The SAAB JAS 39 Gripen

v1.2.1 / 01 may 16 / greg goebel

* Since World War II, the Swedish SAAB aircraft firm has maintained a tradition of building cutting-edge fighter aircraft for the defense of Sweden. The latest of this series of aircraft, the SAAB "JAS 39 Gripen (Griffin)", is now in operational service. The Gripen is a state-of-the-art multirole combat aircraft, arguably the first "fourth-generation" jet fighter to reach service. It maintains the tradition of excellence in Swedish fighter design, but departs from tradition in proving a competitive item for export sales. This document provides a history and description of the Gripen.

SAAB JAS 39A Gripen



* In the 1970s, the SAAB 37 Viggen began to go into service with the Flygvapnet (Swedish Air Force) as the nation's first-line combat aircraft. Swedish military planners then began to look down the road for a next-generation fighter to follow the Viggen. While US-made aircraft such as the F-16 or F/A-18 were considered, the Swedes had proven capable of building their own first-class combat aircraft, tailored precisely to their specifications -- and besides, modifying a foreign aircraft to fit into the tightly-linked Swedish defense network system would have been troublesome.

In 1980, the Swedish Defense Materiel Administration (FMV) issued a requirement to Swedish manufacturers for a next-generation combat aircraft, then known as the "JAS (Jakt, Attack, & Spaning / Fighter, Attack, & Reconnaissance)". As the name implied, it was to be a multirole combat aircraft, with excellent performance and high agility to counter new Soviet fighters then going into service. It was to be simpler and cheaper to maintain than the Viggen, and easy to turn around quickly to ensure a high combat sortie rate. Long range was not a requirement, since the Flygvapnet's traditional focus was on the defense of Sweden, not power projection.

A consortium named "IndustriGruppen JAS" was formed between SAAB-Scania, Volvo Flygmotor, Ericsson, and Foerenade Fabriksverken (now FFV Aerotech). The group's proposal, with the company designation "SAAB 2110", was accepted in the spring of 1982, with a contract signed in June for five prototypes featuring some modifications from the original proposal, plus an initial production batch of 30 aircraft and an option for 110 more.

* Work on the prototypes began in 1984, with a full-size mockup completed in early 1986. The program ran into technical problems, cost increases, and schedule slips, leading to political pressure for its cancellation and purchase of a foreign aircraft. However, the first single-seat "JAS 39A Gripen (Griffin)" prototype flew on 9 December 1988, with test pilot Stig Holmstroem at the controls, and the controversy faded. Design work on the "JAS 39B" two-seat version for operational conversion training began in 1989.

Unfortunately, the first JAS 39A prototype, the "39-1", was lost on 2 February 1989 due to a software glitch in the flight-control system. The aircraft became unstable on landing and cartwheeled, with the pilot, Lars Raadstroem, suffering a broken arm. The whole ugly event was filmed and caused a bit of a public sensation. Work on cleaning up the software and fixing engine problems led to additional schedule slips. The problems were resolved, and the second prototype, "39-2", took to the air on 4 May 1990. The third prototype to fly, which was actually designated "39-4" and featured operational avionics but no radar, performed its initial flight on 20 December 1990. The next prototype, the "39-3", was fitted with radar and flew on 25 March 1991; followed by the last of the five prototypes, "39-5", which was close to production spec, and flew on 23 October 1991.

By this time, the bugs had been largely ironed out. The Flygvapnet decided the Gripen had been worth the wait and trouble, since it easily exceeded many of its design specifications -- and the fact that it was such a pretty aircraft didn't hurt. In June 1992, SAAB got the go-ahead for building the two-seat JAS 39B, and the government formally signed off on the option for 110 more Gripens, which were to be built to an improved "Batch 2" standard. The new order included 96 JAS 39As and 14 JAS 39Bs.

