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

[captain_dalan]

On 5/11/2023 at 4:56 AM, Harlikwin said:

I mean I agree. All I'm saying is that compared to real life where you don't have unlimited lives to figure out how to "game" the missile defense. And you know there is an actual risk of dying. You are gonna fly very differently than what DCS looks like in PVP. 

Ah. no argue from me there. After all, even the AMRAAMs have abyssal hit ratio once you know what you're doing. 

[Temetre]

Main scenario where Aim-120s seem nearly unbeatable is when you majorly outrange the opponent. Especially when facing off against semi-active missiles with less range. Attacking plane doesnt even need to use radar if its got AWACS or other "spotter" fighters backing it up.

Thats just such a massive advantage its hard to overcome, probably even in reality. But that doesnt mean the missiles has to be unbetable in any situation. 

Edited May 18, 2023 by Temetre

[Redounet]

is there any news regarding the switch to the new 120 api for the aim54 now that sd10 api switch is being considered ?

[Karon]

Quick video to, hopefully, answer the question that pops up now and then. Which version is the best? In 2019, the A Mk60 dominated due to its vastly better kinematic performance. Nowadays, every version has pros and cons, and ranges at which they work best. It all comes down to how you use them.
 

 

[Karon]

I put together another brief video, this time showing missile performance vs *Time*.

It's often taken from granted, but I'm finding this aspect, or the lack of understanding of it, to be one of the main causes when people call the Phoenix "bad" or "broken".

TLDW: in 30", a Phoenix travels ~10nm. An R-27ER covers almost 17nm, but the longer the range, the greater the advances of the Phoenix. Therefore, manipulating geometry (e.g. cranking) helps to offset the disadvantages in terms of acceleration, top speed, and trajectory.

Edited May 31, 2023 by Karon

[FWind]

2022/12/4 AM12点25分，tavarish palkovnik说：

More or less but mostly  everything can be calculated with just simple involving elementary study of rocket motors. Luckily there are plenty of motors sharing same diameter 380mm or 15’’ and having similar composite fuels so even visible differences forcing directions.

All these three are in 380mm

 

 

5V27 of S-125 Neva (SA-3), R-33 and Kh-58…all in same diameter as AIM-54

5V27 is primarily for low and near to intermediate altitudes and nozzle is sized respectively 

 

 

Kh-58 is more for low intermediate and near to low altitudes

This motor’s cross section is my creation but I stand for it very firmly 

And this is Mk47 Mod 0

with nozzle bell sized, obviously not optimized for sea level or intermediate altitudes but for up there altitudes just as R-33 

 

http://aviationarchives.blogspot.com/2023/05/naval-air-launched-guided-missiles.html

[Karon]

Last video about Phoenix kinematics (on top of AIM-7s and AIM-120C-5), covering the effects of speed and altitude, and how they are not always worth it. The main reason is that the Phoenix hits the brakes in the last few miles, sometimes wasting all the energy advantage provided by flying high and fast. This, and other factors, such as fuel, mission objectives and tasking, may make the whole effort quite pointless, depending on the scenario.

I do not plan any additional videos on the topic, I don't think there are aspects still to be discussed (also, enough with the spam! ).
 

In the example above (from the video), the first pair is co-alt, 0TA, 0ATA, 35k, M1. The second ("FAST") is flying at ~M1.15. The last ("HF") is higher and faster: 45,000ft, M1.15.
However, the additional 10k the Phoenix has to dive, makes it waste the whole speed advantage it accumulated before. Ergo, the gains are more on the flight time side, rather than the speed at impact.

This is, however, only one scenario. When employing at 80nm, for example, the advantages of flying even only 5,000ft higher are really tangible (+ ~M0.5 at impact, flight time -30s).

EDIT: I know what I said, but a user on Hoggit asked for more details about Cold War missiles, so here we have another video

 

Edited June 8, 2023 by Karon

[Fulcrumkiller31]

The most frustrating aspect of the 54C right now is how easy it is to notch, not sure how realistic that is. Everything else seems pretty close. AI just can hit that perfect notch every time, and the missile just does a random pull up maneuver. 

[The_Tau]

2 hours ago, Fulcrumkiller31 said:

The most frustrating aspect of the 54C right now is how easy it is to notch, not sure how realistic that is. Everything else seems pretty close. AI just can hit that perfect notch every time, and the missile just does a random pull up maneuver. 

