Paper analyzing a Patriot PAC-2 ‘s probability of intercepting a Kh-47 M2 Kinzhal missile

[HoHun]

Hi Scott,

? Huh? Specific Impulse is measured in seconds, not in meters per second.

That seems to be the NASA convention at least: https://www.grc.nasa.gov/WWW/k-12/airplane/specimp.html

However, that's a convention based on mass and force using the same unit in US customary units. (And even "metric" only cleaned this up in the late 1970s, or thereabouts.)

The sane definition of specific impulse would be: The ratio of thrust force to fuel mass flow rate, in units: N/ (kg/s) or (kg*m/s^2)/(kg/s), which simplifies to m/s. I assume that's what the paper Paralay linked is using.

The NASA definition really is: The ratio of thrust force to the fuel-weight-under-Earth-standard-conditions flow rate. That's awkward, but you end up with specific impulse in s.

Regards,

Henning (HoHun)

 

[AndersJ]

I just noticed that paralay has a signature citing Vladimir Putin. If this is OK, then I can't see why I can't have a sig citing Theodore Roosevelt?

 

[sferrin]

Well if the Kinzhal is launched horizontally like in that video it will not reach very far: Either it will hit the ground shortly due to no ballistic trajectory and flying in dense air, or it will expend a lot of energy to transition to a 45 degree climb in order to reach a ballistic trajectory and less dense air.

Yep.

 

[paralay]

I hope it won't be difficult for you to provide a photo of the body of the downed Dagger? Moreover, our young, naive friend claims that the Dagger flies very slowly and certainly did not suffer in the fall

 

[AndersJ]

Yep.

Yes, and this was why I thought that Kinzhal-video parlay posted earlier on with the horizontal launch did not say very much about range. OTOH for an attack at shorter ranges, the short warning time associated with a direct attack at under 100 km (like I outline in my paper), could of course be an option. But I think anyone launching a Kinzhal these days will be very careful not to stray into the launch envelope of a Patriot battery , which was why I thought the 300 km scenario more appropriate.

So for attaining longer ranges, then the carrier aircraft should pull up to loft the missile, and not make the missile expend energy on transitioning to a ballistic trajectory.

Here is a link showing a US trial launching an anti-satellite missile which weighed only 1800 kg and was smaller. But the F-15 only managed to get up to M=1.22 in level flight and then when pulling up into the launch angle lost speed so that the launch was only at 17 km with a speed of 992 km/h (M=0.93). More about the ASM-135 ASAT here.

And this is a far cry from what parlay posted earlier on about the launch parameters for the Kinzhal 2000 km attack, and then later on for what they claim to be doing at KasKosmos: "The take-off weight of the MiG-31I aircraft with a launch vehicle is 50 tons, the flight range to the launch point is 600 km, the height of the launch point is from 15 to 18 km, the speed at the launch point is 2120-2230 km/h."

So this means either of two things: Either US technology simply does not attain the stratospheric heights of Russian engineering, or those numbers paralay posted earlier on about the Mig-31 attaining those launch numbers for the Kinzhal delivery are fairy tales.

 

[activeaero]

I hope it won't be difficult for you to provide a photo of the body of the downed Dagger? Moreover, our young, naive friend claims that the Dagger flies very slowly and certainly did not suffer in the fall

View: https://www.youtube.com/watch?v=Q5XmvAVH1Nc

Russia recognises first crew to use hypersonic missile in Ukraine, TASS reports

The first Russian crew to use hypersonic, air-launched Kinzhal missiles during Moscow's military operation in Ukraine has been presented with state awards, the Russian TASS state news agency reported on Monday.

www.reuters.com

Media suggested based on photo that Kinzhal missile shot down over Kyiv for the first time

The Defense Express media outlet, after analysing photos of the missile wreckage, has suggested that a hypersonic Kh-47 Kinzhal missile was successfully shot down over Kyiv for the first time in the early hours of 4 May. This has not yet been officially confirmed.

www.pravda.com.ua

Also, are you going to address my post to you, or just ignore it because it refutes your claims?