The first production Gripen performed its maiden flight on 4 March 1993, with Raadstroem at the controls. The second production item was the first to be handed over formally to the Flygvapnet, with delivery on 8 June 1993. However, the first production machine crashed during a flight demonstration in Stockholm on 8 August 1993, Raadstroem ejecting without serious injury. Once again, the problem turned out to be a glitch in the flight control system software. All the Gripens were grounded until the bug was traced down and fixed.

The first JAS 39B was rolled out on 29 September 1995. It was actually a production-line modification of one of the 30 Batch-1 JAS 39As. The JAS 39A reached initial operational status in 1995 and full operational status in 1997. The first Batch 2 machine was delivered in December 1996, the same month that an order for 64 improved "Batch 3" machines was placed, including 50 single-seat "JAS 39Cs" and 14 two-seat "JAS 39Ds".



* The Gripen is a true lightweight fighter, with about three-quarters the empty weight of an F-16C and about half the empty weight of the Viggen, the F/A-18E/F Super Hornet, or the Dassault Rafale. The Gripen's airframe features extensive use of composite assemblies to reduce weight. The modest size reduces purchase cost to a degree, and definitely reduces operating cost; makes the machine easier to handle on the ground; and gives it a lower radar signature.

The Gripen is a canard-configuration aircraft, featuring a cropped delta wing with a sweep of 45 degrees, along with all-moving canard forewings with a sweep of 45 degrees and dihedral. The wings are midbody-mounted to provide clearance for underwing stores, each wing having a leading-edge flap plus two trailing-edge drooping "elevons" to improve short-field performance, as well as maneuverability. There are two tiny strakes on the nose to generate vortices that improve flight control at high angles of attack.

Gripens in formation

The Gripen is powered by a Volvo Aero RM-12 bypass turbojet engine with afterburner. The RM-12 was developed in cooperation with General Electric and is derived from the GE F404J turbofan used on the Boeing F/A-18 Hornet. The F404J was selected due to its reliability and growth potential. The Swedish version of the engine features a larger fan to provide more airflow and greater power; greater resistance to birdstrikes; and a Swedish-designed afterburner. The RM-12 provides 81.9 kN (8,350 kgp / 18,400 lbf) thrust in afterburner. 60% of the engine's components are built by GE and shipped to Sweden, where they are integrated with the Swedish-built components.

Unlike the Viggen, the Gripen does not have a thrust reverser. The canard foreplanes can be tilted almost 90 degrees to act as airbrakes on landing. There are carbon brakes on all the wheels of the tricycle landing gear to reduce landing roll. Interestingly, pilots using the Gripen flight simulators have performed simulated carrier landings, without an arresting hook; it seems a bit unlikely that this will ever be done in practice, though no doubt some Gripen pilots would give it a shot if they got the chance. The landing gear has an antiskid system. The two-wheel nose gear retracts backward, while the single-wheel main gear retract at a forward angle.

   _____________________   _________________   ___________________
   spec                    metric              english
   _____________________   _________________   ___________________

   wingspan                8 meters            26 feet 3 inches
   length                  14.1 meters         46 feet 3 inches
   height                  4.7 meters          15 feet 5 inches

   empty weight            6,620 kilograms     14,600 pounds
   max loaded weight       12,470 kilograms    27,500 pounds

   maximum speed           Mach 2 at altitude
   service ceiling         15,240 meters       50,000 feet
   combat radius           800 km              500 MI / 430 NMI
   _____________________   _________________   ___________________

Swedish defense plans include a concept known as "BAS 90", which envisions dispersal of aircraft in groups of four to six to "road bases" organized around specially reinforced lengths of highway, with associated dispersal areas. This scheme dictates the Gripen's short-field capabilities. The Gripen can take off and land in less than 600 meters (2,000 feet). Once deployed to a road base, the Gripens are serviced by a ground crew of six, including one highly trained specialist and five minimally trained conscripts. A service team can refuel and rearm a Gripen in ten minutes.

