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

[Timo Niemelä]

39 minutes ago, Sindar said:

P.S. The reasonableness of adopting an aircraft with such a powerful radar and such energetically weak missiles raises doubts. But NASA knows better.

I've also wondered why the AIM-54C received such a weak motor. The AMRAAM was in the works roughly during the same time, so clearly there should have been more efficient propellant options available. It doesn't make sense to upgrade all the electronics of a very expensive missile and then upgrade the motor as well, but with one that limits the missiles performance. Yes there was less smoke, but judging from AIM-54C test launch videos still quite a bit.

And when the C-model entered service, it was very much expected to counter thread from enemy fighters, not just to hit bombers. I quote Dave “Bio” Baranek from an internet article:

"When we started to get serious about the threat, especially when the AA-10 Alamo arrived, we realized we had to employ AIM-54s against enemy fighters. So of course we began to train with them. I think the capability was in TACTS all along, we just never used it. Fortunately the Navy introduced the AIM-54C in 1987, when we really needed it.

----One of the coolest visuals I remember was from TACTS debriefs at Fallon, when a division of Tomcats launched AIM-54Cs against simulated Fulcrums at 30-plus miles."

It sure sounds like the Sparrow wasn't expected to cut it against the R-27.

[IronMike]

4 hours ago, Sindar said:

I totally agree. Now the F-14 is realistic and lives up to its mission of the 70s: to shoot down bombers from a distance. The problem is that these bombers are not in the game. What you have done is this: a good product for itself, but for what? Like an iPhone without electricity. A beautifully made thing, but useless without an outlet. F-14 with realistic missiles - beautiful and useless. For fans collection.

P.S. The reasonableness of adopting an aircraft with such a powerful radar and such energetically weak missiles raises doubts. But NASA knows better.

 

I respect your opinion, I do, but I also have to disagree, and I think that you will likely find that many folks will disagree with you regarding its usefulness. It has its place online as much as offline, as much as in air to air as in air to ground, pitted agains its contemporary cannon fodder, or a much more modern and advanced challenge - it is, in the end, what you make of it. So, if for you it has a seemingly narrow purpose, to best eagles, vipers and hornets day in day out online, all the time, with a nigh 100% success rate, then yes, I guess one could argue that it is useless. But the idea to make it purposefully unrealistic to give it a place - in what exactly? - is not something that is in any way feasible, or acceptable, when doing realistic simulations. Thank you for your kind understanding.

Edited September 20, 2022 by IronMike

[IronMike]

9 hours ago, Бойовий Сокіл said:

The Mach 5 claims are often brochure or some report data without context. The 54C range probably comes down to much better guidence and electronics. At least now we know that it follows a smooth profile in TWS unlike the A.

It comes from the test where a phoenix got fired from an F15 iirc at around 50k feet, without a warhead (to see/prove if it can go mach 5 potentially). Would one reduce the weight with the current missile accordingly, and launch it from the same or similar conditions, it would likely achieve that in game as well.

[Machalot]

8 hours ago, Sindar said:

But NASA knows better.

What does this mean? In this thread there is a graph showing a good match between DCS and the NASA sim results. 

[near_blind]

7 hours ago, Timo Niemelä said:

It sure sounds like the Sparrow wasn't expected to cut it against the R-27.

I would argue it's the opposite. In the R-27 the USSR had finally achieved something approaching parity with the AIM-7. Without spending a page droning on about BVR, the tl;dr is you never want to fight on an equal footing if you can help it. The AIM-54C could help maintain the stand off advantage US aircraft had enjoyed since Vietnam until the AIM-120 and AIM-152 could be completed, so they'd use it. It's a shame history didn't quite work out the way they expected. 

[Timo Niemelä]

6 hours ago, near_blind said:

In the R-27 the USSR had finally achieved something approaching parity with the AIM-7. Without spending a page droning on about BVR, the tl;dr is you never want to fight on an equal footing if you can help it.

Agree. I didn't mean that they necessarily expected the R-27 to be better than the Sparrow (poor framing on my part), but rather that it no longer provided a sufficient edge. Plus you need to leave room for error when estimating the capabilities of the enemy. Underestimating might prove catastrophic and not much was known about the R-27 at the time.

I feel the AIM-152 would have allowed the Tomcat to live up to its true potential (okay maybe even more so when combined with an AESA radar on the ST21) Even though the AIM-54C offered improved performance, it was envisioned as a stopgap measure, not a long term solution. Too bad it ended up being the big Cat's sharpest claw.

