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Chizh

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8 минут назад, Chizh сказал:

Why don't you think that the game's R-27ER missile is already the same as it is in reality and nothing else can be press out of it?

Потому что вот 👇

 

14 минут назад, Chizh сказал:

We do not have any official documents with ranges of 120B/C.

наверное?
 

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22 minutes ago, TotenDead said:

Подскажи, а откуда взяты значения тяги двигателей этих амраамов?

Масса топлива известна, тип топлива и размеры сопла тоже. Удельный импульс топлива выбран исходя из усреднённого значения по паре двигателей с таким же типом топлива и  справочнику по топливам. Время работы - по видео пусков. Удельный импульс двигателя - газодинамический расчет с учетом потерь. Это достаточно точная оценка.

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3 hours ago, Chizh said:

I already wrote. We have reviewed these charts many times, but they differ greatly from the SUV-27 simulator. We concluded that the big inaccuracies were due to the hand drawing of these drawings. Here, in lines with a very large slope, a millimeter error on paper gives kilometers of range.

 

Here I drew in some of the ranges from your SUV-27 sim.

They are consinstently less.

Do you really think such a huge, consistent error would be a result of hand drawing? Especially at times where the range would be exactly on the circle??

Absolutely not! Totally implausible!

 

The actuall answer for the SUV-27 consistently showing reduced launch ranges should be that it includes a safety margin. For example to account for unprecise meassuring of the target coordinates. Or simply because a shot at maximum kinematic range is a wasted missile under real conditions.

 

These range charts are the best you have. They should be taken seriously. If the missile does not reach the ranges of the chart, then the simulation is not accurate and needs to be improved. Especially concerning is the fact that the R-27ER WITHOUT base drag is not able to reach the range of the chart.

 

For example, there were claims that the modelling of the atmoshpere is inaccurate, with too much drag down low and too little drag up high. If that is the case, then it is no suprise that after CFD the ER does not reach the correct range at 1 km altitude.

 

image.png


Edited by BlackPixxel
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55 minutes ago, BlackPixxel said:

 

Here I drew in some of the ranges from your SUV-27 sim.

They are consinstently less.

Do you really think such a huge, consistent error would be a result of hand drawing? Especially at times where the range would be exactly on the circle??

Absolutely not! Totally implausible!

 

We know this is a safety margin. It is necessary mainly because of different ambient tepmerature and some total impulse variations(from motor to motor).

 

55 minutes ago, BlackPixxel said:

 

These range charts are the best you have. They should be taken seriously. If the missile does not reach the ranges of the chart, then the simulation is not accurate and needs to be improved. Especially concerning is the fact that the R-27ER WITHOUT base drag is not able to reach the range of the chart.

 

All data we have we take seriously. But unfortunately, different sources often does not match and have some differences and we should careful think how to merge data and what source is the best. Also whe check data by calculations when it possible. BTW, the body base drag is not such powerful as you may think.

 

55 minutes ago, BlackPixxel said:

For example, there were claims that the modelling of the atmoshpere is inaccurate, with too much drag down low and too little drag up high. If that is the case, then it is no suprise that after CFD the ER does not reach the correct range at 1 km altitude.

You really think what such a simple mistake as wrong air density may be unnoticed for years? Ballistics of every weapon we add to DCS or update we carefully calculted with using ISA befor adding into DCS. If thre was any mistke with atmopshre in DCS it would be noticed as mismatch between DCS and calculations.

 

 

 

Anyway we have chaged R-27ER/ET thrust profile and zero-lift drag beacse there was made some mistkes (those missiles were adjusted togeter with communtiy many years ago) such as worng terminal condition for rear hemispere launches (missile velocity should be equal to target one plus 150m/s, but not just equal). Below you can see impact of this changes on missile range. Pay your attention to chart grid and original semi-circles mismatch and quite too big distance between dashed and solid curves at 5km altitude, rear hemisphere. All this is obvious mistakes of typography, original drawing or somewhat else. New adjustment of missiles is the best in terms of minimum of total mismatches at all velocities and altitudes.