 

[sferrin]

Here is a link showing a US trial launching an anti-satellite missile which weighed only 1800 kg and was smaller. But the F-15 only managed to get up to M=1.22 in level flight and then when pulling up into the launch angle lost speed so that the launch was only at 17 km with a speed of 992 km/h (M=0.93). More about the ASM-135 ASAT here.

And this is a far cry from what parlay posted earlier on about the launch parameters for the Kinzhal 2000 km attack, and then later on for what they claim to be doing at KasKosmos: "The take-off weight of the MiG-31I aircraft with a launch vehicle is 50 tons, the flight range to the launch point is 600 km, the height of the launch point is from 15 to 18 km, the speed at the launch point is 2120-2230 km/h."

So this means either of two things: Either US technology simply does not attain the stratospheric heights of Russian engineering, or those numbers paralay posted earlier on about the Mig-31 attaining those launch numbers for the Kinzhal delivery are fairy tales.

Both the YF-12A and B-58 could achieve those figures.

 

[sferrin]

I hope it won't be difficult for you to provide a photo of the body of the downed Dagger? Moreover, our young, naive friend claims that the Dagger flies very slowly and certainly did not suffer in the fall

We've been over this before when you tried to claim everybody was looking at a bomb instead of a missile warhead.

 

[AndersJ]

Oh.
I suspected this was another thread by a newly signed person designed to portray a political message, but disguised in a certain way.
The posts above speaks volumes, and illustrates this.

Mods, do we really need this political, polarising nonsense?

Why don't you read my paper and look at my homepage instead of insinuating that I have a hidden agenda. I did a paper on the Kinzhal's performance and invited to a technical discussion. In anything got derailed, it got derailed by the ATACMS being introduced, but from the way you framed your reply I see you have no problem with parlay's postings? A rather one-sided way to look at things I would say.

 

[AndersJ]

Both the YF-12A and B-58 could achieve those figures.

View attachment 711288

View attachment 711289

Fair enough, but I see larger similarities between the F-15 and Mig-31, than with either the Hustler or Blackbird which IMHO play in another league altogether.

 

[activeaero]

Both the YF-12A and B-58 could achieve those figures.

View attachment 711288

View attachment 711289

And both have much better engines than the MiG-31. They can actually fly at those speeds without eating themselves, and the severe lack of maintenance and spare parts doesn't help the MiG-31's cause. There's been, what, 3-4 MiG-31 crashes since the start of the SMO?

 

[sferrin]

The MiG-31 is much larger and heavier than an F-15. It is designed to cruise at supersonic speed, albeit in afterburner ( like the YF-12A and B-58).

 

[Jemiba]

Looking at the title of this thread, it's something about Patriot PAC-2 vs Kh-47 M2 Kinzhal, isn't it ?
Quite a lot of the last posts are just kind of rant against another one, or some rather against quite a
lot of forum members.
I would recommend to come back to the original toipc and refrain from offenses and personal attacks.

​

 

[AndersJ]

Well in an attempt to get things back on track: I have been doing missile simulations since 2014 and posted results in the DCS forum before under the handle Pilum. However, I have always had an eye out for what goes on in this forum since there seems to be a lot of knowledgeable people here.

My interest in the Kinzhal and why I modeled it was because media has been saying things like it's a hypersonic missile, impossible to intercept and can do M=10 etc. But based on what I know about missile kinematics, this did not add up to me, and this in turn prompted me to do the simulations. When I had the results, I thought other people could be interested in them as well and also provide me with feedback. So this was why I posted the paper in the first place, and therefore welcome any further technical input on it.

 

[paralay]

[Also, are you going to address my post to you, or just ignore it because it refutes your claims?

The Su-34 has nothing to do with the Kinzhal missile, guess why

 

[AndersJ]

Some would consider it rude and bad form to take a swipe at someone who can no longer reply but each to his own I guess.