[Timo Niemelä]

6 hours ago, Machalot said:

14 hours ago, Sindar said:

But NASA knows better.

What does this mean? In this thread there is a graph showing a good match between DCS and the NASA sim results.

I think he was just surprised to learn about the Phoenix's relatively weak motor, but acknowledged that NASA probably has the most accurate data. I don't think he disagreed with the sim results. 

I think many of us here were rather surprised to find out how low the C's impulse actually was. You'd think they would have equipped it with something more powerful to compliment its long range potential.

[Lurker]

On 9/19/2022 at 10:28 PM, IronMike said:

Btw everyone, I kept saying "NASA tests" in my previous posts, and @Machalot was kind enough to remind me of not being precise, I of course meant the NASA simulations. Apologies!

Are there any tests, real world Phoenix tests down low? As in below 30,000 feet or lower? For years I have had suspicions that most if not all missiles in DCS World are way too draggy at low to medium altitudes. 

If this were true (not saying that it is, it's just a feeling based on years of flying in DCS World) wouldn't this be the reason for the large discrepancy that most people are experiencing with the Phoenix, especially since this would be exacerbated by it's "girth" compared to longer and thinner missiles in DCS world? 

Edited September 21, 2022 by Lurker

[Lurker]

19 minutes ago, Бойовий Сокіл said:

heavy and thick missile will be more draggy than a thin and light one down low.

Missile weight does not factor into drag. It does however factor into it's acceleration, on the flipside a heavier or rather a missile with more mass should retain more of it's energy and take longer to slow down. 

[GGTharos]

1 hour ago, Lurker said:

For years I have had suspicions that most if not all missiles in DCS World are way too draggy at low to medium altitudes.

Based on what?  If you have even back-of-the-envelope calculations to back that up, please share.

1 hour ago, Lurker said:

If this were true (not saying that it is, it's just a feeling based on years of flying in DCS World) wouldn't this be the reason for the large discrepancy that most people are experiencing with the Phoenix, especially since this would be exacerbated by it's "girth" compared to longer and thinner missiles in DCS world? 

Feelings are worthless in these cases.   Math/physics is the only thing that matters.

[Lurker]

4 minutes ago, GGTharos said:

Feelings are worthless in these cases.   Math/physics is the only thing that matters.

I quite agree, hence my question. Are there any real world tests of the Phoenix below 30,000 feet? Or any other missile for that matter, which could then be compared to its DCS counterpart?

Edited September 21, 2022 by Lurker

[Jayhawk1971]

vor 37 Minuten schrieb Lurker:

I quite agree, hence my question. Are there any real world tests of the Phoenix below 30,000 feet? Or any other missile for that matter, which could then be compared to its DCS counterpart?

 

Towards the end of the AIM-54's service life, the Navy had their Tomcat crews live-fire a crapload of those, as I assume this was the easiest method to clean out the inventory. I bet the Navy collected tons of data in the process. The question is: who's privy to that data. I somehow doubt that'll include the DCS crowd, at least for now.

Edit: one would assume they tested the Phoenix in all kinds of scenarios, including low, mid and high altitude shots. "Puck" Howe said in a recent interview that it turned out their tactics charts were too "pessimistic".

 

Edited September 21, 2022 by Jayhawk1971

[Machalot]

21 hours ago, Lurker said:

For years I have had suspicions that most if not all missiles in DCS World are way too draggy at low to medium altitudes. 

As far a I can tell by poking around the lua files, there is no altitude dependency of the drag coefficient, which is pretty much true to real life (IRL there is a small change in viscous drag, but that can be ignored for our purposes.) The speed of sound varies a bit with altitude which affects Mach number, but that is modeled and is not primarily an altitude effect.

The main cause is that air density doubles every 15 kft you descend, which doubles the drag. So at the same airspeed, there should be about ~3x more drag at 20 kft compared to 45 kft, and ~4x at 10 kft.  Does that jibe with your experience? 

Here's a reference for the Standard Atmosphere: https://www.engineeringtoolbox.com/standard-atmosphere-d_604.html

Here's a plot showing the effect on dynamic pressure, which is directly proportional to drag.

Edited September 22, 2022 by Machalot
add plot

[Machalot]

8 hours ago, Timo Niemelä said:

I think he was just surprised to learn about the Phoenix's relatively weak motor, but acknowledged that NASA probably has the most accurate data. I don't think he disagreed with the sim results. 

The NASA paper says: 

Quote

Preliminary performance analysis for the proposed ALSM test platform has been conducted using publicly available data on the Phoenix missile and a simple in-house trajectory analysis code at NASA Dryden. ... Because of possible inaccuracies in the publicly available data for the Phoenix missile, higher-fidelity performance analyses should be conducted to determine the suitability of the ALSM test platform prior to actual hypersonic flight research experiments.

