Heatblur: AJS-37 Viggen



A really good video! The low level stuff was really cool.

A couple of terminology and TTP (Tactics Techniques and Procedures) points from the real world of ELINT collection .

The place where two (2) lines of bearing (LOB) cross on a emitter is called a “two bering cross”. It is not called a “fix”. As stated in the video, many things effect the accuracy of the LOBs. Generally speaking, there is actually a very small likely hood that the emitter willl be exactly on te two line cross.

For a “fix” you need 3 LOBs which will form a triangle (a “three bering fix”). If the LOBs are spaced far enough apart angularly, it should be a fairly small triangle and the emitter should be inside the triangle. However–and this is important–there is still a non-insignificant chance that the emitter will be outside of the triangle…probably not a lot outside but still…it depends on a lot of things, but for DCS purposes, call it a 75% change that it is inside the triangle, meaning a 25% chance that it is outside. Still that is pretty good.

These guys were doing a multiplayer 3 plane and had coms with each other. Ideally, they would have set off of different routes far enough apart to try to detect the same emitter at the same time–communicating between themselves to record time of the “hit” and its parameters (to make sure they have the same emitter).

This is extremely important if the emitter is mobile (SA-8, ZSU-23-4, etc, or a ship) if two or three planes get get 2 or more fixes on the emitter, spread over time, they will show if the emitter is moving (ships are always moving) or stationary. If moving it will give you a rough course and speed. A single plane (or planes in close formation as these were) cannot tell if target emitter is stationary (unless it is something like a SA-3, SA-6 or SA-10 site) or moving, and if it is moving, the fixes will be big and erroneous. Also, you have to do a lot less flying to get fixes.

Now I’m off to fly some of this cool stuff!




  • Spinny Boi
  • some fixes
  • some workarounds
  • bork


Børking job! Absobörking incredible…


Over the next several patches we will be introducing some of the final “major” items remaining: e.g.: …, in-cockpit pilot

…this is evidently the current working version for the Viggen pilot image

@Troll…what have you been doing in your spare time?

Seriously…an awesome jet getting even awesomer!


You know… Börking around.

Good to see the Viggen getting some love. :heart_eyes:



The BK-90 is the most modern weapon carried by the AJS-37. It is a guided cluster munitions dispenser, which means that once released, it will glide towards the target and dispense the submunitions over an area from its 24 launch tubes.

The weapon is designed to be released from low altitudes, and has a range of about 7 km when released at high speed. The weapon will sync up to the aircraft’s navigation system and will guide towards the coordinates of the current selected waypoint, leaving the releasing aircraft free to maneuver away from the target area.

As for the submunitions, they come in two flavors:

The first is the MJ1 (or MUSJAS 1), which is a 3.7 kg fragmentation warhead, with three fitting per launch tube for a total of 72 submunitions. The main purpose is unarmored targets, which will render an area of 300x200 meters quite inhospitable to anything not behind armor.

The second alternative is the MJ2 (MUSJAS 2) which is the larger 16.9 kg submunition designed for lighter armored vehicles. Only a single MJ2 fits in each tube, leading to a total of 24 submunitions per launcher. The warhead will explode over the target and will shower the area with explosively formed projectiles, punching lots of small holes in anything unfortunate to be in the way.

In DCS we have three versions of the BK-90:

The MJ1 version contains 72 MJ1 submunitions. The large amount of submunitions will cover a large area and essentially providing the equivalent high-explosive firepower of a large mortar barrage.

The MJ2 version contains 24 MJ2 submunitions, and is primarily for concentrations of lighter IFV / AFV, and anything that requires a bit more punch.

The MJ1+2 does exactly what it says on the tin, it contains a mix of two, providing some of the best of two worlds. The lower amount of MJ1 warheads will provide slightly less impact density, but the MJ2’s provides a bit more flexibility on armored and unarmored targets.

For a higher impact density, you can fire the weapons in salvo mode. In salvo mode. you can choose between compact, long and, wide impact profiles to customize the impact area for the target layout. Alternatively, you can launch the weapons one by one at multiple target coordinates by switching waypoints (or moving them).

This has been a feature we have been looking forward to pretty much from starting the AJS-37 project all those years ago, and we are now glad that it will be available next patch.



Bjorkening intensifies


Weapon system is a true Bjorkinator!


Udi borki boo




I’ve used this in a attack against aircraft 2 x IL-76 off loading military equipment and ammo at the apron of Abu Must airfield. The offload area guarded by a couple of M-113s ad included a couple of trucks. I used a 2 plane each carrying a pair of BK-90.

Borking Bottom Line: When you get it working correctly, an awesome weapon - total destruction of the target area.

How to get it working correctly in DCS:

This took a bit of trial and error…a number of AI wingmen gave their virtual lives in the process.

For your AI wingman:
1 - Use ground Attack mission
2 - Set the target WP about 5-7 km from the target
3 - Use Bombing - set the target triangle at the center of target area
4 - DCS considers the BK-90 a missile - set Missile weapon type
5 - Set number of weapons to ALL and number of attacks to 1

This will get your wingman to shoot both BK-90s at the target and then break off.

For yourself:
1- Enter release altitude code into the Nav computer. Default is 60 m. Turn to TAKT / Input, use a 91XXX0 will set release altitude between 30 to 500 m (example 91200 = 200 m release). 91000 resets to default. Set VALB/STD switch to VALB (pilot entered). Press LS/SKU to enter - should go all 0’s Note, this is a MSL altitude; set the QFE from the kneeboard card for the target WP)

2 - Use multiple launches to determine coverage size/shape. Again in TAKT / Input, use a 92X000 for size of release (92100=Long; 92200=wide; 92300=compact). Press LS/SKU to enter - should go all 0’s Obviously the release mode seeds to be SERIE since this tactic requires multiple weapons.

