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[RESOLVED] AIM-54 inconsistency with CFD whitepaper


dundun92
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On 1/11/2022 at 9:51 PM, near_blind said:

An Apple is of similar size, shape, and weight as an orange (perhaps a little heavier). I would expect my Apple to taste like an Orange. It does not. To whom do I address this bug report? It's going to upset my carefully planned fruit tasting contest. 

Then you'd better try to throw em both and not try to taste missiles. That's a pure sophism. 


Edited by Velik
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23 minutes ago, Velik said:

Then you'd better try to throw em both and not try to taste missiles. That's a pure sophism. 

Exaggerated for comedic effect, absolutely, but hardly fallacious. Why don't we try another example?

The R-3S and the AIM-9M have nearly the same length, shape, size and weight, and yet the AIM-9M outperforms the R-3 in every metric. Ignoring that they both have completely different components, their performance should clearly be normalized because of their superficial similarity.

 

OP's statistical analysis is perfectly valid, but the implication by others that the AIM-54s performance should be made more similar to the R-33 because they look a like is ridiculous. They are different missiles with different sensors, motors, weights, airfoils and performance.

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We most certainly will not start comparing the AIM-54 to the R-33. Not even as an afterthought.


Edited by IronMike
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5 hours ago, near_blind said:

The R-3S and the AIM-9M have nearly the same length, shape, size and weight, and yet the AIM-9M outperforms the R-3 in every metric. Ignoring that they both have completely different components, their performance should clearly be normalized because of their superficial similarity.

So, funny story, the R-3/K-13 was based on an AiM-9B recovered unexploded from a Chinese MiG-17 where it had gotten lodged when fired from a Taiwanese F-86.

Yeah, I'll be that guy, too:

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1 hour ago, Swordsman422 said:

So, funny story, the R-3/K-13 was based on an AiM-9B recovered unexploded from a Chinese MiG-17 where it had gotten lodged when fired from a Taiwanese F-86.

So you're saying an AIM-9B performs about the same as an AIM-9M? 🙂

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1 hour ago, Naquaii said:

So you're saying an AIM-9B performs about the same as an AIM-9M? 🙂

Heh. God, no. That post was entirely lacking in subtext of any kind. I do think it's a funny story, though.

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Yeah, I'll be that guy, too:

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4 minutes ago, Swordsman422 said:

Heh. God, no. That post was entirely lacking in subtext of any kind. I do think it's a funny story, though.

It is for sure! Rumour has it the Finns even tried swapping them around having both in inventory!

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I always love these threads, the dev apologists and those who assume malice by the devs. The OP posted a thoughtful evidence backed report HB responded and yet third parties love to partake in a wonderful show of internet attrition. It's clear HB have acknowledged there to be an issue and have already committed themselves to doing something. Now I has much as the other guy find the discrepancies to be much but how about instead of waging a war over the reason we are in this situation we wait like normal people for the patch 🙂 .  At least when we present reasonable evidence to these Devs they dont ask if we are rocket scientists.  

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3 hours ago, Cookie. said:

I always love these threads, the dev apologists and those who assume malice by the devs. The OP posted a thoughtful evidence backed report HB responded and yet third parties love to partake in a wonderful show of internet attrition. It's clear HB have acknowledged there to be an issue and have already committed themselves to doing something. Now I has much as the other guy find the discrepancies to be much but how about instead of waging a war over the reason we are in this situation we wait like normal people for the patch 🙂 .  At least when we present reasonable evidence to these Devs they dont ask if we are rocket scientists.  

Nitpick: It's not rocket science. It's aerospace engineering.

With you on this one. These threads generally go OP: "Hey, I found a problem." Dev: "Okay, cool, we'll look into that." Everyone else: "Yeah, but we think you should fix right now! It should never have been wrong."

I don't apologize for Heatblur, but I will challenge the impatient ones to do it better themselves if they think they can.

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Yeah, I'll be that guy, too:

CPU: i9-10850k 3.6 GHz

RAM: 64GB DDR4

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HD: 1 TB SSD, 2 TB 15k RPM HDD, 1 TB M.2

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4 hours ago, Swordsman422 said:

rocket science

I think he used that term specifically because of an ongoing meme in the Russian missile thread 😅

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On 1/13/2022 at 5:03 AM, DCSoping said:

I don't think you read the whole thread ?
It was not ignored at all. Also whatever HB or ED did should never give such massive super capabilities to it's missile ever. Work in progress or not. 


