DCS: F-14 Development Update - AIM-54 Phoenix Improvements & Overhaul - Guided Discussion

[DSplayer]

8 minutes ago, Alicatt said:

The NASA simulation, not an actual live test then with the AIM54? 

Trying to find live fire information is hard. Plus NASA never actually fired an AIM-54 for their hypersonic tests before the program went down.

 

9 minutes ago, Alicatt said:

This AIM54 in DCS is a simulation of a simulation then?

I think this would apply to other missiles in DCS as well.

[Gareth Barry]

Ultimately, what i think would satisfy everyone, would be multiple actual live firings under different conditions, with telemetry data for speed and altitude. I dont know if any such thing exists- if it did then Nasa wouldnt have needed to run computer simulations? Maybe Grumman and the navy did get telemetry from live firings? Would seem amazing for 1960s tech. 

It does seem that for most people, guidance is far more of an issue than kinematics. 

Maybe we can all plan an espionage trip to a certain country in the middle east, do a maverick and steal an f14 with a phoenix, and bring it back? How hard could it be? I reckon i have the skills for the font seat, who's willing to be my Rooster?

[-Cipher-]

@Gareth Barry I'll be it no worries, I know their language as well

[TomcatFan1976]

On 11/30/2024 at 3:52 AM, Alcatraz SVK said:

Yeah tracking of phoenix is miserable for some time. Its better to use only sparrows for its more reliable than phoenix and tws auto even if i can see targets launch ang guide t doesnt track or goes to hunt satellites. Only way its good for use ow is medium - short range fox 3 in STT.

I basically gave up flying the Tomcat as much as I use too. I use to love flying it everyday, now i barely fly it twice a week because it has become such a frustration and headache. Between the crappy Phoenix tracking, Jester being completely useless at anything and the dumb jokes he says all the time, especially during dogfights, it has become a pain instead of fun. Let's admit it, ED and HB doesn't give a crap about what people say and point out. How long has the Phoenix been useless now? The 2 answers you always get is it's someone else's fault, or it's more realistic. Face it, they don't give crap about anyone's opinions, they are right and that's the end of conversation. Just look how long people have been saying the Phoenix doesn't track anything? I just think, if the real Phoenix performed like they modeled it, then the Navy wasted Tax dollars on a worthless missile that does nothing good, but I highly doubt it was like that.

On 11/30/2024 at 3:52 AM, Alcatraz SVK said:

 

 

Edited December 2, 2024 by TomcatFan1976

[draconus]

8 hours ago, TomcatFan1976 said:

I just think, if the real Phoenix performed like they modeled it, then the Navy wasted Tax dollars on a worthless missile that does nothing good, but I highly doubt it was like that.

The Navy tests performed quite well so they went for it and then practically neved used it. The only 3 combat fires didn't went well and then they scrapped or test fired the rest of the supply after 2006. So yeah, looks like they really wasted the doughs or there were no enemies brave enough to try and stand against it, unless you have other data.

Look here:

Does it still look like a useless missile?

On 11/30/2024 at 7:19 PM, Alicatt said:

This AIM54 in DCS is a simulation of a simulation then?

No, NASA paper was only one of many data sources used to compare against.

[Katsu]

15 hours ago, TomcatFan1976 said:

I just think, if the real Phoenix performed like they modeled it, then the Navy wasted Tax dollars on a worthless missile that does nothing good, but I highly doubt it was like that.

In fairness to the developers, I don't think the missile is “unusable”. 

But it is kinetically unrealistic if we take into account the mathematical validations, as we have seen the missile even has an amount of fuel incompatible with the current burn time if everything is calculated as Tavarish did.

But yes, it is possible to use the missile quite successfully using it within the zone below 25nm against fighters at altitudes from block 2 to block 3.

It would be interesting if you could post a video of your shots showing your TID to see if we can help. (If you're using the A version of the missile the chance of it being fooled by the Chaff is enormous, sometimes it even seems a little worse than the AIM-7 I may be wrong because I haven't stopped to look at the AIM-7's resistance data it's just an impression, also check if ACM cover is up because if you fire with the ACM cover up and the target is not in the search cone of the missile's seeker, it will not track. ) 
 

On 11/30/2024 at 3:19 PM, Alicatt said:

The NASA simulation, not an actual live test then with the AIM54? 

This AIM54 in DCS is a simulation of a simulation then?