The Gripen features an auxiliary power unit (APU) to reduce its dependence on ground systems, and the fighter's onboard digital systems include "built-in self-test" capabilities that can download diagnostic data to a tech's laptop computer. Service doors to critical systems are at head level or lower, allowing easy access by technicians. Flygvapnet experience shows that the Gripen requires 40% less maintenance work-hours and only half the fuel of the Viggen.

The Gripen cockpit layout contains three multi-function displays (MFDs), plus a wide-angle head-up display (HUD) with a 28-by-22 degree field of view. The left MFD contains flight data and reflects HUD information; the lower MFD contains a tactical image in a "horizontal situation display" format; and the right MFD provides imagery from the radar, and potentially FLIR or an optical reconnaissance pod. Batch 1 and 2 machines used monochrome (green) MFDs.

The pilot flies the machine with an "hands on throttle and stick (HOTAS)" controls, including a center-mounted short-throw "ministick", and a throttle control that also operates as a joystick to perform selections on the MFDs. The cockpit is climate-conditioned and pressurized, and fitted with a Martin-Baker Mark S10L zero-zero (zero altitude, zero speed) rocket-propelled ejection seat. The Gripen is the first Swedish fighter not to use a SAAB-built ejection seat, and in fact the machine has considerable foreign content. The canopy hinges open sideways to the left.

The aircraft is controlled by a digital fly-by-wire (FBW) system with triple redundancy and an analog backup. The analog backup system provides a simple, reliable capability, and is automatically activated if two of the three digital FBW systems go down. The pilot can also activate the analog system with the push of a button. The Gripen was designed from the outset to use the FBW system, which was evaluated on a modified Viggen. The FBW system compensates automatically for the degree of instability built into the Gripen to increase its maneuverability. The FBW system also allows the aircraft to adapt to combat damage, for example using differential control of the canards to fly the aircraft if the ailerons are disabled.

The Gripen's Ferranti-Ericsson PS-05/A X-band pulse Doppler radar has three times the processing power of the Viggen's PS-46/A radar, but only 60% of its volume and weight. The PS-05/A has all-altitude look-down capability, resistance to jamming, and provides a number of operating modes. Air-to-air modes include:

Air-to-ground modes include:

A mission computer alerts the pilot to priority threats. The Gripen has a ring-laser inertial navigation system (INS), and a suite of electronic warfare (EW) aids. The initial EW suite was built around the CelsiusTech (now Saab Avionics) AR830 radar-warning receiver (RWR), with receiving antennas on the front and back of the wingtip missile launch rails. The EW system controls a set of chaff-flare dispensers, all built by Saab Avionics. BOL dispensers are built into the end of the missile launch rails and have a total capacity of 160 chaff packs or flares. BOP/C dispensers are built into the fuselage, while BOP/B dispensers are built into the end of the wing pylons. The BOP/B dispenser can trail a "BO2D" towed repeater RF decoy, which can be deployed at supersonic speed and programmed to operate in several different modes.

* Avionics are linked by three MILSTD 1553B data buses, one for basic aircraft and flight data; one for cockpit displays and data; and one for tactical and weapons data.

The Flygvapnet was a pioneer in the development and deployment of radio datalinked combat systems, secretly fielding an initial version of a national defense datalink network with the SAAB 35 Draken fighter in the mid-1960s. The service has continued to refine the network.

The Gripen is fitted with the "Tactical Information Datalink System (TIDLS)", which gives the fighter four high-bandwidth, two-way datalinks with a range of about 500 kilometers (310 miles) and very high resistance to jamming. The datalinks allow the Gripen to engage in combat using another aircraft's sensors or from targeting data provided by other defense systems. Data acquired from remote sources is fused and displayed on the fighter's main MFD. The link is fully operational when the aircraft is on the ground, allowing a pilot on standby to have high situational awareness of the battle environment.