You can do all this set up on the ground beforehand or in the air, en route. I used 100 m release and a compact release. I think the AI wingmen just use standard settings. Regardless the effect is awesome! :open_mouth::sunglasses:


Dat frame rate though when all 4 go off at once…


I don’t have the time to test it right now but as I’ve been watching the videos and screen shots roll in of the new BK90, I’ve started wondering about taking out S-300 sites with them. It seems normally they are rather clustered. I know that would mean charging right in, face first but it would still give you a little stand off range… :thinking:


I was going to say you’re already that close, I’m not sure it’d be a radical game changer, but a couple of things crossed my mind.

  1. Bork Jet has limited CM
  2. I’m pretty sure you can fire it off bore
  3. Sneaky Ivans could and would have another layer of air defense assets defending the site (a metric stalin load of MANPADS).

I wonder if you launched it behind a small terrain feature interposed between you and the target if it would have enough smash to get over that terrain feature.


My responses in italics


Looking into this:

I’ve been doing some experiments (that’s what I told the Mrs and I’m sticking too it) to see if I can develop a profile something like this…or at least pop up from behind terrain masking into a SAM envelope, take the shot and get out of Dodge before I get shotdown.

There are a couple of unknowns that I am working my way through.

You need the QFE of the target site. Get it from the kneeboard. So far so good. However, it doesn’t say anything about the QFE of where you are launching from. Most of the time there is probably little difference. However, if my Launch point is over the top of a tall hill, the QFE differences between that and the target are pretty big. The launch parameters are 100-500 m AGL…is that radio altimeter AGL or barometric altimeter-corrected with QFE AGL? Which does the missile recognize? I had a few launches where the BK90s came off and, as far as I can tell, flew up, back into the aircraft…boom…big boom.

The “solution” seems to be to fly over the hill for a few seconds so as to get over downward sloping terrain…but that puts you farther into the SAM envelope. (A not so successful attempt can be seen in the screenshots section).

I think a workable tactic will be something like:
Set up: Set the BK90s for a low altitude attack - 100 m or less. Set the jammer to auto and countermeasures either to auto or Program 1 or 2, chaff only.

  1. Head straight at the target WP below high terrain (no RWR indications). Set radar for attack and take trigger safety off.
  2. Pop up and level off just above the top of the masking terrain - skimming over it at less that 100 m. As you do, initiate chaff.
  3. If you planned it correctly you will already be in range so don’t bother with the range bar. Rather watch the radar altimeter read out on the HUD. When it goes above the 100-200 m, launch.
  4. As soon as you get the ordnance gone light, break, dive and go zone 3 AB. The idea is to get close and parallel to the terrain masking feature, then basically do a barrel roll over it to the other side.

That’s the idea from today’s experiments. If that works, I’ll move on to trying to launch during the pop up maneuver.


Experiment Complete:

1 - You cannot not fire a BK90 from the opposite side of a ridge in a loft mode. When the weapon comes off the jet it immediately heads for it assigned gliding altitude–practically does a flip in the air and heads sharply down. I had a “team” to pop smoke on the top of the ridge line to line me up wit the target. At least one BK90 didn’t make it out of its dive and killed them all (minus points for fratricide).

2 - It is possible to pop over the ridge, level off and fire, however this tactic has issues. The AGL you launch at has a different QFE than the target. This causes odd behavior. Bottom line, I was getting about a .10 Pk using that tactic.

The best bet is to pop through a pass or saddle in a ridge line and then make a fast run towards the target, leaving the ECM pods on auto.

That said, the accuracy of the weapon is not fantastic and really you need to be using for large areas. See screen shot:

This is 4 x BK90w at an airfield ammo depot. They were set to 100m and wide dispersal. Take a look at the red DMPI triangle (Dedicated Point of Mean Impact…a RL targeting thing). I got the target but was definitely left and short.

EDIT: Question for @Troll. Were there any “favorite” settings for these things? Or was it always target dependent? A very cool weapon. :slightly_smiling_face:


I never saw it in person. I don’t think it was operational on the Viggen Attack squadrons. BK-90 was developed for the AJS 37 and JAS 39, but only saw operational use on the 39, for a very short time.
Sweden signed a cluster munitions ban, after the weirdest defense debate ever, IMO. Sweden was not supposed to use ’inhumane weapons’. What is a ’humane weapon’?

So, the Mjölnir went to Aasgard.

Our defense doctrine was to lay mines all over the northern areas, to slow down a land based invasion from the east.


Mostly has to do with long term damage to the area if I understand it correctly. Cluster ammunitions are absolutely terrible for the long term on the civilian population hence why everyone wants to get rid of them.

The impetus for the treaty, like that of the 1997 Ottawa Treaty to limit landmines, has been concern over the severe damage and risks to civilians from explosive weapons during and long after attacks. A varying proportion of submunitions dispersed by cluster bombs fail to explode on impact and can lie unexploded for years until disturbed

It’s rather interesting to note that 40% of the Isreali cluster munitions used in Lebanon failed to explode, posing a long term risk if not properly disposed off and well. We all know how well these kinds of things are taken care of after war(not really well at all).


Absolutely! And that part is not hard to grasp, at all.
It’s just that there were plans for this. Mines that blew after a cerain time, mapping, etc.
Still, mines are incredibly effective for the type of guerilla warfare, that the Swedish defense was based on.