Apparently we had two “batteries” of simulations trying to validate the PMHT (Phoenix Missile Hypersonic Testbed) project 

One of them seems to have been the first where simpler simulations were carried out:

And another that seems more complete (which is the one I asked to be reproduced) where more elaborate aerodynamic factors have been studied also this simulation has a altitude chart which is very important for validating the data, because then we know the trajectory that the missile traveled and not just its speed: 

Not every simulation is definitive, but it is an important parameter for comparison. 

What happens when I try to reproduce this simulation is that at the missile's peak speed at around 80,000 feet in both cases (in the NASA simulation and in the game reproduction) in the game the missile barely passes Mach 4, while in the NASA simulation the missile both at 80,000 feet during its route is around 4.6/4.7 mach.

This reinforces the approach presented by Tavarish that the missile lacks thrust and burn time is wrong also: 
 

On 9/24/2024 at 6:02 PM, Katsu said:

an interesting fact is that Tavarish's data comes close to what the missile's performance could be is that with some programming knowledge and the data he provided, I was able to get close to the performance that Nasa simulation "presumably" presented.

null                   

If we get the first 60 seconds of flight we will a have a very close performance, just with minors tuning at thrust and burn time.

Just for comparision what we have now: 

 

Edited December 2, 2024 by Katsu

[Katsu]

On 11/29/2024 at 4:44 PM, Naquaii said:

And yes, we have other data which we value as more accurate than what is presented here, which we at this time aren't willing to share due to various reasons. It is how it is and by far not the only thing modelled in DCS that is based on data not available to the end users.

Interpretation of data is subject to error , need I remind you of the induced drag of the flap that you guys spent 5 years saying was right? 

And it wasn't. 

Just as trust is something you gain, it's also something you lose. It's not as if this is the first time you've guys insisted that something is right without it being. 
(even the same treatment that is being given to Tavarish and me was given to the Lockheed Martin engineer who showed the flap error) of course, due to the pressure and great support of being something that made the plane have an unrealistic dogfight performance drew more attention because it prejudiced not only HB's customers but other in general.

I don't want to take any credit away from the product, it's a great product, but it's not perfect, there are problems that have accumulated over time, just like all products and that's normal.

But what is not normal is the way that anyone who tries to argue this is treated as a layperson without any knowledge where only you have the knowledge and yes, we should just accept that. 

The data that you said cannot be disclosed and that the missile is correct is even mathematically impossible unless you have also discovered that all the blueprints of the Mk47 engine are wrong and you have a larger fuel compartment in the missile. 

Now, however, the only parties to be penalized are the customers who buy this plane, who have the wrong reproduction of this armament. 


 

Edited December 2, 2024 by Katsu

[Naquaii]

23 minutes ago, Katsu said:

Interpretation of data is subject to error , need I remind you of the induced drag of the flap that you guys spent 5 years saying was right? 

And it wasn't. 

Just as trust is something you gain, it's also something you lose. It's not as if this is the first time you've guys insisted that something is right without it being. 
(even the same treatment that is being given to Tavarish and me was given to the Lockheed Martin engineer who showed the flap error) of course, due to the pressure and great support of being something that made the plane have an unrealistic dogfight performance drew more attention because it prejudiced not only HB's customers but other in general.

I don't want to take any credit away from the product, it's a great product, but it's not perfect, there are problems that have accumulated over time, just like all products and that's normal.

But what is not normal is the way that anyone who tries to argue this is treated as a layperson without any knowledge where only you have the knowledge and yes, we should just accept that. 

The data that you said cannot be disclosed and that the missile is correct is even mathematically impossible unless you have also discovered that all the blueprints of the Mk47 engine are wrong and you have a larger fuel compartment in the missile. 

Now, however, the only parties to be penalized are the customers who buy this plane, who have the wrong reproduction of this armament. 


 

If anything the example of the flaps is a good example of the fact that we listen and change stuff if we get new evidence of something needing change. We're never going to just change something straight up day to day, it'll always be a process of validating the information over time and trying to change our model to make it better. And the main issue with the flaps was lack of data initially (and still to some degree) coupled with users using it in a non-intended way. There's still ideas to improve it further if possible.

In this case it's different as we look at the information presented here and simply do not agree. I'm not going to say that our model is absolutely right unlike what you're doing about what you believe. And we're also not calling you guys laymen or any of the sort, like I said previously, regardless of how right the equations are (and I believe they are) it doesn't matter if the information they're based on isn't. And no, I haven't seen anything in here that could be regarded as the complete (previously classified or still classified) technical blueprints of the AIM-54 rocket motors.

