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Saab 35 Draken

Saab 35 Draken

Picture - An Austrian Air Force Draken in a special paint scheme.

Role: Fighter
National origin: Sweden
Manufacturer: Saab
First flight: 25 October 1955
Introduced: 8 March 1960
Retired: 1993 Denmark 1999 Swedish Air Force 2000 Finland 2005 Austria
Status: Retired from military service
Primary users: Swedish Air Force Austrian Air Force Finnish Air Force Royal Danish Air Force
Produced: 1955-1974
Number built: 644
Developed from: Saab 210

The Saab 35 Draken is a Swedish fighter aircraft manufactured by Saab between 1955 and 1974. The Draken was built to replace the Saab J 29 Tunnan and, later, the fighter variant (J 32B) of the Saab 32 Lansen. The indigenous J 35 was an effective supersonic Cold War fighter that was also successfully exported to Austria, Denmark and Finland.

Design and development

As the jet era started, Sweden foresaw the need for a jet fighter that could intercept bombers at high altitude and also successfully engage fighters. Although other interceptors such as the US Air Force's F-104 Starfighter were being conceived during the same period, Saab's "Draken" would have to undertake a combat role unique to Sweden. Other demanding requirements were the capability to operate from reinforced public roads used as part of wartime airbases, and for refuelling/rearming to be carried out in no more than ten minutes, by conscripts with minimal training. In September 1949, the Swedish Defence Material Administration issued a request for a fighter/interceptor aircraft, and work began at Saab the same year.

Picture - A line-up of J 35As.

Draken's design incorporated a distinctive "double-delta" configuration, with one delta wing within another larger delta. The inner wing has an 80° angle for high speed performance, while the outer 60° wing gives good performance at low speeds. Propulsion was provided by a single Svenska Flygmotor RM 6B/C turbojet (Rolls-Royce Avon 200/300). A ram turbine, under the nose, provided emergency power and the engine had a built-in emergency starter unit. The Draken could deploy a drag chute to reduce its landing distance.

The double-delta shape was so revolutionary that it warranted the only sub-scale test aircraft built in Sweden: the Saab 210, unofficially nicknamed "Lilldraken" (the little kite). The Saab 210 tested the concept of the double delta, first flying on 21 January 1952. The 210's successful testing results led to an order for three full-size Draken prototypes. The first prototype, not fitted with an afterburner, made its maiden flight on 25 October 1955. The second prototype, equipped with an afterburner, unintentionally broke the sound barrier on its first flight while climbing.

Operational history

Although not designed to be a dogfighter, the J 35 Draken proved to have good instantaneous turn capability and was a very capable fighter. It entered service in 1960 with the Swedish Air Force; 644 Saab Drakens were built for Sweden as well as other European nations. Sweden's Draken fleet came in six different variants while two Draken models were offered for export. The early models were intended purely for air defence. The last model built was the J 35F, the final variant to remain in Swedish service. These aircraft were retired in the 1990s and replaced by the Saab Gripen.

Picture - Ex-RDAF RF-35XD N217FR operated by the National Test Pilot School takes off from the Mojave Spaceport.

The J 35 Draken design underwent several upgrades. The last was the J 35J version, in the late 1980s, although by then, the Draken had been almost totally replaced by the Saab 37 Viggen in Swedish service. The J 35J was a service-life extension program since the delivery of the new Saab JAS 39 Gripen was still in the development stage and suffering from delivery delays. The extension program was to keep the Draken flying into the 2000s, but due to cutbacks and high maintenance costs the Draken was eventually phased out. The Swedish Drakens were officially retired in December 1998, although the type remains in limited numbers in both military and civilian versions. Export customers included Denmark and Finland. In 1985, the Austrian Air Force purchased 24 J 35D s reconditioned by Saab, designated J 35x–.

All Drakens are interceptors with limited air-to-ground capability, with the sole exception of the Danish Drakens, which are strike aircraft capable of carrying AGM-12 Bullpup missiles, advanced "jammers", and increased internal and external fuel stores. The Danish Drakens are so far the heaviest of the series to have been in service. Danish F-35 aircraft were retired in 1993.

Finland updated its 35XS fleet with new avionics, cockpit displays, navigational/attack systems and electronic countermeasures during the 1990s but finally retired the Draken in 2000.

