The Blériot VI "Libellule" ("Dragonfly"), was built in 1907 and was one of the series of experimental aircraft built by Louis Blériot which eventually led to the Blériot XI aircraft in which he made the first flight across the English Channel .
125-522: Abandoning the canard layout of the Blériot V , Blériot and his chief engineer Louis Peyret next built a tandem wing configuration aircraft, possibly influenced by the Langley Aerodrome . In its initial form the aircraft had two pairs of identical wings rigged with pronounced dihedral mounted on the lower longerons at each end of the wooden box-girder fuselage, with small tip -mounted elevators on
250-479: A horizontal stabilizer , whether stability is achieved statically or artificially (fly-by-wire). Being placed ahead of the centre of gravity, a canard foreplane acts directly to reduce longitudinal static stability (stability in pitch). The first aeroplane to achieve controlled, powered flight, the Wright Flyer , was conceived as a control-canard but in effect was also an unstable lifting canard. At that time
375-451: A badly-placed foreplane can cause severe problems. By bringing the foreplane close to the wing and just above it in a close-coupled arrangement, the interactions can be made beneficial, actually helping to solve other problems too. For example, at high angles of attack (and therefore typically at low speeds) the canard surface directs airflow downward over the wing, reducing turbulence which results in reduced drag and increased lift. Typically
500-512: A canard foreplane and rear-mounted pusher propeller. The C 1 was a failure. First flown in 1927, the experimental Focke-Wulf F 19 "Ente" (duck) was more successful. Two examples were built and one of them continued flying until 1931. Immediately before and during World War II, several experimental canard fighters were flown, including the Ambrosini SS.4 , Curtiss-Wright XP-55 Ascender and Kyūshū J7W1 Shinden . These were attempts at using
625-493: A cockpit air-data camera and tape recorder for mission analysis. "Red Baron" and a SKa 24D 600 mm LOROP camera pods were usually carried on the fuselage pylons. The centreline fuel tank was converted for a short period of time to a camera pod with two Recon/Optical CA-200 1676 mm cameras. In addition to the reconnaissance equipment, the SH 37 could also use all weapons for the AJ 37. For
750-407: A conventional aft-tail which sometimes generates negative lift that must be counteracted by extra lift on the main wing. As the canard lift adds to the overall lift capability of the aircraft, this may appear to favour the canard layout. In particular, at takeoff the wing is most heavily loaded and where a conventional tail exerts a downforce worsening the load, a canard exerts an upward force relieving
875-426: A flight of 150 m (490 ft). During these flights Blériot made various modifications: he locked the wingtip ailerons and installed a sliding seat, so that he could maintain longitudinal trim by shifting the aircraft's centre of gravity , and extended the vertical tail surface. On 6 August he managed to reach an altitude of 12 m (39 ft), but one of the blades of the propeller worked loose, resulting in
1000-543: A foreplane would tend to destabilise an aeroplane but expected it to be a better control surface, in addition to being visible to the pilot in flight. They believed it impossible to provide both control and stability in a single design, and opted for control. Many pioneers initially followed the Wrights' lead. For example, the Santos-Dumont 14-bis aeroplane of 1906 had no "tail", but a box kite -like set of control surfaces in
1125-438: A fully variable nozzle. During 1964, construction of the first prototype aircraft commenced; on 8 February 1967, the first of an eventual seven prototypes conducted its maiden flight , which had occurred as per the established development schedule. This first flight, which lasted for 43 minutes, was flown by Erik Dahlström, Saab's chief test pilot, who reported the prototype to have been easy to handle throughout. Writing at
1250-479: A heavy landing which damaged the aircraft. He then fitted a 50 hp (37 kW) V-16 Antoinette engine. Tests on the 17 September showed a startling improvement in performance, with the aircraft quickly reaching an altitude of 25 m (82 ft), when the engine suddenly cut out and the aircraft went into a spiralling nosedive. Blériot later said that his immediate thought was that he was finished: in desperation he climbed out of his seat and threw himself towards
1375-456: A low-flying McDonnell Douglas F-4 Phantom II within a single scan and possessed a high level of resistance to interference from ECM. Saab and Honeywell co-developed an automatic digital flight control system for the JA 37 Viggen, which has been claimed to be the first such system in a production aircraft. To assist low altitude flight, a Honeywell radar altimeter with transmitter and receiver in
SECTION 10
#17328586399171500-530: A military-technology agreement. In what was known as the " 37-annex ", Sweden was allowed access to advanced U.S. aeronautical technology that made it possible to design and produce the Viggen much faster and more cheaply than would otherwise have been possible. According to research by Nils Bruzelius at the Swedish National Defence College , the reason for this officially unexplained U.S. support
1625-585: A minimum of 450 flight hours performed on an initial mixture of the Saab 105 , the Lansen, and finally the Viggen itself; dedicated Viggen simulators were also used, the latter of which was seen as a decisive factor in the ease of conversion to the type. In October 1973, Skaraborg Wing was reportedly close to achieving full operational effectiveness; by May 1974, the Swedish Air Force had two operational squadrons using
1750-597: A more capable and newer version of the Sidewinder missile than employed on earlier Viggen variants. Following the evaluation of several alternative cannons, including the British ADEN cannon , the American M61 Vulcan , and French DEFA cannon , an Oerlikon KCA 30mm cannon was selected for the JA 37. The KCA was carried, along with 126 rounds of ammunition, in a conformal pod under the fuselage. The firing rate of
1875-406: A multifunction display. In July 1971, the first production AJ 37 Viggen was delivered to the Swedish Air Force. The Skaraborg Wing (F 7) became the first wing to receive deliveries of both the single-seat AJ 37 attack model and the twin-seat SK 37 training model of the Viggen, where upon the type began to replace their existing Lansen aircraft. Conversion training to pilot the Viggen involved
2000-476: A navigator/copilot, facilitating handling in tactical situations where, among other things, high speeds and short decision times determined whether attacks would be successful or not, a system not surpassed until the introduction of the Panavia Tornado into operational service in 1981. Development work begun during the early 1950s to develop a successor to the Saab 32 Lansen in the attack role, as well as to
