SAAB JAS 39 GRIPEN

SAAB JAS 39 GRIPEN

The Saab JAS 39 Gripen is a light single-engine multirole fighter aircraft manufactured by the Swedish aerospace company Saab. It was designed to replace the Saab 35 Draken and 37 Viggen in the Swedish Air Force (Flygvapnet). The Gripen has a delta wing and canard configuration with relaxed stability design and fly-by-wire flight controls. It is powered by the Volvo RM12, and has a top speed of Mach 2. Later aircraft are modified for NATO interoperability standards and to undertake in-flight refuelling.

In 1979, the Swedish government began development studies for an aircraft capable of fighter, attack and reconnaissance missions to replace the Saab 35 Draken and 37 Viggen. A new design from Saab was selected and developed as the JAS 39, first flying in 1988. Following two crashes during flight development and subsequent alterations to the aircraft’s flight control software, the Gripen entered service with the Swedish Air Force in 1997. Upgraded variants, featuring more advanced avionics and adaptations for longer mission times, began entering service in 2003.

In order to market the aircraft to export customers, Saab has formed several partnerships and collaborative efforts with multiple overseas aerospace companies. One example of such efforts was Gripen International, a joint partnership between Saab and BAE Systems formed in 2001. Gripen International was responsible for marketing the aircraft, and was heavily involved in the successful export of the type to South Africa; the organization was later dissolved amidst allegations of bribery being employed to secure foreign interest and sales. On the export market, the Gripen has achieved moderate success in sales to nations in Central Europe, South Africa and Southeast Asia; bribes have been reportedly involved in some of these procurements.

A further version, designated Gripen JAS 39 E/F, is under development as of 2014; it has been referred to as Gripen NG or Super-JAS. The changes include the adoption of a new powerplant, the General Electric F414G, an active electronically scanned array radar, and significantly increased internal fuel capacity. Saab has proposed other derivatives, including a navalised Sea Gripen for carrier operations and an optionally-manned aircraft for unmanned operations. Sweden has ordered the Gripen E/F and Brazil and Switzerland initially selected it for procurement. As of 2013, more than 247 Gripens have been built.

Origins

By the late 1970s, Sweden needed a replacement for its ageing Saab 35 Draken and Saab 37 Viggen. The Swedish Air Force required an affordable Mach 2 aircraft with good short-field performance for a defensive dispersed basing plan in the event of invasion; the plan included 800 m long by 9 m wide rudimentary runways as stated in the Base 90 directives. One goal was for the aircraft to be smaller than the Viggen while equalling or improving on its payload-range characteristics. Early proposals included the Saab 38, also called B3LA, intended as an attack aircraft and trainer, and the A 20, a development of the Viggen that would have capabilities as a fighter, attack and sea reconnaissance aircraft. Several foreign designs were also studied, including the General Dynamics F-16 Fighting Falcon, the McDonnell Douglas F/A-18 Hornet, the Northrop F-20 Tigershark and the Dassault Mirage 2000. Ultimately, the Swedish government opted for a new fighter to be developed by Saab (Svenska Aeroplan Aktiebolag).

In 1979, the government started a study calling for a versatile platform capable of “JAS”, standing for Jakt (air-to-air), Attack (air-to-surface), and Spaning (reconnaissance), indicating a multirole, or swingrole, fighter aircraft that can fulfill multiple roles during the same mission. A number of Saab designs were accordingly reviewed, with the most promising being “Project 2105” (redesignated “Project 2108” and, later, “Project 2110”), recommended to the government by the Defence Materiel Administration (Försvarets Materielverk, or FMV). In 1980, Industrigruppen JAS (IG JAS, “JAS Industry Group”) was established as a joint venture by Saab-Scania, LM Ericsson, Svenska Radioaktiebolaget, Volvo Flygmotor and Försvarets Fabriksverk, the industrial wing of the Swedish armed forces.

The preferred aircraft was a single-engine, lightweight single-seater, embracing fly-by-wire technology, canards, and an aerodynamically unstable design. The powerplant selected was the Volvo-Flygmotor RM12, a license-built derivative of the General Electric F404-400; engine development priorities were weight reduction and lowering component count. On 30 June 1982, with approval from the Riksdag, the FMV issued contracts worth SEK25.7 billion to prime contractor Saab covering five prototypes and an initial batch of 30 production aircraft. To test avionics intended for the JAS 39, such as the fly-by-wire controls, a Viggen was converted to operate as a test aircraft, flying by January 1983. Through a public competition, the JAS 39 received the name Gripen (griffin), which is the heraldry on Saab’s logo.

Testing, production and improvements

 

The first Gripen was rolled out on 26 April 1987, marking Saab’s 50th anniversary. Originally planned to fly in 1987, the first flight was delayed by 18 months due to issues with the flight control system. On 9 December 1988, the first prototype (serial number 39-1) took its 51-minute maiden flight with pilot Stig Holmström at the controls. During the test programme, concern surfaced about the aircraft’s avionics, specifically the fly-by-wire flight control system (FCS), and the relaxed stability design. On 2 February 1989, this issue was dramatically highlighted with the crash of the prototype during an attempted landing at Linköping; the test pilot Lars Rådeström walked away with only a broken elbow. The cause of the crash was identified as pilot-induced oscillation, caused by problems to the FCS’s pitch-control routine.  To rectify the problem, Saab and US firm Calspan introduced major software improvements to the aircraft. A modified Lockheed NT-33A was used to test these improvements, which allowed flight testing to resume within 15 months following the accident. The programme was again hindered when, on 8 August 1993, production aircraft 39102 was destroyed in an accident during an aerial display in Stockholm. Test pilot Rådeström lost control of the aircraft during a roll at low altitude, and the aircraft rapidly stalled, forcing him to eject. Saab later found the problem to be high amplification of the pilot’s quick and significant stick command inputs. The ensuing investigations and flaw rectification delayed test flying by several months, resuming in December 1993.

The first order included an option for another 110, which became a firm order in June 1992. Batch II consisted of 96 one-seat JAS 39As and 14 two-seat JAS 39Bs. The JAS 39B variant is 66 cm (26 in) longer than the JAS 39A to accommodate a second seat, which also necessitated the deletion of the cannon and a reduced internal fuel capacity. By April 1994, five prototypes and two series-production Gripens had been completed; the only major decision remaining was to select a beyond-visual-range missile (BVR).A third batch was ordered in June 1997, composed of 50 upgraded single-seat JAS 39Cs and 14 JAS 39D two-seaters, known as ‘Turbo Gripen’, with NATO compatibility for exports. Batch III aircraft, delivered between 2002 and 2008, possess more powerful and updated avionics, in-flight refuelling capability via retractable probes on the aircraft’s starboard side, and an on-board oxygen-generating system for longer missions. In-flight refuelling was tested via a specially equipped prototype (39‐4) used in successful trials with a Royal Air Force VC10 in 1998.

  • Role: Fighter, Attack and Reconnaissance Aircraft

  • Primary Users: Swedish Air Force, Czech Air Force, South African Air Force, Hungarian Air Force

  • Produced: 1987–present