So the data NASA used is not gospel and they don't stand behind it.

On the other hand, in theory it should be accessible by HB to match their model, at which they have already done a pretty good job. 

[GGTharos]

3 hours ago, Lurker said:

I quite agree, hence my question. Are there any real world tests of the Phoenix below 30,000 feet? Or any other missile for that matter, which could then be compared to its DCS counterpart?

Sure there are, after all I have the DLZ, along with its listed limitations and those will have been refined by test firing the weapons.  Unfortunately the same DLZ is subject to a loft algorithm that DCS does not provide (No, HB cannot do it - it's provided by the game and AFAIK cannot be overriden).

But the question here, with respect to what you posted has nothing to do with the phoenix and everything to do with your impression oh how missiles should work at a certain altitude which again ... is not worth anything.  You could always take missiles with known DLZs and compare, and then also pick up Fleeman's book and do the computation yourself using the basic shape -> drag coefficient assignment.   While it's a far cry from a CFD, it gets you in the right ballpark for an evaluation of too fast/too slow.

My point here is very simple though:  If you're going to make the accusation, do the work.

Edited September 21, 2022 by GGTharos

[GGTharos]

3 hours ago, Jayhawk1971 said:

The question is: who's privy to that data. I somehow doubt that'll include the DCS crowd, at least for now.

That's right, ie for all intents and purposes:  No one.

3 hours ago, Jayhawk1971 said:

Edit: one would assume they tested the Phoenix in all kinds of scenarios, including low, mid and high altitude shots. "Puck" Howe said in a recent interview that it turned out their tactics charts were too "pessimistic".

That's a weird statement to make, and utterly meaningless.   Tactics are made to ensure outcomes, if you can afford (as opposed to being forced) to be pessimistic you probably should be.  It really all depends what he means by pessimistic.

[Jayhawk1971]

I meant to write "charts" without the "tactics" in front of it. I just missed that I left the word  in there. I was going to write something else about tactics but changed my mind since it's not what Lurker was asking.

Nevertheless:

Tactics are - or should be - developed based on the expected performance of a weapon system under "real world conditions". And, just to be safe from further  hairsplitting, I'll ad: among other considerations. 

In the context of the interview, I interpreted his statement as the Phoenix performed "better than anticipated". In what aspects, by what margin, he of course leaves out. I also noted that he seems to be deliberately vague and steers the conversation in a different direction.

Edited September 21, 2022 by Jayhawk1971

[lunaticfringe]

 

18 minutes ago, Jayhawk1971 said:

Tactics are - or should be - developed based on the expected performance of a weapon system under "real world conditions". 

Opfor specialists who spend their days red teaming expected threats don't operate to the mean; they present the threat to a higher degree than the actual force themselves in the aims of increasing the reliability of tactics and weapons performance.  These are the environments in which tactics are developed, and the raw tested performance of weapons are backed down from.  

When that 95% of the time baseline gets cut back to 85% to make a published tactic, the difference in reliability is night and day. You tell a man how far out he can shoot and at what sort of angles, he's going to shoot there whether it's an edge case or 99% reliable.  But if you want to structure your planning and tactics schemes to what gets him out there, gets the enemy downed with the lowest risk to him, and gets him home- you don't build to edge cases and wishful thinking. 

[Sindar]

I will tell you a big secret. I do not have the F-14 module (I play my 2 weeks of bonus and my son has this module). The magical effect of the AIM-54 over any surface and its speed in a dense layer of the atmosphere infuriated me. But I learned to resist the AIM-54 ultimatum. I feel sorry for the F-14 module itself. It was not for the novice user. He was not often used, but he was the most interesting opponent. Now he will be completely forgotten. I already see it. In the game now, he does not have the attack targets for which he was created.

This is the first time I see that the developers have sacrificed temporary popularity and profit for the sake of truth. Thanks again for your work.

 

[Jayhawk1971]

vor 30 Minuten schrieb lunaticfringe:

 

Opfor specialists who spend their days red teaming expected threats don't operate to the mean; they present the threat to a higher degree than the actual force themselves in the aims of increasing the reliability of tactics and weapons performance.  These are the environments in which tactics are developed, and the raw tested performance of weapons are backed down from.  