2125-448: A negative trimming force which makes the wing work harder, a canard pushes up so the wing works less hard. This actually reduces the net drag, resulting in negative trim drag. The use of landing flaps on the main wing causes a large trim change, which must be compensated for. The Saab Viggen has flaps on its canard surface which may be deployed simultaneously with the main flaps. The Beech Starship uses variable-sweep foreplanes to trim
2250-411: A new generation of electronics being adopted, and a revised armament configuration employed; the principal externally visible changes from most earlier variants were a taller tailfin and the underfuselage gunpack arrangement. The JA 37, in addition to its principal aerial combat mission, also retained a secondary ground-attack capability, and was better suited to low-level operations. In November 1977,
2375-530: A new generation of military canard designs. The Dassault Rafale multirole fighter first flew in 1986, followed by the Saab Gripen (first to enter service) in 1988, and the Eurofighter Typhoon in 1994. These three types and related design studies are sometimes referred to as the euro-canards or eurocanards . The Chinese Chengdu J-10 appeared in 1998. Like any wing surface, a canard contributes to
2500-594: A number of types derived from the popular Dassault Mirage delta-winged jet fighter. These included variants of the French Dassault Mirage III , Israeli IAI Kfir and South African Atlas Cheetah . The close-coupled canard delta remains a popular configuration for combat aircraft. The Viggen also inspired the American Burt Rutan to create a two-seater homebuilt canard delta design, accordingly named VariViggen and flown in 1972. Rutan then abandoned
2625-410: A propeller located ahead of the canard (increasing the lift slope of the canard) has a strong destabilising effect. A canard foreplane may be used to trim an aeroplane in pitch, just as a tail plane can. The trimming force in pitch is also a lifting force, and the greater it is, the greater the associated induced drag , known as trim drag . However, where a conventional tail typically pushed down with
SECTION 20
#17328586399172750-412: A reference to the aircraft's canard configuration, as "canard" is French for duck. Vigg is also åskvigg , or "thunderbolt" (thunder wedge), stemming from the thunderstones of Nordic folklore , called "åskviggar", said to come from the lightning strikes of Norse god Thor when he hunted giants with his war hammer , Mjölnir . The Viggen was initially developed as an intended replacement for
2875-483: A sole pre-production JA 37 model, to test the control systems, engine, avionics, and armaments respectively. In June 1974, the first of these prototypes conducted its maiden flight; later that year, an initial order for 30 JA 37s was issued by the Swedish government. The JA 37 Viggen featured various changes from its predecessor, including revisions to the design of the airframe, the use of the more powerful RM8B powerplant,
3000-404: A staggered second canopy for an instructor, was delivered to the Swedish Air Force. On 21 May 1973, the first prototype of SF 37 Viggen, a tactical reconnaissance variant featuring a modified nose to accommodate seven sensors, conducted its first flight. While other variants entered production during the 1960s, Saab continued the development of the more capable all-weather interceptor version of
3125-518: A substantial upgrade. In 1999, a new tactical liquid-crystal display (LCD) system derived from the Saab JAS 39 Gripen, which replaced the CRT-based AP-12 system, began flight tests with the Swedish Air Force. On the twin-seat SK 37 trainer, the rear cockpit used by the instructor is only fitted with conventional instrumentation and lacks a HUD, computer controls and other features. The ejection seat
3250-423: A supersonic delta wing design which gains lift in both transonic flight (such as for supercruise ) and also in low speed flight (such as take offs and landings). In the close-coupled delta wing canard, the foreplane is located just above and forward of the wing. The vortices generated by a delta-shaped foreplane flow back past the main wing and interact with its own vortices. Because these are critical for lift,
3375-425: A tailless delta design, such as in the Viggen, is that the elevons, which replace more conventional control surfaces, operate with a small effective moment arm ; their use adds substantial weight to the aircraft at takeoff and landing. Hinged leading edge surfaces can help counteract this, but an even more effective tool is the canard. The canard surfaces were positioned behind the inlets and placed slightly higher than
3500-421: A tandem arrangement. The design requirements imposed by the large anti-ship missiles employed upon the Viggen necessitated that both the undercarriage and vertical stabilizer be quite tall. To accommodate this, and to allow the main landing gear to be stowed outside of the wing root, the undercarriage legs shortened during retraction. The vertical stabilizer could also be folded via an actuator in order that
3625-408: A thrust reverser to use during landings and land manoeuvres, which, combined with the aircraft having flight capabilities approaching a limited STOL-like performance, enabled operations from 500 m airstrips with minimal support. The thrust reverser could be pre-selected in the air to engage when the nose-wheel strut was compressed after touchdown via a pneumatic trigger. The requirements from
3750-406: A very high reliability level for the generation of avionics systems involved. The displays in the original cockpit were all of the traditional analogue/mechanical type with the exception of an electronic head-up display (HUD), which Saab has claimed makes the Viggen easier to fly, especially at low altitudes during air-to-ground strike missions. Unusually for a 1970s fighter, the JA 37 variant of
3875-481: Is 72.1 kN dry and 125.0 kN with afterburner. Owing to the increased length and weight of the RM8B engine over its predecessor, the airframe of the JA 37 was stretched in order to accommodate it. Onboard electrical power was provided by a 60 kVA generator. In the event of an in-flight engine failure, emergency power was provided by an automatically deploying ram air turbine (RAT), capable of generating 6 kVA. In
Blériot VI - Misplaced Pages Continue
4000-453: Is a high aspect ratio canard with higher lift coefficient (the wing loading of the canard is between 1.6 and 2 times the wing one) and a canard airfoil whose lift coefficient slope is non-linear (nearly flat) between 14° and 24°. Another stabilisation parameter is the power effect. In case of canard pusher propeller : "the power-induced flow clean up of the wing trailing edge" increases the wing lift coefficient slope (see above). Conversely,