Veteran AI is much more forgiving and realistic for Red force average pilot skill level

[tavarish palkovnik]

On 6/4/2023 at 11:18 PM, Karon said:

EDIT: I know what I said, but a user on Hoggit asked for more details about Cold War missiles, so here we have another video

 

Diagrams of these Soviet missiles are with lot of issues, inaccuracies and incorrectness, starting from R-33 and backwards

[Karon]

31 minutes ago, tavarish palkovnik said:

Diagrams of these Soviet missiles are with lot of issues, inaccuracies and incorrectness, starting from R-33 and backwards

These are what we have in-game, though. I wanted to comment about the missile API, or the variables used to describe CM resistance, for example, but I have preferred staying on the pure kinematics discussion. On the positive side, as soon as ED improves their missiles, I will be able to immediately compare the datapoints.

If you have resources that can help ED to implement more realistic missiles, please do get in touch with them. We all want DCS to improve, and the work they are doing on F-16/18's radars is very promising.

[tavarish palkovnik]

As much as I know there is no some official text about what R-33 motor gives except one solid info that active time is 15-24 seconds (it is for +60 to -60 degC), however luckily cross cut view of motor is available and it gives a lot. I think I've already wrote something about this but don't remember where and when

It is shematically this form ->

 

 

Such finocyl grains usually have buster stage then transition part in duration depending of configuration and at last sustaining stage, and more or less after some work thrust f(t) should looks like this at 10 km altitude 

 

 

In game you have very weak booster in 4 seconds then rapid (immediate) drop to continuous sustaining stage taking so long and unnaturally for such configuration.

And at the end, velocity M f(t) and distance* nm f(t)

 

*-kinematically overloaded horizontal flight at 35000 ft 

So, although total travel is similar, distribution in time is significantly different

 

 

Edited June 12, 2023 by tavarish palkovnik

[Kageseigi]

On 9/1/2022 at 12:01 PM, lunaticfringe said:

For sake of clarity (and Бойовий Сокіл has the gist of it): 

54C in RL, in the event of a lost STT lock, would independently go active, and remain SARH all the way to the target if the lock was held. 

In DCS, to have the ability for the missile to go active in the event of a lost lock, the missile has to go active at some point in its flyout.  So the C does this at the appropriate time.  

The flipside of this, and why you want to take your STT shots when appropriate, is the fact that STT isn't susceptible to all of the issues TWS has for maintaining a track.  So you get all of the reliability of a STT shot, with the added bonus of the active fallback. 

 

 

I just watched a BVR fight in which it appeared the Tomcat pilot was attempting to keep the bandit higher than him, which I'm assuming was so he could have the MLC filter off in order to avoid getting notched using STT. I'm also assuming he was using the AIM-54C variant. Anyway, the tactic got me to come back and read some of this thread, and it made me question something.

Since the C version has to go active in DCS instead of remaining SARH if supported all of the way to the target, does this make using the above tactic rather ineffective? In other words, since the C goes active, does the target only have to notch the missile's radar instead of the F-14's? If so, then how much more susceptible is the Phoenix's radar to being notched than the AWG-9 with the MLC filter off? And would that make an A version or even a Sparrow a more attractive missile to use with that tactic?

Edited June 18, 2023 by Kageseigi

[Karon]

3 minutes ago, Kageseigi said:

Since the C version has to go active in DCS instead of remaining SARH if supported all of the way to the target, does this make using the above tactic rather ineffective? In other words, since the C goes active, does the target only have to notch the missile's radar instead of the F-14's? If so, then how much more susceptible is the Phoenix's radar to being notched than the AWG-9 with the MLC filter off? And would that make an A version or even a Sparrow a more attractive missile to use with that tactic?

You can't notch the AWG-9 in DCS if you do not want. However, in-game you see missiles (either AIM-7 or 54) guide until a certain point where they just go for chaffs, even dropped 10" earlier, seemingly notched by the defending aircraft, even if the AWG-9 always maintains a solid lock.
In other words, both STT and ARH can be notched in DCS. The resilience vs chaff of the various missiles is described by a parameter in the lua files. I wouldn't know how to compare the two though.

Also, ARH launches never reacquire a target, they start climbing in a very odd way. It wasn't happening before the AIM-54 overhaul. The problem is, I highly doubt this in HB's hands.

@tavarish palkovnik Interesting, unfortunately I am not competent enough to comment; you should post them to ED and see what they say.