Austria was the last country to operate the Draken in military service. They bought refurbished J 35D which was the last Austrian Air Force fighter with two internal cannons due to the restriction in the Austrian State Treaty of 1955 of not being allowed to carry air-to-air missiles. This restriction was dropped in 1993 due to airspace violations from the nearby Yugoslavian internal conflict on its southern border, AIM-9 Sidewinder missiles were purchased. These Drakens were retired in 2005, when they were replaced by former Swiss Tiger IIs, while waiting for new Eurofighters.

In the United States, the National Test Pilot School (NTPS) owns six Drakens that were formerly in Danish service; of these, two TF-35XD s and one RF-35XD are operational, based at the Mojave Spaceport.

Variants

Proof of concept

Saab 210 Draken (also known as Lilldraken) - A scaled-down, "proof of concept" experimental aircraft to evaluate the double-delta wing configuration, not specifically a Draken variant but included here for sequence purposes.

Full-size Drakens

J 35A Fighter version, total production: 90. The J 35As were delivered between 1959-1961. The tail section was lengthened after the 66th aircraft to house a new afterburner for additional thrust. This forced the installation of a retractable tail-wheel. The two versions were nicknamed Adam kort (Adam short) and Adam lx¥ng (Adam long). J 35B Fighter version, built and delivered between 1962-1963, total production: 73. This variant had improved radar and gun sights, and was also fully integrated into the Swedish STRIL 60 system; a combat guidance and air surveillance system. SK 35C 25 J 35As with short tail sections rebuilt into a twin-seated trainer version. The minor modification meant that the aircraft could easily be converted back to a J 35A standard if necessary. The trainer version lacked armament. J 35D Fighter version, delivered between 1963-1964, total production: 120. The aircraft had a new and more powerful Rolls-Royce Avon 300 (RM 6C), which could deliver 77.3 kN thrust when using its afterburner. This was also the fastest Draken version, capable of accelerating until out of fuel. It was also the last Draken to carry two cannons. S 35E Reconnaissance version, total production: 60. The radar and the armament had been removed and several cameras (of ortho and oblique types) fitted. The aircraft was unarmed but was fitted with a countermeasure system to increase its survivability. A total of 28 aircraft were re-built J 35Ds. J 35F Fighter version, delivered between 1965 and 1972, total production: 230. This variant had improved electronics and avionics, e.g. integrated radar, aim and missile systems. The aircraft's main armament were IR and SARH versions of the Hughes Falcon missile originally intended for the J 35D, but one of the cannon was removed to make space for more avionics. The J 35F2 was a J 35F, produced with a Hughes Aircraft Company N71 infra red sensor, a so-called IR seeker. This was a change in the production line from the no. 35501 airframe. J 35J In 1985 the Swedish government decided to modify 54 J 35F2s to J 35J standard. In 1987, 12 more modifications were ordered. Between 1987 and 1991, the aircraft were given a longer lifespan, more modern electronics, a modernized cannon, an additional two sidewinder pylons under the air intakes and increased fuel capacity. The final operative J 35J flew for the last time in 1999. Saab 35H Proposed export version for the Swiss Air Force; none sold or delivered. Saab 35XD Danish export versions: F-35 single-seat Strike Aircraft, TF-35 two-seat trainer and RF-35 reconnaissance aircraft. The type was heavily modified to make it into a strike aircraft compared the Swedish versions. Saab 35XS Fighter version for the Finnish Air Force; built by Saab and assembled under licence by Valmet in Finland. Saab 35BS Used J 35Bs sold to Finland. Saab 35FS Used J 35F1s sold to Finland. Saab 35CS Used SK 35Cs sold to Finland. Saab 35x– In the mid-1980s, Saab purchased back 24 J 35D aircraft from the Swedish Air Force and converted them into the J 35x– version (also called J 35OE in English literature). These were later exported to Austria.

Proposed modifications

Before it was decided to develop the JAS 39 Gripen in the late 1970s, an intensive study was undertaken on an AJ 35 modification for the remaining S 35E and J 35F variants. The main goal was to give the aircraft strike capability while waiting for a replacement for the AJ 37 Viggen.

35 MOD Level 4 The most ambitious modification in the program. The proposed modifications were; new outer wing, additional weapon stations, RBS 15 capability, the addition of canard wings by the air intakes for increased maneuverability and maximum take-off weight increased to 15 000 kg. 35 MOD Level 1b Essentially the aircraft that became the J 35J.

The total number of Drakens produced and delivered: 644.

Operators

Picture - former Saab 35 Draken Operators in red

The Saab 35 Draken was withdrawn from military use in 2005. Several aircraft fly in the civil circuit, mainly in the USA.

