Cold War 1947 - 1991

[m4ti140]

Interesting tracking..

 

R-60 is only slightly less broken than Rb-24J right now, that's why it's not on the server, so this is a moot argument. R-60M is correct, but it's a better missile with all aspect capability, slightly better than AIM-9P5, and would need a few 9Ls/74s available to compensate. But it's realistic, unlike 24J having thrust vectoring.

 

Also the only thing your images show is that it can track front aspect, which it should do to badly to be of use (and that's what is broken about it). You can show telemetry graphs in tacview, but it seems they didn't push the point you had.

Edited July 20, 2020 by m4ti140

[Sideburns]

The Vne in Viggen is 1350 km/h indicated. At sea level in ISA conditions that translates to Mach 1.1. To go faster you need to go higher, or risk damaging the aircraft (and this risk simply doesn't exist in DCS right now, load factors are taken into account but Vne not so much).

 

I have had an engine failure after a Mach 1.4 low level flight, but the engine did fail on the following sortie. Also over G is a real risk above Mach 0.9, wings can come off. So it is not without risks.

 

On a similar note I trust all you MiG21 pilots are sticking to 7G limit with 4 missiles loaded or 4G with the 800l tank?

 

 

But it's realistic, unlike 24J having thrust vectoring.

 

Thrust vectoring, how did you come to that conclusion?

[Hiromachi]

Thanks for this overview, my question was genuine and I appreciate a genuine answer. Was not aware this is how the flaps work on the MiG21. So there is no flaps overspeed and flaps can contribute, albeit minimally, to braking effect at higher speeds. I had observed a MiG21 loosing speed incredibly quickly while travelling in a straight line hence my original question. I will probably take out my MiG21 module to see if I can recreate.

 

On the earlier points of missile effectiveness the stats posted earlier are interesting, but bear in mind these numbers are the combination of both the missiles base effectiveness and their employment. I still see MiG21's try to evade missiles in AB, presumably emergency AB and I know that within my group we do hold back shots until the aspect and/or target speed is favourable. We also co-ordinate together in dogfights to create these favourable conditions as wing pairs. When a missile is fired upon we practice an IR missile defence, maximum performance turn with engine to idle (often resulting in an overshoot of the enemy). Also in comparing the MiG21 and AJS-37 ability to dodge missiles don't forget that the AJS-37 also has a turbofan which helps reduce IR signature vs the MiG21 turbojet.

 

On the comment that the AJS-37 do mach 1.2+, well that is what they are designed to do. The MiG21 can also go fast if you want to, but not as fast as the AJS-37 at low level, probably faster at high level. Once more if you are fighting the enemy at his advantage you are not doing it right.

 

Hey, no worries, I can always answer any other MiG-21 related questions if you want.

 

I dont know how many MiGs try to evade missiles in AB but its possible that they havent seen missile launch (I often dont even see due to how limited view from the cockpit is) what is happening behind me. The other explanation that for the MiG-21 might be the case is that without afterburner there really is no maneuverability. No afterburner turns, especially if prior to launch 21 was maneuvering, just dont happen since available G is extremely low. And of course, R-25 spool down takes time. You can retard throttle but engine RPM goes low in delay.

 

As for the Viggen top speed. Well, not according to available sources:

 

 

 

 

We've seen Viggen during the Blue Flag Ramble even go with four / six pylons and missiles attached up to 840 - 860 kts down low. That's Ma=1.3 and I have pictures of Viggen going even faster on CW. Which makes it at least 0.2 M faster than according to the above graph. Now, this graph clearly shows that there is some artificial speed restriction as aircraft itself has enough thrust to go even faster. That restriction (Vne) could be because of engine structural limitations or other reasons. I don't know what is the reason, but we know for certain that there had to be something as otherwise such top speed limit would not be imposed.

 

To give an example, although not exactly game related, I can bring the case of MiG-21PF / PFM with R-11F2-300 or R-11F2S-300 engines. MiG-21 PF / PFM were restricted to speeds of 1100 km/h or 1200 km/h Indicated at altitudes up to 11.000 meters. Above that top speed limit was Ma 2.05

Aircraft had enough thrust to overcome drag and clearly could go faster but wasnt allowed. Why ? Because of structural limitations of the air-frame. Or more specifically the engine, due to maximum speed pressure - dynamic pressure of the airflow affecting the engine unit during the flight. In normal conditions MiG-21 PF up to 2000 m was restricted to 1100 km/h (except with some modernized engine, if so than limit was lifted to 1200 km/h) and 1200 km/h above 2000 m, but not more than Ma 2.05 at all altitudes.

