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

[JNelson]

On 8/6/2023 at 11:00 PM, Aekay said:

So, We have to assume, JNelson and HB team Cheated DCS "Atmosphere" code, to make a 1.5Mach Initial Mother Aircraft left a 4.4Mach Phoenix Son alive? What sense in this?

Some of this thread appears deleted, but I can only assume you are referring to my quick test where I verify the "max demonstrated" figure mentioned in a DOD hearing.

As you will note in that comment I added the tacview so you can replicate the test at your own leisure.

[tavarish palkovnik]

Just to correct myself, it is not topic but as I wrote it here it would be good to make correction on same address

Seems AIM-7E and AIM-7E-2 in respect of motors are equal, also seems that all types Mk38 Mod.0, 1 and 2 ; Mk38 Mod.3 and 4 and Mk52 Mod.1 and 2 although with different approaches, propellant type, grain formation, chamber pressure, nozzle sizes etc give nearly same result in term of thrust, total impulse and burning time. Meaning all these motors are about 3 seconds of 31,5 kN   

[draconus]

22 minutes ago, tavarish palkovnik said:

Just to correct myself, it is not topic but as I wrote it here it would be good to make correction on same address

Seems AIM-7E and AIM-7E-2 in respect of motors are equal, also seems that all types Mk38 Mod.0, 1 and 2 ; Mk38 Mod.3 and 4 and Mk52 Mod.1 and 2 although with different approaches, propellant type, grain formation, chamber pressure, nozzle sizes etc give nearly same result in term of thrust, total impulse and burning time. Meaning all these motors are about 3 seconds of 31,5 kN   

This should go here:

https://forum.dcs.world/forum/259-sim-research/

or

https://forum.dcs.world/forum/540-weapon-bugs/

[GGTharos]

5 hours ago, tavarish palkovnik said:

Just to correct myself, it is not topic but as I wrote it here it would be good to make correction on same address

Seems AIM-7E and AIM-7E-2 in respect of motors are equal, also seems that all types Mk38 Mod.0, 1 and 2 ; Mk38 Mod.3 and 4 and Mk52 Mod.1 and 2 although with different approaches, propellant type, grain formation, chamber pressure, nozzle sizes etc give nearly same result in term of thrust, total impulse and burning time. Meaning all these motors are about 3 seconds of 31,5 kN   

2.9s 8000lbs.  Yep.

There are two main drivers of the different motor types:   Diversity of vendors (one goes bankrupt or something else happens, you have the other) and reliability improvements for the rocket motors.

[tavarish palkovnik]

@GGTharos

You were right about these motors!

By the way, think I figured out numbers given behind Mk60. If this motor is like Mk47 with slotted tube grain, what is most likely, and if I take what was in front of nose all the time and just make reverse calculations, numbers given to Mk60 become very obvious.

If it looks like a duck, if it swims like a duck, if it sounds like a duck…then it is the most probably a duck 

[MBot]

There is a problem with lofting Phoenix against low supersonic targets. I tried to engage SS-N-19 Shipwreck missiles. If the Phoenix lofts, it comes down too late resulting in a terminal perpendicular dive from which it has no chance to hit the target. It would need to dive earlier and flatter to hit the target head-on.

The only success I had was launches under 20 NM where the Phoenix doesn't loft at all and goes straight for the target. If it lofts it is a guaranteed miss.

No track because they don't play back correctly anyway, but you can check out the test scenario in the mission below.

Phoenix_Shipwreck.miz

[IronMike]

31 minutes ago, MBot said:

There is a problem with lofting Phoenix against low supersonic targets. I tried to engage SS-N-19 Shipwreck missiles. If the Phoenix lofts, it comes down too late resulting in a terminal perpendicular dive from which it has no chance to hit the target. It would need to dive earlier and flatter to hit the target head-on.

The only success I had was launches under 20 NM where the Phoenix doesn't loft at all and goes straight for the target. If it lofts it is a guaranteed miss.

No track because they don't play back correctly anyway, but you can check out the test scenario in the mission below.