The tl:dr is still that, no, we're not going to change the model from the information presented here as we don't agree with it and no, we're also not going to share our sources for this for varous different reasons. We're not going to disregard information just because we can't share it, if that was our stance this module wouldn't have happened. You're absolutely free to disagree with that but as far as I'm concerned this discussion is over until such a time as new information is found.

 

 

[tavarish palkovnik]

11 minutes ago, Naquaii said:

In this case it's different as we look at the information presented here and simply do not agree. I'm not going to say that our model is absolutely right unlike what you're doing about what you believe.

After “trusting method” of determination something strictly of technical matters now it is “believing method” and turned on my side

@Naquaii may I ask, with what exactly you don’t agree? More than detailed I tried to explain every step of finding numbers behind this motor, everything is presented, nothing hidden so it shouldn’t be tough to point on, what exactly is that makes you not agreeing. Or if there are several points, no matter, I would gladly repeat with extra explanations 

[Naquaii]

1 minute ago, tavarish palkovnik said:

After “trusting method” of determination something strictly of technical matters now it is “believing method” and turned on my side

@Naquaii may I ask, with what exactly you don’t agree? More than detailed I tried to explain every step of finding numbers behind this motor, everything is presented, nothing hidden so it shouldn’t be tough to point on, what exactly is that makes you not agreeing. Or if there are several points, no matter, I would gladly repeat with extra explanations 

The sources for your information is what I don't value as better than what we have. I have no questions or contentions about any of your calculations.

[tavarish palkovnik]

8 minutes ago, Naquaii said:

The sources for your information is what I don't value as better than what we have. I have no questions or contentions about any of your calculations.

Sorry but me again 

What exact source or what sources are not so trustworthy? Here in all this gymnastics of finding answer, there were several sources. Some gave geometry, some gave weights, some nozzle details, some thermodynamics parameters etc etc 

It shouldn’t be, I hope so, that all are questionable to you. Which one/ones is/are debatable?

[Naquaii]

1 minute ago, tavarish palkovnik said:

Sorry but me again 

What exact source or what sources are not so trustworthy? Here in all this gymnastics of finding answer, there were several sources. Some gave geometry, some gave weights, some nozzle details, some thermodynamics parameters etc etc 

It shouldn’t be, I hope so, that all are questionable to you. Which one/ones is/are debatable?

Like I said, we're not in a position where we can debate or show our information we use and as it is we value that information as a better source.

[tavarish palkovnik]

Fair enough although I didn’t ask anything from you regarding your source. Just to point with what you don’t agree presented here. Is it NASA nozzle handbook (extremely helpful data) or W.T.Brooks paperwork (same if not even more helpful data).

These two sources just made Phoenix motor to “drew” it self, like said, literally.

 

[Naquaii]

15 minutes ago, tavarish palkovnik said:

Fair enough although I didn’t ask anything from you regarding your source. Just to point with what you don’t agree presented here. Is it NASA nozzle handbook (extremely helpful data) or W.T.Brooks paperwork (same if not even more helpful data).

These two sources just made Phoenix motor to “drew” it self, like said, literally.

 

Contemporary sources to when the missile was classified just won't be 100% reliable. You don't classify something and then just hand the data out in a freely to everyone who asks.

When a document like this is created it either gets classified in itself also or the data is obfuscated or changed enough that it's not. And in that case the data won't be 100% correct.

[tavarish palkovnik]

OMG…you guys are really unbelievable. NASA handbook is from 70’s and do you really think you could just go to any library and get same in that time !? It was for their use only, that should be perfectly clear to anyone reasonable, and by that still classified enough. But even that, still they mentioned that classified data from CPIA were not disclosed. Of course decades after that, handbook is publicly available and so we have it now.

Same with W.T.Brooks paperwork, it was presented back there in 70’s again just to small group of engineers on those seminars where they were exchanging knowledges…same like handbook, do you really think that Peter Pan and Donald Duck have entrance to those meetings!?

But let’s break this chain, this layer’s arguments I don’t buy, I’m engineer and by that with different postulates. So I still haven’t got any dispute of technical matter while your model is full of holes in foundation so I will continue to shake it

 

[Naquaii]

Just now, tavarish palkovnik said:

OMG…you guys are really unbelievable. NASA handbook is from 70’s and do you really think you could just go to any library and get same in that time !? It was for their use only, that should be perfectly clear to anyone reasonable, and by that still classified enough. But even that, still they mentioned that classified data from CPIA were not disclosed. Of course decades after that, handbook is publicly available and so we have it now.