4125-418: Is automated, including the removal of the canopy; in the event of a malfunction, a reserve trigger can be activated. A combined parachute and seat harness is used, which features a barometric interlock to appropriately release the occupant and harness from the seat during the ejection sequence, a manual override handle is also provided for this function. There were dedicated warning caption panels each side of
4250-528: Is used primarily for pitch control during maneuvering. A pure control-canard operates only as a control surface and is nominally at zero angle of attack and carrying no load in normal flight. Modern combat aircraft of canard configuration typically have a control-canard driven by a computerized flight control system . Canards with little or no loading (i.e. control-canards) may be used to intentionally destabilize some combat aircraft in order to make them more manoeuvrable. The electronic flight control system uses
4375-408: Is varied in flight by swinging the foreplanes forward to increase their effectiveness and so trim out the nose-down pitching effect caused by the wing flaps when deployed. A moustache is a small, high aspect ratio foreplane which is deployed for low-speed flight in order to improve handling at high angles of attack such as during takeoff and landing. It is retracted at high speed in order to avoid
4500-455: The Eurofighter Typhoon , Dassault Rafale , Saab JAS 39 Gripen and the IAI Kfir , but principally for the purposes of providing agility during flight rather than for its STOL capabilities. Further aerodynamic refinements during the later stage of development included the addition of dog-tooth patterns upon the main wing to generate vortices , allowing for the elimination of blown flaps from
4625-514: The McDonnell Douglas X-36 research prototype. The Chengdu J-20 Fifth-generation fighter uses canards in the belief that they offer the optimal balance of stealth vs. aerodynamics. Some question whether this compromises its stealth characteristics. Saab Viggen The Saab 37 Viggen ( The Tufted Duck , ambiguous with The Thunderbolt ) is a single-seat, single-engine multirole combat aircraft designed and produced by
4750-657: The North American XB-70 Valkyrie and the Soviet equivalent Sukhoi T-4 flying in prototype form. But the stability and control problems encountered prevented widespread adoption. In 1963 the Swedish company Saab patented a delta-winged design which overcame the earlier problems, in what has become known as the close-coupled canard. It was built as the Saab 37 Viggen and in 1967 became the first modern canard aircraft to enter production. The success of this aircraft spurred many designers, and canard surfaces sprouted on
4875-555: The OMAC Laser 300 , Avtek 400 and Beech Starship . Static canard designs can have complex interactions in airflow between the canard and the main wing, leading to issues with stability and behaviour in the stall. This limits their applicability. The development of fly-by-wire and artificial stability towards the end of the century opened the way for computerized controls to begin turning these complex effects from stability concerns into maneuverability advantages. This approach produced
5000-473: The Paris Air Show . On 23 February 1971, the first production aircraft, an AJ37 model, conducted its first flight. In July 1971, the first production aircraft was delivered to the Swedish Air Force. As the initial AJ 37 Viggen was being introduced to service, further variants of the Viggen proceeded to complete development and enter production. In 1972, the first SK 37, an operational trainer variant with
5125-412: The Saab 32 Lansen in the attack role and later the Saab 35 Draken as a fighter. In 1955, as Saab's prototype Draken, the most aerodynamically advanced fighter in the world at that point, performed its first flight, the Swedish Air Force was already forming a series of requirements for the next generation of combat aircraft; due to the challenging nature of these requirements, a lengthy development time
Blériot VI - Misplaced Pages Continue
5250-528: The Saab 35 Draken as a fighter. Saab's design team opted for a relatively radical delta wing configuration, as well as to produce the aircraft as an integrated weapon system that operated in conjunction with Sweden's STRIL -6 national electronic air defense system. It was also designed to be operated from runways as short as 500 meters. Work was aided by the " 37-annex " under which Sweden could access advanced U.S. aeronautical technology to accelerate both design and production. The aircraft's aerodynamic design
5375-506: The Voisin brothers : also among the spectators was Blériot's wife Alice, who had come to watch one of her husband's flights for the first time. Esnault Pelterie paced out the length of the flight, measuring it at 184 m (604 ft). This made it the longest flight achieved in France that year to date, and although the flight had not been officially witnessed, Blériot was awarded a special medal by
5500-1208: The wave drag penalty of a canard design. It was first seen on the Dassault Milan and later on the Tupolev Tu-144 . NASA has also investigated a one-piece slewed equivalent called the conformably stowable canard, where as the surface is stowed one side sweeps backwards and the other forwards. The Rockwell B-1 Lancer has small canard vanes or fins on either side of the forward fuselage that form part of an active damping system that reduces aerodynamic buffeting during high-speed, low altitude flight. Such buffeting would otherwise cause crew fatigue and reduce airframe life during prolonged flights. Canard aircraft can potentially have poor stealth characteristics because they present large angular surfaces that tend to reflect radar signals forwards. The Eurofighter Typhoon uses software control of its canards in order to reduce its effective radar cross section . Canards have nevertheless been incorporated in some later stealth aircraft studies such as an early mock-up of Lockheed Martin's Joint Advanced Strike Technology (JAST) contender and
5625-549: The Aero Club de France for the feat. General characteristics Canard (aeronautics) In aeronautics , a canard is a wing configuration in which a small forewing or foreplane is placed forward of the main wing of a fixed-wing aircraft or a weapon. The term "canard" may be used to describe the aircraft itself, the wing configuration , or the foreplane. Canard wings are also extensively used in guided missiles and smart bombs . The term "canard" arose from
5750-596: The CK 37 proved to be more reliable than predicted. On later variants of the Viggen, from the JA37 onwards, it was decided to adopt a newer and more powerful Singer-Kearfott SKC-2037 digital central processor, license-manufactured and further developed by Saab as the CD 107. The computing techniques and concepts, such as distributed computing , went beyond use of the Viggen, in addition to civil-orientated derivatives, it directly contributed to
