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

[tavarish palkovnik]

Series Mk38 and Mk52 are indeed of two different producers, while first is of Rockedyne second is of Aerojet. But there is much more behind it.

Mk38 Mod 0, 1 and 2 are first group and these motors operate in mentioned 3 seconds. On page before this one, there is a table giving nozzle geometry, average time and thrust for Mod.1

 

 

These motors are of this concept (Mod.0 in this cross cut view). Cylindrical grain molded, cured and then inserted in chamber. Free burning all around of this pipe formed grain. These elements which can be seen in sectional view are for positioning of the grain in chamber assuring necessary gap between burning surface and inner wall of the chamber. Differences between Mod.0 to Mod.2 should not be some significant, these pressure to time diagrams are for Mod.0 and Mod.1, and here can be seen slight pressure difference (1200 vs 1300 psi)

 

 

 

Mk38 Mod.3 and Mod.4 however are of completely different concept, these have grain casted directly in chamber and burning from inside, in channel with star formation.

 

 

This sectional view is Mk38 Mod.4 with 5-point star channel. Nozzle is with different dimensions compared to previous Mods, burning time surly is not 3 seconds but more about 5 to 6 seconds. And this concept of motor I believe should be in AIM-7E2.

 

Edited July 8, 2023 by tavarish palkovnik

[Karon]

8 hours ago, tavarish palkovnik said:

Although this topic is not related to Sparrow, just to ask about this AIM-7E-2 because based on this graph it seems so wrong. AIM-7E2 should be very much related to Skyflash isn't it? If I'm not wrong, both are equipped either with motor type Mk52 or motor Mk38 Mod.4 

@Karon what motor is behind this graph?

Motors of Sparrow 7E family can be divided in three groups:

Mk38 Mod.0, 1 and 2

Mk38 Mod.3 and 4

Mk52

and between some of these groups difference is significant. If there will be interest we could shortly go through these motors, although all looks same from outside, inside they are very different, especially these Mods 0, 1 and 2 compared to others   

These are in-game values, so whatever rocket motor was represented there. Sorry for the vague reply!

[tavarish palkovnik]

All right, I thought there is some description behind every rocket, motor this or that, thrust like that etc.

In any case I think this one is simply just wrong. 

 

There is no reason not to believe that series 38 and 52 follows each other so Mk38 Mod.3 should be somewhere in line with Mk52 Mod.3 and if AIM-7E-2 is more or less in line with Skyflash then it is about 5 seconds active time.

Of course not with same thrust of 7085 lbf as previous models, however could be said with same total impulse more or less.

 

[CarbonFox]

The later AIM-7MH and P feel like they're underperforming particularly as the P reportedly had better low altitude performance and mid-course correction.

[near_blind]

Seeker performance for sarh missiles across the board is... Disappointing.

 

Unfortunatly that ball is in EDs court

[tavarish palkovnik]

New findings about Mk47 Mod 0

 

 

 

 

So it is tube with slots after all, it has sense although it can't be recognized on that cross cut photo

That is something like this, and of course to have final answer how this motor works (in single or dual mode) number, position and dimensions of slots have to be determinated. Four slots will give nearly continuous burning surface while 6 for example will give booster phase (or better to say a bit regressive process). Photo of cross cut model in better resolution would give all what is needed

 

Edited July 13, 2023 by tavarish palkovnik

[CarbonFox]

I'm actually finding the AIM-54C Mk 47 to be the best to carry in most circumstances. That extra 7.4 seconds of burn makes a difference and I made a 100nm shot last night with it. The Mk 60 still does this weird ballistic trajectory where I didn't experience that with the Mk 47.

