Saab 37 Viggen

From FlightGear wiki
(Redirected from Saab JA-37 Viggen)
Jump to navigation Jump to search
Saab 37 Viggen
Saab JA-37 Viggen Blue Peter Livery.png
Type Fighter aircraft, Attack aircraft, STOL aircraft
Configuration Canard aircraft, Delta-wing aircraft, Retractable gear aircraft
Propulsion Single-engine jet (Jet aircraft, Single-engine aircraft)
Manufacturer Saab
  • Anders Lejczak
  • Justin Nicholson
  • Nicola B. Bernardelli
  • Isaac Protiva
  • Enrico Castaldi
  • Joshua Davidson
  • Nikolai V. Chr.
  • Colin Geniet
--aircraft= JA37-Viggen
Status Production
 FDM Stars-4.png
 Systems Stars-5.png
 Cockpit Stars-4.png
 Model Stars-4.png
Supports Canvas Checklists
 Repository The development repository of the Saab 37 Viggen.
Download Download the Saab 37 Viggen aircraft package for the current stable release (2020.3).
Forum 'Saab 37 Viggen' topic on the FlightGear forum.
License GPLv2+

The Saab 37 Viggen is an all-weather attack/fighter aircraft. It had Europe's first pulse-doppler radar, and one of only two jet fighters in the world to sport reverse thrust, the other being Panavia Tornado. This version of JA-37 Viggen was manufactured from 1980-1990, and the JA 37D variant flew in the Swedish airforce until 2005. The AJ-37 Viggen was introduced in 1971, the AJS-37 Viggen in 1993.

AJS-37 in vertical ascend.

Flightgear version

The package contains two variants: AJS-37 and JA-37Di.

Notice that the JA37 is much more accurate and well developed than the other variants.

Flightgear compatibility

  • The latest Viggen version is compatible with Flightgear version 2020.3.1 or later.

Help and Documentation

Flight manual

The flight manual is located under JA37/Doc/ in the aircraft directory. There is also a shortcut in the JA-37 menu to open it from FlightGear. There are two versions of the manual, for the JA-37Di and the AJS-37. Although it is far from completed, the flight manual is the most detailed and up to date source of information.

In FlightGear

The aircraft help dialog contains a summary of the keybindings, and some additional information. Detailed checklists are available, including the full startup procedure.


The file readme.ja37.txt contains some information on the most advanced JA-37 systems, which is not yet available in the flight manual.

Tutorial video series

Outdated to varying degrees. Still contains a lot of useful information, notably regarding navigation systems.

Feature overview


  • JSBSim FDM based mostly on original Saab windtunnel data.
  • 47 individual aerodynamic coefficients.
  • Aerodynamic effect of air intake factor, ground effects and control surface shading.
  • At high alpha asymmetric vortex detachment of left or right side, resulting in adverse effects.
  • Very high alpha handling including realistic departures such as stall, spiral dive, flat spin and inverted spin.
  • Aerodynamic response to payload. (droptank & armament)
  • Aerodynamic drag from canopy open and canopy detachment.
  • Significantly reduced lift and roll damping when wings detach.
  • High compliance with various performance numbers. (true not indicated instrument values)
  • Capable of landing with a heavy crosswind.
  • Mach tuck in transonic/supersonic regime.

Flight control system

  • Autopilot with 3 modes: stability assist, attitude hold, and altitude hold. Autothrottle intended for landing, with speed and AoA hold modes.
  • Foreplane flaps are linked to the landing gear.
  • Elevon and rudder deflection is limited depending on hydraulic pressure, air density and speed.
  • Filter based pitch, yaw and roll dampers lets the pilot control the plane without adverse effects such as turbulence, dutch roll, accelerated rolls and pitch oscillations which would otherwise be present.
  • Gear will not retract on runway, and not extend above certain speeds.


  • Detailed electrical system based on the flight manual schematics. Includes several AC and DC bus, battery, external power, generator, ram air turbine. Each instrument and system is powered by the correct bus.
  • Two hydraulic systems modeled, the second having a reserve pump.
  • Terrain warning system, with HUD indication and annunciator.
  • Open canopy can be torn off by high wind speeds.
  • Simulated airconditioner unit, which become handy when ice or fog forms on windshield in ALS.
  • Automated fuel system that works like in the real Viggen. It uses pneumatics, hydralics and electricity.
  • TILS (tactical instrument landing system) that auto tunes to nearby ILS frequencies.
  • Custom flight recorder records 53 extra properties for accurate replay functionality. Also record fidelity has been increased for smoother replay.
  • 7 internal fuel tanks plus a drop tank that can be jettisoned.

Failure system

  • 26 extra failures beside the standard ones.
  • Canopy motor, canopy hinges, wings attachment and individual gear locking mechanisms are preset to fail under specific conditions.
  • Engine fire preset to start under certain conditions. Can fail engine if left burning too long.
  • Crash-detection and high-G structural break tied into the failure system; it can randomly fail components proportional to the damage the plane takes.
  • Damage system for getting hit by ordnance.