5875-636: The Ericsson PS 46/A radar which was capable of guiding the medium-range semi-active radar homing RB 71 Skyflash air-to-air missiles. Both the RB 71 and the PS 46/A radar were designed to provide the Viggen with a look-down/shoot-down capability and to engage targets at beyond visual range distances. The JA 37 could carry up to two RB 71s on the inner wing pylons; in a typical air defense loadout, these would typically have been combined with four RB 24J air-to-air missiles,
6000-466: The JA 37 fighter-interceptor model, the PS 37 radar was replaced by the more capable Ericsson PS 46 X-band pulse-doppler radar , which had an all-weather look-down/shoot-down capability reportedly in excess of 50 kilometers and continuous-wave illumination for the Skyflash missiles as well as the ability to track two targets while scanning . According to Ericsson, it had a 50 per cent chance of spotting
6125-565: The Medway engine was cancelled due to the intended launch aircraft, the de Havilland Trident , being downsized during development. In place of the Medway, Saab chose to adopt a licence-production version of the American Pratt & Whitney JT8D engine, the Volvo RM8 , instead. The RM8 was heavily redesigned, using new materials to accommodate flight at Mach-2 speeds, a Swedish-built afterburner, and
6250-516: The Swedish Air Force dictated Mach 2 capability at high altitude and Mach 1 at low altitude. At the same time, short-field take-off and landing performance was also required. Since the Viggen was developed initially as an attack aircraft instead of an interceptor (the Saab 35 Draken fulfilled this role), some emphasis was given to low fuel consumption at high subsonic speeds at low level for good range. With turbofan engines just emerging and indicating better fuel economy for cruise than turbojet engines,
6375-444: The Swedish Air Force in the late 1950s. Bas 60 revolved around force dispersal of aircraft across many wartime air bases, including road runways acting as backup runways. Utilizing partially destroyed runways was another factor that motivated STOL capability. Bas 60 was developed into Bas 90 in the 1970s and 1980s, and included short runways only 800 meters in length. Enabling such operations imposed several critical demands upon
SECTION 50
#17328586399176500-433: The Swedish Air Force, in which it had been envisioned that 800 or more Viggens would be produced, which was in turn intended to allow all other combat aircraft then in service with the Swedish Air Force to be replaced with this single type. However, a combination of inflation and other factors eventually reduced the total number of aircraft manufactured to 329. By 1980, up to 149 JA 37 Viggens were projected to be built, and
6625-510: The Swedish Air Force, its only operator; by this point, it had been replaced by the newer and more advanced Saab JAS 39 Gripen . Viggen is the definite form of the Swedish word vigg , which has two meanings. According to Saab, the aircraft's name alluded to both. The first meaning refers to the Swedish name for the tufted duck , a small diving duck common in Sweden. In this sense, it serves as
6750-494: The Swedish aircraft manufacturer Saab . It was the first canard -equipped aircraft to be produced in quantity and the first to carry an airborne digital central computer with integrated circuits for its avionics, arguably making it the most modern/advanced combat aircraft in Europe at the time of introduction. The digital central computer was the first of its kind in the world, automating and taking over tasks previously requiring
6875-418: The Swedish government gave its approval for the development of Aircraft System 37 , which would ultimately become the Viggen. By 1962, all elements for the project either existed or were close to fully developed; these included the aircraft itself, the powerplant, ejector seat, armaments, reconnaissance systems, ground servicing equipment, and training equipment such as simulators. In February 1962, approval of
7000-417: The Viggen along with a third squadron in the final process of achieving that status. By 1974, the safety and reliability levels of the Viggen were reportedly above expectations, despite the overall complexity and relative newness of the aircraft. In practice, one of the most significant issues encountered with the Viggen during low-level flight, as extensively performed during a typical attack mission profile,
7125-448: The Viggen ceased and the final aircraft was delivered. In May 1991, a SEK 300-million program to upgrade 11 AJ37, SF37 and SH37 Viggens to a common multirole variant, designated AJS37, was announced. Amongst the changes involved, interchangeable armaments and sensor payloads were implemented in addition to the adoption of new mission planning and threat analysis computer systems. The onboard ECM systems were also improved. Specifically,
7250-456: The Viggen featured three multi-purpose cathode-ray tube (CRT) display screens were fitted within the cockpit, in a system called AP-12, developed by Saab and Ericsson. These displays would be used to display processed radar information, computer-generated maps, flight and weapons data, along with steering cues during precision landings. Between 1989 and 1992, the AP-12 display system was subject to
7375-514: The Viggen had the first version of the RM8A engine with uprated internal components from the JT8D that it was based on. Thrust was 65.6 kN dry and 115.6 kN with afterburner. For the JA 37, the RM8A was developed into the RM8B, achieved by adding a third low-pressure compressor stage over the preceding model, increasing the turbine inlet temperature and fuel diffusion within the combustion chamber. Thrust
7500-523: The Wright brothers believed that instability was a requirement to make an aeroplane controllable. They did not know how to make a tailplane unstable, so they chose a canard control surface for this reason. Nevertheless, a canard stabiliser may be added to an otherwise unstable design to obtain overall static pitch stability. To achieve this stability, the change in canard lift coefficient with angle of attack (lift coefficient slope) should be less than that for
7625-509: The Wrights, experimented with both fore and aft planes on the same aircraft, now known as the three surface configuration. After 1911, few canard types would be produced for many decades. In 1914 W.E. Evans commented that "the Canard type model has practically received its death-blow so far as scientific models are concerned." Experiments continued sporadically for several decades. In 1917, de Bruyère constructed his C 1 biplane fighter, having
SECTION 60
#17328586399177750-486: The ability to make short landings at low angles of attack (to avoid damaging improvised runways). The aircraft was also designed from the beginning to be easy to repair and service, even for personnel without much training. One radical requirement of the proposed aircraft was the ability for it to be operated from relatively short runways only 500 meters long; this was part of the Bas 60 air base system that had been introduced by