One Gripen can provide radar sensing for four of its colleagues, allowing a single fighter to track a target, while the others use the data for a stealthy attack. TIDLS also permits multiple fighters to quickly and accurately lock onto a target's track through triangulation from several radars; or allow one fighter to jam a target while another tracks it; or allow multiple fighters to use different radar frequencies collaboratively to "burn through" jamming transmissions. In addition, TIDLS gives the Gripen transparent access to the SAAB-Ericsson 340B Erieye "mini-AWACs" aircraft, as well as the overall ground command and control system. This system provides Sweden with an impressive defensive capability at a cost that, though still high, is less than that of comparable systems elsewhere.

* The Gripen's built-in armament consists of a single Mauser BK-27 27-millimeter cannon, housed in a fairing on the aircraft's belly, offset to left to the rear of the engine intake. Given the aircraft's relatively small size, it generally carries guided weapons to ensure maximum combat effectiveness. Possible external stores include:

The Gripen's rapid turnaround time will help increase its combat effectiveness, allowing to be rapidly rearmed and sent on consecutive missions.

* The two-seat JAS 39B Gripen is 67 centimeters (2 feet 2 inches) longer than the single-seat version. Fuel capacity is the same for both aircraft. There is no HUD for the back-seater in the two-seat version, though HUD and other video information can be linked into the back-seat display system. The JAS 39B has twin clamshell canopies. One of the interesting features of the machine is an airbag to protect the back seater from shards thrown out by a front-seat ejection. The airbag pops full in an instant, and then just as rapidly deflates to allow the back-seater to eject.

South African JAS 39D Gripen

The JAS 39B is not really intended for flight training as such, since the Gripen is a very docile aircraft. Its primary purpose is tactical training, and except for the lack of a built-in cannon, it is fully combat-capable. Flight training for the Gripen is supplemented by four ground-based "Multi-Mission Trainer (MMT)" simulators built by Loral. Each MMT contains three wide-screen displays and a Gripen cockpit with a head-up display. The MMTs can be linked with dome simulators and other MMTs to provide interactive combat training.

* After obtaining initial production machines, the Flygvapnet moved on to deliveries of Batch 2 Gripens, which featured a Sundstrand APU, replacing the older Microturbo APU, which was too noisy and not reliable enough; a new Lockheed Martin flight control system computer, replacing a Lear-Siegler unit; a Kaiser HUD, replacing the Hughes-built HUD; and a new display processor. The Sundstrand APU was retrofitted to Batch 1 Gripens, as well as early Batch 2 aircraft that had an interim improved Microturbo APU.

Following deliveries were of Batch 3 JAS 39C/D machines, which featured:

The last 20 Batch 2 aircraft included some Batch 3 features, such as the color MFDs, CDL 39, and the five data buses. The changes in Batch 3 provided a substantial increase in capability, and the Batch 3 JAS 39C/D machines are sometimes referred to as "Super Gripens".

Gripen production quantities have been steadily decreasing. When the type went into formal service, the Flygvapnet expected to obtain a total of 204 aircraft, but in 2007 the total buy was cut to 100, the last being delivered in 2015. In compensation, all earlier production was brought up to Super Gripen standard by 2012. That represented a major downsizing of the air force, since in the late 1980s the country had 425 combat aircraft in 26 squadrons, and the original plan had been to obtain 350 Gripens.



* Although the Swedes have traditionally been reluctant to export weapons, the end of the Cold War led to relaxation of this policy. In 1995, SAAB formed a partnership with BAE Systems named "Gripen International" to sell the Gripen on the world market. SAAB was forced to seek international sales for the Gripen, since the Swedish government contract for the fighter was so tight-fisted that Gripen International's president, Hans Kruger, once said he'd "lost his shirt, tie, and jacket on the Batch 1 deal."