Same with W.T.Brooks paperwork, it was presented back there in 70’s again just to small group of engineers on those seminars where they were exchanging knowledges…same like handbook, do you really think that Peter Pan and Donald Duck have entrance to those meetings!?

But let’s break this chain, this layer’s arguments I don’t buy, I’m engineer and by that with different postulates. So I still haven’t got any dispute of technical matter while your model is full of holes in foundation so I will continue to shake it

 

That doesn't matter even in the slightest, if it wasn't classified it's not going to have data as accurate as you're treating it to be. In any case, this isn't in any way why we're preferring to trust the data we have. I was just trying to give an explanation as to how that data should be interpreted. Even non-withstanding that it'd not change our stance in this case in us preferring the data we have.

Like I said, feel free to continue this discussion. I'm out.

[tavarish palkovnik]

Roger out  

Discussion (argumentation) will be continuing…only technical of course 

[Xhonas]

4 hours ago, Naquaii said:

If anything the example of the flaps is a good example of the fact that we listen and change stuff if we get new evidence of something needing change. We're never going to just change something straight up day to day, it'll always be a process of validating the information over time and trying to change our model to make it better. And the main issue with the flaps was lack of data initially (and still to some degree) coupled with users using it in a non-intended way. There's still ideas to improve it further if possible.

 

 

In these 5 years many people have reported to heatblur the issue with the flaps, everyone (except the people that loved to exploit that bug) have shown to you that your old flap model contradicts basic aerodynamic principles and you ignored, told that it was our (users) fault and made fun of people getting passionate over it. In your discord an aerospace engineer showed up with science, math, demonstrating what was wrong and you simply tried to ridicularize the dude instead of listening. But i'm glad that you decided to come down from the high heels and made the necessary changes (some stuff still incorrect but at least the major problem is fixed). Anyways, just pointing this out because seeems like a common behavior for you. People show up with a lot of data, with science, with math that you can't disproof then you come to gaslight the people, making them believe that whatever you have is correct, only because you can't do the necessary changes, for whatever reason. May be money, may be inability, may be ego..  

[Naquaii]

1 hour ago, Xhonas said:

In these 5 years many people have reported to heatblur the issue with the flaps, everyone (except the people that loved to exploit that bug) have shown to you that your old flap model contradicts basic aerodynamic principles and you ignored, told that it was our (users) fault and made fun of people getting passionate over it. In your discord an aerospace engineer showed up with science, math, demonstrating what was wrong and you simply tried to ridicularize the dude instead of listening. But i'm glad that you decided to come down from the high heels and made the necessary changes (some stuff still incorrect but at least the major problem is fixed). Anyways, just pointing this out because seeems like a common behavior for you. People show up with a lot of data, with science, with math that you can't disproof then you come to gaslight the people, making them believe that whatever you have is correct, only because you can't do the necessary changes, for whatever reason. May be money, may be inability, may be ego..  

Apart from basically disagreeing with you about everything you just wrote I guess we should just remove everything based on information we can't show you guys?

Edit: You don't need to answer. I think I'm quite done with this thread.

Edited December 2, 2024 by Naquaii

[Machalot]

11 hours ago, Katsu said:

What happens when I try to reproduce this simulation is that at the missile's peak speed at around 80,000 feet in both cases (in the NASA simulation and in the game reproduction) in the game the missile barely passes Mach 4, while in the NASA simulation the missile both at 80,000 feet during its route is around 4.6/4.7 mach.

It has been pointed out a few times that the NASA simulation was produced by an optimization solver to maximize the peak Mach number.  This overrides the usual missile guidance, and is not representative of how the AIM-54 would fly tactically nor in DCS, even if it were modeled perfectly.

[Katsu]

2 hours ago, Machalot said:

It has been pointed out a few times that the NASA simulation was produced by an optimization solver to maximize the peak Mach number.  This overrides the usual missile guidance, and is not representative of how the AIM-54 would fly tactically nor in DCS, even if it were modeled perfectly.

I focused on comparing the initial acceleration, its maximum speed, trajectory, and the altitude at which it reaches its maximum speed.

And yes, at least I managed to get the initial trajectory very close to the moment of maximum speed, which is around 80,000ft, that's why I say that the altitude table is indispensable for validating, with it we can check the climb profile and achieve conditions very close to the aerodynamic parameters observed in the simulation. (Assuming that the aerodynamic calculations of the missile's drag are correct, which does not seem to have changed from the CFD data) 

the other factors of the flight are not relevant to discuss thrust now, because these are the ones where the trajectory system will optimize high-speed flight as much as possible (but this is after the missile has already reached its maximum speed).