7875-500: The aerodynamic configuration was radical: it combined an aft-mounted double delta wing with a small, high-set canard foreplane, equipped with powered trailing flaps mounted ahead of and slightly above the main wing; this would be judged to be the best means to satisfy the conflicting demands for STOL performance, supersonic speed, low turbulence sensitivity at low level flight, and efficient lift for subsonic flight. Canard aircraft have since become common in fighter aircraft, notably with
8000-430: The aircraft could be stored in smaller hangars, hardened aircraft shelters , and underground hangars , the latter of which were employed by the Swedish military to limit the damage of preemptive attacks. The six tanks in the fuselage and wings held approximately 5,000 litres of fuel with an additional 1,500 litres in an external drop tank. The specific fuel consumption was only 0.63 for cruise speeds (fuel consumption
8125-510: The aircraft failed to lift off. Blériot then enlarged the wings slightly, and on 11 July a short successful flight of around 25–30 metres (84–100 ft) was made, reaching an altitude of around 2 m (7 ft). Because some onlookers were in the way Blériot then shut off the engine and landed. Although the achievement was marred by slight damage to the undercarriage, this was Blériot's first truly successful flight. Further successful flights took place that month, and by 25 July he had managed
8250-423: The aircraft's longitudinal equilibrium, static and dynamic stability characteristics. The Wright Brothers began experimenting with the foreplane configuration around 1900. Their first kite included a front surface for pitch control and they adopted this configuration for their first Flyer . They were suspicious of the aft tail because Otto Lilienthal had been killed in a glider with one. The Wrights realised that
8375-456: The aircraft, the JA 37. In 1970, Sweden's air defenses had been closely inspected and it was determined that the prospective JA 37 Viggen was highly suited to the role. In 1972, the Swedish government authorized the development of the fighter-interceptor variant to proceed, which was followed by several major contracts for the JA 37's further development. A total of five prototypes would be produced, four of which being modified AJ 37s and one being
8500-571: The appearance of the Santos-Dumont 14-bis of 1906, which was said to be reminiscent of a duck ( canard in French) with its neck stretched out in flight. Despite the use of a canard surface on the first powered aeroplane, the Wright Flyer of 1903, canard designs were not built in quantity until the appearance of the Saab Viggen jet fighter in 1967. The aerodynamics of the canard configuration are complex and require careful analysis. Rather than use
8625-463: The canard configuration to give advantages in areas such as performance, armament disposition or pilot view. Ultimately, no production aircraft were completed. The Shinden was ordered into production "off the drawing board" but only prototypes had flown by the time the war ended. In 1945 in Europe, what may have been the first canard designed and flown in the Soviet Union appeared as a test aircraft,
8750-431: The canard wings was used. The aircraft was also fitted with a Decca Type 72 Doppler navigation radar . TILS (Tactical Instrument Landing System ), a landing-aid system made by Cutler-Hammer AIL, improved landing accuracy to 30 m from the threshold on the short highway airbase system. In order to effectively enforce Sweden's air space, the Viggen was integrated with STRIL 60 national defence system. The JA 37 Viggen
8875-492: The canard. The use of a thrust reverser enabled the sought short landing performance. During development, Saab had opted to power the type using a single large turbofan engine. Originally, the British Rolls-Royce Medway engine had been selected to power the Viggen, which was then considered to be ideal for the basis for a supersonic engine equipped with a fully modulated afterburner ; however, development of
9000-503: The cannon was selectable at 22 or 11 rounds per second. It fired the same cartridge as the GAU-8 , reportedly 50% heavier shells at a higher velocity than the ADEN cannon, resulting in six and a half times the kinetic energy on impact, and was effective up to 2,000 meters. This, in conjunction with the fire control system, allowed air-to-air engagements at longer range than other fighters. Perhaps
9125-464: The case of the earlier Draken, in addition to accuracy issues. The computer, called CK 37 [ sv ] (short for Centralkalkylator 37 , "central calculator 37"), was the world's first airborne computer to use integrated circuits . Developed by Datasaab , the CK 37 was the integrating unit for all electronic equipment to support the pilot, performing functions such as navigation, flight control, and weapon-aiming calculations. In practice,
9250-448: The computers used on board the Viggen's replacement, the Saab JAS 39 Gripen. Various electronic countermeasures (ECM) were installed upon the Viggen, these were typically provided by Satt Elektronik. The ECM systems consisted of a Satt Elektronik radar warning receiver system in the wings and the tail, an optional Ericsson Erijammer pod and BOZ-100 chaff / flare pod. Infrared warning receivers were also later installed. In total,
9375-413: The conventional tailplane configuration found on most aircraft, an aircraft designer may adopt the canard configuration to reduce the main wing loading, to better control the main wing airflow, or to increase the aircraft's maneuverability, especially at high angles of attack or during a stall . Canard foreplanes, whether used in a canard or three-surface configuration, have important consequences for
9500-448: The delta wing as unsuited to such light aircraft. His next two canard designs, the VariEze and Long-EZ had longer-span swept wings. These designs were not only successful and built in large numbers but were radically different from anything seen before. Rutan's ideas soon spread to other designers. From the 1980s they found favour in the executive market with the appearance of types such as
9625-414: The design, including a modest landing speed, no-flare touchdown, powerful post-landing deceleration, accurate steering even in crosswinds on icy surfaces, and high acceleration on take-off. In 1960, the U.S. National Security Council , led by President Eisenhower , formulated a security guarantee for Sweden, promising U.S. military help in the event of a Soviet attack against Sweden; both countries signed
9750-463: The downward pitching moment caused by the deflection of its trailing-edge flaps . Pitch control in a canard type may be achieved either by the canard surface, as on the control-canard or in the same way as a tailless aircraft , by control surfaces at the rear of the main wing, as on the Saab Viggen. In a control-canard design, most of the weight of the aircraft is carried by the wing and the canard