[draconus]

21 hours ago, Kageseigi said:

Since the C version has to go active in DCS instead of remaining SARH if supported all of the way to the target, does this make using the above tactic rather ineffective? In other words, since the C goes active, does the target only have to notch the missile's radar instead of the F-14's? If so, then how much more susceptible is the Phoenix's radar to being notched than the AWG-9 with the MLC filter off? And would that make an A version or even a Sparrow a more attractive missile to use with that tactic?

Mind that it goes active only at 10nm to the target so it's only a few seconds before impact and rather hard to change tactics in the right moment and notch the missile perfectly, but still possible. Would A be better - I doubt it, since it has worse game parameters. A Sparrow is whole other story and not really comparable as it's a different missile, used in different shots.

[Kageseigi]

On 6/19/2023 at 2:17 AM, draconus said:

Mind that it goes active only at 10nm to the target so it's only a few seconds before impact and rather hard to change tactics in the right moment and notch the missile perfectly, but still possible. Would A be better - I doubt it, since it has worse game parameters. A Sparrow is whole other story and not really comparable as it's a different missile, used in different shots.

Yeah, in this particular fight, the bandit fired an AMRAAM at 11 miles, and immediately went defensive for a notch in case the Tomcat fired... which it did right within 10 miles a few seconds later. The bandit stayed in the notch until the last second, then broke into the missile which missed. So I don't know if it was defeated by the notch or chaff.

Granted, the Tomcat did turn cold at some point to defend against the AMRAAM, so the pilot may have not tried to support the Phoenix all the way in (knowing it was already pitbull). And the Phoenix did track most of the way. But it still makes me wonder if a fully supported AIM-54C would have an advantage over the currently modeled auto-active AIM-54C in this type of situation. Or perhaps they have it modeled where the supporting radar overrides the missile radar if it is still tracking? Probably not, but I don't have that knowledge.

Then again, I don't even know how good the AWG-9 tracking capabilities are compared to an AIM-54's internal tracking capabilities, A or C model.

P.S. It may have been mentioned before, but is the AWG-9 itself even susceptible to being spoofed by chaff at all? Perhaps the AIM-54 versions are overly susceptible in DCS currently, but would chaff ever even have a prayer of spoofing an AWG-9 supported missile?

[Harlikwin]

1 hour ago, Kageseigi said:

Yeah, in this particular fight, the bandit fired an AMRAAM at 11 miles, and immediately went defensive for a notch in case the Tomcat fired... which it did right within 10 miles a few seconds later. The bandit stayed in the notch until the last second, then broke into the missile which missed. So I don't know if it was defeated by the notch or chaff.

Granted, the Tomcat did turn cold at some point to defend against the AMRAAM, so the pilot may have not tried to support the Phoenix all the way in (knowing it was already pitbull). And the Phoenix did track most of the way. But it still makes me wonder if a fully supported AIM-54C would have an advantage over the currently modeled auto-active AIM-54C in this type of situation. Or perhaps they have it modeled where the supporting radar overrides the missile radar if it is still tracking? Probably not, but I don't have that knowledge.

Then again, I don't even know how good the AWG-9 tracking capabilities are compared to an AIM-54's internal tracking capabilities, A or C model.

P.S. It may have been mentioned before, but is the AWG-9 itself even susceptible to being spoofed by chaff at all? Perhaps the AIM-54 versions are overly susceptible in DCS currently, but would chaff ever even have a prayer of spoofing an AWG-9 supported missile?

Go read about how chaff works on the M2k, its likely similar for the AWG-9. In general DCS gets it horribly wrong by treating chaff as "flare" for radar.

[draconus]

6 hours ago, Kageseigi said:

Yeah, in this particular fight, the bandit fired an AMRAAM at 11 miles...

Sounds like already lost fight. AMRAAM is faster, more maneuverable, less susceptible to CMs, less draggy...

6 hours ago, Kageseigi said:

But it still makes me wonder if a fully supported AIM-54C would have an advantage over the currently modeled auto-active AIM-54C in this type of situation.

No, C will always go active in DCS.

6 hours ago, Kageseigi said:

...would chaff ever even have a prayer of spoofing an AWG-9 supported missile?

In DCS - yes.

[tavarish palkovnik]

 

Does anybody have this document in complete form? This motor will make me crazy 

Total impulse 97000 lb*s or 431477 Ns together with 376 lbs or 170,5kg of fuel (if all this will be taken as fuel weight because some small part should be igniter, ablative isolation etc) makes specific impulse of 258s. It is huge and it doesn't have any sense.

