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Ракеты в DCS


Chizh

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3 часа назад, okopanja сказал:

 

Well, I am the guy who normally pays attention to the details (or maybe I am just not tired of endless arguing in this topic yet), it would seem that perhaps the image is not a photoshop after all. Do you actually know this for a fact, or you just presume it is a photoshop?

The drone appears to be launched from ground at 00:34. I made a still image here. There are Cyrillic letters there, so this could be of Bulgarian (most likely since this practice took place there), Russian, Ukrainian or Serbian origin.

Also the drone that took that picture is fairly small. I can not judge its RCS, but I suspect it is rather low. The wing colors and shapes correspond to the one found in the original still, as well as the position of motor and camera. Image appears to be transmitted, since I do not thing much left from this drone.

image.png

It is impossible with a conventional remote video camera to freeze a frame with a hi speed missile in such a way that there is no motion blur of movement at a speed of 300-600 m/s. This is not real.

image0 (1).png

In any case, I am not saying that the R-27R missiles are not capable of hitting anything. It is able.
Only for some reason, in real combat operations, they showed extremely low performance.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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1 hour ago, okopanja said:

 

Well, I am the guy who normally pays attention to the details (or maybe I am just not tired of endless arguing in this topic yet), it would seem that perhaps the image is not a photoshop after all. Do you actually know this for a fact, or you just presume it is a photoshop?

The missiles are photoshopped into the the exact same still frame from the video. Nothing moves except the missile. You can tell that it is the same frame because the noise in the image from the analog video transmission does not change.

It is still possible that one of the images is a real one, but all others from the sequence are fake.

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1 hour ago, BlackPixxel said:

The missiles are photoshopped into the the exact same still frame from the video. Nothing moves except the missile. You can tell that it is the same frame because the noise in the image from the analog video transmission does not change.

You are right here, later frames do not change in terms of noise and HUD updates (I focused myself on identifying the drone). However I see that first 3 or 4 frames we do have changes of noise and HUD (-9.1 m/s turns into -4.5 m/s and altitude reduces from 1808 to 1807). After that yes, it appears to have been modified, and even the angle does not look right.

None of the "authentic" frames can be used to identify the missile. If the camera had frame rate of 30 seconds this would have placed the distance traveled by the  missile between frames at 10-20m. If 60 FPS -> 5-10. The missile would have already detonated or passed beyond the camera FOV. Hence they had to add it.

Either-way it can not be trusted.

The motivation behind this is a bit odd: I assume they wanted the video to be more dramatic.

I doubt that company behind this drone still has the original material, and since this was still from official youtube channel from 6 years ago, I do not think it was intended to cheat the ED, but rather TV audience. 🙂

 


Edited by okopanja
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AGM 86C block 0 (1986 г. С ОФ БЧ весом 900 кг  Дальность стр. – 1100 км)AGM 86C block 1  (ОФ БЧ весом 1450 кг 1996).А в игре ещё и проникающая бч в 450кг.C  проникающей бч в 540кг нашёл только AGM 86D(2001).


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10 hours ago, Chizh said:

Nothing like this. No pilot in his right mind would waste an expensive missile just like that. All launches are performed with target lock in the DLZ.

I think this is too sweeping a statement. I remember reading in Desert Storm, F-15's expended many Sparrows on fleeing Foxbat...common sense would tell you this is an extremely low probability shot from further than a few miles and I doubt it was done within DLZ. A missile is expensive but an enemy aircraft even more

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10 часов назад, henshao сказал:

I think this is too sweeping a statement. I remember reading in Desert Storm, F-15's expended many Sparrows on fleeing Foxbat...common sense would tell you this is an extremely low probability shot from further than a few miles and I doubt it was done within DLZ. A missile is expensive but an enemy aircraft even more

Give me a quote where it says that the launch was outside the DLZ or without target lock.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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On 12/4/2021 at 5:59 AM, Chizh said:

Give me a quote where it says that the launch was outside the DLZ or without target lock.