 

[paralay]

But based on what I know about missile kinematics, this did not add up to me, and this in turn prompted me to do the simulations

Try to simulate the flight of a rocket of the previous generation - "Oka". She made her first flight in 1977. The dimensions and weight are almost the same as those of the Iskander and Kinzhal. The flight range is 300 - 400 km. The speed at the end of the active section M = 4 (4248 km/h), the speed of meeting with the target M = 9.6 (11520 km/h)

 

[sferrin]

Try to simulate the flight of a rocket of the previous generation - "Oka". She made her first flight in 1977. The dimensions and weight are almost the same as those of the Iskander and Kinzhal. The flight range is 300 - 400 km. The speed at the end of the active section M = 4 (4248 km/h), the speed of meeting with the target M = 9.6 (11520 km/h)

Doubt it. If anything it's going to be slower than burnout velocity of M4.

 

[AndersJ]

Doubt it. If anything it's going to be slower than burnout velocity of M4.

Exactly. A figure of M=9.6 at impact for a surface to surface missile shot in a ballistic trajectory and that has a burnout velocity of M=4 fails a simple sanity check. When such a ballistic missile enters denser air on its way down it slows down very rapidly and the Mach at impact will be less than that attained in the burnout phase on the way up.

 

[paralay]

Kinzhal
Calculation in the Sputnik program:
starting mass 3800 kg, fuel mass 2300 kg, specific impulse 2700 m/s,
launch speed 650 m/s, launch height 15,000 m.
engine operating time 52 seconds, maximum flight altitude 60 km,
flight time 483 seconds,
maximum speed 2792 m/s, ground speed 1815 m/s (6534 km/h, M=5.3), flight range 980 km

 

[Archibald]

Some would consider it rude and bad form to take a swipe at someone who can no longer reply but each to his own I guess.

He said
The average age here has to be 60.

I'm 41, so sue him !

 

[AndersJ]

He said
The average age here has to be 60.

I'm 41, so sue him !

Well my comment was not directed at activeaero. And he was contributing actual data to the thread, so I hope that the ban was only temporary and that he will be able to come back and defend himself. Anyone can get carried away by the moment and I hope he gets a second chance.

 

[AndersJ]

Kinzhal
Calculation in the Sputnik program:
starting mass 3800 kg, fuel mass 2300 kg, specific impulse 2700 m/s,
launch speed 650 m/s, launch height 15,000 m.
engine operating time 52 seconds, maximum flight altitude 60 km,
flight time 483 seconds,
maximum speed 2792 m/s, ground speed 1815 m/s (6534 km/h, M=5.3), flight range 980 km

First observation is that even with your own calculations, you now only get a range of 980 km with the launch from 15 km at 2300 km/h while the figure you posted initially showed 1300 km. I said already then that that figure was awfully optimistic, and you yourself now only get 980, not 1300 km. And this is even after having tweaked the ISP to a fantastic 2700 m/s (i.e. 275 s). In context, I should say that I too with my simulations, get a range of over 900 km using this overly optimistic launch speed and ISP.

But an ISP of 275 s for a solid fuel would be ground breaking. Take a look at the attached figure showing the development of solid fuel technology and how it has asymptotically closed on around 252 s. But maybe there has been some secret development where Russian technology has now taken a step up from the best western solid fuels of around 252 to a staggering 275 s specific impulse? If so, whoever did that deserves the Red Star first class and a new Lada, because that would be truly groundbreaking.

Finally, you earlier in this thread said I should avoid making “mistakes” by assuming wrong numbers for the impulse and that the Kinzhal has better fuel than I assumed. I then ask you what you think is appropriate and you come back with a table showing ISP’s ranging from 2300 to 2460 m/s, while I was already using 252*9.91=2472 m/s. But now you suddenly use 2700 m/s. Why is that? Why don’t you show the results for the top ISP in your own table which was 2460 m/s? I’m sorry, but I don’t find your way of presenting your case to be honest, and you are more and more coming across as a bad faith actor with an agenda here.

 

[paralay]

I am a new person in rocket technology. I became interested in them only after the big rocket was suspended under the MiG-31. And I didn't make the settings in the program. However

Удельный импульс — Википедия

ru.wikipedia.org

And a photo from an interesting article....

