R-73 180° degrees loop

[Vitormouraa]

Hello, I found two curious gifs, my friend sent me, I don't know the author, on the gif you can see the R-73 performing a 180° degrees loop and I wanted to know, is that possible in real life? how real is that? I have no information about it, I tried to find anything about it but nothing.

 

First gif is the Su-25T firing into an A-10, the missile makes a loop and almost hit the target: https://gfycat.com/AbsoluteClosedCottontail

 

Then this guys made the test again, but now the F-15C, which is more faster, and boom, the R-73 hits the target: https://gfycat.com/NeglectedGlisteningCrow

 

That's pretty awesome, is it possible in real life? :helpsmilie:

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My theory is:

 

analyzing better, the R-73 has a good seeker angle, it can lock targets at high degrees, so it kept the lock at the looping (when it was climbing) and it almost hit the target, it didn't hit because the A-10 was slow enough to stay inside of the "circle".

 

Let's try to explain that drawing, I don't have photoshop here, but the paint,so let's try:

 

As you can see here, the R-73 couldn't catch up the A-10, because its maneuverability wasn't enough

http://i.imgur.com/uaPstnQ.png

 

Now, let's analyze the F-15, while the R-73 was performing the loop (climbing) the F-15 was fast enough to reach there, out the circle and the A-10 wasn't, as you can see here: http://i.imgur.com/2kBF6UX.png

Edited December 12, 2015 by Vitormouraa

[OutOnTheOP]

That's pretty awesome, is it possible in real life? :helpsmilie:

 

No. If I recall correctly, the R73 only has a 60 degree seeker gimbal (might be as high at 75 degrees, but I know it's not over 90). The target is clearly outside that 60 degree arc for almost the entire path from launch to impact; a real missile would have lost track almost immediately and gone "stupid".

 

The AIM-9X would be able to pull off this shot, because it a) has a larger seeker field of view/gimbal (I think 110 or 120 degrees?), and b) it has lock-on-after launch/ INS navigation to point it at a cued target that is outside it's field of view. I believe ASRAAM also has this capability. R73 certainly does not.

[Vitormouraa]

The AIM-9X would be able to pull off this shot, because it a) has a larger seeker field of view/gimbal (I think 110 or 120 degrees?), and b) it has lock-on-after launch/ INS navigation to point it at a cued target that is outside it's field of view. I believe ASRAAM also has this capability. R73 certainly does not.

 

Yes, the AiM-9X can perform 360°. If the missile lost the lock, is it possible get the lock again? I don't think so

[OutOnTheOP]

That depends on what you mean. The AIM-9X can be fired at a target it can't "see" when it comes off the launcher. Like I said, it can see about a 120 degree arc. However, if the launching aircraft acquires a target, say, 180 degrees off boresight (straight behind), the seeker head can't see it. The aircraft will "tell" the AIM-9X that there's a target back there 180 degrees back, the AIM-9X comes off the rail, uses an onboard INS system to figure out where it is pointing and where it needs to point to see the target, turns itself to face, and then "looks for" the target, because it was told where to look by the launching aircraft. However, I am not sure if there is a datalink between launching aircraft and missile *after* the AIM-9X leaves the rail. So, if the AIM-9X doesn't "find" the target where it "expected" it to be, you might be right, it may not continue to try to acquire it.

 

However, R73 has none of that functionality. It doesn't have the capability to "point" itself at a target outside it's seeker gimbal limits and look for it after launch. It has to maintain a lock from launch to impact. Once it looses lock, it will not continue to turn to "find" the target. It will just go dumb. It *may* lock onto something else that wanders into it's field of view, but it won't keep going around a 180 degree turn, because it's not "smart" enough to predict where the target has gone once the target is no longer visible to the seeker.

 

Short version is that the AIM-9X (and I think ASRAAM) "predicts" where the target will go, but R73 does not.

Edited December 12, 2015 by OutOnTheOP

[Vitormouraa]

So, that should not be possible? Why does it happen in DCS?

[Brisse]

Thrust vector control helps the missile turn at a very high angle of attack which helps point the nose of the missile so that the seeker can stay on target. It's the sum of the gimbal limit and the angle of attack that matters, not just the gimbal limit on it's own.

[OutOnTheOP]

Thrust vector control helps the missile turn at a very high angle of attack which helps point the nose of the missile so that the seeker can stay on target. It's the sum of the gimbal limit and the angle of attack that matters, not just the gimbal limit on it's own.

 

 

True, but there are points in those clouds where angle - off- tall of the missile is easily 150 degrees. 60 for the seeker leaves 90... I'm finding it hard to believe it's maintaining a 90 degree AOA, even with TVC

[Bushmanni]

R-73 has 75 degree gimbal limit. If you have enough lateral separation you can fire the Archer on a target coming at you so that the missile can keep the target at less than 100 degrees of flight path axis all the time while making a over 180 degree turn and catching the target from behind.

 

In the video below the missile is fired 60 degrees off boresight and it keeps the target always less than 100 degrees off velocity axis during the turn (pulling 35 degrees AOA and 40G's). All of that is within limits of the missile.

 

 

If DCS missiles lose lock they will still keep turning and make it seem like it is still chasing the target but keep turning past the target (but not smoking anymore so you can see it well only in Tacview). There's also s small chance that the missile is able to re-acquire if the missile seeker stumbles directly on the target again but that is very rare.

Edited December 12, 2015 by Bushmanni