DCS: AJS-37 Viggen Discussion

[RagnarDa]

The AJ and AJS radar has a air to air mode, just not like the ones you are used to ;) Not sure about A/G on the fighter-Viggen but I don't think so.

[QuiGon]

The AJ and AJS radar has a air to air mode, just not like the ones you are used to ;) Not sure about A/G on the fighter-Viggen but I don't think so.

 

Thanks, that sounds interesting. I guess you don't want to reveal already how it works exactly? :P

[microvax]

Who needs RADAR anyway. If you are flying at -5m RADAR altitude in submarine mode you cant see stuff anyway. ))

 

Same thing with KA50, you can fly so low that nothing apart from some robocop units detects you, problem is, you cant detect anything either. :D

 

Question is, would you [as a DEV] rate the Air to Air mode more or less usefull then the MIG21 Radar ? :D

 

Anyway, flew the Mirage in scramble from taxiway, no time for Radar warmup mode and it was loads of fun. So I guess you would keep the Radar off anyway as long as you arent using it for NAV fix or searching illegal fishing boats. ;) I think the Viggen will be quite good for heli hunting.

Good low speed charachteristics afaik, 2 AKAN pods and a mix of sidewinders RB05 or Mavs. What do you want more ? :D

[RaXha]

Question is, would you [as a DEV] rate the Air to Air mode more or less usefull then the MIG21 Radar ? :D

 

My guess would be less since it's not really an air to air radar at all. :) I'm no dev though. :P

[RagnarDa]

The radar in the attack-Viggens doesn't do any processing or interpretation of the radar-signal, it just shows you the raw input from the receiver (except for scaling of course and a anti-jamming filter). It is up to the pilot to figure out what everything is. Air-to-air mode is same as terrain-mapping mode except the antenna is pointed upward. Air contacts is shown as "blimps". Symbols on the radar-screen are fed from the navigation computer and shows where for example the current waypoint is believed to be. It might or it might not match with the real location as shown by the radar picture. As for comparison with the MiG-21 I unfortunately haven't had enough time to compare the two in-game but I wouldn't be surprised if the detection-ranges of air-targets is similar.

[Crowbar]

What kind of navigational aids can be used on a Viggen? I know it has the rudimentary INS but anything land-based?

[Jediteo]

No external navigation aids except for the TILS (Instrument landing system) which automatically makes navigation fixes during the final approach phase.

I believe the SK and SH had some DME solution implemented, there is a switch in the AJS for DME but has no function.

[microvax]

That all sounds really good, looking forward to manual radar image interpretation. ;)

 

How good is the Terrnav option ? Does it have a alt map of the entire map or just the

flightroute ?

 

Cruise missiles only had the flightpath, but mid90s is really on the edge where I cant decide if its just flightpath or entire region. But tbh i expect it to be flightpath +/- 2km or something like that.

 

Question is, how accurate is that ? Do you only roughly know where you are [accuracy 500m or something like that] or is it accurate enough to launch RBS15 and or BK90. [something sub 150m of error.]

 

So many exciting things happening, Info is really appreciated ! :)

[RagnarDa]

DCS: AJS-37 Viggen Discussion

 

The terrnav has the whole region of operation (at least that what's what we think). They probably loaded the map of where they where supposed to be flying, as opposed to all of Sweden for example. I don't have info about the resolution (at least from memory, do you Jedi?) but the current guesstimation is 100m based on the fact that that's the resolution of the estimated navigational error presented to the pilot (it is reset to 0, or below 100m when the TERRNAV performs a "fix").

 

Edit: some quick calculations: Georgia is ~70 000 square kilometers so a 16-bit height map with resolution 100m is roughly 1.4 megabytes of data. Wikipedia tells me they have been making 2mb SSDs since middle of the 70's and tape-drives are of course even larger...

Edited July 14, 2016 by RagnarDa

[microvax]

The terrnav has the whole region of operation (at least that what's what we think). They probably loaded the map of where they where supposed to be flying, as opposed to all of Sweden for example. I don't have info about the resolution (at least from memory, do you Jedi?) but the current guesstimation is 100m based on the fact that that's the resolution of the estimated navigational error presented to the pilot (it is reset to 0, or below 100m when the TERRNAV performs a "fix").