 

[AndersJ]

I am a new person in rocket technology. I became interested in them only after the big rocket was suspended under the MiG-31. And I didn't make the settings in the program. However

Удельный импульс — Википедия

ru.wikipedia.org

OK fine, I thought you entered that value yourself but if you only used the default then I apologize. But I do hope you understand why I thought as I did given the table you posted before.

But Wikipedia is as we all know not always to be trusted, and that figure of 270 s comes without any reference at all so I would treat it with extreme caution until we know if it has been pulled out of a hat or if it is actually based on something substantial. In addition, to be picky, its not really 2700 m/s is it? Because 270 s translates to 2649 m/s. But if anyone can come up with some information on this, this would of course be very interesting.

 

[Scott Kenny]

Fair enough, but I see larger similarities between the F-15 and Mig-31, than with either the Hustler or Blackbird which IMHO play in another league altogether.

Visual similarities, yes, but compare sizes.

F-15 has an MTOW of 68klbs, empty weight of 28k.
MiG-31 has an MTOW of 102klbs, empty weight of 48k.
SR-71 has an MTOW of 172klbs, empty weight of 67.5k.
B-58 has an MTOW of 177klbs, empty weight of 56k.

MiG-31 makes an F-15 look small.

 

[Ronny]

The paper linked below analyses the performance of the Kh-47 M2 Kinzhal, and how likely it is that this type of missile can be intercepted by air defenses. However, in order to keep this post free of information that could be construed to be politically sensitive, the linked paper has been redacted so that only the parts focused on the technical analysis remain.

I did this paper because there have been so many rumors and speculation regarding the actual performance of this missile in the media and on different forums, most of which have been overly optimistic about the Kinzhal’s capabilities in my humble opinion.

Link to page with the paper in pdf format. On my homepage I also have a page with a description of the simulation model used.

Note that I in no way claim this paper to be the gospel truth, and this is just my assessment based on my simulations and the assumptions I outline in the paper.

Consequently, I would welcome any constructive input on it. However, please remember to keep it all related to the technical aspects in order to comply with the forum rules.

Thanks for your effort, but to be honest, I feel like there are some serious mistake with your number (may be have something to do with air density?, burn time?).
Kinzhal was delivered from Iskander, which is a ground launched, surface to surface missile that can reach 500 km when launched fromm ground. I honestly don't see how the range will be reduced by 200 km when air launched.
Beside, M39A1 ATACMS can already reach 300 km when launched from ground, and Kinzhal is basically 2.57 times heavier than ATACMS. It hard to believe that it can't reach much longer range especially when air launched.

​

Another notable example is AGM-69 SRAM, which weight around 1 tons, it can already reach the range of 300 km. And this is a missile from the 70s.


I also have some issue with this paragraph:
A missile does not necessary need an engine that utilizing the air it fly through to achieve meaningful range at hypersonic speed. Especially if it fly at extremely high altitude where the air drag is minimal or even not exist. The most notable example are ballistic missile like Trident-II
The newly build boost glider such as ARRW, Avangard also does not have an engine inside the boost glider, yet they have no issue achieving massive range at hypersonic

 

[AndersJ]

Visual similarities, yes, but compare sizes.

F-15 has an MTOW of 68klbs, empty weight of 28k.
MiG-31 has an MTOW of 102klbs, empty weight of 48k.
SR-71 has an MTOW of 172klbs, empty weight of 67.5k.
B-58 has an MTOW of 177klbs, empty weight of 56k.

MiG-31 makes an F-15 look small.

For sure, in terms of weight I see what you mean. But when looking at aerodynamics and the planform, the F-15 and Mig-31 have more in common with each other. In addition, I don’t think it’s the absolute weights we should look at but the relationship between the weight of the missile and the weight of the plane. And using your figures, the F-15 ASM-135 combo comes out at 2600/68000=4% while the Mig-31 Kinzhal combo is 8370/102000=8% so in relative terms, the Mig is carrying around double the weight.