There is a difference between "in DLZ" (AIM-7M: 20-30miles) and "cannot kinematically defeat the missile" (AIM-7M: less than 5 miles on the deck)

"Basically, we’d enter the fight high, fast, and as head-on to the threat as possible (giving our AIM-7s the longest possible ranges), launch at max optimum range, and immediately crank into hard turns away, right to radar gimbal limits."

Source: https://hushkit.net/2019/03/17/f-15-versus-flanker-an-eagle-pilots-view/

By the way, your DCS AI F-15s are firing their sparrows even beyond what any normal person would consider maximum range. And for some reason, they dont follow up with another missile even though their current shot is completely defeated. And then, when getting close, it does not fire multiple missiles+guns, but instead lets the enemy merge and then dies. It would be advisable to reprogram the AI to understand the absolute basics of a semi-active missile fight.


Edited by Max1mus
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Just checked F-15 with AIM-7M. It was launch missile in the DLZ.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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The AI will decide to second launch only after the first missile has missed (the range to the target has become less than to the missile).
In this track, I see that after the first AIM-7M misses, he launches AIM-9.

Единственный урок, который можно извлечь из истории, состоит в том, что люди не извлекают из истории никаких уроков. (С) Джордж Бернард Шоу

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6 hours ago, Chizh said:

The AI will decide to second launch only after the first missile has missed (the range to the target has become less than to the missile).
In this track, I see that after the first AIM-7M misses, he launches AIM-9.

Thats way too late. When the target has maneuvered sufficiently to where the missile will not kill him, the AI should fire again. Otherwise it is waiting until the target passes a defeated, stalling AIM-7.

 

The AI firing only AIM-9s there is also a big problem. Radar guided missiles in DCS will be effective even at 1 mile, and i would expect an ACE level AI to understand that a heatseeker on an aware target is not an effective, turn signaling shot. Obviously, they can mix missiles together. In general, your AI does not spam missiles sufficiently when getting close to a target, making it very predictable and useless regardless of difficulty.


Edited by Max1mus
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Ничего противоестественно не делали с Р-27Э?

Ракета проде "энергетическая", а летает как бревно - что Т, что Р..

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@Chizh

Have a look at this document: https://www.dpi-proceedings.com/index.php/dtcse/article/view/30688/29273

It is about using the ukranian made R-27E missiles for surface to air applications, here they get called "Wicher"

On page 14 there is altitude/speed over time chart:

image.png

We see a burntime of 9.5 seconds for the R-27E. This is very much in line with the values from the MiG-29 manual (8.6 - 11 s).

Boost lasts 4 s.

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We have saying “Selo veselo” … it could be “Happy village” although it sounds much better in original 😆

What v f(t) saying… 700=Isp * ln (m0/m1) -> 700=Isp * ln (350/230) -> Isp=1665 … garbage fuel

However, no it isn’t garbage fuel but vertical launch. That is why velocity reduction is such a massive, rocket would be under extremely high kinematic overload to get directed toward target. 
First what should be forgotten immediately is to have warm start of such rocket from the container. It would knock down that container together with the truck in black mother ground underneath. Furthermore, this rocket is with only aerodynamic controlling surfaces and for that initial velocity is expected and needed. No, they will not implement gas dynamics surfaces,  if this system ever “see light of living” in what I doubt.

The principal is to have strong cold start, either by gas generator, either by some kind of “mortar catapult” and that flight time should be incorporated in velocity envelope presented in this graph. And I think it is

 

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The graph is not showing a vertical flight, the missile is flying at an angle. It might even be for a simulated engagement of a target with maneuvering, who knows.

For example, from 40 s to 60 s, the average speed is close to 200 m/s, but it only covers about 2000 m instead of 4000 m as it would if it flew vertical.

So at that part of the flight, it is flying about 30° upwards compared to the horizon.

I think the most interesting is the motor burntime and the boost/sustain time ratio.


Edited by BlackPixxel
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Recently two of us enthusiasts created program for determination of trajectories of unguided ballistic rockets. Irrelevant to this topic, but BlackPixxel, try to make some clicks to see what kind of drag you should apply to rocket such as R-27ER, to limit it's velocity to 500m/s after 4 seconds of active work of such monster of motor

 

Snimka zaslona (223).png

 

Snimka zaslona (224).png

Here you can find link to the program ->   Vanjskobalistički proračun (program) leta rakete (mycity-military.com)

 

 

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On 12/13/2021 at 9:51 PM, BlackPixxel said:

I think the most interesting is the motor burntime and the boost/sustain time ratio.