From some old patent documents this Flexadyne fuel can be described as composition of 66%AP, 18%PB and 16%Al. These percentages and in this composition give some ideal and theoretical specific impulse of 261s

 

   

 

And now somehow Phoenix motor should be close to ideal value if this total of 97000 lb*s is for sea level . Ideal impulse from diagram is for pressure ratio 68, Phoenix if it is with single thrust of 4000 lbs (17793N) have to be with chamber pressure under 68 bar, and for sure with such nozzle, even if chamber pressure is somehow near to 68bar, no way whatsoever that it will expand in optimized way to atmospheric pressure at sea level.

Just with that fact specific impulse of 261s will be lower. Then losses from ideal case, and losses are always present in real case. Loss of heat, loss due to friction, loss in nozzle, loss due to condensation phase, loss of unburned fuel etc etc.

 

Just comparation, I believe this Phoenix fuel is same or very similar to what is in AIM-9D and its motor smoky Mk36

 

 

 

 

Specific impulse 231s ! And that is how it should be because for this Mk36 motor I'm giving some 50bar to chamber pressure, nozzle configuration is such to give near to optimized expanding at sea level. 

Something is smelling in these numbers given to Phoenix. Either it is not even close to sea level but numbers given for some high altitudes what is not practise in such documenets, either some words like average are missing. Total impulse of 431000 Ns could be possible, but if motor has buster and transition phase when chamber pressure is 1/3 of total time over 100 bar.

Motor of R-33 from page before, it is similar in size. It is a bit more heavier, I'm giving it 185kg of fuel and with its way of work (full blood dual thrust) at sea level it gives something like 485000 Ns of total thrust at sea level. That is what my calculation gives and specific in that case is 267s, but at least 5 seconds it is with chamber pressure over 100 bar. Russian composite fuels used in motors of A-to-A missiles are with some 245-250s at ratio 40:1.  And it has nice expanding at sea level in these 5 seconds, it expands to ambient pressure. Phoenix motor with single thrust and with such nozzle would be only motor of tactical rockets I was working on, with such awkward design.

 

So if somebody has this document it would be appreciated to see is perhaps something written ''between lines'' 

[tavarish palkovnik]

In addition and in the meantime while waiting for something concrete about Phoenix motors rise up.

Motor of Neva/Pechora SAM rocket. Of course 380mm diameter, same as Phoenix and variant which timely correspond to Phoenix. 

 

Вес топлива второй ступени (fuel weight of second stage) … 151kg

 

 

Марка топлива ПЭКА-18Д (Fuel type PEKA-18D)

Время работы (working time) …15,3-24 seconds 

Максимальная и минимальная тяга (max and min thrust) … 3100-1600 kg

Суммарный импульс (total impulse) … 35600-34000 kgs 

Visually it looks like this ->

 

Interesting, 230-232s specific impulse   for nearly continuous operating at 50bar chamber pressure. 
This PEKA-18D fuel is, just like Flexadyne, CTPB based composite and it is with specific impulse (in ideal theoretical conditions) of 247s but at pressure ratio 40:1.

All right, let’s see what would be for PEKA-18D at 68:1 …

Isp=Isp (40:1) + 190,3 + 76*pk - 3,058*pk^2 - 7000*pa + 25484*pa^2 = 247*9,81 + 190,3 + 76*6,8 - 3,058*6,8^2 - 7000*0,1 + 25484*0,1^2 = 2545 Ns/kg = 259s 

This seems correct, transparent and true because physical laws are same on east and west. 
For sure something stinks with those numbers given to Phoenix if read literally or we read it completely wrong.

 

[Temetre]

From what Ive read, the Aim-54 Flexadyne propellant can have up to a specific impulse of 260, though obviously lower in practice. Seens speculation that the reduced smoke propellant they used in the later american rocket motors might be a tiny bit less efficient. 

Either way, it seems kinda arbitrary to disregard a document because you think it doesnt make sense, and then just assume the Aim-54 has similar efficiency to Aim-9D or some random russian rocket. You can do as much math as you want, but its not that useful if everything is based on assumptions.

And if I understand you right, then on the other hand you chose to believe that the R-33 does have some insane ISP for a limited time? Seems a bit biased frankly.