 

[AndersJ]

Thanks for your effort, but to be honest, I feel like there are some serious mistake with your number (may be have something to do with air density?, burn time?).
Kinzhal was delivered from Iskander, which is a ground launched, surface to surface missile that can reach 500 km when launched fromm ground. I honestly don't see how the range will be reduced by 200 km when air launched.
Beside, M39A1 ATACMS can already reach 300 km when launched from ground, and Kinzhal is basically 2.57 times heavier than ATACMS. It hard to believe that it can't reach much longer range especially when air launched.

​

View attachment 711329

Another notable example is AGM-69 SRAM, which weight around 1 tons, it can already reach the range of 300 km. And this is a missile from the 70s.
View attachment 711331

I also have some issue with this paragraph:
A missile does not necessary need an engine that utilizing the air it fly through to achieve meaningful range at hypersonic speed. Especially if it fly at extremely high altitude where the air drag is minimal or even not exist. The most notable example are ballistic missile like Trident-II
The newly build boost glider such as ARRW, Avangard also does not have an engine inside the boost glider, yet they have no issue achieving massive range at hypersonic
View attachment 711330

That figure from my paper may have been a bit misleading: Just taking a cursory glance at it, it looks like a launch at 45 degrees but it’s not: The x- and y-scales are different and with the same scales on both axes it looks like this:



Secondly, the 300 km attack profile in the paper is not to attain the longest range: It was an example of how an attack from a safe airspace and distance could be done with the shortest possible warning time for the defenders. And in this case a launch at a 14 degrees loft angle was enough. However, lofting the Kinzhal at 45 degrees would give it a much longer range than the ATACMS which I don’t dispute.

So the attack profile in my paper is more the one I assumed had been used for the missile that was purportedly shot down by the Ukrainians, and which according to them had been traveling at 1240 m/s at intercept. But for sure, the same target (let’s assume it was a Patriot battery) could have been attacked with an Iskander from the same range in a ballistic trajectory, but that would have given the defenders much more warning time.

Then about the what classifies as a hypersonic missile: For sure, a lot of missiles may be able to be fitted under that heading, but I think it should be reserved for missiles flying fast at relatively low level for extended periods of time at speeds over M=5 with some sort of maneuvering capability and having a decent range as well. And in that case that rules out solid fueled ballistic type missiles IMHO. Because in order to get a decent range at hypersonic speeds other than in ballistic trajectories, you need to reserve all space inside the missile other than the payload for fuel, and not take up space and weight for the oxidizer as well.

 

[Scott Kenny]

For sure, in terms of weight I see what you mean. But when looking at aerodynamics and the planform, the F-15 and Mig-31 have more in common with each other. In addition, I don’t think it’s the absolute weights we should look at but the relationship between the weight of the missile and the weight of the plane. And using your figures, the F-15 ASM-135 combo comes out at 2600/68000=4% while the Mig-31 Kinzhal combo is 8370/102000=8% so in relative terms, the Mig is carrying around double the weight.

Sure, but we know that the MiG-31 airframe is capable to speeds of Mach 2.8+, while carrying missiles (designed to intercept Blackbirds, remember).

So I'm expecting it to be able to hit Mach 2 even with that monster of a Kinzhal slung underneath.

 

[sferrin]

First observation is that even with your own calculations, you now only get a range of 980 km with the launch from 15 km at 2300 km/h while the figure you posted initially showed 1300 km. I said already then that that figure was awfully optimistic, and you yourself now only get 980, not 1300 km. And this is even after having tweaked the ISP to a fantastic 2700 m/s (i.e. 275 s). In context, I should say that I too with my simulations, get a range of over 900 km using this overly optimistic launch speed and ISP.

But an ISP of 275 s for a solid fuel would be ground breaking. Take a look at the attached figure showing the development of solid fuel technology and how it has asymptotically closed on around 252 s. But maybe there has been some secret development where Russian technology has now taken a step up from the best western solid fuels of around 252 to a staggering 275 s specific impulse? If so, whoever did that deserves the Red Star first class and a new Lada, because that would be truly groundbreaking.