9875-442: The early 1960s, it was decided that the Viggen should be a single seat aircraft, Saab having recognized that advanced avionics such as a digital central computer and a head-up display could perform the workload of a human navigator and entirely replace the need for a second crew member. A use of a digital computer would reduce or entirely replace analogue systems, which had proven to be expensive to maintain and alter, as had been
10000-415: The electronics weighed 600 kg, a substantial amount for a single-engine fighter of the era. The aircraft's principal sensor was an Ericsson PS 37 X-band monopulse radar , which used a mechanically steered parabolic reflector housed in a radome . This radar performed several functions, including air-to-ground and air-to-air telemetry , search , track , terrain-avoidance and cartography . On
10125-496: The experimental Mikoyan-Gurevich MiG-8 Utka (Russian for "duck"), a lightweight propeller aircraft. It was noted for its docile slow-speed handling characteristics and flew for some years, being used as a testbed during development of the swept wing of the (conventional layout) MiG-15 jet fighter. With the arrival of the jet age and supersonic flight, American designers, notably North American Aviation , began to experiment with supersonic canard delta designs, with some such as
10250-443: The first production JA 37 Viggen conducted its maiden flight. Operational trials for the new variant were conducted between January and December 1979, which resulted in the type being introduced to operational service that year. According to Flight International , at the time of the JA 37's introduction, it was the most advanced European fighter then in service. In April 1964, the Swedish government revealed its budget proposal for
10375-411: The foreplane creates a vortex which attaches to the upper surface of the wing, stabilising and re-energising the airflow over the wing and delaying or preventing the stall. The canard foreplane may be fixed as on the IAI Kfir , have landing flaps as on the Saab Viggen , or be moveable and also act as a control-canard during normal flight as on the Saab Gripen . A free-floating canard pivots so that
10500-431: The former was favoured, since the latter were mainly limited by metallurgy development resulting from limitations in turbine temperature . Mechanical simplicity was also favoured, so the air intakes were simple D-section types with boundary layer splitter plates , while the fixed inlet had no adjustable geometry for improved pressure recovery. The disadvantage was that the required engine would be very large. In fact, at
10625-423: The front wings. Triangular fins were mounted above and below the rear fuselage, with a small rudder hinged to their trailing edge. The undercarriage consisted of a pair of wheels on V-struts at the front of the aircraft and a third wheel mounted slightly behind the midpoint of the fuselage. It was powered by a 24 hp (18 kW) Antoinette V-8 engine. First trials were made at Issy-les-Moulineaux on 7 July but
10750-414: The front, pivoting on a universal joint on the fuselage's extreme nose. This was intended to provide both yaw and pitch control. The Fabre Hydravion of 1910 was the first floatplane to fly and had a foreplane. But canard behaviour was not properly understood and other European pioneers—among them, Louis Blériot —were establishing the tailplane as the safer and more "conventional" design. Some, including
10875-416: The fuselage pylons. The fighter-interceptor version of the Viggen, the JA 37, featured various avionics changes, including the extensive use of digital electronics alongside mechanical technology. In 1985, the "fighter link" went into service, permitting encrypted data communication between four fighters; this enabled one fighter to "paint" an airborne enemy with guidance radar for the Skyflash missiles of
11000-524: The implementation of a new stores management system and MIL-STD-1553 serial data bus , similar to that used on the newer JAS 39 Gripen, allowed for the integration of the AIM-120 AMRAAM air-to-air missile; an upgraded Ericsson PS-46A radar was installed, and a new tactical radio. On 4 June 1996, the first upgraded prototype JA37 Viggen performed its first flight. In 1996, according to Swedish air force material-department chief General Steffan Nasstrom,
11125-535: The in-development AJ 37 Viggen would be both cheaper than and superior to the McDonnell Douglas F-4 Phantom II . In April 1968, the Swedish government formally issued the authorization for manufacturing of the Viggen to proceed, issuing an order for 175 Viggens that year. Also in 1968, Saab began work on the Viggen's maritime reconnaissance and photo reconnaissance variants. In May 1969, the Viggen made its first public appearance outside of Sweden at
11250-541: The inboard wing pylons. Self-defence measures included various ECM systems, as well as either the AIM-4 Falcon (Swedish designation "RB 28") or AIM-9 Sidewinder (Swedish designation "RB 24") air-to-air missiles. At one point, the AJ 37 Viggen was under consideration as a carrier of both a Swedish nuclear weapon and chemical weapons , although no nuclear or chemical weapons were ultimately adopted by Sweden. The JA 37 fighter interceptor, introduced in 1979, featured
11375-471: The lift, (in)stability and trim of an aircraft, and may also be used for flight control. Where the canard surface contributes lift, the weight of the aircraft is shared between the wing and the canard. It has been described as an extreme conventional configuration but with a small highly loaded wing and an enormous lifting tail which enables the centre of mass to be very far aft relative to the front surface. A lifting canard generates an upload, in contrast to
11500-407: The line to be closed within the decade as the Swedish aerospace industry changed focus to the impending Saab JAS 39 Gripen, the Viggen's eventual replacement. Over time, advances in computing, such as the microprocessor , had enabled greater flexibility than the physical configuration of the Viggen, so further development of the Viggen platform was not viewed as cost-effective. In 1990, production of
11625-414: The load. This allows a smaller main wing. However, the foreplane also creates a downwash , which may affect the wing lift distribution favourably or unfavourably, so the differences in overall lift and induced drag are not obvious and they depend on the details of the design. With a lifting canard, the main wing must be located further aft of the centre of gravity than a conventional wing, increasing
11750-457: The main plane. A number of factors affect this characteristic. For example, seven years after the Wrights' first flight, the ASL Valkyrie adopted the canard position in order to make the aeroplane stable and safe. For most airfoils , lift slope decreases at high lift coefficients. Therefore, the most common way in which pitch stability can be achieved is to increase the lift coefficient (so
