Initial Impressions: DCS: AJS 37 Viggen by Leatherneck Simulations


Hello there fellow sim-heads!

A rare gem is upon us, an aircraft whose song has never been sung in the virtual skies of flight sims. At least not in full detail. An almost obscure, and yet fairly sophisticated aircraft, the unique Swedish SAAB Viggen.

I have always wanted Viggen to be featured in a realistic sim, and finally we have just that, and the version I’d first ask for too. What we have from Leatherneck Simulations of MiG-21Bis fame is, the quintessential attack version of the Viggen, and it’s 90s upgraded variant to be specific: the AJS37.

AJS stands for Attack, Jakt (hunt, meaning air-to-air), and Spaning (recon), and they matter exactly in that order for this version.

For historical purposes, other version of the Viggen include, the original attack variant AJ37, reconnaissance verisons SF37 and SH37, training version with two cockpits the SK37 and finally the interceptor variant JA37. They all differ quite a lot among each other.

Anyway, back the AJS, what we have is mainly an interdictor/striker. Aircraft’s design revolves around a few pillars: great short take-off and landing performance, great high speed and

Cockpit is excellent in usual Leatherneck fashion

The cockpit is excellent in usual Leatherneck fashion

very low altitude mission capability, and high level of sophistication/automation for its day. Viggen is build around the mission concept of “one pass-haul ass”. Few of its weapons can be released individually, by default, one press of trigger lets loose the entire air/ground ordnance it carry. Ericsson PS37 radar helps with navigation, target location, and calculation of firing solutions. Yes, this is the first air to ground radar we have in DCS! CK37, one of the first mission computers in the fighter aircraft, is the central brain of the Viggen… well… apart from human-meatbag pilot’s brain that is… With the radar in terrain avoidance mode, the Viggen can do its low altitude high speed navigation thing even in bad visibility or night. Aside from preplanning in the mission editor, navigation waypoints can either be fed to the system via coordinate input to with a keypad, or existing points can be shifted with taking a fix on them with the radar.

The system relies on a database that model the terrain, and uses this in conjuction with air data systems such as radar/baro altimeter, pitot tubes etc. to provide the pilot with navigational status. However, the system doesn’t have an INS or satellite component, so it can drift, especially with maneuvering or high altitude flying. Thankfully, there are several ways to fix that via either a manual “known point” fix, or a fix with the radar.


Viggen works whether it’s sunny and bright…

Graphically, the module has the hallmark quality we came to expect of the Leatherneck Simulations. Both the cockpit and the external model look excellent in geometry and textures. The module already includes some training missions, single missions, and both a full and a mini campaign will be coming for the Viggen. A first among the modules so far, Viggen module will eventually freely include a campaign for both the Caucasus and Nevada terrains, if all goes according to plan. Flight model in this early access state, shows us the advantages, as well as the eccentricities of Viggen’s design. It has great stability and low altitude handling, can accelerate at a ridiculous rate with maximum afterburner, and when it is fast, it can turn a 180 very, very quickly. After that 180 two things happen : canard delta drag, and an engine that absolutely, positively HATE high angles of attack. Therefore this bird’s flight characteristics are both rewarding, but also difficult.

Speaking of the design, Viggen when entered serivce originally in 1971, had many features which it was either first, or among the first to have. A

...or cold and bleak

…or cold and bleak

mission computer, a thrust reversing afterburner, and the first operational canard delta layout, to name a few. Viggen module, similarly bring many firsts to DCS’ table: thrust reversing, first canard delta, first programmable gliding submunition dispenser with a standoff range, first player controllable aircraft with anti ship missiles, first way point programmable missiles, and last but certainly not the least, air to ground radar!