 

Ah that sounds great so with Terrnav the error is smaller then 100m, thats brilliant. the RBS15 has its own seeker and the DWS39 can be loaded with the MJ2 submunition which is self targeting like the sensor fuzed clusters. So that is also fine with something below 100m error, I guess.

 

Rest of the weapon set doesnt really care about the Aircraft location, so thats great. I guess one could not really align it with better accuracy by flyover or radarfix, unless its a clearly distinguishable reflector, but even then, at range that should add up fairly quickly to 100m error.

 

Sounds really good, looking forward ! :) And thx again for le info ! :))

Edited July 14, 2016 by microvax

[Skjold]

Ragnar, how are the RB 04 / RBS 15 guided? I'd imagine the two have different ways of doing things. Do you mark a position on your radar and tells it to go to that general area via INS and then the radar seeker goes active and hopefully the intended target passes past the seeker or what? Clarification would be much appreciated.

Edited July 14, 2016 by Skjold

[microvax]

[ame=

]

[/ame]

 

Yep, it seems like

go route;

find target fitting specs;

hope to get through CIWS;

[RaXha]

Ragnar, how are the RB 04 / RBS 15 guided? I'd imagine the two have different ways of doing things. Do you mark a position on your radar and tells it to go to that general area via INS and then the radar seeker goes active and hopefully the intended target passes past the seeker or what? Clarification would be much appreciated.

 

 

Better aswer below! :D

Edited July 14, 2016 by RaXha

[RagnarDa]

Ragnar, how are the RB 04 / RBS 15 guided? I'd imagine the two have different ways of doing things. Do you mark a position on your radar and tells it to go to that general area via INS and then the radar seeker goes active and hopefully the intended target passes past the seeker or what? Clarification would be much appreciated.

 

 

 

In short, you aim the Rb04 with a wind-corrected line on the radar (straight ahead) or just visually. When released it dives to sea-skimming height using the radar altimeter and start searching for targets. If you have selected the single-target mode it will target the first contact it sees. If you selected the group-mode it will search for three targets that is in a straight line from the POV of the seeker (themselves not more that 2,7km from each other). Then it selects one of these three targets depending on a switch selected by ground crew. This way, if you for example launch two missiles one could target the first ship and the other missile target the third ship.

 

The Rb15 is different. It can be launched "straight ahead" like the Rb04 but usually you'll use waypoints for it. It uses up to 4 waypoints: one is where the target is (or search area), one is a turning point, one where it is to dive to sea-skimming altitude (or rather the distance to turning-point) and the last is a auto-destruct point. You can set them up by inputting coordinates in the computer, or moving a cursor on the radar screen. There are many different search modes and options for for example how the targets would be selected in a group (randomly or depending on closeness to target-waypoint for example) or the size of the search area. The navigation computer in the aircraft can use a set "missile-in-target" target time so you can coordinate an attack from different directions and all missiles will arrive at the same time.

[microvax]

In short, you aim the Rb04 with a wind-corrected line on the radar (straight ahead) or just visually. When released it dives to sea-skimming height using the radar altimeter and start searching for targets. If you have selected the single-target mode it will target the first contact it sees. If you selected the group-mode it will search for three targets that is in a straight line from the POV of the seeker (themselves not more that 2,7km from each other). Then it selects one of these three targets depending on a switch selected by ground crew. This way, if you for example launch two missiles one could target the first ship and the other missile target the third ship.

 

The Rb15 is different. It can be launched "straight ahead" like the Rb04 but usually you'll use waypoints for it. It uses up to 4 waypoints: one is where the target is (or search area), one is a turning point, one where it is to dive to sea-skimming altitude (or rather the distance to turning-point) and the last is a auto-destruct point. You can set them up by inputting coordinates in the computer, or moving a cursor on the radar screen. There are many different search modes and options for for example how the targets would be selected in a group (randomly or depending on closeness to target-waypoint for example) or the size of the search area. The navigation computer in the aircraft can use a set "missile-in-target" target time so you can coordinate an attack from different directions and all missiles will arrive at the same time.

 

That ancient looking radar screen has a cursor which apparently can spill out coordinates ?

Wow thats really awesome. Can the BK90 also be launched by marking a point on the radar image with a cursor ? I mean that would completely take the NAV drift out of the equation, since if you feed the dispenser with your own drifted coordinates, it just doesnt care, will still go straight to the defined point.