  • Gauges are in metric and have Swedish descriptions. But they have Tooltips, showing Imperial and English units.
  • Switches, knobs and buttons have English text for convenience.
  • Two custom Canvas HUD (one for each variant) built from Saab flight manual several operation modes.
  • HUD values depend on indicated values, not real values.
  • HUD can switch between Imperial and Metric units (JA37 only).
  • At ILS landings the HUD will show a glideslope guide, if the runway supports it.
  • Other HUD features such as distance scale, variant altitude scale, heading scale on horizon in landing mode, diamond at missile lock, altimeter calibration warning etc.
  • Radar with 120 Km range that show MP and AI objects alike, simulating line of sight and pulse doppler filtering.
  • Several complex Canvas displays (radar screen on the AJS-37, radar and HSD on the JA-37).
  • Complex navigation system on the JA-37, allowing to load 4 mission routes and 8 return routes.
  • Auto-start and auto shut down scripts.
  • Very accurate sound warnings for terrain proximity, high load or AoA, speed, etc.
  • Realistic modeled indicator panels for various warnings, alerts and notices.
  • Datalink between JA-37, which displays aircraft positions on the HSD.


  • Volvo RM-8B (AJS37: RM-8A) turbine with accurate fuel consumption and performance in different air density and speed regimes.
  • A thrust reverser is equipped which require proper hydraulics and electricity to work.
  • Afterburner that has 3 continuous zones of operation.


  • 58 distinct sounds, including 19 annunciation warnings.
  • When canopy is open wind and exterior engine sounds can be heard.
  • No out of place sounds being played at start of sim.
  • When guided missiles hit, the sound is propagated according to the speed of sound at the altitude, and so the explosion will be realistically delayed.
  • Thunder (when using adv. weather) and rain sounds.


  • JA37: 30mm internal cannon, rocket pods, and RB-24J, RB-74, RB-99, RB-71 air to air missiles that can be fired at AI and MP alike.
  • AJS37: 30mm cannon pods, rocket pods, bombs, and guided RB-75, RB-04, RB-05, M90 and RB-15F air to ground missiles. Plus 3 kinds of sidewinders.
  • Detailed fire control system, with trigger safety, weapon selection knob (for the AJS 37).
  • Several aiming modes for both JA37 and AJS37, including CCIP for cannon, rockets, and bombs.
  • Radar warning receiver, with both sound and display. Warns of radar, radar lock, and incoming missiles from MP aircrafts.
  • IFF system for multiplayer.
  • Option to enable damage over multiplayer. No longer compatible with the Bombable addon, Sorry.


  • 12 authentic Swedish Airforce and 10 fictive Flightgear liveries included.
  • Selection view, with camera pointing to the aircraft from outside and towards the current selected MP/AI aircraft.
  • Ubershaded exterior model and cockpit panels. Also flood light is supported if model shader is enabled.
  • Normal mapped exterior model.
  • Fully ALS ready, but with no light influences.
  • Animated gear scissors, compressions and spinning wheels.
  • Pilot eye view is tuned for getting good view of runways at landings, while at the same time give good view of HUD and instrument panel.
  • Preloaded exterior view, for fast switching to exterior view.


  • Aerobatic smoke in yellow or blue.
  • Wing vapour under the right atmospheric conditions.
  • Under right conditions, contrails will form and if persistent contrail shader is on they will show also.
  • Lights that depends on distance viewed and sun position.
  • Beacon light that simulate rotating beacons.
  • Frost, fog and rain splashes on canopy in ALS. They depend on canopy position, aircondition, outside/inside temperate and dewpoint and rain.
  • Vapour cone in transonic regime.
  • Landing light cone on runway in ALS.
  • Explosion at crash if plane takes enough damage and has enough fuel.
  • In ALS rain drops will form on the fuselage.
  • Buffeting of cockpit view, at high G, on runway, transonic and high alpha, depending on altitude.


  • The following is transmitted and shown over MP: Gear compression, flight surfaces animation, afterburner flame, engine flame light, landing light, flash light, beacon lights, navigation lights, canopy animation, canopy detachment, wings detachment, explosion, wing vapour, engine smoke, reversers, frontgear steering, missiles, rocket pods, drop tank, transonic vapour, contrails, aerobatic smoke, external power truck, control surfaces, livery and engine heat blur.
  • Different Viggen version are to high degree compatible with each other in Multiplayer.


  • 12 Checklists, 9 for normal procedures and 3 for emergency procedures. Most are translations of real Viggen checklists. Complete with markers, conditions, and bindings.
  • Performance monitor with environment stats, aerodynamic ratios, landing/takeoff distance measurement and other interesting values.
  • Systems monitor, that reveals internal systems state.
  • Options panel, with many configurable options.




Some HUD situations

The HUD assists with ILS landings. This is how the HUD looks most often. This is typical HUD situation before takeoff.


Red ghost livery for the Saab JA-37 Viggen

Vapour on the Viggen in a high AoA situation.
Transonic pass of freighter
Frontpanel will full functioning indicator panels.

Notice the light effect on the fuselage from the afterburner flame. Reverse petals Grey/black camo livery AJS-37 doing an attack run.

See more screenshot in this gallery here.


The Flightgear Viggen has its own Discord chat server: Discord invite link

External links