Phoenix_Shipwreck.miz 9.65 kB · 0 downloads

Thank you. Tactical ping @JNelson

[tavarish palkovnik]

So like said, think that I managed to get to what is given for Mk60 Mod.0 motor and why not to share it here

 

 

I used this grain configuration, slotted tube, only with mutually dislocated slots to have this part with slots in participation all the time. Also I took and used data of slow burning USA propellant type RDS-501, common for that time and got this ->

 

   

 

It is very much on the trail of numbers given to Mk60 Mod.0, 20-30 seconds and average thrust values 5000-1000 lbf (22241-4448 N). Pressure is also on the trail, they said maximal is 1000 psi (69 bar) I got very close

 

 

This motor sucks down there at sea level as it supposes to do with nozzle like it is, however up there it gives what should give. If I would create this motor for purpose of this game, this is what I would do.

 

 

So I would make it as linear function from 23000 N to 4500 N of thrust during 25 seconds. It makes total impulse of 343750 Ns or average 13750 N or average specific impulse of 206,1 s. That is for sea level. To get numbers for altitudes, first with this motor principle of 7% should be forgotten because it sucks here. Actually any kind of single valued percentage for increasing should be avoided becuase it will give false result for this case. Here I would use instead of percentages increasing with adding extra force and for 10km it would be extra 3000 N in each second, all that can be explained of course.

 

   

 

Now it is from 26000 to 7500 N, total impulse of 418750 Ns and average Isp 251,1 s. And I would use function F f(t) instead of making it as continuous average thrust of 16750 N because these two inputs give sometimes very much different outputs.

 

  

 

Yes, total impulse is the same but...

 

 

 

 

 

This is some hypothetical ballistical shot from 10km at 1,5M with elevation of 20 deg where ''red'' is continuous 16750 N thrust. 

And this is hypothetical horizontal flight at 10km with kinematic overload

 

 

 

In any case, function or continuous average thrust can go depending of desire for precision but with changing of thrust values with altitues, with this and similar motors, extra care should be taken   

 

[FWind]

16小时前，tavarish palkovnik说：

So like said, think that I managed to get to what is given for Mk60 Mod.0 motor and why not to share it here

 

 

I used this grain configuration, slotted tube, only with mutually dislocated slots to have this part with slots in participation all the time. Also I took and used data of slow burning USA propellant type RDS-501, common for that time and got this ->

 

   

 

It is very much on the trail of numbers given to Mk60 Mod.0, 20-30 seconds and average thrust values 5000-1000 lbf (22241-4448 N). Pressure is also on the trail, they said maximal is 1000 psi (69 bar) I got very close

 

 

This motor sucks down there at sea level as it supposes to do with nozzle like it is, however up there it gives what should give. If I would create this motor for purpose of this game, this is what I would do.

 

 

So I would make it as linear function from 23000 N to 4500 N of thrust during 25 seconds. It makes total impulse of 343750 Ns or average 13750 N or average specific impulse of 206,1 s. That is for sea level. To get numbers for altitudes, first with this motor principle of 7% should be forgotten because it sucks here. Actually any kind of single valued percentage for increasing should be avoided becuase it will give false result for this case. Here I would use instead of percentages increasing with adding extra force and for 10km it would be extra 3000 N in each second, all that can be explained of course.

 

   

 

Now it is from 26000 to 7500 N, total impulse of 418750 Ns and average Isp 251,1 s. And I would use function F f(t) instead of making it as continuous average thrust of 16750 N because these two inputs give sometimes very much different outputs.

 

  

 

Yes, total impulse is the same but...

 

 

 

 

This is some hypothetical ballistical shot from 10km at 1,5M with elevation of 20 deg where ''red'' is continuous 16750 N thrust. 

And this is hypothetical horizontal flight at 10km with kinematic overload

 

 

 

In any case, function or continuous average thrust can go depending of desire for precision but with changing of thrust values with altitues, with this and similar motors, extra care should be taken   

 

https://ntrs.nasa.gov/citations/19660024251

[tavarish palkovnik]

@FWind This is great stuff, thanks a lot man !

English is not my native language so if you guys can help me to understand what author actually wanted to say ...

 

 

''The outside half of these start points'' with accent to word HALF. What half is meaning? Half of 6 is 3 and if only, let's say in immaginary grain with 6 points star, 3 extended points will be inhibited it gives nothing good.

If all 6 extended poits will be inhibited in half of it radial length it also gives nothing good.