 

*excitement sparkles* I mean if you get SAM site coordinates by an external source you want to have the alignment but even for that the TERRNAV accuracy seems to be good enough. Brilliant ! :D

[renhanxue]

RBS 15 yes, as far as I know it can be programmed to fly a route with multiple waypoints. The rb 04E is a lot more primitive - as far as I can tell from the manual the only setting you can select in the air is the targeting mode, ENKEL or GRUPP (single target mode or group of targets mode). Everything else is programmed on the missile itself by the preflight mechanic, including (as far as I know) if the fallback home-on-jam is enabled or not. Other than that, the only thing you do is find a likely target on your radar B-scope, point your plane thataway, hit weapons release and off it goes, in a straight line. It's completely fire and forget, you can't do anything to influence its targeting really so just turn away and hope for the best.

 

edit: beaten twice over

[renhanxue]

I am a little confused by the radar ranges reported.

 

In the AJ37 manual part2, the range setting can go as high as 120 Km.

In books, and on webpages they report the more powerful JA37 radar to have a scan-while-track range of only 48-50 Km.

 

I am no expert in radars, what does it all mean. Is range-while-search longer range than TWS, or why would the AJ radar be able to be set to 120 KM range?

 

Do you think the 48-50 Km range is meant as for fighter sized targets only? And that it would be able to see much further if it were a big bomber?

 

Could the long range setting in the AJ mean that a datalink could supply targets up to that range from other aircrafts? The jakt(hunter)-link was introduced in the mid 80'ties, but wasn't there a simpler link system in the AJ, or did it have no such system?

 

And if the AJ max setting was 120 Km, what do you reckon it would have been for the JA? Sadly we don't have the JA manual part2, so can't find that out, but a guesstimate could maybe be made.

 

The JA 37's radar was a medium PRF monopulse doppler, the AJ(S) 37's a low PRF monopulse with no doppler function. They had completely different purposes. In the JA 37 avionics seminar they mentioned that choosing medium PRF was a compromise, since they figured it was too complex to support multiple PRF's at the time - but they added it on later JA 37 edits, I believe. Consider though that the JA 37 had datalinks that let it get radar images both from the ground and from other JA 37's and the need for a very long range radar on each aircraft becomes much less pressing. The Swedish air defense kind of assumed that Stril would be available to guide the fighters to intercept - autonomous operation was a last resort.

 

Is that a Ram Air Turbine?

Yep, provides emergency power in case of generator failure or somesuch. Said reserve power will also feed an emergency hydraulic pump to provide pressure to system 2 if that also fails.

 

Yeah, that caught my eye too. Unusual one single wheel behind another like that. You normally expect only two wheel to be side by side.

 

There's a whole bunch of reasons for those - off the top of my head I seem to recall lack of space in the wing for a conventional gear and helping yaw stability when landing.

[Fri13]

The aircraft starts feel far more interesting than anything else in DCS with those targeting systems and flight computers etc.... :D

[Cletust8]

Seems the veil of secrecy is being lifted. I look forward to the teaser/trailer.

[microvax]

The aircraft starts feel far more interesting than anything else in DCS with those targeting systems and flight computers etc.... :D

 

Dunno if you got the memo it's one of the earliest computerized planes to my knowledge. It's the 90 upgrade weapons which make it fairly competitive in DCS. You feed them over a numeric only interface.

 

So if you go with targeting and flight computers which have big capabilities. Ka50 and a10c are way more capable in that department.

 

The Viggens new thing is combination of strike capability and speed. And engineering wise the plane has a whole bag of firsts at the time and some till today.

[QuiGon]

Oh man, the more and more I read the more I'm getting excited. It's really hard to cope with the waiting :joystick:

[MBot]

Yep, waiting for the Viggen is killing me :)

[Hook47]

My excitement with this plane has honestly surpassed the tomcat and I'm so glad we are getting our first strike fighter with some truly unique capabilities

[Schmidtfire]

My excitement has dipped since I read that we will fly it on Caucasus and not over a Sweden map. Landing on swedish roads and rearming at road bases is in the soul of Viggen... Anyways, I am still quite excited and will buy AJS37 on day one.

[drPhibes]

Just crack open a can of surströmming, and it'll be just like flying in Sweden.