Ракеты в DCS

[GGTharos]

While I can guess the axis labels, I think it would be best if you provided a general legend/explanation of your method

 

I assume the blue line is the target aircraft.  Where did the top graph come from?

Edited June 27, 2021 by GGTharos

[tavarish palkovnik]

This is second time that text were not uploaded with pictures 

Is it only me or others have/had same problems

[tavarish palkovnik]

Iteration is with following attempted logic:

 

If the target is at distance less then 15km, fighter to be with extra speed of 50km/h.

If the target is at distance over 15km, fighter to be with extra speed of 250km/h.

In terminal points rocket is to be with extra velocity over target for 225m/s.

 

First diagram is velocity over time, dashed lines are for 1100km/h plus extra as per attempted logic, others for 900km/h with extra as well. The one in middle is actually two profiles, since at 5km when target is with 900km/h then extra for fighter is 250km/h and when target is with 1100km/h extra for fighter is 50km/h what is 1150km/h in both cases. It is only up to 475 or 530m/s when counting stops.

 

i58 in passive where 1,6 at 10km ; 1,52 at 5km and 1,45 at 1km.

 

Second diagram is travel of rocket and target simultaneously, dashed lines again in cases of 1100km/h for target and fighter with extra speed provisions in launching for figher.   

Edited June 27, 2021 by tavarish palkovnik

[GGTharos]

Thank you for the explanation.  The diagrams we have do not specify the shooting fighter having more speed ... but in some ways it makes sense, because having 0 closure IIRC would drop the lock.

 

However, I think now the complaint will be that once more, the parameters do not exactly match the diagram.

 

What is the source of the first graph?

Edited June 27, 2021 by GGTharos

[tavarish palkovnik]

Indeed, the parameters do not match exactly, however 5 of 6 quite close. I think you will agree that something about 15km distance is key for complete understanding. There is reason why it is mentioned in Боевое применение самолета Миг-29, and the fact is that curving in horizontal sections suggest something like that. Simply, over 15km in ZPS they are different.

 

First graph is mine, calculation of trajectory with forced horizontal flight. 

[GGTharos]

I do agree with your logic, and thanks for doing the work!  What remains is to match the HuD image performance, but this is difficult to do because the information provided on that HuD is not meant for science.

Edited June 27, 2021 by GGTharos

[SAB]

@Chizh читаю, вижу ты используешь логику. График от производителя не правильный. В 5-ти источниках.

 

Я просто прекрасно помню настройку ракет - данные, документы и мнения которыми оперировали. На сегодняшний день новых документов не появилось. Вот твоё, оно относительно логичное и правильное:

 

«В результате мы имеем избыток дальность в ППС и нехватку в ЗПС.

Если мы будем подтягивать ЗПС, то в ППС ракета будет летать на несколько километров дальше.»

 

https://forums.eagle.ru/topic/78139-rakety-v-dcs/?do=findComment&comment=1992278

 

Но на сегодня 120b перелетает номограмму в ЗПС и как следствие в ППС.  Данные вами получены в результате моделирования CFD, на график не ориентируемся. Но логичный вывод - ракета может лететь дальше.

 

@goroлогично обосновывает, что «Отсюда полагаю, монограммы ЗВП остаются более актуальными для настройки ракет.

А расчётные ЗРП для настройки СУВ по выдаче команды ПР.»

 

https://forums.eagle.ru/topic/78139-rakety-v-dcs/?do=findComment&comment=1996419

 

Ты с этим соглашаешься: «Разница между ЗВП и ЗРП где-то 5-10%»

 

https://forums.eagle.ru/topic/78139-rakety-v-dcs/?do=findComment&comment=1996719

 

Сегодня имеем недолет 5-10%. То есть ты фактически ограничиваешь энергетику ракет программой СУВ, которая помимо энергетики учитывает возможности БРЭО и Pk (заданную заказчиком вероятность поражения). При этом 120b перелетает номограмму, хотя я уверен что у западных самолётов возможности СУВ так же не безграничны, особенно в TWS.

 

График в 5 ти источниках не правильный - это конечно логично. Но раньше было значительно логичней.

Edited June 27, 2021 by SAB

[Chizh]

У нас есть симулятор СУВ Су-27 который рассчитывает ЗРП для заданных условий пуска. С его помощью я построю диаграмму для 27ЭР, там будет видно на сколько и как диаграмма из книжки отличается от того, что зашито в борт.

[Terrificfool]

There seems to be a lot of swirl about this chart, the criteria used for the chart, and whether or not it can have any error in it.

This looks like a range chart to me, which indicates the range at which the missile needs to be launched to impact the target with some kind of termination criteria. Keep in mind that just because it's a range chart, it doesn't mean that it isn't a DLZ chart. A launch range chart with the same termination criteria used in the DLZ implementation would represent the launch ranges the DLZ would indicate. Setting a certain Pk can be as simple as selecting the termination criteria to have some excess kinetic energy, TOF margin, etc. However, without knowing the explicit termination criteria, you won't know how to interpret the chart.