The arrangement allowed SAAB to leverage off the British firm's international marketing clout. BAE Systems felt that the Gripen would neatly fit in their product line, between the Hawk and the Eurofighter Typhoon. Three years later, BAE Systems obtained a 35% share in SAAB. The arrangement didn't last; in 2005, BAE Systems finally reverted all marketing to Saab, the Swedish company having acquired enough clout to do the job on its own, and that was effectively the end of Gripen International.

There was skepticism in the aircraft industry that the Gripen could meet the competition from American and French manufacturers, but events have proven the skeptics wrong. The first export success for the Gripen occurred in 1999, when South Africa ordered 28, with initial deliveries in the spring of 2008. The South African deal wasn't heavily contested, but late in 2001, Hungary committed to a ten-year lease for 14 Gripens from the Flygvapnet. Deliveries of the Hungarian Gripens began in 2006 with final deliveries in late 2007. In 2012, Hungary extended the lease another ten years, to 2026.

Immediately after the Hungarian win, the Czech Republic announced a preliminary agreement to buy a batch of Gripens. Although the deal was put on hold in 2002 -- after Central Europe was hit with some of the worst floods in memory, with governments scrambling to respond to the emergency -- it was revived, resulting in a lease deal established in late 2003 for twelve single-seaters and two two-seaters. All deliveries were performed in 2005, with the lease deal to end in 2015, though it was later extended to at least 2026. Czech Gripens are armed with US-built AIM-120 AMRAAM missiles.

The success of the Gripen in Hungary and the Czech Republic was a real surprise, since there had been strong competition from US and French offerings. Thailand was the next customer, buying six Gripens in 2008, with first flight of a Thai Gripen in 2009 and initial deliveries in 2011. A second batch of six was purchased in 2010, with deliveries in 2013.

Gripen with SDB, BVRAAM, & IRIS-T

Export Gripens are generally Batch 3 standard aircraft; the Hungarians, being an early adopter, settled for a "near-Batch 3" configuration, with mixed features of Batch 2 and Batch 3 machines. The latest munitions -- the the ASRAAM and Israeli Rafael Python 4 short-range heat-seeking AAMs, and the US-made 120-kilogram (250-pound) GPS-guided Small Diameter Bomb -- have been or are being integrated, along with the Rafael "Litening" targeting and navigation pod and the Thales "Vicon 70" reconnaissance pod. SAAB offers a "Mark 4" upgrade for the PS-05/A radar that gives it enhanced range and improved functionality, particularly more ability to pick up stealthy targets.



* SAAB developed a demonstrator for a next-generation Gripen, rebuilt from a Flygvapnet JAS 39D, which performed its initial flight on 28 May 2008. The "Gripen Demonstrator" featured ten revised hardpoints to provide an external load of 6,000 kilograms (13,200 pounds); a GE F414G engine with 25% uprated thrust; upgraded landing gear; and fuel capacity increased by at least 35% to provide a range of up to 4,000 kilometers (2,500 miles).

Of course, avionics were enhanced as well -- in particular, with the demonstrator fitted in 2011 with an Selex ES-05 Raven "active electronically-scanned array (AESA)" radar; although Selex is based out of Italy, the Raven was actually built by its UK arm, previously Ferranti. An AESA consists of an array of programmable "transmit-receive (TR)" modules that can operate in parallel to perform separate or collaborative functions, performing, for example, jamming and target acquisition at the same time. The Raven AESA will provide enough range to make full use of the Meteor AAM, and in general will pave the way for continuing updates of Flygvapnet Gripens -- and for the "JAS Gripen NG" AKA "Gripen E". The Gripen E will be accompanied by a two-seat variant, the "Gripen F".

The Gripen E will be a true "next-generation" Gripen, featuring:

The Flygvapnet indicated that it wanted the Gripen E, but the status of the effort was unclear until 2011, when Switzerland ordered 22 Gripen Es to replace its Northrop F-5 fleet. In 2012 the Swedish government decided to order 60 new-build Gripen Es as well, collaborating with the Swiss on procurement, with the total then raised to 70 in response to Russian provocations. A contract was also placed to update 60 Gripen Cs to Gripen E standard, but it was then abandoned -- giving SAAB an opportunity sell refurbished Gripen Cs on the international market.