Finally, you earlier in this thread said I should avoid making “mistakes” by assuming wrong numbers for the impulse and that the Kinzhal has better fuel than I assumed. I then ask you what you think is appropriate and you come back with a table showing ISP’s ranging from 2300 to 2460 m/s, while I was already using 252*9.91=2472 m/s. But now you suddenly use 2700 m/s. Why is that? Why don’t you show the results for the top ISP in your own table which was 2460 m/s? I’m sorry, but I don’t find your way of presenting your case to be honest, and you are more and more coming across as a bad faith actor with an agenda here.

View attachment 711317

I've seen the Peacekeeper ICBM motors quoted at 280-282 ISP in several locations over the years. Then again it was designed to sit protected in climate-controlled conditions. Things done to ruggedize motors for other applications tend to lower ISPs. Also not all HTPB motors are equal. Things like density packing (what percentage of the fuel load is actually powder vs binder), operating temp, nozzle profile, etc. make a difference. I've seen several antiaircraft missiles quoted in the 260-275 range. These are all US missiles but it at least gives an indicator of the possibilities. Also remember (assuming they optimized the nozzle for higher altitude with Kinzhal) that the same motor will perform better at altitude due to less backpressure. (But it will also perform worse due to lower temperature of the fuel. )

TU-903 / Castor-120

Gunter's Space Page - Information on Launch vehicles, Satellites, Space Shuttle and Astronautics

space.skyrocket.de

 

[AndersJ]

Sure, but we know that the MiG-31 airframe is capable to speeds of Mach 2.8+, while carrying missiles (designed to intercept Blackbirds, remember).

So I'm expecting it to be able to hit Mach 2 even with that monster of a Kinzhal slung underneath.

With what kind of missile load was the Foxhound supposed to do M=+2.8? In addition, I think that’s at much higher altitudes than 15 km, more in the order of 20 km. At 15 km the flight envelope showing M=2.83 at 20 km is limited to around M=2.2. And if this is with missiles only, then M=2 with a Kinzhal sounds like a stretch to me.

 

[kaiserbill]

Then about the what classifies as a hypersonic missile: For sure, a lot of missiles may be able to be fitted under that heading, but I think it should be reserved for missiles flying fast at relatively low level for extended periods of time at speeds over M=5 with some sort of maneuvering capability and having a decent range as well. And in that case that rules out solid fueled ballistic type missiles IMIMHOl.

Hypersonic is by its etymological definition speed related only.
Missile, in relation to the military definition, implies guidance of some sort. This might be pre or post launch.

 

[AndersJ]

I've seen the Peacekeeper ICBM motors quoted at 280-282 ISP in several locations over the years. Then again it was designed to sit protected in climate-controlled conditions. Things done to ruggedize motors for other applications tend to lower ISPs. Also not all HTPB motors are equal. Things like density packing (what percentage of the fuel load is actually powder vs binder), operating temp, nozzle profile, etc. make a difference. I've seen several antiaircraft missiles quoted in the 260-275 range. These are all US missiles but it at least gives an indicator of the possibilities. Also remember (assuming they optimized the nozzle for higher altitude with Kinzhal) that the same motor will perform better at altitude due to less backpressure. (But it will also perform worse due to lower temperature of the fuel. )

TU-903 / Castor-120

Gunter's Space Page - Information on Launch vehicles, Satellites, Space Shuttle and Astronautics

space.skyrocket.de

Well that was very interesting information indeed! Do you have any references or links to these high performance solid rocket motors? And for sure, there are a lot factors governing what you actually get out of the fuel, but just the ISP is for sure a first order effect important to get right. And just like you say, its not only the ISP, but the specific density is important as well since what we usually have to go from is a drawing showing how much fuel volume there is.

So I would really appreciate if you could give me some references or links to where one can find information about these high performance (The Peacekeeper and those anti-aircraft missile engines) solid rocket motor fuels.