I can't exactly recall, how long is the boost/sustain and burntime on DCS R-27ER just for a reference?

-------

All the people keep asking for capabilities to be modelled.... I want the limitations to be modelled.... limitations make for realistic simulation.

Arguing with an engineer is like wrestling with a pig in the mud, after a bit you realize the pig likes it.

 

Long time ago in galaxy far far away:

https://www.deviantart.com/alfafox/gallery

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1 hour ago, FoxAlfa said:

I can't exactly recall, how long is the boost/sustain and burntime on DCS R-27ER just for a reference?

In DCS it was changed to 2.5 s boost with 5.5 s sustain, so just 8 seconds of total burntime. A value that is lower than the one from the MiG-29 manual (8.6 s - 11 s).


Edited by BlackPixxel
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Maybe the initial angle of 30° was not estimated accurate enough.

So I put the chart into blender to get the area below the velocity line. It is 28842 cm² in my case. Divided by the length of the 60 s time (363 cm) I get the average velocity of somewhere around 420 m/s.

image.png

60s * 420 m/s is 25200 m of altitude. But in the chart we reach about 9800 m.

sin(pi/180*23°)*25200 m = 9850 m

So the angle of the shot is about 23° upwards.

 

I tried recreating that in DCS by firing the ER after a stall from a cobra at the right time directly above the water surface. Here is the resulting chart:

image.png

The DCS missile reaches a higher top speed, as it has a shorter burntime. It also self-destructs after 50 s in this test.

Up until 17.5 s the DCS missile has a slight speed + altitude advantage. But after that the R-27ER from the other chart is leading. After 50 s of flight time the missile from the real chart has about 1 km of lead in altitude, so it has travelled more than 10% further.

So from this observations it appears that the DCS missile has to much drag and the wrong thrust profile. The motor might be a bit to strong to compensate for that at least to some degree, but we also don't know about the launch condition of the real chart (upwards + turn to 23°, or directly from 23°?)


Edited by BlackPixxel
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5 hours ago, BlackPixxel said:

Maybe the initial angle of 30° was not estimated accurate enough.

So I put the chart into blender to get the area below the velocity line. It is 28842 cm² in my case. Divided by the length of the 60 s time (363 cm) I get the average velocity of somewhere around 420 m/s.

image.png

60s * 420 m/s is 25200 m of altitude. But in the chart we reach about 9800 m.

sin(pi/180*23°)*25200 m = 9850 m

So the angle of the shot is about 23° upwards.

 

I tried recreating that in DCS by firing the ER after a stall from a cobra at the right time directly above the water surface. Here is the resulting chart:

image.png

The DCS missile reaches a higher top speed, as it has a shorter burntime. It also self-destructs after 50 s in this test.

Up until 17.5 s the DCS missile has a slight speed + altitude advantage. But after that the R-27ER from the other chart is leading. After 50 s of flight time the missile from the real chart has about 1 km of lead in altitude, so it has travelled more than 10% further.

So from this observations it appears that the DCS missile has to much drag and the wrong thrust profile. The motor might be a bit to strong to compensate for that at least to some degree, but we also don't know about the launch condition of the real chart (upwards + turn to 23°, or directly from 23°?)

 

Also could be that the speed on the chart is speed above initial launch speed, which may not be 0.  Without exact start conditions hard to say.

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So, we are talking about a bit more range and a bit more speed down the range, but slower to get there.

Longer burn time makes sense, since you don't want to overspeed the missile too much since that vreally hurts at too high speed....

-------

All the people keep asking for capabilities to be modelled.... I want the limitations to be modelled.... limitations make for realistic simulation.

Arguing with an engineer is like wrestling with a pig in the mud, after a bit you realize the pig likes it.

 

Long time ago in galaxy far far away:

https://www.deviantart.com/alfafox/gallery

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