 

Why? nobody should be using any module in competition until it's out of Early Access RIGHT?

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If people want to talk about the Whitepaper or Improving performance/accuracy of the module that's great. 

HB acknowledged the issue in less than 24 hours said we would see progress on this in the upcoming patch, and the AIM-54 being switched to the API is item #2 on their public roadmap. Thats a pretty fast response time.  At least wait for the new patch and then test it - and then you can present it the way DunDun did with data.

Otherwise you aren't helping and just screaming into the ether like a crazy person.

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4 hours ago, DCSoping said:


Are you sure the phoenix hasn't had this bug from the beginning?
Because does anybody know when exactly this bug was introduced then ?

The most recent ED guidance logic update.  It's not difficult to go back and see that the CFD data hasn't changed accordingly.  

Had this been from launch, this would have been a topic of discussion from within a few weeks of release- not this past week.

4 hours ago, DCSoping said:

And i'm glad this is finally getting sorted , i hope, don't get me wrong but i don't feel the multiplayer community should thank you on their knees

He didn't infer or expect you to, so you can come down from the cross you've discovered. 

4 hours ago, DCSoping said:

for fixing such a pretty serious bug that i'm sure has caused a lot of frustration over time. 😡😢

It was so serious a bug, for so long, that the aforementioned MP community thought it was worth waiting to mention this discovery to Heatblur until just a few days ago. 

It just took a few weeks since the guidance update to drum up the necessary drama on their Discords, a few dropped hints from tournament organizers that they should come start hassling HB (appropriately changed after the fact, don'tcha know), and here we are- victim mentality abounding. 

Meanwhile, Cobra, IronMike, and Naquaii acknowledged there might be an issue, explained why the CFDs were positioned as they were, and put it in the focus cue to be fixed- all within a day. 

Maybe next time the MP community should try, I dunno- acting like adults and sending out just the guy with the data, instead of attempting a multi-thread press with all the dramatic trappings of "OMG- THE TOMCAT IS BEING REMOVED FROM ANOTHER TOURNAMENT!!1!".  Because it doesn't impress anyone, and it doesn't change anything- the data did, not the demands of the emotionally over-involved.

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As a person who has some experience with CFD, I would like to address that CFD result is not a holy grail and it is always the best to use the experiment data if it is available.

Especially in calculating maximum lift or drag survey where it is not uncommon to have a drag discrepancy with wind tunnel result, sometime as much as 10-20% in transonic region.

There are many factor that could influence the result from CFD especially the mesh quality even though HB paper stated that they did a grid independent study already which should be alright.

Sure if the mesh and grid resolution can be increase (to the point of LES or DNS turbulence model) the accuracy would likely be better but that is far beyond what is possible with a computing power today. 

Thus CFD result should be adjusted accordingly to ensure a proper behavior observed in real life experiment or available testing reports. 


Edited by ChockP51
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19 hours ago, DCSoping said:


Are you sure the phoenix hasn't had this bug from the beginning?
Because does anybody know when exactly this bug was introduced then ?
Because as i mentioned earlier i personally can't say that it suddenly would not lose speed in a tial chase, as far as i know this has always been the case. 
And i'm glad this is finally getting sorted , i hope, don't get me wrong but i don't feel the multiplayer community should thank you on their knees for fixing such a pretty serious bug that i'm sure has caused a lot of frustration over time. 😡😢



 

It wasn't an issue before the most recent API changes. And you don't need to thank us for anything.

We fix bugs for being bugs, not because of subjective emotions such as frustration or gratitude or anything like that. It bares no influence on our work. Objective impact on gameplay, realism, etc however does. Maybe re-read my first reply to you again, which again you managed to ignore, as some in the MP community choose to ignore what we have to say from the perspective of a developer time and time again. That is all your perogative of course, but do not come complaining to us then, when we choose to ignore overly emotional input, too. It has not and will not ever have influence on our work. And yet we listen and respond to it, which should tell you something, too. And if we speak of emotions you can trust one thing: whatever you deem as frustrating, is most likely double as frustrating for us. We know the place where you're coming from, we've been there ourselves, twice, both as customers and as developers...


