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AIM-120C LAR


Ahmed

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The LAR calculations for the AIM-120 seem to grossly mismatch and underestimate actual missile performance.

In the two tracks attached you can see that the missile end-games with the same speed in both the in-lar and the out-of-lar tracks, and in both it is flying faster than its launcher.

However, in the out-of-lar track, the Raero/Rmax indications show it well out of LAR, at 140% of the displayed Raero/Rmax value.

in_lar.trk out_of_lar.trk

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I concur, just never got around to making a new report for this. Was previously reported and "fixed" but is still very inaccurate.

I wonder if this is also a contributor to why the LOST cue is still extremely inaccurate.

I would have thought DCS knows precisely the range of its own missiles in its own simulation and no guess work would be required. Then after that exact value is determined, add some minor percentages of error to account for what would have otherwise been real world inaccuracies. There must be a math error in the code somewhere to account for this issue.


Edited by MARLAN_
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 1A100.png?format=1500w  

Virtual CVW-8 - The mission of Virtual Carrier Air Wing EIGHT is to provide its members with an organization committed to presenting an authentic representation of U.S. Navy Carrier Air Wing operations in training and combat environments based on the real world experience of its real fighter pilots, air intercept controllers, airbosses, and many others.

 

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7 hours ago, MARLAN_ said:

I concur, just never got around to making a new report for this. Was previously reported and "fixed" but is still very inaccurate.

I wonder if this is also a contributor to why the LOST cue is still extremely inaccurate.

I would have thought DCS knows precisely the range of its own missiles in its own simulation and no guess work would be required. Then after that exact value is determined, add some minor percentages of error to account for what would have otherwise been real world inaccuracies. There must be a math error in the code somewhere to account for this issue.

 

That's not how complex dynamical system modeling works.

Most often in these scenarios, there are no "analytical solutions" to a "perfect range equation" as the school system often implies when teaching math. They'd have to run their own sets of optimization/simulation scenarios and generate either a simplified model for range estimation or most likely look-up tables.

Not to imply this is not an issue/bug, it definitely is, but it is not a simple as you describe.


Edited by toilet2000
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5 hours ago, toilet2000 said:

That's not how complex dynamical system modeling works.

Most often in these scenarios, there are no "analytical solutions" to a "perfect range equation" as the school system often implies when teaching math. They'd have to run their own sets of optimization/simulation scenarios and generate either a simplified model for range estimation or most likely look-up tables.

Not to imply this is not an issue/bug, it definitely is, but it is not a simple as you describe.

 

Yea, I'm definitely just simplifying a complex problem, all I meant was since it's a simulation they have perfect values available so they could obtain a perfect range in the code and then use that as they desire. I'm probably misunderstanding what you're mean, but I don't want to derail, feel free to DM me!


Edited by MARLAN_

 1A100.png?format=1500w  

Virtual CVW-8 - The mission of Virtual Carrier Air Wing EIGHT is to provide its members with an organization committed to presenting an authentic representation of U.S. Navy Carrier Air Wing operations in training and combat environments based on the real world experience of its real fighter pilots, air intercept controllers, airbosses, and many others.

 

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17 hours ago, MARLAN_ said:

Yea, I'm definitely just simplifying a complex problem, all I meant was since it's a simulation they have perfect values available so they could obtain a perfect range in the code and then use that as they desire. I'm probably misunderstanding what you're mean, but I don't want to derail, feel free to DM me!

 

Don't want to derail it either but I figured this might be some info worth sharing:

Basically, it's not because you have a model of something that it is easy to predict its behavior. A dynamical model (a missile moving through the atmosphere) is made such as there is no specifics on the output (range, altitude over time, speed over time, available g over time, actual g over time or whatever). You make a model, and you use that model to simulate the missile in-game. Outputs such as range are not the direct "outputs" of the model.

This means that if you want to know the range of the missile, you have to do as you would with an actual missile: simulate it over time with the initial values and check the range against some criteria (range until available g falls below a threshold or whatever is needed for Rmax and Rne). Now this might be quick, but what makes it problematic is that the initial values can have a huge spread and be highly dimensional.

Just think about it: the missile could be launched from anything from 0 kts to 1200 kts, from any altitude from -2000 ft to 50000 ft or more, from any launch g from 0g to 10g (or w/e), from any temperature from -60 to 60 C. Now if you want to infer the range from that while the sim is running, you'll have to generate look-up tables for those parameters, which are then going to be used for range estimation. This can be a time intensive process and it has to be redone every time something changes in the sim, be it the atmosphere model, the missile guidance parameters, the missile's FM, the missile's engine model, etc.

Now I'll keep quiet and stop derailing this thread, sorry! 🙂

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