What is the consensus on the termination criteria for the chart in question? Some are arguing that the missile needs to impact with +150m/s of velocity and others are arguing that it needs to have that velocity margin plus meet the constraint of the missile being able to maneuver at some load factor. Keep in mind: to satisfy both constraints you only need to find a velocity that meets both constraints. If the +150 m/s velocity at impact already allows the missile to maneuver at the specified load factor (some say 2-3 G?) then there is no additional speed required... the +150m/s meets both constraints! And to add more confusion: the chart has no obvious discontinuities, so are the termination criteria at both head-on and tail-chase shots the same? Or is there a different termination criteria for head-on vs tail-chase?

Without answers to these questions, you cannot interpret the chart. There are too many unknowns to draw any meaningful conclusions. In the absence of answers, you may want to make guesses, but 477 pages later no one can settle on a set of guesses to agree on. Meanwhile Chizh has performed a CFD analysis of the missile, which is rooted in physics rather than a chart. He claims it closely matches the DLZ simulator he has access to. His analysis is immune to the pitfalls listed above because it relies only on the estimates of the physical properties of the missile, rather than a chart with many unknowns.

 

If someone wants to challenge his CFD modelling with an analysis based on this  chart, they need to rigorously define their guesses to the above questions and their interpretation of the  chart. Simply saying that the chart has to be right because the manufacturer would know better is not going to be an adequate assertion. You need to know the answers to the questions above to know what the chart means, and even then it could still be in error because there's no reason to suspect the manufacturers would have a perfect chart.

 

[Max1mus]

6 hours ago, Chizh said:

У нас есть симулятор СУВ Су-27 который рассчитывает ЗРП для заданных условий пуска. С его помощью я построю диаграмму для 27ЭР, там будет видно на сколько и как диаграмма из книжки отличается от того, что зашито в борт.

 

Что этот симулятор показывает для Р-27Р в ЗПС для 1100 против 900 км/ч? Сделаете такую диаграмму тоже, пожалуйста. Сравните с диграммой в книжки.

Edited June 28, 2021 by Max1mus

[BlackPixxel]

Found another chart (R-60MK) to debunk the myth that the launch range chart has to be shaped like an easteregg:

 

Edited June 28, 2021 by BlackPixxel

[Max1mus]

2 hours ago, BlackPixxel said:

Found another chart (R-60MK) to debunk the myth that the launch range chart has to be shaped like an easteregg:

 

 

Looks exactly like the ER chart to me. And my AIM-54 tests. Small, bigger, biggest. Except that the ER has battery life decreasing the gap at 10km.

[tavarish palkovnik]

One more option, this time more likely how computer in BRLS actually calculate Drmax1 in ZRP and show it on ILS.

 

Unchanged internal and external ballistic of the rocket...

 

 

 

Black profiles are for 900km/h and red for 1100km/h. Now I used recommendation as written in manual (actually Mig-29 with R-27R only) that if distance is less then 15km to have velocity of approach of fighter toward target as 50km/h, and if more then 15km approach velocity to be 150km/h.

 

Computer works on the principle to calculate Drmax1 in way to multiply ''average approaching velocity of rocket and target'' with maximal time of rocket's flight, and this time is limited with admissible final velocity of the rocket. I used now that minimal approaching velocity (скорость сближения) should not be less then 200m/s it means that final velocity of the rocket must not be less then 450m/s (450-250=200m/s) and 505m/s (505-305=200m/s) respectively.

And upper graphs are stopped it those points. 

 

So for example case 10km, target 900km/h and fighter 900+150=1050km/h...in second 50,3 rocket is with velocity of 450m/s, скорость сближения is 200m/s. Average approaching velocity (средная скорость сближения) is 572,7m/s * 50,3 = 28806km as Drmax1.

On same principle other Drmax1 calculated values are 26539 (45,9s) ; 16832 (30,6s) ; 14988 (27,8s) ; 11198 (22s) ; 10244 (20,3s) ... all close to previous iteration only this method is like said more likely how computer actually calculate. 

 

Interesting is that even I've changed now extra speed values for fighter from 250km/h to 150km/h and terminal approaching velocity from 225 to 200m/s final results are very very close what means to me that effect of those adjustment is almost irrelevant compared to necessity to match ballistic of the rocket as much closer to reality.

 

 

[tavarish palkovnik]

Determination when to stop counting in PPS is much more complicated and harder then in ZPS. OK, velocity of rocket must be above velocity of target, active time of battery and/or PAD is 60 sec, but available over load is the most complicated to calculate and to make boundaries to these values.

 

 

 

 

One of eventual placements:

 

10km ... in both case (900 and 1100km/h) velocity of rocket is above velocity of target with second 60, N is also above 3 so 60 seconds is limit

59312 km (vi=vc=900km/h) 60s

63964 km (vi=vc=1100km/h) 60s

 

5km ... here I would make 6G available overload as limit (official graph and trajectory data suggest something like that)

38022 km (vi=vc=900km/h) 41,1s

41337 km (vi=vc=1100km/h) 41,6s ... who knows, maybe first case with 900km/h is 6G and 1100km/h is with 7G and then fits (39661 km)

 

1km ... here 9G should be limit

26915 km (vi=vc=900km/h) 29,8s

29401 km (vi=vc=1100km/h) 30,2s

 

 

For comments ready 

 

 

[FoxAlfa]

56 minutes ago, tavarish palkovnik said:

Determination when to stop counting in PPS is much more complicated and harder then in ZPS. OK, velocity of rocket must be above velocity of target, active time of battery and/or PAD is 60 sec, but available over load is the most complicated to calculate and to make boundaries to these values.