Going by the most “mainstream” generation classsifications, Viggen is considered a 3rd gen fighter-bomber. I have said it in the past but, 3rd gen is my favorite in DCS, and with MiG-21Bis, F-5E already available, now joined in with Viggen, it is fleshing out nicely! Even though AJS is a early-ish 90s update to Viggen, if certain payload options are not used, and certain navigation options are not used, it is pretty much the same as an earlier AJ37 version, therefore it can take roles in both pre 90s scenarios, and post 90s scenarios.

Often, when it comes to a DCS module, one of the first questions that materialize in many of virtual pilots is “what kind of weapons can it use”. Viggen does have many options there, and let us have a look right now:

First and foremost, AKAN pods, 30mm gun pods that carry an ADEN cannon with 150 rounds.

It uses standard NATO 30mm cartridge of 30×113, which is NOT the same as A-10’s monstrous 30x173mm. Currently, the guns seem to fire fairly flat, and with low dispersion and almost no recoil is felt on the virtual airframe. ADEN is a fairly fast-ish gun for a single barrel weapon, capable up to 1700 rpm. Viggen has various sight modes for either air to air or air to groun utilization of these pods. It is worth mentioning however, big, heavy, and draggy pods won’t help with Viggen’s already delicate maneuverability in an aerial fight, so air to air use should normally be considered against slower and less maneuvrable aircraft, rather than nimble fighters. For ground attacks, it can theoretically provide the Viggen with some lasting power against softer targets, but with 150 rounds per pod it isn’t much. Spent casings are retained inside the pod, so firing won’t lighten you up all that much.

Interestingly, interceptor version, JA37 does have an internal cannon, which is an Oerlikon KCA. That one actually IS the same monster 30x173mm caliber as the GAU-8 Avenger of A-10 fame (colloquially known as brrrrrtt). It even has a special mode where autopilot maneuvers the aircraft itself, so that the shells will hit the target locked by the radar. Anyway, these are features of another toy, not of ours :).

Viggen’s systems can handle only one type of air to ground ordnance loaded into the aircraft at any time. AKAN pods however, are an exception, and they can be paired up with RB 75 missiles, which are basically rebranded AGM-65 Mavericks.

These gunpods can be carried on inner wing pylons only, which are also the pylons where the antiship missiles or countermeasure pods can be carried under. Therefore, these 3 categories of payload are mutually exclusive to each other.

Radar in action

Radar in action

Speaking of the countermeasures, Viggen does not carry them internally, at least not the attack Viggen. JA Viggen did eventually get on board chaff/flare dispensers pretty late in it’s career around mid to late 90s. In our AJS Viggen however, they are available in under wing pods. KB pod is for loading up and releasing chaff and flare. It can do so in various programs. U/22 and U/22A are ECM pods.

Before we get into the actual meat, the air to ground weaponry, let us first look at air to air options:

AJS 37, if need be, can act in a secondary interceptor role as well. The outermost wing pylons are always reserved for air to air missiles, and inner wing, as well as chin pylons can all carry air to air missiles too, for a total of 6 missiles. Missiles are licenced Swedish versions of AIM-9 Sidewinder:

  • RB24 are copies of AIM-9B: We all know and (not quite) love… Rear aspect, short ranged, and unless you are in the 1950s, totally craptastic. By the time of AJS update, these were retired decades ago, but are included in the module for possibility of simulating older AJ Viggens in 70s scenarios.
  • RB24J are copies of AIM-9J: Also rear aspect but overall a much, much better missile. Very similar in capability to AIM-9P3 and R-13M1.
  • RB74 are the real deal… they are copies of AIM-9L: It is just a little bit less capable than the AIM-9M, it can be considered very similar actually. All aspect, very decent range for a heat seeker, maneuverable in the air, and has a good warhead. The caveat is, Viggen can carry RB74 only on the inner wing pylons and the chin pylons, but not the outer wing pylons.
Yes, yes, that is the normal operational altitude :P

Yes, yes, that is the normal operational altitude 😛

Now… the actual main course, Viggen’s air to ground repertoire:

  • ARAK M/70 135mm rockets: Viggen can carry these under both the inner wing and chin pylons, in pods that contain 6 rockets each. Rockets are fairly potent, being of larger caliber than Zuni or S-13 rockets that are used by USA and Russia. Either blast HE or HEAT warheads are available. True to it’s one-pass approach to the matters of the attack, Viggen IRL don’t release these rockets one by one, rather, one press of the trigger means releasing all of the rockets in all of the pods in a little more than half a second. DCS: AJS 37 acts identically by default: you press the trigger, and off goes all the rockets in 0.6 seconds. However, you can use ENKEL – GRUPP switch, to use only one pod with each trigger pull if you like, as a “gameplay option”. According to a post by Cobra, later on ARAK functionality will be divided between two pod types, one allowing IRL “one press, off goes ’em all” and another pod that will fire one rocket per trigger pull. This is realistic, as the training pods IRL did so, and theoretically there is nothing barring real rockets from being used in them.
    Viggen has various mods to assist with rockets aiming, and if your nagivation system is not drifted much, and you have entered the correct QFE setting for target area altitude, you rockets will be very accurate indeed, at least from an “area target” point of view, which is the intented role for this weapons anyway. If you were fast while firing, they will also have a surprisingly long range!One thing very noticable in RL Viggen footage is the very characteristic thick and dark black smoke plume these rockets leave, and Leatherneck team has captured this characteristic effect pretty well, your rockets will stand out from the other rockets in game, be sure! 🙂
  • Bombs: Viggen can carry 4 x 120kg bombs per any of it’s 4 main pylons, for a total of 16 bombs. They can either be of low drag or parachute retarded configurations. Compared to other 3rd gen fighter bombers, F-5E, the lightest and tiniest, is also surprisingly the one that can carry by far the heaviest bombload. MiG-21 on the hand, while can’t carry as much, still has access to heavier bombs like 500 or 250kg ones, as well as cluster bombs. What Viggen makes up for this is however, it’s ability use these 16 x 120kg bombs with it’s many different and accurate bombing modes. Theoretically, if your NAV fix is good, and you fly accurately enough, you can even bomb a point in no visibility conditions.
  • Lysbomb: These are flare bombs to light an area up for night ops.
  • RB 75 (&B&T): Mavericks! RB75 is Swedish built version of American AGM-65A Maverick. Being the first version, you can’t ground stabilize it without something to lock, and it doesn’t have zoom function either. However, it is still the good old fire and forget guided air to ground missile we all know. It is aimed witha a funky little viewfinder/sight right next to the hud, the circular EP-13 sight. B version is not a historical one, and it represents AGM-65B with more magnification for engaging from a larger distance. Since there isn’t really much difference technologically between A&B versions, Viggen would have been able to utilize the B too if Sweden chose to obtain them, and for this reason Leatherneck has opted to include these as a choice as well. Finally the T version is the Swedish change into the A versions with a larger blast warhead. Apart from the anti-ship missiles and RB05, this would be the largest warhead of weapons the Viggen carry.Bear in mind, these are older generation Mavericks, and not the D,G,H,&K we came to know from the A-10C. These Swedish Mavericks will have more difficulty acquiring an accurate lock from distance, or show you an image that is good enough to discern and pick individual targets quickly.
  • RB 05: Viggen can carry two of these, on the chin pylons. Aside from the anti-ship missiles, these have the largest warhead among the Viggen’s arsenal. RB05 are supersonic MCLOS missiles that the pilot has to “fly” from his cockpit with a separate stick. A bright flare is lit at the back of missile to help the pilot with tracking it’s movement.
  • RB 04E: The first of the anti ship missiles, this missile allow the Viggen to engage enemy ships from about a distance of 30 kilometers.
  • RB 15F: Majorly upgraded from RB04, this one has a range of 70km, but more interestingly it can be programmed with waypoints of it’s own. This weapon is added as part of the AJS upgrade in 90s.
  • BK 90 Mjölnir: Perhaps the most interesting of Viggen’s weaponry, these are gliding submunition dispensers that can be released at a standoff distance, will then head themselves towards the waypoint set before the release, and will release lots of submunitions over the area once they reach that location. Pattern of the release can be set to compact, wide, or long, via inputting special command codes to TAKT mode of CK37. Viggen can carry 4 of these.