Edited June 30, 2023 by Temetre

[GGTharos]

ISP can vary by altitude, that's why any thrust/ISP figure by itself is not enough.  ISP can increase (and does) with an increase in altitude (drop in pressure) and this is modeled in DCS in a simple way IIRC.  A missile can have +7% thrust at high altitudes compared to SL.

[tavarish palkovnik]

1 hour ago, Temetre said:You can do as much math as you want, but its not that useful if everything is based on assumptions.

Look mate, this is not what I’m doing for living but as mechanical engineer with decades of working experience I know some sh.t about it. Thermodynamic, fluid dynamics and mechanics in general are parts of all this, those are not assumptions but questions risen from calculations.

First we need to remove prejudices that US or Russian rocket technology is better than other, I’m giving both equal, in some segments one is slightly better in some others second is slightly better. But like already said, physics is same everywhere.

Here it is one more “random” rocket, motor actually 

 

 

Smerch rocket, composite fuel type PD-13/9 which is HTPB based, same and similar subtypes like PD-17/18 or PD-19/15 or PD-14/18 are more or less in all recent Russian air-to-air rocket motors, surface-to-air as well. Not rubbish, but high grade. 
Just sample to express that something smells with those numbers given to AIM-54.

For Smerch I have everything and that’s why it is suitable to use it as one more sample. Total impulse is 82000kg and fuel weight is 329kg so specific impulse is 249s.

To repeat numbers of AIM-54, 97000lbs*s and 376lbs of fuel making specific impulse 258s.

All right, let’s try now in other way…

 

 

 

Two equations, just two. F is thrust, pk is chamber pressure, Skr is nozzle throat area, pa is ambient pressure, S is area ratio (ratio of exit and throat area), Cp and Ct are thrust coefficients, in vacuum and at ambient pressure respectively, thetas are losses.

And now inputs for Smerch motor, nozzle throat diameter 101mm, exit diameter 255mm, adiabatic coefficient k=1,18 , average working time 6 seconds, chamber pressure for it 105bar…

S=6,374 and Cp for k=1,18 is 1,688 [0,157*ln(S)+1,3972] or manually from -> 

 

 

 

Ct=1,688-(101300*6,374)/(0,98*0,98*10500000)=1,624

F=0,98*0,98*1,624*0,00801*1050000=131175N

Ftot=131175*6=787000N or 80000 kg

And now @Temetre you try with AIM-54, I will give you every possible assist with all this boring math just to figure it out from where the hell this f..king 97000 lbs*s came from.

 

PS: in same time you will get answers from where “insane” Isp for R-33 came from 

[Temetre]

vor 17 Stunden schrieb tavarish palkovnik:

Look mate, this is not what I’m doing for living but as mechanical engineer with decades of working experience I know some sh.t about it. Thermodynamic, fluid dynamics and mechanics in general are parts of all this, those are not assumptions but questions risen from calculations.

First we need to remove prejudices that US or Russian rocket technology is better than other, I’m giving both equal, in some segments one is slightly better in some others second is slightly better. But like already said, physics is same everywhere.

Here it is one more “random” rocket, motor actually 

 

 

Smerch rocket, composite fuel type PD-13/9 which is HTPB based, same and similar subtypes like PD-17/18 or PD-19/15 or PD-14/18 are more or less in all recent Russian air-to-air rocket motors, surface-to-air as well. Not rubbish, but high grade. 
Just sample to express that something smells with those numbers given to AIM-54.

For Smerch I have everything and that’s why it is suitable to use it as one more sample. Total impulse is 82000kg and fuel weight is 329kg so specific impulse is 249s.

To repeat numbers of AIM-54, 97000lbs*s and 376lbs of fuel making specific impulse 258s.

All right, let’s try now in other way…

 

 

 

Two equations, just two. F is thrust, pk is chamber pressure, Skr is nozzle throat area, pa is ambient pressure, S is area ratio (ratio of exit and throat area), Cp and Ct are thrust coefficients, in vacuum and at ambient pressure respectively, thetas are losses.

And now inputs for Smerch motor, nozzle throat diameter 101mm, exit diameter 255mm, adiabatic coefficient k=1,18 , average working time 6 seconds, chamber pressure for it 105bar…

S=6,374 and Cp for k=1,18 is 1,688 [0,157*ln(S)+1,3972] or manually from -> 

 

 

 

Ct=1,688-(101300*6,374)/(0,98*0,98*10500000)=1,624

F=0,98*0,98*1,624*0,00801*1050000=131175N

Ftot=131175*6=787000N or 80000 kg

And now @Temetre you try with AIM-54, I will give you every possible assist with all this boring math just to figure it out from where the hell this f..king 97000 lbs*s came from.