When that 95% of the time baseline gets cut back to 85% to make a published tactic, the difference in reliability is night and day. You tell a man how far out he can shoot and at what sort of angles, he's going to shoot there whether it's an edge case or 99% reliable.  But if you want to structure your planning and tactics schemes to what gets him out there, gets the enemy downed with the lowest risk to him, and gets him home- you don't build to edge cases and wishful thinking. 

I think I don't quite get the point you're making, in this context.

Are you saying that at some point the numbers are becoming negligible when "fine tuning" tactics? As in the charts are "close enough"? Because if so, that wasn't in dispute. 

But you need to know the effective range of your rifle in order to even begin to develop tactics. Sure, at some point it probably won't matter that much whether or not you can hit something 5 meters further downrange. But up to that point,  it would be nice to know if I can train infantry to reliably hit a target, say, at 100 meters or 250 meters.

Edit: My statement was made in response to someone above apparently telling me that weapon system performance was a "meaningless" factor in developing tactics to employ said weapon system. I disagree with that if that is what he meant.

To circle back to the Phoenix, if I understood Puck correctly, the Navy apparently erred on the conservative side; by how much, or if knowing what they knew after those tests would even have made much of a difference in their BVR timelines, I have no way of knowing.

And as long as it has no bearing on my small world of PC sims, it really doesn't matter. I'm not Iran. 

Edited September 21, 2022 by Jayhawk1971

[DD_Fenrir]

8 minutes ago, Sindar said:

I will tell you a big secret. I do not have the F-14 module (I play my 2 weeks of bonus and my son has this module). The magical effect of the AIM-54 over any surface and its speed in a dense layer of the atmosphere infuriated me. But I learned to resist the AIM-54 ultimatum. I feel sorry for the F-14 module itself. It was not for the novice user. He was not often used, but he was the most interesting opponent. Now he will be completely forgotten. I already see it. In the game now, he does not have the attack targets for which he was created.

This is the first time I see that the developers have sacrificed temporary popularity and profit for the sake of truth. Thanks again for your work.

 

The above should be noted for being the dictionary definition of “clap-trap”, “balderdash” and “piffle”. Male cow manure may also suffice.

[Sindar]

4 часа назад, Jayhawk1971 сказал:

Towards the end of the AIM-54's service life, the Navy had their Tomcat crews live-fire a crapload of those, as I assume this was the easiest method to clean out the inventory. I bet the Navy collected tons of data in the process. The question is: who's privy to that data. I somehow doubt that'll include the DCS crowd, at least for now.

Edit: one would assume they tested the Phoenix in all kinds of scenarios, including low, mid and high altitude shots. "Puck" Howe said in a recent interview that it turned out their tactics charts were too "pessimistic".

 

 

This is what I meant when a developer relies on NASA tests. NASA is a mathematics model, static and dynamic stands, full-scale model testing with prepared conditions. These are scientists. And for the sake of money, a lot of their data ... well, not quite what it really is. Only the US Navy is a reliable source of data. I absolutely agree with you.

 

Edited September 21, 2022 by Sindar

[Jayhawk1971]

I don't think neither the Navy nor Hughes relied solely on NASA tests. The Navy ran a whole missile test center at NAS Point Mugu. I bet they've launched their fair share of Phoenix missiles over the decades of its lifespan.

Edit: Oh, by "developer" you mean Heatblur, not Hughes. Sorry, I misunderstood.  That happens when intermittently posting while working . 

Well, to be fair, Heatblur and other developers for the civilian market are dependent on material that is publicly available, and is subject to "fair use". 

 

 

Edited September 21, 2022 by Jayhawk1971

[WarthogOsl]

6 hours ago, Lurker said:

Missile weight does not factor into drag. It does however factor into it's acceleration, on the flipside a heavier or rather a missile with more mass should retain more of it's energy and take longer to slow down. 

I'd think the weight would matter when the missile starts maneuvering, and the induced drag becomes a factor (or if the missile is launched in ACM mode and doesn't loft).

[Machalot]

35 minutes ago, WarthogOsl said:

I'd think the weight would matter when the missile starts maneuvering, and the induced drag becomes a factor (or if the missile is launched in ACM mode and doesn't loft).

I think you guys are saying the same thing: mass matters. Mass doesn't affect the drag force, but it affects the acceleration due to drag.  That effect is captured nicely by a quantity called the ballistic coefficient. 

B = mass / (CD x FrontalArea)

Higher mass doesn't affect CD, but it increases the value of B, which means it retains speed better even though the drag force is the same. 

Maybe more to your point, a heavier missile needs to pull more angle of attack to generate a certain number of Gs, so it has more induced drag for any given maneuver. 

Edited September 21, 2022 by Machalot