    Mjölnirs released...

    Mjölnirs released…


  • Air to air: Well, TL;DR: this is NOT an air to air radar. However, it does have an air to air search mode for finding and ranging aerial contacts. This achieved by simply tilting the antenna up, and basically work in more or less the same way as in air to ground modes.
  • Air to ground: The radar can operate either in a B-scope or PPI type of display, and has a range up to 120 kilometers. Radar display will show a circle, noting the current navigation point/target location. Using the radar fix control and radar stick, a cross shaped cursor will appear on the radar screen and using this cursor a new point can be chosen, this can be used for fixing drifts in the navigation system, or designating / fine tuning a target location.
  • Terrain avoidance: Radar can also be used in a terrain avoidance mode, where the display will show what’s right in front of the aircraft, at the same altitude. This can help with nagivation in low altitude and low visibility situations.

Flying the Viggen32723527105_37ce5b47fc_h

  • SPAK & modes: The Viggen features an autopilot / control augmentation system named SPAK. Normally it should always be on, and this is indicated by leftmost green light on top felt panel being lit. Two other green lights next to it are attitude and altitude hold modes, respectively. Attitude hold allows for the pilot to remain in a trajectory for an attack, only do small adjustments as needed, where as the altitude hold will low altitude flying less of a chore.
  • Engine hates AoA: Yup, it just hates it, and will experience compressor stalls if pushed too hard there. It will complain with a loud thumping noise, and if the AoA isn’t relaxed it will eventually flame out. This is one of the primary limitations on Viggen’s maneuverability; it doesn’t like getting slow for this reason. However…
  • It has a fairly crazy high speed instantaneous turn: When fast, Viggen can reverse course pretty quickly, but watch out, you may exceed the G limits and break your wings, or just find out how quickly this relatively heavy delta canard can shed its energy.
  • Speaking of the energy, the zone 3 after burner is ridiculously powerful, acceleration is crazy, but so is the fuel consumption. You can drain your tanks dry in a matter of minutes if you just keep it on! That being said, when in zone 3, it really does create enormous power, and a lightly loaded Viggen at zone3 will have a great thrust to weight ratio, even greater than a Mirage 2000 for example. This leads a great acceleration ability, even down on the deck, and unlike MiG-21Bis’ similarly boosting emergency afterburner feature, Viggen’s zone 3 can be used effectively on altitudes higher than 4000 meters too, even if that is 3990 meters higher than where a Viggen should be ;).

Overall, the Viggen is a great addition to both DCS World, and the flight sims in general. The weapons and features it bring on the table are very cool and interesting, as is the aircraft itself. Visual quality, both externally and in-cockpit, are excellent as usual from Leatherneck Simulations. Also the custom flight model, majority of the systems, a manual, and some training and combat missions were included from day one of early access. There are issues to iron out with a few of systems and weapons, but overall everything is already pretty functional, deep, and fun! As the AJS version, it also bridges between a 90s aircraft and 70s aircraft, being able to be used in scenarios covering a wide time frame, depending on weapons load. Looking forward to its completion (and hoping it will a smoother between versions compared to the otherwise great MiG-21), but it already is a great module.

Congrats to Leatherneck, as well as my thanks for bringing us another “obscure and cool” plane ;).


2 Responses to "Initial Impressions: DCS: AJS 37 Viggen by Leatherneck Simulations"

  1. Karl Trimble  March 8, 2017 at 11:16 pm


    • Erdeniz Sanlav  March 10, 2017 at 1:02 pm

      Thanks! 🙂

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