Edited by IronMike
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Heatblur Simulations

 

Please feel free to contact me anytime, either via PM here, on the forums, or via email through the contact form on our homepage.

 

http://www.heatblur.com/

 

https://www.facebook.com/heatblur/

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  • 2 weeks later...

@Naquaii @IronMike

 

That was very quick turn around. Thank you. 

 

Could you guys provide any data around what you changed and your testing data? It would be good to see how close it is to the CFD now, and where you expect changes when it eventually ports over to the new API.

 

Anecdotally, people are reporting it's a pretty significant change- but most importantly, let's help build the consensus that it's accurate so we can all move on to other things 🙂

 

appreciate it

 

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2 hours ago, DoorMouse said:

@Naquaii @IronMike

 

That was very quick turn around. Thank you. 

 

Could you guys provide any data around what you changed and your testing data? It would be good to see how close it is to the CFD now, and where you expect changes when it eventually ports over to the new API.

 

Anecdotally, people are reporting it's a pretty significant change- but most importantly, let's help build the consensus that it's accurate so we can all move on to other things 🙂

 

appreciate it

 

Can it do it's real life manouvers now without overperforming in a straight line at low alt? 

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29 minutes ago, Comstedt86 said:

Can it do it's real life manouvers now without overperforming in a straight line at low alt? 

Thats the question. It's got significant deficiency in guidance, but that's not up to HB. It seems to more closely match the CFD in a straight line though.

 

Edit- corrected. 


Edited by DoorMouse
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1 minute ago, DoorMouse said:

Thats the question. It's got significant deficiency in guidance, but that's not up to ED. It seems to more closely match the CFD in a straight line though.

You mean other way around ED/HB? 🙂

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1 hour ago, DoorMouse said:

Thats the question. It's got significant deficiency in guidance, but that's not up to HB. It seems to more closely match the CFD in a straight line though.

 

Edit- corrected. 

 

If the old API is still present, those 54s will still drain all their speed with those harsh turns. But I haven’t tested them out for myself though but I’ve seen videos how their low altitude performance is significantly poorer.

 

Edit:

 


Edited by DSplayer

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We do not believe the current performance to be realistic due to guidance issues. Less than when we adjusted numbers to avoid these issues; and yet enough to cause lessened performance.

Unfortunately this has turned out to be a multi-step process and we'll be working hard to rectify this with urgency where we are able.

Nicholas Dackard

 

Founder & Lead Artist

Heatblur Simulations

 

https://www.facebook.com/heatblur/

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1 hour ago, Cobra847 said:

We do not believe the current performance to be realistic due to guidance issues. Less than when we adjusted numbers to avoid these issues; and yet enough to cause lessened performance.

Unfortunately this has turned out to be a multi-step process and we'll be working hard to rectify this with urgency where we are able.

What were changed during this patch specifically? Rocket motor performance? Drag profiles?

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52 minutes ago, DSplayer said:

What were changed during this patch specifically? Rocket motor performance? Drag profiles?

Drag profiles, the missile much more closely matches the CFD result, however this has revealed a problem with regards to the guidance we are looking into.

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@IronMike@JNelson@Cobra847

To replicate it: AIM-54A Mk60, 15ºC 720mmHg (ISA), starting at exactly M1.1 on active pause to avoid other launch speed (you can see it on the on rail speed) and straight shoot on maddog (without loft)

12000m

12000.png

 

6000m

6000m.png

 

500m

500m.png

P.S. Ask for tacview files if you want it.


Edited by riojax
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27 minutes ago, riojax said:

@IronMike@JNelson@Cobra847

To replicate it: AIM-54A Mk60, 15ºC 720mmHg (ISA), starting at exactly M1.1 on active pause to avoid other launch speed (you can see it on the on rail speed) and straight shoot on maddog (without loft)

12000m

12000.png

 

6000m

6000m.png

 

500m

500m.png

P.S. Ask for tacview files if you want it.

 

Thanks, the tacviews would be excellent, just to clarify the wobbles you are seeing in the telemetry is the missile actually oscillating, not just noise in the data? We were not seeing any such behaviour on our end. 

 

Thanks.

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  • IronMike changed the title to [RESOLVED] AIM-54 inconsistency with CFD whitepaper
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