Or ''half'' means half of longitudinal length of points extendings will be inhibited...something like this ->

 

 

 

 

 

If author ment on this half than with variations of star configuration, for example with shorter star arms like this

 

 

it becomes actually nothing much different to what slotted tube is and what is expected to be in some of forms in both of these two motors 

[tavarish palkovnik]

Clear now after read complete text…exposed area were nearly same for these samples, conventional star cylinder (Fig C-11) and inhibited wedge star (Fig C-12)

“Star point” for inhibited wedge star…conventional star point plus extension till motor case wall is star point for inhibited wedge star…half of it etc etc

Interesting indeed

Edited August 22, 2023 by tavarish palkovnik

[Machalot]

18 hours ago, tavarish palkovnik said:

English is not my native language so if you guys can help me to understand what author actually wanted to say ...

I think figure of yours this is one of the best interpretations, in which the orange represents asbestos fill, and extends from the outer edge radially halfway toward the inner bore surface.  The other possibility is that the asbestos covers the inner surface as shown but does not fill the volume.

null

[tavarish palkovnik]

That's right, process of fabrication is such that liners remain only on the sides of slots, inside are molding matrixes which after fuel is cured are taken away.

However, all this has to be taken ultimate. If such star configuration (6-point star and half of star points inhibited) would be inside of this motor, in full length of grain, it would give nothing close to what is expected. This would result, becuase of big initial burning surface, with very high pressure and thrust respectively, and relatively short burning time.

This text and connecting wedge star principle with Mk47 motor is I believe just to explain wedges itself, or what I want to say, yes most likely slots are done that way but slots are not all the way long through to grain, but like earlier said, grain should be slotted tube configuration, or if someone likes, tube with star portion.

 

 

 

And again we are back to what is reality. I was writing about Neva motor (SAM-3) and more and more all this becomes closer and closer. And this most likely will be just one more motor which will have in many details opponent on other side, you would be surprised how many details in Aerojet's motors you can find on other side.

This motor on cross section, in perhaps final configuration where it got CTPB based propellant (151kg) was giving 34000-35600 kgs in 15,3-24 seconds 

 

 

Edited August 23, 2023 by tavarish palkovnik

[FWind]

https://ntrs.nasa.gov/citations/20090012144

[Karon]

What we have in-game is not too far, depending on the rocket motor and whether the speed was recorded when pitching up or at the separation.

Also, NASA copied my AIM-54 loft tests! *badum tss*

[tavarish palkovnik]

Why is limit only miserable 16,88 kB for attachment ?

I have some very interesting tables to show ... 

 

 

and this is how it looks, what is point of this

[draconus]

4 hours ago, tavarish palkovnik said:

Why is limit only miserable 16,88 kB for attachment ?

You already used your limits for attachments. You can remove older ones.

[tavarish palkovnik]

Limit for personal cumulative attachments !?  First time I hear for something like this on forums 

So, to delete previous ones to put new one 

Good old paper form books and brain memory, that is what will survive internet apocalypse 

 

[MBot]

On 7/29/2023 at 7:38 PM, MBot said:

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?

May I kindly ask about this again? I am doing a lot of bomber intercepts and this is a very common problem. The target is non-maneuvering and the interpolated track remains in the target vicinity, yet the Phoenix stops to guide.

[Comstedt86]

15 hours ago, MBot said:

May I kindly ask about this again? I am doing a lot of bomber intercepts and this is a very common problem. The target is non-maneuvering and the interpolated track remains in the target vicinity, yet the Phoenix stops to guide.

With the A, the few times I've seen it go active despite lost track was when it was only 1-2 seconds tops from going active anyway. 

[Spurts]

The C goes active on drop track, the A does not and waits for the command

[Karon]

On 8/30/2023 at 10:19 PM, MBot said:

May I kindly ask about this again? I am doing a lot of bomber intercepts and this is a very common problem. The target is non-maneuvering and the interpolated track remains in the target vicinity, yet the Phoenix stops to guide.

I was looking at how the extrapolated guidance works these days, and I ran into this...

I'm afraid it is on ED's side, and HB can't really do much about it.

 

[captain_dalan]

On 9/1/2023 at 4:12 PM, Karon said:

I was looking at how the extrapolated guidance works these days, and I ran into this...

I'm afraid it is on ED's side, and HB can't really do much about it.

 

Is the AMRAAM, that is the new missile API subject to the same oddities? 

[Karon]

20 hours ago, captain_dalan said:

Is the AMRAAM, that is the new missile API subject to the same oddities? 

Possibly. I am not particularly interested in the AIM-120 and modern stuff, so I rarely check them.
It's a quick test though.

[captain_dalan]

19 hours ago, Karon said:

Possibly. I am not particularly interested in the AIM-120 and modern stuff, so I rarely check them.
It's a quick test though.

It would be much appreciated!