ... Messerschmitt is a famous German aircraft manufacturer, known primarily for their World War II fighter aircraft, notably the Bf 109 and Me 262. ... Dr Dietrich Küchemann CBE FRS FRAeS (1911–1976) was a German aerodynamicist who made several important contributions to the advancement of high-speed flight. ...

Richard T. Whitcomb, after whom the rule is named, independently discovered this rule in 1952, while working at NACA. While using the new Eight-Foot High-Speed Tunnel, a wind tunnel with performance up to Mach 0.95 at NACA's Langley Research Center, he was surprised by the increase in drag due to shock wave formation. The shocks could be seen using Schlieren photography, but the reason they were being created at speeds far below the speed of sound, sometimes as low as Mach 0.70, remained something of a mystery. Richard T. Whitcomb (1921, Evanston, Illinois) is an aeronautical engineer who spent most of his career at the Langley Laboratory of the NACA and its successor organization, NASA. In the 1950s, Whitcomb proposed the Area Rule. The Area Rule states that two bodies having the same cross-sectional area distribution... 1952 (MCMLII) was a Leap year starting on Tuesday (link will take you to calendar). ... NACA official seal The National Advisory Committee for Aeronautics (NACA) was a U.S. federal agency founded on March 3, 1915 to undertake, promote, and institutionalize aeronautical research. ... NASA wind tunnel with the model of a plane A wind tunnel is a research tool developed to assist with studying the effects of air moving over or around solid objects. ... Langley Research Center NASA Langley 14 x 22 foot Subsonic Wind Tunnel. ... Schlieren photography is a visual process that is used to photograph the flow of air (or other compressible fluids) around objects. ...

In late 1951 the lab hosted a talk by Adolf Busemann, a world-famous German aerodynamicist who had moved to Langley after World War II. He talked about the difference in the behaviour of airflow at speeds approaching the supersonic, where it no longer behaved as an incompressible fluid. Whereas engineers were used to thinking of air flowing smoothly around the body of the aircraft, at high speeds it simply didn't have time to "get out of the way", and instead started to flow as if it were rigid pipes of flow, a concept Busemann referred to as "streampipes", as opposed to streamlines, and jokingly suggested that engineers had to consider themselves "pipefitters". Adolf Busemann at Langley Adolph Busemann (* 20 April 1901 in Lübeck, † 3 November 1986 in Boulder, Colorado) was an influential early pioneer in aerodynamics, specialising in supersonic airflows. ... Combatants Major Allied powers: United Kingdom France Soviet Union United States Republic of China and others Major Axis powers: Germany Italy Japan and others Commanders Winston Churchill Charles de Gaulle Joseph Stalin Franklin Roosevelt Chiang Kai-Shek Adolf Hitler Benito Mussolini Hideki Tojo Casualties Military dead: 17,000,000 Civilian... In fluid mechanics, an incompressible fluid is a fluid whose density (often represented by the Greek letter ρ) is constant: it is the same throughout the field and it does not change through time. ... In fluid dynamics, a streamline is the path that an imaginary massless particle would make if it followed the flow of a fluid in which it was embedded. ...

Several days later Whitcomb had a "Eureka" moment. The reason for the high drag was that the "pipes" of air were interfering with each other in three dimensions. You could not simply consider the air flowing over a 2D cross-section of the aircraft as you could in the past; now you also had to consider the air to the "sides" of the aircraft which would also interact with these streampipes. Whitcomb realized that the Sears-Haack shaping had to apply to the aircraft as a whole, rather than just the fuselage. That meant that the extra cross sectional area of the wings and tail had to be accounted for in the overall shaping, and that the fuselage should actually be narrowed where they meet to more closely match the ideal. Eureka (Eureka!, or Heureka; Greek (later ); IPA: (modern Greek), (ancient Greek, both former and later forms), Anglicised as ) is a famous exclamation attributed to Archimedes. ...

The area rule was immediately applied to a number of development efforts. One of the most famous was Whitcomb's personal work on the re-design of the F-102 Delta Dagger, which was demonstrating performance considerably worse than expected. By indenting the fuselage beside the wings, and (paradoxically) adding more volume to the rear of the plane, transonic drag was considerably reduced and the original Mach 1.2 design speeds were reached. The Convair F-102 Delta Dagger fighter aircraft was part of the backbone of the United States air defenses in the late 1950s. ...