11875-411: The main wing, with a higher stall angle than the wing, and were equipped with flaps. The lifting canard surfaces act as a vortex generator for the main wing and therefore provide more lift. An added benefit was that they also improved roll stability in the transonic region. The canard flaps were deployed in conjunction with the landing gear to provide even more lift for takeoff and landing. To withstand
12000-497: The most important improvement was the expanded STRIL datalink which entered service in 1982–85. It allowed not only ground control-aircraft communication, but also between up to four aircraft simultaneously regardless if airborne or on the ground. Datalink information was displayed on the Horizontal Situation Display and a tactical display, the latter using link symbology that could be overlaid with an electronic map on
12125-408: The munitions fitted into the aircraft's central computer using a load-selector panel, which would automatically choose the correct values for fire control, fuel consumption, and other calculations. The AJ 37 was typically equipped with a total of seven hardpoints , three underneath the fuselage and two under each wing, a further two wing-mounted hardpoints could be optionally fitted but this facility
12250-409: The onset, the Viggen was planned as an integrated weapon system, to be operated in conjunction with the newest revision of Sweden's national electronic air defense system, STRIL -60. It was used as the nation's standard platform, capable of being efficiently adapted to perform all tactical mission roles. Other requirements included supersonic ability at low level, Mach 2 performance at altitude, and
12375-458: The overall configuration was given and was followed by a development contract in October 1962. According to aviation authors Bill Gunston and Peter Gilchrist, the project was "by far the largest industrial development task ever attempted in Sweden". During the 1960s, the Viggen accounted for 10 per cent of all Swedish R&D funding. In 1963, Saab finalized the aerodynamic design of the aircraft;
12500-496: The performance requirements to a large extent dictating the choice of the engine, the airframe turned out to be quite bulky compared to contemporary slimmer designs with turbojet engines. The first prototypes had a straight midsection fuselage that was later improved with a "hump" on the dorsal spine for reduced drag according to the area rule . The wing had the shape of a double delta with a dogtooth added to improve longitudinal stability at high incidence angles. A consequence of
12625-450: The photographic SF version, the radar in the nose was omitted in favour of four SKa 24C 120 mm and two SKa 31 570 mm photographic cameras as well as one 57 mm VKa 702 Infrared linescan camera and air-data camera; all of which were integrated with and controlled by the aircraft's central computer. Additional equipment, such as more camera pods, fuel tanks, ECM pods, and self-defense air-to-air missiles could also be carried upon
12750-487: The pilot's legs. On the right console panel were numerous dedicated controls and indicators, including weapons and missile controls, nav panel, oxygen on/off, windshield de-fogging, IFF control, lighting controls. Situated on the left console panel were radar controls, canopy handle, landing gear handle, radio controls and the cabin pressure indicator. As per then-standard practice within the Swedish Air Force, all cockpit instrumentation and labeling were in Swedish. With
12875-590: The pitch control function of the canard foreplane to create artificial static and dynamic stability. A benefit obtainable from a control-canard is the correction of pitch-up during a wingtip stall. An all-moving canard capable of a significant nose-down deflection can be used to counteract the pitch-up due to the tip stall. As a result, the aspect ratio and sweep of the wing can be optimized without having to guard against pitch-up. A highly loaded lifting canard does not have sufficient spare lift capacity to provide this protection. A canard foreplane may be used as
13000-404: The position of the lift force. When the main wing is most loaded, at takeoff, to rotate the nose up a conventional tailplane typically pushes down while a foreplane lifts up. In order to maintain trim the main wing on a canard design must therefore be located further aft relative to the centre of gravity than on the equivalent conventional design. A close-coupled canard has been shown to benefit
13125-425: The roles of fighter bomber / strike fighter (AJ 37), aerial reconnaissance (SF 37), maritime patrol / anti-surface (SH 37) and a two-seat trainer (Sk 37). During the late 1970s, the all-weather interceptor / strike fighter JA 37 variant was introduced. Attempts to export the Viggen to other nations were made, but ultimately proved unsuccessful. In November 2005, the last Viggens were withdrawn from service by
13250-460: The stresses of no-flare landings, Saab made extensive use of aluminium in the airframe of the Viggen, which was constructed using a bonded metal honeycomb structure ; the entire rear section of the fuselage, downstream of the engine nozzle, formed a heat-resistant ring composed of titanium . The main landing gear, manufactured by Motala Verkstad, was highly strengthened as well; each leg held two small wheels fitted with anti-skid brakes placed in
13375-578: The tail. The aircraft partially pulled out of the dive, and came to earth in a more or less horizontal attitude. His only injuries were some minor cuts on the face, caused by fragments of glass from his broken goggles. After this crash Blériot abandoned development of the aircraft, concentrating on his next machine, the Type VII . This event was witnessed by a large proportion of the French aviation community, including Robert Esnault-Pelterie , Ferdinand Ferber and
13500-418: The three other fighters in a group while they had their search and guidance radar switched off. This system was operational ten years before any other country's. The autopilot was also slaved to the radar control to obtain better precision firing the cannon. Once in service, the Viggen's software was regularly updated every 18 months. In 1983, the mean time between failures (MTBF) was reported as 100 hours,
13625-520: The time of introduction, it was the second-largest fighter engine, with a length of 6.1 m and 1.35 m diameter; only the Tumansky R-15 was bigger. Saab had originally wanted the Rolls-Royce Medway as the Viggen's powerplant. Owing to the cancellation of the Medway, the JT8D was instead chosen as the basis for modification. The RM8 became the second operational afterburning turbofan in
13750-526: The time, aerospace publication Flight International described the flight as having been "Sweden's astonishing unilateral stand in the front rank of advanced aircraft-building nations…" Each of the seven prototypes were assigned different roles, although the initial aircraft were focused on supporting the development of the initial production variant, the AJ37. In 1967, the Swedish Government concluded that