 

[sferrin]

Unfortunately, it's not one specific site. More like breadcrumbs I've stumbled over here and there over the years. The one with Peacekeeper I had in mind I couldn't find. It gave an ISP of 282 and density packing of 87%. Where they got the info I have no idea but it had the info for all Peacekeeper stages. Saw another one once, a document of some sort that laid out all the stage of the SM-3 IA. Burn times, mass of fuel ISPs etc. A typical example might be this:

U.S. Surface-to-Air Missiles

Bottom of the page gives an ISP for the Patriot motor of 258. One line on the entire page and the only motor for which an ISP is given. Where did they get it? Which variant of Patriot? The owner of that site is a member, so maybe he could say, but he might not even remember. Nature of the beast I suppose.

 

[Scott Kenny]

With what kind of missile load was the Foxhound supposed to do M=+2.8? In addition, I think that’s at much higher altitudes than 15 km, more in the order of 20 km. At 15 km the flight envelope showing M=2.83 at 20 km is limited to around M=2.2. And if this is with missiles only, then M=2 with a Kinzhal sounds like a stretch to me.

4x AA-9/R-33s

 

[AndersJ]

Unfortunately, it's not one specific site. More like breadcrumbs I've stumbled over here and there over the years. The one with Peacekeeper I had in mind I couldn't find. It gave an ISP of 282 and density packing of 87%. Where they got the info I have no idea but it had the info for all Peacekeeper stages. Saw another one once, a document of some sort that laid out all the stage of the SM-3 IA. Burn times, mass of fuel ISPs etc. A typical example might be this:

U.S. Surface-to-Air Missiles

Bottom of the page gives an ISP for the Patriot motor of 258. One line on the entire page and the only motor for which an ISP is given. Where did they get it? Which variant of Patriot? The owner of that site is a member, so maybe he could say, but he might not even remember. Nature of the beast I suppose.

Well, a 258 s ISP is a step up from the 252 I was using before, but still some way to go to the 270-280 range. The Castor 120 number of 280 s on “Gunter’s space page” is intriguing, but the specific density is missing and I’m not sure where he got the numbers from. OTOH, the reference to Thiokol and the very specific numbers makes it likely it came from the maker. OTOH, seeing the application, that ISP is probably for conditions close to vacuum, and it would probably be less for an application such as an air-air system like the Patriot operating in the atmosphere. Still, the page you linked to above, does mention that while the MIM-104 (Which I believe they used to down the Kinzhal) has motor with an ISP of 258 s, later version have “propellant for greater thrust”, but with how much? Anyway, thanks for the info! But I’m now as the saying goes, still confused, but on a higher level!

 

[AndersJ]

4x AA-9/R-33s

Sure, there are pictures of it with 4 x R33 but are we sure that that is the configuration that does M=2.83? Where did you find that info?

 

[Scott Kenny]

Sure, there are pictures of it with 4 x R33 but are we sure that that is the configuration that does M=2.83? Where did you find that info?

Can't do the design mission of intercepting Blackbirds if it can't go almost that fast while carrying missiles.

 

[Arjen]

Correct me if I'm wrong - I thought it was the MiG-25's mission to intercept Blackbirds. The MiG-31 was developed to counter cruise missile carrying B-52s.
I have the English edition of MiG - 1939-1989 (Docavia 1991 French edition, Airlife 1994 English edition) by Jacques Marmain and Rostislav Belyakov, on the Mig-25 they write (p.383):

Originating in the late 1950s as a response to the ambitious Lockheed A-11 project [], the aircraft that was to become the MiG-25 - still referred to inside the OKB as the Ye-155 - helped the Soviet aerospace industry to make great strides forward.

On the MiG-31 (p.407):

The MiG-31 was intended to counter a very specific threat: that of American B-52 bombers carrying long-range cruise missiles, each bomber representing several potential dangers all by itself (and consequently several targets). The future Mig-31 was to be capable of destroying multiple invaders at high or low altitudes in the forward and rear sectors and providing true look-down/shoot-down capability whatever the weather conditions, even if the invaders try to maneuver and use active countermeasures.