Edited December 3, 2024 by Katsu

[RustBelt]

On 11/29/2024 at 3:07 PM, draconus said:

Btw, I simply asked ED about it and they say they plan to take on AIM-54 at some point.

 

“Soon”

[tavarish palkovnik]

A bit more about impulses, nozzle expansion ratios etc etc. Once upon a time Phoenix in DCS if I'm not wrong, you guys will confirm, had specific impulses in range of 250s. Internet said it is specific impulse of CTPB and HTPB types of propellants and how not to accept it. However, there is so many behind it and simply it was wrong. Developers either figure it out alone, or somebody draw attention to them or simply with time some documents of various motors appeared where miraculously specific impulses were more about 230 than 250 and propellant inside were CTPB and similar. Hmmm...what to do now...all right it will be 230 or something like that in Phoenix as well...wrong again

 

    

 

Let's see something about these AP aluminized propellants with polybutadiene rubber as binder. Here I drew two RDS propellants, one with 14% of aluminium and 69% of ammonium perchlorate and second with 4% of aluminium and 82% of ammonium perchlorate. This second one is what I believe similar to what was in Phoenix. So these are theoretical values of specific impulses for such composition, maximal values, but only if ratio between chamber pressure and atmospheric pressure is 68. This is from American literature so it is chamber pressure of 1000psi vs atmospheric pressure of 14,7 psi (1000/14,7=68) or 69 bar / 1,013 bar. Russian standard is 40/1.

 

All right...maximal theoretical specific impulse for 4% aluminized CTPB would be 250s. We need not theoretical value but delivered value, what exactly nozzle gives, and it is hard study, but generally bigger percentage of aluminium is always with bigger losses or better to say with lower nozzle efficiency. It is not huge difference but few percent and for 4% it shouldn't be more than 1 or 2%. Let's say 1% so delivered specific impulse would be 247,5s ... again ... only with ratio of pressures as 68.

 

 

 

 

Some imaginary motor with chamber pressure of 69 bar to fully expand all to the atmospheric pressure of 1,013 bar needs to have nozzle with expansion ratio of 8,8. I don't have diagram for 8,8 ratio but this one for 8 could be easily used. What we see, if chamber pressure would be 1000 psi (69 bar) such nozzle at see level (atmospheric pressure 14,7 psi or 1,013 bar) will deliver specific impulse of something like 245s. Great, that is what we need. By the way, this delivered specific impulse is also with additional reduces, major reason is losses in divergent zone, again only about few percent we are talking. You can see that on these 3 nozzles and 3 chamber pressures, delivered specific impulse at see level vary a lot, from 220 to 250s but neither of these 9 cases, except marked one, is full expansion, either over expanded either under expanded nozzle.

 

All right, so nozzle should be with expansion ratio 8,8 that chamber pressure of 69 bar fully expand to 1 bar

 

    

 

That is case of these ''red'' marks, and this Phoenix propellant like most of other similar propellants is with heat ratio of 1,2 or very close to 1,2. This is perfect, line of 8,8 nozzle expansion ratio and curve of pressure ratio 69 perfectly hit curve of optimum. Let's see Phoenix with its 18,5 nozzle expansion ratio. To hit curve of optimum chamber pressure should be 175 bar to have full expansion to atmospheric pressure. Chamber pressure is not even close to 175 bar but average pressure is something like 46 bar...take a look how much it drops in overexpanded zone at see level. Thrust coefficient is only 1,4 ... 1,4*4,6*55,372˄2*3,14/4=15500 N ... looks familiar isn't it ... actually now I remembered that it was 45 bar in my calculation but it doesn't matter or change things in principles.

I've already showed how much this motor is different from other motors of tactical missiles, this is just other form of same. This ''blue'' area is where most of other motors fit and take a look how much Phoenix is far a away of that.

For questions at disposal of course, what ever is in my power and level of knowledge I will try to explain. This has nothing with sources but just common theory of rocket propulsion, sorry guys but without this it will be hard to understand how Phoenix motor worked 

 

[IronMike]

I think it is time to lock this thread, at least for the time being.

The fact remains that we have data on the motor, which we will not share, which we deem more accurate than what has else been presented here. Please be so kind and accept that.

The remaining issues with the phoenix are something that both ED and us will continue to work on. But we are starting to turn in circles here, and a back and forth will not get us anywhere.

Thank you all for your kind contributions and understanding. Once more progress has been made, we will open a new thread, or re-open this one.