13875-455: The various upgrades performed to the Viggen since its introduction had "doubled the effectiveness of the overall system". The Viggen was powered by a single Volvo RM8 turbofan. This was essentially a heavily modified licence-built variant of the Pratt & Whitney JT8D engine that powered commercial airliners of the 1960s, with an afterburner added for the Viggen. The airframe also incorporated
14000-441: The whole surface can rotate freely to change its angle of incidence to the fuselage without pilot input. In normal flight, the air pressure distribution maintains its angle of attack to the airflow, and therefore also the lift coefficient it generates, to a constant amount. A free-floating mechanism may increase static stability and provide safe recovery from high angle of attack evolutions. The first Curtiss XP-55 Ascender
14125-445: The wing landing gear. The centreline pylon was the only pylon plumbed for carrying an external fuel tank, and was usually so occupied. A pair of air-to-air missiles were intended to be placed on the outboard wing pylons, which were more lightweight than the other attachment points. The pylons behind the landing gear were not used until the JA 37D modification when BOL countermeasure dispensers were fitted to them. Ground crew would enter
14250-427: The wing loading) of the canard. This tends to increase the lift-induced drag of the foreplane, which may be given a high aspect ratio in order to limit drag. Such a canard airfoil has a greater airfoil camber than the wing. Another possibility is to decrease the aspect ratio of the canard, with again more lift-induced drag and possibly a higher stall angle than the wing. A design approach used by Burt Rutan
14375-466: The world, and also the first equipped with a thrust reverser. According to aviation author Christopher Chant, the RM8 has the distinction of being the first engine to be fitted with both an afterburner and a thrust reverser. It had a bypass ratio of around 1.07:1 in the RM8A, which reduced to 0.97:1 in the RM8B. The RM8A was the most powerful fighter engine in the late 1960s. The AJ, SF, SH and SK 37 models of
14500-499: Was also equipped with a Garrett AiResearch digital Central Air Data Computer , modified from the unit used upon the Grumman F-14 Tomcat . Initially, only a single reconnaissance (S) variant was considered, but fitting cameras as well as a radar proved to be impossible. The SH 37 maritime strike and reconnaissance variant was very similar to the AJ 37 and differed mainly in a maritime-optimized PS 371/A radar with longer range,
14625-606: Was anticipated, with the first flight intended to be no earlier than the middle of the next decade. Between 1952 and 1957, the first studies towards what would become the Viggen were carried out, involving the Finnish aircraft designer Aarne Lakomaa . Over 100 different concepts were examined in these studies, involving both single- and twin engine configurations, both traditional and double delta wings, and canard wings . Even VTOL designs were considered, with separate lift engines, but were soon identified as being unacceptable. From
14750-497: Was finalised in 1963. The prototype performed its maiden flight on 8 February 1967 and the following year the Swedish government ordered an initial batch of 175 Viggens. The first of these entered service with the Swedish Air Force on 21 June 1971. Even as the initial AJ 37 model entered service, Saab was working on further variants of the Viggen. Accordingly, several distinct variants of the Viggen would be produced to perform
14875-563: Was further developed to become the more capable RBS-15 , also integrated on the Viggen. An optional load consisted of two Rb 05 air-to-surface missiles on the fuselage pylons. The RB 05 was later replaced by AGM-65 Maverick (Swedish designation "RB 75") television-guided missiles. In a ground-attack role, a combination of unguided 135 mm rockets in sextuple pods and 120 kg fragmentation bombs on quadruple-mounts could be used. Other armaments include explosive mines , and 30 mm ADEN cannon pods with 150 rounds of ammunition on
15000-429: Was initially fitted with a small free-floating canard lacking sufficient authority. Even on subsequent prototypes fitted with larger surfaces, "the stall was quite an experience". Secondary movable surfaces may be added to the free-floating canard, allowing pilot input to affect the generated lift, thus providing pitch control and/or trim adjustment. The Beechcraft Starship has a variable-sweep canard surface. The sweep
15125-532: Was rarely used. Various munitions could be carried, such as several types of rockets: the 135 mm M56GP 4 kg armour-piercing, the M56B with 6.9 kg of high explosives , and the M70 with a 4.7 kg HEAT warhead. The AJ 37 was designed to carry two RB 04 E anti-ship missiles on the inboard wing pylons with an optional third missile on the centreline pylon. The RB-04 was a relatively simple cruise missile that
15250-559: Was rated 18 mg/Ns dry and 71 with afterburner). The Viggen's consumption was around 15 kg/s at maximum afterburner. A pair of inlets placed alongside the cockpit feed air to the engine; simple fixed-geometry inlets were adopted, similar to the Draken, except for being larger and standing clear of the fuselage. A weapons load of up to 7,000 kg could be accommodated on nine hardpoints: one centreline pylon, two fuselage pylons, two inner and two outer wing pylons and two pylons behind
15375-461: Was the Raketstol 37 (literally; Rocket chair 37) and was the last Saab designed seat in service. A derivative of the Saab 105 trainer seat, the seat was optimized for low altitude, high speed ejections. Once activated by the pilot via triggers built into the armrests (on twin-seat models, the occupant of the forward cockpit position is able to initiate the ejection of both seats), the ejection sequence
15500-564: Was the threat posed by birds; thus, the Swedish Air Force paid close attention to their migratory patterns. During the later half of the 1970s and into the 1980s, the introduction of various variants of the Viggen proceeded; these included the SK 37, a two-seat operational-conversion trainer, introduced in 1972, the SF 37, an overland reconnaissance model, introduced in 1977, and the SH 37, a maritime reconnaissance version, introduced in 1975. By September 1980,
15625-447: Was to protect U.S. Polaris submarines deployed just outside the Swedish east coast against the threat of Soviet anti-submarine aircraft. However, Bruzelius' theory has been discredited by Simon Moores and Jerker Widén. The connection also appears doubtful due to the time scale – the Viggen's strike version only became operational in 1971, and the fighter version in 1978, by which time Polaris had already been retired. In December 1961,
#916083