Above those speeds pressure built on first stage of compressor and heat created in afterburner chamber were too great and could cause permanent damage. The restriction could be lifted only for preselected engines with improved compressor blades and improved thermal treatment of the afterburner chamber or later engine versions (incorporating improvements) like R-11F2SK-300, permitting top speed up to 1300 km/h. Alternatively, manual indicates that 21 PF / PFM could be equipped with R13-300 engine, which allowed for the same top speed.

Ma 2.05 speed limit up high was imposed due to directional instability that appeared beyond that speed (although there are recorded events of pilots going up to 2.1, 2.15, etc.).

 

So whatever reason is there, limiting Viggens top speed down low, it was likely due to engine structural limitations. Which might not be present. But that is something Heatblur would have to be asked about.

 

Thrust vectoring, how did you come to that conclusion?

Rb-24J on launch has maneuverability similar to AIM-9X according to Lazzyseal test, so I guess he used metaphor here :)

[m4ti140]

I have had an engine failure after a Mach 1.4 low level flight, but the engine did fail on the following sortie. Also over G is a real risk above Mach 0.9, wings can come off. So it is not without risks.

 

On a similar note I trust all you MiG21 pilots are sticking to 7G limit with 4 missiles loaded or 4G with the 800l tank?

 

 

21's engine dies around 1250 indicated. You can steel run away at 500kph relative speed, you don't need to manoeuvrer to run, it's only a risk if someone doesn't know what they're doing and yeets the stick.

 

 

 

Thrust vectoring, how did you come to that conclusion?

 

 

Read the thread before you post. There's a post by LazzySeal where he compares it to an AIM-9X, and it's not far off - max turn rate right at engine ignition, to the point it breaks tacview telemetry plot. He also showed P5 for comparison, to show how it should fly. P5 was significantly inferior to what is supposed to be P3.

[rossmum]

The 21's engine most commonly dies around 1350km/h. Sometimes less, very rarely more. There used to be a way around this by manually manipulating the cone (too minmax for my tastes, like the ARU 'tricks') but as far as I know and according to testing based on my own curiosity, that no longer works. 1300 is your 'safe' limit, 1350 is your fudge factor. Beyond that, goodbye engine. The Viggen can be pushed 200km/h beyond this with a drop tank and 6 AAMs without any switch foolery, but I suspect there are some manual overrides you can throw to get even more speed out of it, as only a few people seem able to consistently pass M 1.4.

 

As for G limits... any 21 who's still got a tank on during combat probably has bigger issues. One of my issues with the 21 is that the airframe doesn't actually break when subjected to violent over-G situations (which really mostly come about as a result of ARU manipulation - with the ARU in operation it's possible to scrape up around 11-12G for a split second, but almost every F-5 defensive break from a missile sits in the same range). I don't think this gets abused much, though, as only a few people really seem to mess with the ARU and even then you're risking GLOC and killing the engine, and dumping all your speed to do so. MiGs might make a single high-G turn through the merge but after that point, simply lack the available speed or control authority to pass 7-8G, winding down steadily as speed bleeds off. The Viggen is in the same boat there except that a sustained pull above 9G seems to rip the wings fairly consistently. Now this is conjecture, but as the limit is 8G I think this is too aggressive of a limit - while the crew chief would not be happy with you, a single and brief 9G event causing catastrophic structural failure on an 8G aircraft is... odd.

 

The other thing I'm really not too sure about is the way that any time something clearly broken or at least questionable is pointed out, the question is immediately turned around onto the team not adopting interdictors as fighters, complaining if they run out of missiles to do so while the actual fighters with missiles that should be equal or better (on paper) sit gathering dust...

[Sideburns]

21's engine dies around 1250 indicated. You can steel run away at 500kph relative speed, you don't need to manoeuvrer to run, it's only a risk if someone doesn't know what they're doing and yeets the stick.

 

I have had the MiG21 quicker than 1250 sustained with no issues or tricks. And the need to manoeuvre will sometimes depend which way you're pointing when you decide to egress. The Viggen can be fragile at higher speeds and sustained "at the limit" G's, No "yeeting" required.

 

 

Read the thread before you post. There's a post by LazzySeal where he compares it to an AIM-9X, and it's not far off - max turn rate right at engine ignition, to the point it breaks tacview telemetry plot. He also showed P5 for comparison, to show how it should fly. P5 was significantly inferior to what is supposed to be P3.

 

Just a polite request for evidence of claimed thrust vectoring in your post. Assuming you are referring to #2739 and #2740 unfortunately the Rb24, Rb24j and Rb74 all report as ROBOT in tacview so this isn't as conclusive as it appears. Also the comparison appears to be an aim9p. You might also wish to read the thread before posting.

[Hiromachi]

He meant 1350 km/h I think, just a typo :) Thats the speed limit. Going to 1400+ km/h causes flameout.