Edited July 13, 2023 by CarbonFox

[Machalot]

19 hours ago, tavarish palkovnik said:

New findings about Mk47 Mod 0

 

 

 

 

So it is tube with slots after all, it has sense although it can't be recognized on that cross cut photo

That is something like this, and of course to have final answer how this motor works (in single or dual mode) number, position and dimensions of slots have to be determinated. Four slots will give nearly continuous burning surface while 6 for example will give booster phase (or better to say a bit regressive process). Photo of cross cut model in better resolution would give all what is needed

 

 

Impressive source mining. It's not a guarantee that a general document citing a classified source means the -47 has a slotted grain, but it is an interesting piece of evidence. 

It would be interesting too if somebody made an FOIA request for that Rocketdyne qual report.  It would likely contain recorded thrust and chamber pressure data from hotfire tests at various temperatures.

[tavarish palkovnik]

6 hours ago, Machalot said:

It would be interesting too if somebody made an FOIA request for that Rocketdyne qual report.  

That would be so nice if possible. In literature author gave every possible grain formation, finocyl as well, so I guess when citing is done exactly in text about slotted tubes that should be very valid evidence that Mk47 and perhaps Mk60 as well are really in that form. And that makes job much easier, burning of such formation is quite easy to program and of course all other formations are excluded from further considerations.

This form of grain will never give classic booster stage, for example few seconds of continuous or nearly continuous thrust then transition to sustaining phase, like finocyl gives. Four slots in some 1/3 of total length will result with slightly regressive burning, but such output thrust numbers can't be connected to nothing we have till now (except that it could be not for sea level).

However six slots in same 1/3 length gives some numbers close to what we have about Mk60 Mod.0, in mean of thrust and chamber pressure.

 

 

 

Pressure and burning surface plus thrust at 0 and 10km

 

 

 

 

This although looks quite awkward, in same time looks realistic as well

[tavarish palkovnik]

Just to add it here to be on same place, in addition to Mk38 Mod.0 and Mk38 Mod.4 this is Mk52 of some Mod which corresponds to Mk38 Mod.3 and/or Mod.4, 5-points star channel burning

 

 

And this is Mk65 which is Aerojet's alternative to Mk58 of Hercules

 

 

This is of course Mk58

 

 

With these 5 cross cuts AIM-7E, AIM-7E2 and AIM-7F are covered

Edited July 18, 2023 by tavarish palkovnik

[MBot]

It is my experience that when guiding a AIM-54A in TWS and the track goes in extrapolation mode, the missile gets trashed. It never seems to go active. It is my understanding that the missile should continue to be guided and getting an activation command on the extrapolated track but that is currently not possible in DCS. I frequently get track extrapolations when attacking non-maneuvering bomber formations when close targets start to get resolved individually. The extrapolated track frequently continues to be close with newly created tracks and if the missile would continue to guide it would probably detect a target in the bomber formation when going active. Is it planned that this will eventually work in DCS?

[Karon]

If you are close to the a activation distance when you lose it, it often works fine with the C.

[WarthogOsl]

Can someone help me with what just happened here?  As you can see, the missile went pitbull and turned toward the bandit, but then it just went sailing over the top of him.  As far as I can tell, there was never any orientation that put the bandit at 90 degrees to the missile.

[Karon]

9 hours ago, WarthogOsl said:

Can someone help me with what just happened here?  As you can see, the missile went pitbull and turned toward the bandit, but then it just went sailing over the top of him.  As far as I can tell, there was never any orientation that put the bandit at 90 degrees to the missile.

Can you upload the whole track, please?

[WarthogOsl]

56 minutes ago, Karon said:

Can you upload the whole track, please?

I can upload the tacview file later, if that helps.

[Karon]

4 hours ago, WarthogOsl said:

I can upload the tacview file later, if that helps.

Ah, yeah, that's what I meant. DCS tracks are not reliable.

[WarthogOsl]

4 hours ago, Karon said:

Ah, yeah, that's what I meant. DCS tracks are not reliable.

Okay, I actually found 2 or 3 incidents that happened yesterday that seemed almost exactly the same.