Austria

Austrian Air Force, 24 aircraft:
Fliegerregiment 2
Staffel 1
Staffel 2

Denmark

Royal Danish Air Force, 51 aircraft:
No. 725 Squadron
No. 729 Squadron

Finland

Finnish Air Force, 50 aircraft:
Fighter Squadron 11
Fighter Squadron 21

Sweden

Swedish Air Force
F 1 Hx¤sslx¶
F 3 Malmslx¤tt
F 4 Frx¶sx¶n
F 10 x„ngelholm
F 11 Nykx¶ping
F 12 Kalmar
F 13 Norrkx¶ping
F 16 Uppsala
F 17 Kallinge
F 18 Tullinge
F 21 Lulex¥

United States

National Test Pilot School (6)

Survivors

J 35J, 35556 in the Swedish Air Force Museum at F 14 Halmstad, Sweden Only airworthy Saab J 35 in Sweden
J 35J, 35630 at the at the Angelholms Flyg Museum on the former Scandia Air Force Wing F 10 x„ngelholm

Specifications (J 35F Draken)

Data from The Great Book of Fighters

General characteristics

Crew: One
Length: 15.34 m (50 ft 4 in)
Wingspan: 9.42 m (30 ft 10 in)
Height: 3.89 m (12 ft 9 in)
Wing area: 49.22 m² (529.82 ft²)
Empty weight: 7,865 kg (17,340 lb)
Loaded weight: 11,400 kg (25,132 lb)
Max takeoff weight: 16,000 kg (35,273 lb)
Powerplant: 1x— Volvo Flygmotor RM 6C afterburning turbojet
Dry thrust: 56.5 kN (12,787 lbf)
Thrust with afterburner: 78.4 kN (17,637 lbf)

Performance

Maximum speed: Mach 2+, 2,120 km/h (1,317 mph) at 11,000 m (36,100 ft)
Range: 3,250 km (2,020 mi) with external drop tanks
Service ceiling: 20,000 m (65,600 ft)
Rate of climb: 175 m/s (34,450 ft/min)
Wing loading: 231.6 kg/m² (47.4 lb/ft²)
Thrust/weight: 0.70
Takeoff roll: 650 m (2,133 ft)

Armament

1x 30 mm M-55 ADEN cannon with 100 rounds (2x 30 mm M-55 ADEN cannon with 90 rounds each in earlier models)
Four hardpoints for either fuel tanks or air-to-air or missiles
Rb 24, Rb 27 and Rb 28 air-to-air missiles
2x 75 mm Air to Air rocket pods could be carried on the belly instead of two tanks or missiles
12x 135mm rockets on six underwing pylons in place of the outer two missile/fuel tank pylon
55, 220, 500, and 1,000 pound bombs
Maximum ordnance 2,900 kg (6,393 lb)

Related development

Saab 210

Comparable aircraft

Avro Canada CF-105 Arrow
Convair F-102 Delta Dagger
Convair F-106 Delta Dart
Dassault Mirage III
Mikoyan-Gurevich MiG-21

Bibliography

Dorr, Robert F., René J. Francillon and Jay Miller. Saab J35 Draken (Aerofax Minigraph no. 12). Arlington, TX: Aerofax Inc., 1987. ISBN 0-942548-17-5.
Erichs, Rolph et al. The Saab-Scania Story. Stockholm: Streiffert & Co., 1988. ISBN 91-7886-014-8.
Jx¸rgensen, Jan. Saab 35 Draken: Scandinavian "Cold War" Warrior. Shrewsbury, UK: Airlife Publishing Ltd., 1997. ISBN 1-853107-29-8.
Laukkanen, Jyrki. Saab 35 Draken in Finnish Air Force (Suomen Ilmavoimien lentokoneet, osa 3)(in Finnish).
Peacock, Lindsay. "Saab Draken Variant Briefing". World Air Power Journal, Volume 17 Summer 1994. London:Aerospace Publishing. ISBN 1 874023 43 3. ISSN 0959-7050. pp. 116-135.
Taylor, John W.R. "Saab 35 Draken." Combat Aircraft of the World from 1909 to the present. New York: G.P. Putnam's Sons, 1969. ISBN 0-425-03633-2.
This Happens in the Swedish Air Force (brochure). Stockholm: Information Department of the Air Staff, Flygstabens informationsavdelning, Swedish Air Force, 1983.
Widfeldt, Bo. Draken. Inbunden, Sweden: Air Historic Research AB U.B., 1995. ISBN 91-971605-4-7.

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Source: WikiPedia