Numerous designs of the era were likewise modified in this fashion, either by adding new fuel tanks or tail extensions to smooth out the profile. The Tupolev Tu-95 'Bear', a Soviet-era bomber, was modified by adding large bulged nacelles behind its four engines, instead of decreasing the cross section of the fuselage next to the wing root. It remains the highest speed propeller aircraft in the world. The Convair 990 used a similar solution, adding bumps called antishock bodies to the trailing edge of the upper wing. The 990 remains the fastest US airliner in history, cruising at up to 0.89 Mach. Designers at Armstrong-Whitworth took the concept a step further in their proposed M-Wing, in which the wing was first swept forward and then to the rear. This allowed the fuselage to be narrowed on either side of the root instead of just behind it, leading to a smoother fuselage that remained wider on average than one using a classic swept wing. The Tupolev Tu-95 (NATO reporting name Bear) is the most successful Tupolev strategic bomber and missile carrier from the times of the Soviet Union, still in service as of 2006 and expected to remain in service with the Russian Air Force until at least 2010 [1]. The Bear is... Motto: Пролетарии всех стран, соединяйтесь! (Transliterated: Proletarii vsekh stran, soedinyaytes!) Translation: Workers of the world, unite!) Anthem: The Internationale (1922-1944) Hymn of the Soviet Union (1944-1991) Capital (and largest city) Moscow Official languages None; Russian de facto Government Socialist Republic/Federation of Soviet Republics  - Last President Mikhail Gorbachev  - Last Premier Ivan Silayev... A bomber is a military aircraft designed to attack ground targets, primarily by dropping bombs. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... NASA Convair 990 The Convair 990 Coronado was a jet airliner produced by the Convair division of General Dynamics, a stretched version of their earlier Convair 880 produced in response to a request from American Airlines. ... An Airbus A340 airliner operated by Air Jamaica An airliner is a large fixed-wing aircraft with the primary function of transporting paying passengers. ... An F/A-18 Hornet breaking the sound barrier. ... Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. ...

One interesting outcome of the area rule is the current shaping of the Boeing 747's upper deck. The aircraft was originally designed to carry standard cargo containers in a two-wide, two-high stack on the main deck, which was considered a serious accident risk for the pilots if they were located in a cockpit at the front of the aircraft. They were instead moved above the deck in a small "pod", which was deliberately designed to be as small as possible given normal streamlining principles. It was later realized that the drag could be reduced much more by lengthening the pod, using it to reduce wave drag offsetting the tail surface's contribution. The new design was introduced on the 747-300, improving its cruise speed and lowering drag. The Boeing 747, commonly called a Jumbo Jet, is among the most recognizable jet airliners and is the largest passenger airliner in service. ...

Aircraft designed according to Whitcomb's area rule looked odd at the time they were first tested, (e.g. the Blackburn Buccaneer), and were dubbed "flying Coke bottles," but the area rule is effective and came to be an expected part of the appearance of any transonic vehicle. Later designs started with the area rule in mind, and came to look much more pleasing. Although the rule still applies, the visible fuselage "waisting" can only be seen on the B-1B Lancer and the Tupolev Tu-160 'Blackjack' — the same effect is now achieved by careful positioning of aircraft components, like the boosters and cargo bay of rockets, the jet engines in front (and not below) the wings of a Airbus A380, the jet engines behind (and not purely at the side) the fuselage of a Cessna Citation X , the canopy of the F-22 Raptor, and this image of the Airbus A380 in flight shows obvious area rule shaping at the wing root, but these modifications are practically invisible from any other angle. Aftershock bodies are likewise "invisible" today, serving double duty as flap actuators, which also visible in the A380 image above. The Blackburn Buccaneer was a British attack aircraft serving with the Royal Air Force and the Fleet Air Arm. ... The Boeing (formerly Rockwell International) B-1B Lancer is a long-range strategic bomber in service with the United States Air Force (USAF). ... A Tupolev Tu-160 in flight The Tupolev Tu-160 (NATO reporting name Blackjack) is a supersonic, variable-geometry heavy bomber designed by the Soviet Union. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... The Airbus A380 is a double-deck, four-engined airliner manufactured by EADS (Airbus S.A.S.) It first flew on April 27, 2005 from Toulouse in France. ... The Cessna Citation X is a medium-sized business jet aircraft designed to fly at high subsonic speeds. ... The Lockheed Martin F-22 Raptor is a stealth fighter aircraft. ... The Airbus A380 is a double-deck, four-engined airliner manufactured by EADS (Airbus S.A.S.) It first flew on April 27, 2005 from Toulouse in France. ...

See also

• Supersonic aerodynamics
• Sound barrier
• Mach number
• Sonic boom
• Shock wave
• Küchemann Carrots

This article is about the branch of Physics. ... U.S. Navy F/A-18 at transonic speed. ... An F/A-18 Hornet breaking the sound barrier. ... A sonic boom is the audible component of a shock wave in air. ... Introduction The shock wave is one of several different ways in which a gas in a supersonic flow can be compressed. ... Küchemann Carrots is a colloquial term used to refer to antishock bodies placed at the trailing edge of a subsonic aircrafts wings in order to reduce the drag it experiences as it enters the transonic flight regime. ...

External links

• German patent search system - look for Patent DE 932410 Filled March 21, 1944
• DGLR document
• Whitcomb, Richard T.: A Study of the Zero-Lift Drag-Rise Characteristics of Wing-Body Combinations Near the Speed of Sound. NACA Report 1273, 1956.
• The Whitcomb Area Rule: NACA Aerodynamics Research and Innovation
• NASA 2004:Overuse increases drag but still reduces boom heard on the ground
• See Image 4 for an extreme example: fuselage before wing
• Aerospaceweb.org: Area rule explained
• Aerospaceweb.org: Whitcomb Area Rule and Küchemann Carrots