The Swiss order seemed particularly significant, in that the Swiss buy their aircraft to use for a long time, and give them a very good looking-over before they buy. Unfortunately, in the spring of 2014 a referendum of Swiss citizens for approval of the funding for the Gripen buy resulted in a NO vote, with the Swiss Gripen E sale thrown into limbo. The Swiss fighter program has been restarted, but there's no saying what will happen next.

However, SAAB is still bullish on the Gripen E -- it being substantially cheaper than the competition, the Eurofighter Typhoon and the Dassault Rafale. SAAB official say the JAS 39E will have a lower purchase cost than the JAS 39C, and will have the lowest operating cost of any advanced fighter. Other countries are interested: after a protracted selection process, in late 2013 Brazil ordered 36 Gripens, including 28 single-seat Gripen Es and four Gripen Fs, with initial delivery in 2018, giving a further boost to SAAB. Brazil may acquire at least 108 Gripens in all. SAAB officials believe that they can sell hundreds of JAS 39Es internationally; the company is also offering upgrades for Gripen C/D users to some facsimile of Gripen E spec.

SAAB has also proposed a carrier-based "Sea Gripen", a Gripen E with ruggedized landing gear, some airframe reinforcement, plus carrier-deck recovery kit. Given the Gripen's good short-takeoff capabilities, it would not need catapult launch; the aircraft's short span would also make folding wings unnecessary. The concept was floated in response to an Indian Navy requirement that went nowhere, but the Brazilian Navy also had a requirement for 24 carrier-based fighters, giving an opening for the Sea Gripen.



* One item that didn't quite fit in the text above was the fact that the UK Empire Test Pilots School (ETPS) flies the Gripen as the mount to train test pilots on a 5th-generation fighter. They're not really British Gripens though, the flight training taking place in Sweden, with Swedish machines and training facilities, as per a contract established with ETPS. While the Gripens used in ETPS training have the organization emblem painted on the tailfin, the aircraft still retain Swedish "Three Crowns" insignia instead of British roundels. Pity -- it would be fun to see a Gripen in RAF colors.

* The aggressive sales promotion of the Gripen has led to a few odd statements, apparently the products of overactive minds in the marketing department. Some sources have stated that it was specifically designed to only use smart weapons, which leads to the puzzle of why the ability to carry dumb bombs would be designed out, all the more so because with modern attack avionics, unguided weapons can be delivered with surprising precision. In fact, there are plenty of pictures of Gripens carrying dumb bombs and unguided rocket pods.

I used to work with marketing people. There's a saying: "The difference between sales and marketing is that sales knows they are lying."

SAAB fighters in review

* As concerns copyrights and permissions for this document, all illustrations and images credited to me are public domain. I reserve all rights to my writings. However, if anyone does want to make use of my writings, just contact me, and we can chat about it. I'm lenient in giving permissions, usually on the basis of being properly credited.

* Sources include:

* Revision history:

   v1.0.0 / 01 jun 02 
   v1.0.1 / 01 jun 04 / Review & polish.
   v1.0.2 / 01 aug 06 / Review & polish.
   v1.0.3 / 01 oct 07 / Order cut to 100.
   v1.0.4 / 01 sep 09 / Various updates.
   v1.0.5 / 01 may 10 / Review & polish.
   v1.0.6 / 01 apr 12 / Swiss sales deal & Gripen NG.
                        Hungarian lease extension.
   v1.1.0 / 01 mar 14 / Thai deliveries completed, Brazil order.
   v1.2.0 / 01 may 14 / Gripen C/D upgrades, Gripen E details
   v1.2.1 / 01 may 16 / Review & polish.