[m4ti140]

Just a polite request for evidence of claimed thrust vectoring in your post. Assuming you are referring to #2739 and #2740 unfortunately the Rb24, Rb24j and Rb74 all report as ROBOT in tacview so this isn't as conclusive as it appears. Also the comparison appears to be an aim9p. You might also wish to read the thread before posting.

 

 

I was doing this test with him. Even if it was 74 it would still be significantly overperforming. But it wasn't. We can send you track files next, but who are you for us to even care? This went to Alpen. And to ED.

[Foka1]

Just a polite request for evidence of claimed thrust vectoring in your post. Assuming you are referring to #2739 and #2740 unfortunately the Rb24, Rb24j and Rb74 all report as ROBOT in tacview so this isn't as conclusive as it appears. Also the comparison appears to be an aim9p. You might also wish to read the thread before posting.

 

Just a polite request from me too. So you accusing me of being liar? For this test you need tacview , DCS and 15 minutes of your time max. You can do it by yourself to not waste time on discussions .

 

 

PS for your convenience I'm attaching mission file. Just load it, merge with target when its flanking in front of you 90 degrees launch a missile. Check tacview afterwards

90_degrees_2KM_AGL.miz

Edited July 20, 2020 by P61

[Alpenwolf]

Server News:

 

We just flew the new mission Hold The Line. The bug is gone and the mission ran perfectly! A small issue towards the end but that's fixed too as of now.

 

 

Teaser:

A new mission is in the making... and... it's... completely... at midnight!

It's going to be in the Persian gulf map. Moonlight. No clouds. No winds. I ran some tests in the MiG-21 against the F-5. Once in a dogfight and both hit the burners it's a thing of beauty! You can actually see the missile's smoke sometimes, especially when flying over the water. Helicopters will be included. Not sure about the Harrier still, although Harrier pilots would love a night mission, I guess.

So go ahead and get some night mission practice, gents!

[rossmum]

NIGHT TIME IS THE RIGHT TIME :D

 

Can't wait to fly it. The 21's new cockpit lighting and the burner plumes... awesome.

[NELLUS]

I was doing this test with him. Even if it was 74 it would still be significantly overperforming. But it wasn't. We can send you track files next, but who are you for us to even care? This went to Alpen. And to ED.

 

This is a forum where we provide facts and having a sound dialogue around it. Please dont take it personally if secondary questions appear, everyone here have a right to question information that has been provided on the forum, and not only Alpen and ED. Accusations is a different story, but there were non made on Sideburns request.

[Sideburns]

Just a polite request from me too. So you accusing me of being liar? For this test you need tacview , DCS and 15 minutes of your time max. You can do it by yourself to not waste time on discussions .

 

 

I didn't call you a liar, and for what it is worth I don't feel like this is discussion is a waste of time.

 

I said the evidence presented had some ambiguity in it due to the way weapons are represented in Tacview. I am also making my own tests and investigations, granted you do need an upgraded version of Tacview to get the graphs.

[Sideburns]

but who are you for us to even care?

 

Clearly you care enough to respond, but just to be clear it doesn't mean that much to me to mean that much to you.

 

This went to Alpen. And to ED.

 

Do you have a link to the bug report I assume you filed with ED for this? A quick search doesn't reveal anything.

[Foka1]

I didn't call you a liar, and for what it is worth I don't feel like this is discussion is a waste of time.

 

I said the evidence presented had some ambiguity in it due to the way weapons are represented in Tacview. I am also making my own tests and investigations, granted you do need an upgraded version of Tacview to get the graphs.

 

I'll remove ambiguity with a video then. Or you can just find me in some messaging platform and we can test together.

 

PS Why I like when someone else do same check as well and not just asking me to prove something is that I don't believe in my methods unquestionable precision. When someone else doing same thing something else can be uncovered which I missed.

Edited July 21, 2020 by P61

[NELLUS]

I'll remove ambiguity with a video then. Or you can just find me in some messaging platform and we can test together.

 

PS Why I like when someone else do same check as well and not just asking me to prove something is that I don't believe in my methods unquestionable precision. When someone else doing same thing something else can be uncovered which I missed.

 

I’m glad we speaking the same language :thumbup:

You might have some info coming your way shortly.

Edited July 21, 2020 by NELLUS

[Sideburns]

I'll remove ambiguity with a video then. Or you can just find me in some messaging platform and we can test together.

 

PS Why I like when someone else do same check as well and not just asking me to prove something is that I don't believe in my methods unquestionable precision. When someone else doing same thing something else can be uncovered which I missed.

 

Not required, found the issue.