 

 

 

 

One of eventual placements:

 

10km ... in both case (900 and 1100km/h) velocity of rocket is above velocity of target with second 60, N is also above 3 so 60 seconds is limit

59312 km (vi=vc=900km/h) 60s

63964 km (vi=vc=1100km/h) 60s

 

5km ... here I would make 6G available overload as limit (official graph and trajectory data suggest something like that)

38022 km (vi=vc=900km/h) 41,1s

41337 km (vi=vc=1100km/h) 41,6s ... who knows, maybe first case with 900km/h is 6G and 1100km/h is with 7G and then fits (39661 km)

 

1km ... here 9G should be limit

26915 km (vi=vc=900km/h) 29,8s

29401 km (vi=vc=1100km/h) 30,2s

 

 

For comments ready 

 

 

Can't put the markers on the range chart, it is hard to mentally transfer ones to others.... like that you did with -3% -7% etc...

Also, I find the current R-27R quite close, only R-27ER maybe needs a bit of adjustment. 

[tavarish palkovnik]

This is how it could looks...

 

 

 

About available overload, maybe it wouldn't be wrong to show sample of calculation (this is like everything else simplified of course) 

 

For this red dot (H=5km ; 1,06M)  ...  n = Cn * S * q / G = Cy * alfa * S * ro * v * v / (2 * m * g) = 0,55 * 12 * 0,053 * 0,74 * 341 * 341 / (2 * 220 * 9,81) = 6,97

 

 

 

Edited June 29, 2021 by tavarish palkovnik

[FoxAlfa]

2 hours ago, tavarish palkovnik said:

This is how it could looks...

 

 

 

About available overload, maybe it wouldn't be wrong to show sample of calculation (this is like everything else simplified of course) 

 

For this red dot (H=5km ; 1,06M)  ...  n = Cn * S * q / G = Cy * alfa * S * ro * v * v / (2 * m * g) = 0,55 * 12 * 0,053 * 0,74 * 341 * 341 / (2 * 220 * 9,81) = 6,97

 

 

 

 

Looks good!

[Chizh]

DLZ sim vs manual

 

 

 

 

PS

The yellow circle remained in the drawing by accident and does not mean anything.

[Jack1nthecrack]

What does this mean in the context of DCS, will you change the R-27 to match the DLZ simulation? Does the DLZ simulator actually show ranges a certain percentage below the RAero ranges on the missile graph so that the pilot doesn't launch close to maximum parameters, thus has a greater chance to hit the target?

[BlackPixxel]

3 minutes ago, Jack1nthecrack said:

What does this mean in the context of DCS, will you change the R-27 to match the DLZ simulation? Does the DLZ simulator actually show ranges a certain percentage below the RAero ranges on the missile graph so that the pilot doesn't launch close to maximum parameters, thus has a greater chance to hit the target?

 

Yes, DLZ does not show the full kinematic potential, it has a safety margin as pointed out here: 

 

[Chizh]

7 часов назад, Jack1nthecrack сказал:

What does this mean in the context of DCS, will you change the R-27 to match the DLZ simulation?

This means that now the R-27ER missiles in DCS fully comply with and even in some places exceed the ranges calculated by the Su-27 weapon system.

 

Цитата

Does the DLZ simulator actually show ranges a certain percentage below the RAero ranges on the missile graph so that the pilot doesn't launch close to maximum parameters, thus has a greater chance to hit the target?

This shows that the nomogram in the manual is quite distorted. You shouldn't use it.

[FAB999]

1 час назад, Chizh сказал:

...

This shows that the nomogram in the manual is quite distorted. You shouldn't use it.

А теперь для очистки совести такую ж картинку (реальная схема и DLZ sim схема)  для AIM-120B or 120C ! ?

[FoxAlfa]

Just the quick question, was the full CFD done for the R-27ER? 

[tavarish palkovnik]

First time I'm seeing that shooting distance for target in rakurs 4/4 exceeding shooting 0/4 (ZPS) for more then 50%

And very surprised that R-27ER could be considered with drag force exceeding drag force of, for example, 5V27 of ZRK Neva   

[Chizh]

41 минуту назад, FAB999 сказал:

А теперь для очистки совести такую ж картинку (реальная схема и DLZ sim схема)  для AIM-120B or 120C ! ?

Давай симулятор СУВ F-15, сделаю.

 

35 минут назад, FoxAlfa сказал:

Just the quick question, was the full CFD done for the R-27ER? 

Not yet. We have done a partial study with a zero AoA drag.
The full study in the plan.