Vympel R-73 'ARCHER' - History, Design, Performance & Discussion

You should ask this in the British weapon thread on here

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R-73 and R-74M2

The guy i replied commented about ASRAAM

r-73 max range is 30 km

Spoiler

r-74m2 max range is 50 km

Spoiler

also what do you mean by “real range”

I managed to fix tvc missiles spinning out of contol. They also now pull more consistently at different speeds and don’t waste an insane amount of energy for less pull than an aim9l like they to right now in game.

Spoiler

https://youtu.be/jw6xZJGj0z0
https://youtu.be/9G0ulkDfc9E
https://youtu.be/C0EsFR_BLuA
https://youtu.be/o5DJWRyfd5Y

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Ok, so what did you change

Was messing around in test drives of diffrent vehicles when i noticed that kh23m missiles on the yak 38 auto rotate after launch so i was curious and checked what kind of guidance do they use and what made them rotate (“rollStabilization:b = true” is the line). But the interesting line was the one right under drag that i have not seen on any other missile before. That line is CyMaxAoA:r = 1.8. So i just copy pasted it into r73s and they started to work (and changing 1.8 to 40).

An important thing to note this does NOT fix r73s and missiles alike on its own.

Spoiler

To understand that you have to understand what causes the missile to spin out and what max aoa under guidanceAutopilot does. When missiles in war thunder reach 90° aoa (or rather their lead point) the guidance seems to break (why is that i have no idea). Gaijin tried to fix this on r73 by giving at a 40° aoa limit. But the problem is that all of the code under guidanceAutopilot are not hard limits but more of a… well guidance. This means that the missile will try to lead untill it reaches its max aoa and than stop. The problem is that its inertia will cause it to go over that point (again because everything under guidanceAutopilot is not a limit but a guidance (this is also why magic 2 can pull 50g)) wich results in a death wobble and ends with the missile spinning out. So what happens when we give it CyMaxAoA:r = 40 that works more like an aerodynamic “hard” limit and delete the guidanceAutopilot “soft” limit on its guidance? The missile stops spinning out in 9/10 shots. So how do we fix that and give it a 100% success rate? The reason the missile will still spin out in extreme shots is because while it is now aerodynamicly “hard” limited to 40° aoa its guidance is not. This resulst in the missile attempting to lead more even after it has reached the 40° aerodynamic “hard” limit. By keeping both the guidance limit of 40° AND this new aerodynamic limit of 40° the missiles stop spinning out.

Now as far as I can remember r73 is the only tvc missile in game that has a known aoa limit of 40 (correct me if i’m wrong). Thats why when you try to fix other tvc missiles that don’t have one the easiest and most successful method i have found is giving them CyMaxAoA:r = 180 but with no max guidance aoa. For the most part this works but some kind of guidance aoa should porb be applied as well.

TLDR: R73 in game has a guidance limit but no aerodynamic limit which causes them to spin out. Applying this “new” line (CyMaxAoA:r = 180) fixes it.

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With this change you can now also increase the tvc angle form 4,05° to something like 12° with no issues. This is especially important since small tvc angles have no impact on the missiles turning ability at higher speeds which means r73s rely on its fin aoa at speed to turn and its tvc has no impact (wich is why micas and r77 turn the same when you fly at speed but not at 0 speed launches (its also why rolands are so hard to fix))

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Hello, thanks for videos. Could you show high speed launch? R-73 fail a lot when launching at higher speeds, you have to lead them like you would AIM-9L otherwise they spin.

What does focal plane mean for an ir detector

Same as photography, area where the detector is most focused iirc

In my testing with other TVC missiles this does help yeah.

The other thing I prefer to do for it, is to really mess with time to gain values. This doesn’t just help the missile stay stable, but it also really helps it pull harder off the rail in many situations. For instance i use:

  timeToGain0:p2=0.00, 0.55
  timeToGain1:p2=0.315, 1.1
  timeToGain2:p2=0.80, 0.8
  timeToGain3:p2=1.25, 0.865
  timeToGain4:p2=2.4, 0.945

Basically, the first part is so that way the missile will not start steering sharply, but rather gain as it gets speed just after launch, fixing issues with ultra low speed launches. Then it scales up to above the base amount, causing it to pull very high AoA, causing a very sharp turn. Before again reducing itself, causing the excess AoA to be partially maintained, while smoothly transitioning to a more forward flight path.

There are a few issues with it, where in some situations it will miss, particularly when near AoA limits in very HOB shots., and the PID logic does have to be tuned to work with it. Tuning variable PID logics should fix the remaining issues though, I simply haven’t gotten around to it. (Leviathans broke all user missions for me, lmao).

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I’m curious if this can be forwarded in a bug report.

Would love to see if it gets accepted

Cdk is borked right now yes (look at the rudder on my ef2000 lol).

There are a lot of ways you can try to improve the spin out, stability and maneuverability of TVC missiles but with pretty much all of the “fixes” I tried (and trust me i tried a lot of things) some issues remain.
As an example copy paste r73s and than remove WdK:p3 = 0.1, 0.1, 0.1; change the pid0 time from 3 to 5.5; remove pid1 and pid2 entirely; rename pid3 to pid1. This is a kind of universal “fix” that does work on r73s micas and i think sraams also (missiles wont spin out the same way any more, but they still waste a lot of energy and pull way to much aoa and still wobble).

But here is the real issue with this “fix” (and probably the timetogain one as well). Missiles with a small caliber and low acceleration like aim9x and iris-t produce less lift at high aoa than missiles with a large caliber such as mica and r73. So what ends up happening is that this missiles drift across the sky at 90° aoa but don’t actually turn. The best thing about it is that if you increase the wingAreaMult it only makes them spin out sooner instead of increasing their lift.

Spoiler

On another note here are mica and sraam where the only thing i changed was add CyMaxAoA:r = 90 and under guidanceAutopilot add limitAoa:b = true and aoaMax:r = 40
https://youtu.be/tONMMxI_X6U
https://youtu.be/LsFJ6vpCa5s

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0:50 thats ridiculous

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I mean 90 degrees is too much, I generally aim for between 30-40 and it gives much better results, particularly with my time to gain method.

Too much AOA actually decreases a missile’s turning performance to an extent. Firstly from just being less ideal to produce lift. But also due to the vectoring angle to keep it stable, your engine will effectively be less efficient due to its corrections at said angle / the thrust vector relative to CoM / direction of travel.

Yours deffinitly seems more stable at higher AoAs then mine does, i wonder how it handles the different ohysics rate on live servers to closed ones.

Also here are two aim9l missiles with mica tvc copy and pasted onto them. They are identical in every way except one of them has aoa limits while the other doesn’t.

Spoiler

https://youtu.be/uleeb8OyRPo
https://youtu.be/57Z3bYzyXG0

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Here is the funny thing. If you are only using CyMaxAoA than less than 90 is prob better BUT if you also set the guidanceAutopilot to 40 (and leave the other one on more than 40 (90 in this case)) the missile will be able to pull more while still usnig only 40ish degrees of aoa.
On r73s and sraam i set both to 40 but on every other missile i set the first one to 90 and the second one to 40