 

\Program Files\Eagle Dynamics\DCS World\CoreMods\aircraft\AircraftWeaponPack\aim9_family.lua contains the variables for the aim9 missiles

 

\Program Files\Eagle Dynamics\DCS World\CoreMods\aircraft\AJS37\Entry\Weapons.lua contains the Viggen Rb24/Rb24j/Rb74 variable definitions

 

If you look in these files the sensor, thrust, drag and Cl (Coefficient Lift) values (cy_k0, cy_k1) are defined, the Rb24j has some generous Cl values that put it above the aim9p5 (double the Cl) but also below the Aim9l and aim9x. Regardless it probably shouldn't be this way, it should be the same as the aim9p series. Thrust, sensor and drag values otherwise seem sensible for the Rb series. Sensor is superior to aim9p but inferior to aim9p5. Thrust is about the same.

 

If you have submitted a bug report to ED it should probably include this information. Appears to have been an issue since at least 2018.

 

However I will maintain that many of the shots I have taken did not need the missile to manoeuvre hard or far to hit, so don't expect this to cure all redfors issues.

[NELLUS]

I think there has been sufficient data collected to determine the RB24J being superior, and should be removed from the load out selection until an amendment has been done.

[Sideburns]

Reported as a bug, as I couldn't find a relevant previous bug.

 

https://forums.eagle.ru/showthread.php?p=4428923#post4428923

[Alpenwolf]

Sling Loading

 

Just finished testing sling loading an ammo box weighing 1500 kg in the Mi-8 with 100% fuel, no door gunners and no weapons at 265 kph indicated, 25-35 meters ASL. And I'm sure I could've flown a bit faster but it wasn't necessary.

 

The results were very satisfying!

Much less swinging than sling loading a container (bigger in size and of course asymmetric in shape unlike the cubic shaped ammo box). So it seems that the physics taken into consideration there are not as inaccurate as I had thought.

In less than 2 hours the mission Prince of Persia will go online and will include the ammo boxes for sling loading tasking in the Mi-8.

 

 

NOTE:

I don't own the Huey, so someone should please try sling loading an ammo box (the first cargo unit on the list), only not weighing 1500 kg of course. You'll have to adjust the weight.

Please, report back to me so that sling loading, especially in the mission Elbrus can be doable for both the Mi-8 and UH-1 and future missions.

[NELLUS]

Alpenwolf, when do you think the modern planes (Mirage & Mig29) will leave the cold war server?

 

Saw a few low Ping planes behaving like UFO’s tonight. Would be a good idea to tighten the Ping limits.

Edited July 21, 2020 by NELLUS

[Alpenwolf]

Alpenwolf, when do you think the modern planes (Mirage & Mig29) will leave the cold war server?

 

Saw a few low Ping planes behaving like UFO’s tonight. Would be a good idea to tighten the Ping limits.

A matter of days and they'll be gone.

Limiting the ping doesn't work. Players can still join.

[rossmum]

Ping isn't the issue. The problem is inherent to DCS netcode and totally independent of either ping or connection quality. As you close with some players they will begin warping around, and if you reconnect you'll see different players warp instead. The server (or another player) might see two players perfectly fine, but the two players might see each other warping.

 

I don't know what's causing it, but it seems to have come with 2.5.6 and hasn't been fully solved, nor can it be avoided.

[Sideburns]

Ping isn't the issue. The problem is inherent to DCS netcode and totally independent of either ping or connection quality. As you close with some players they will begin warping around, and if you reconnect you'll see different players warp instead. The server (or another player) might see two players perfectly fine, but the two players might see each other warping.

 

I don't know what's causing it, but it seems to have come with 2.5.6 and hasn't been fully solved, nor can it be avoided.

 

If you watch the netstats available it does seem to get worse with dropped packets and higher pings (>300ms*), which makes sense. Just the netcode seems terrible at dealing with this common issue, and I'm fairly sure the netstats show for your connection only.

 

*As a former developer myself there is only so much a simulation engine can do to overcome such latency.

[Alpenwolf]

Server News:

 

- No more MiG-29A's/M-2000C's in Prince of Persia and Once Upon a Time in Abu Dhabi (the latter is currently offline).

- Only 4 x MiG-29A's/M-2000C's in Open Range (will either be removed soon or reduced to 2 fighters each).

- Only 6 x MiG-29A's/M-2000C's in Search & Destroy. In this big mission, both airplanes need to fly hundreds of kilometers to get to the bullseye. I'll keep them a little while longer.

- Working on something to force players unpack their crates to capture an airbase or a FARP. Looking good so far, so there will be no more capturing all with 1 crate.

 

 

EDIT:

Once the last point is achieved, Once upon a Time in Abu Dhabi will go back online.

Edited July 22, 2020 by Alpenwolf