 

PS: in same time you will get answers from where “insane” Isp for R-33 came from 

Hm, how to put it...

Sure, you might know more than me about the math behind this stuff, but if you put bad numbers into a math equation, then its garbage in, garbage out. If I had to take a guess, the problem is that you try to focus on what you know, rather than ask more about what you dont:

 

So, okay, the numbers in the Aim-54 document dont make sense to you. But from what you posted, they are extremely incomplete in the first place. Its not clear of what circumstances the impulse and thrust describe. Is it theoretical fuel performance under specific circumstances? Is it the maximum performance of the rocket engine at one point? Or is it just generic ballpark numbers? Maybe because the exact numbers are limited to another classified document? Even obfuscation could be an element, after all. Or its just inaccurate, but that doesnt matter much because this isnt an indepths technical document.

So we dont know what the document is actually describing, its not necessarily wrong. And if you dont know what the numbers mean, theres no point putting them into a math equation.

Then you use the Smerch/Aim-9D as an approximation, but why? Because to you, they seem more believable. And there is reasons why you might believe so, but its still taking a big guess. This is a different A2A missile and a soviet MLRM. Considering you know the Aim-54 documentation doesnt make sense to you, how do you know the documentation of those missiles isnt inaccurate/incomplete as well? 

Maybe you just dont see the inconsistencies in there because they are less obvious to you. And physics in east and west work the same, but that doesnt mean the documents, estimations and ways of measuring work the same. For all the reasons I wrote, and the idea that documents might be inaccurate, which is literally what you originally wrote about.

 

Thats what Im saying, I dont think you sufficiently put the documents into context. Seeing something that doesnt make sense to you in one document shouldnt just make you go "why is this document wrong", but rather "am i misunderstanding the document" and if so, "am i misunderstanding other documents too?".

That stuff is what makes military documents so opaque and hard to understand, you cant just go the easy way and ignore uncomfortable elements and expect a good result. 

The RD-33 thing is my bias, my sense of skepticism is always skyrocketing when its generalized assumptions like that, and especially when they include western weapons being really bad and russian/soviet weapons being so much better. Usually that skepticism is quite warranted, somehow theres a real pattern in military sim games and soviet weapons being overestimated (and people shocked when it shows they are indeed not super weapons).

Zitat

 

Two equations, just two. F is thrust, pk is chamber pressure, Skr is nozzle throat area, pa is ambient pressure, S is area ratio (ratio of exit and throat area), Cp and Ct are thrust coefficients, in vacuum and at ambient pressure respectively, thetas are losses.

And now inputs for Smerch motor, nozzle throat diameter 101mm, exit diameter 255mm, adiabatic coefficient k=1,18 , average working time 6 seconds, chamber pressure for it 105bar…

 

This is also part of the overly generalized math. Even liquid fuel rockets are not really that simple, but especially solid rocket boosters do not have static thrust, pressure or efficiency. So clearly any single number describing those factors is insufficient information to estimate a rocket engines performance.

[tavarish palkovnik]

It is true that I’m more familiar with motors of Russian origin, I have much more literature about those ones and perhaps after all reading about those concepts I lost ability for wider observation. More or less any motor that I took in deliberation after some time was figured out, somehow, except this one and that’s why it makes me crazy.

I don’t agree with you that all these calculations are without points, my practice showed me that it has grounds and, all right, I agree, that what I said about having or not having sense is wrong. Obviously numbers must have sense only I don’t understand those ones because they can’t be molded in general molds present in so many other motors.

Of course all these calculations are not with precision of real ones, but still close enough to make some answers. After so many other motors it gives me right to believe that way.

 

Total impulse is undeniable, it is number which can’t be changed, it is only about how to use that number. And the fact is that all, but really all, documents I’ve read give that number for sea level. The problem is that motor of AIM-54 and given total impulse can’t be molded in mentioned molds, neither one. That’s why now I’m taking line and going in other direction, what should be done to make it as stated.

This at the end is one of possibilities, now after finish it, it looks achievable, indeed, only what is constant doubt, it is so different compared to all others, of US and Russian origin