I've included 2 tacviews.  The file names indicate the timestamps of the relevant events (48:20 and 20:31).  Or just look for Warthog 1-1 in the event dropdown and see the cases where the AIM-54 missed.

I'd be interested in your thoughts.

 

20-31-Warthog1-1-Through_The_Inferno_MI_v1.1.8.zip.acmi 48-20-Warthog-1-1-Through_The_Inferno_MI_v1.1.8.zip.acmi

[Spurts]

All three missed Phoenixes look like they got notched

[Karon]

I checked one, and it looks like notching. You can also notice by the AI recommitting immediately because they are magical creatures of DCS, and they don't care if the seeker is still illuminating them. They know the missile is defeated. Aye, it's a tad annoying.

[WarthogOsl]

2 hours ago, Karon said:

I checked one, and it looks like notching. You can also notice by the AI recommitting immediately because they are magical creatures of DCS, and they don't care if the seeker is still illuminating them. They know the missile is defeated. Aye, it's a tad annoying.

I just wonder if, since the patch, has anyone seen a missile actually reacquire after a notch?

[WarthogOsl]

7 hours ago, WarthogOsl said:

I just wonder if, since the patch, has anyone seen a missile actually reacquire after a notch?

Perhaps I've just answered my own question here with this new tacview.  Note that the missile turns towards the bandit, but then seems to get locked into a straight line flight that would not intercept.  At around a mile away, it suddenly seems to wake up and does a hard turn to intercept the bandit again.  Unfortunately, it loses too much energy and ends up 1000 feet behind.

Edited July 31, 2023 by WarthogOsl

[The_Tau]

13 hours ago, WarthogOsl said:

Okay, I actually found 2 or 3 incidents that happened yesterday that seemed almost exactly the same.

I've included 2 tacviews.  The file names indicate the timestamps of the relevant events (48:20 and 20:31).  Or just look for Warthog 1-1 in the event dropdown and see the cases where the AIM-54 missed.

I'd be interested in your thoughts.

 

20-31-Warthog1-1-Through_The_Inferno_MI_v1.1.8.zip.acmi 4.32 MB · 3 downloads 48-20-Warthog-1-1-Through_The_Inferno_MI_v1.1.8.zip.acmi 6.88 MB · 2 downloads

to me they looked notched :(.

So missile doesnt pull up when notched anymore, but instead it just flies next to target "blinded" for some reason. 

So it seems ED just fixed "visual" bug of missile pitching up, but they didn't touch the main problem - 54 being unable to find target again after target leaves the notch...

Wow I am so disappointed...

Edited July 31, 2023 by The_Tau

[sLYFa]

I'm also not impressed with the improved notching behaviour tbh. Had an F-4 defeating a PHC at high altitude with a split-s and a couple of chaff. I know the AI have perfect SA but still, I dont see how a non-ECM equiped aircraft can notch a modern PD missile up high.

[CarbonFox]

ED needs to retune the AI some and cutback on the responsiveness to incoming missiles.

[Snappy]

23 hours ago, The_Tau said:

to me they looked notched :(.

So missile doesnt pull up when notched anymore, but instead it just flies next to target "blinded" for some reason. 

So it seems ED just fixed "visual" bug of missile pitching up, but they didn't touch the main problem - 54 being unable to find target again after target leaves the notch...

Wow I am so disappointed...

 

I haven’t touched the phoenixes in quite a while. Did the pre-patch version of it have less susceptibility to notching targets? Or are you disappointed that it has stayed as bad as before?

Also , does the actual problem lie with the phoenix’ inability to pick up targets again after they exit the notch or is it the all-knowing AI that executes perfect unrealistic notching for the exact necessary duration to defeat  the missile completely ?

I mean, is it the missile or the AI behaviour ?

I have no illusion that ED will make the AI behave more realistic or less perfect in the short term, if at all. They seem unable or unwilling to tackle this giant weakness in DCS in general.

Edited August 1, 2023 by Snappy