RU 
Мы изменили профиль тяги и сопротивление при нулевой подъемной силе для Р-27ЭР/ЭТ потому что при настройке были сделаны некоторые ошибки(кто забыл, напоминаю: большинство ракет было настроено совместно с комьюнити много лет назад и эти ракеты - не исключение), вероятно при настройке использовались неверные условия встречи для пусков в заднюю полусферу(при попадании скорость ракеты должна быть равна скорости цели + дополнительные 150м/с). Ниже вы можете видеть как повлияли новые настройки на дальность полета ракеты. Обратите внимание на несовпадение сетки графика и оригинальных полуокружностей, а так же на слишком больше расстояние между пунктирной и сплошной кривой на высоте 5км в задней полусфере. Все это очевидные типографические ошибки и ошибки исходного расчета/построения. Новые настройки являются лучшими по минимум несовпадения с оригинальным графиком на всех скоростях и высотах.

r-27er rnage.png

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So after taking into the consideration that the missile needs 150 m/s minimum closer when it reaches the target at the marked range for the proximity fuze to work, you still end up with less rear aspect range than before?

 

Current version of DCS:

900 km/h ZPS, 1 km altitude

 

Missile travels 18,7 km until it's speed is equal to the target speed (old condition) in 31.3 s. (Time is roughly the one from the normogram, which is good)

In this time, the target moves 7,825 km, so the maximum theoretical engagement range with the old condition is 10,875 km, which is close to the value from the chart.

 

And now the R-27ER should be reduced to 9,9 km in this scenario, even though it should have an even higher speed at when it meets the target?

 

 

What was your change in the thrust profile?

 

Soon R-27R will fly further than R-27ER 😄


Edited by BlackPixxel
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1 hour ago, BlackPixxel said:

So after taking into the consideration that the missile needs 150 m/s minimum closer when it reaches the target at the marked range for the proximity fuze to work, you still end up with less rear aspect range than before?

Yes, think we will not change ballistics anymore, at least until development of new FM. new FM may give another 4-5% of range at low altitude. 150m/s is not only for proximity fuse it's a kind of margin for some other reasons as well, common prictace for all AA na SA misiles

 

1 hour ago, BlackPixxel said:

Current version of DCS:

900 km/h ZPS, 1 km altitude

 

Missile travels 18,7 km until it's speed is equal to the target speed (old condition) in 31.3 s. (Time is roughly the one from the normogram, which is good)

In this time, the target moves 7,825 km, so the maximum theoretical engagement range with the old condition is 10,875 km, which is close to the value from the chart.

 

And now the R-27ER should be reduced to 9,9 km in this scenario, even though it should have an even higher speed at when it meets the target?

 

Yes, the chart I posted above takes into account that additional 150m/s

 

1 hour ago, BlackPixxel said:

What was your change in the thrust profile?

More realistic boost-sustain impulse distribution, but total impulse the same.

54 minutes ago, Time 83 said:

А что такого влияет на ракету что при zps900 она летит дальше чем при zps1100 ?

Снижение скорости улетающей от нас цели дает больший прирост дальности чем ее прирост от увеличение скорости носителя(и соответственно средней скорости ракеты)

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1 hour ago, Маэстро said:

Yes, the chart I posted above takes into account that additional 150m/s

 

More realistic boost-sustain impulse distribution, but total impulse the same.

 

With the current FM the range in ZPS, 900 km/h and 1 km altitude and the +150 m/s condition is about 10,49 km, so the update would shrink the range by about 500 m.

 

Could you tell us the new motor configuration? Would be interesting to see!

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12 часов назад, NineLine сказал:

 is being intentionally ignored, lets not let the conversation spiral into unwanted realms, we are looking and talking about it internally, thanks.

Как тогда такое возможно, что изменения ракет противоборствующей стороны на столько затянулись? И опять же сроки откладываются до лучших времён, так как в приоритете другие проекты, вы представляете сколько было бы критики если р77 получила лофт и большую дальность, р27 Эр доведена, а у другой стороны была чуть изменена аим-7, а об изменениях аим-120 говорилось что есть в планах, когда будет время? 

Хорошо что вы об этом говорите внутри, и знаете об проблеме, но скажите уже конкретные сроки, когда ждать изменений или что просто изменений не будет, и все. Как в теме Су 27. И мы не будем здесь писать тысячу постов и заходить с надеждой, когда же изменения. 

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Цитата

 

Я ожидал что после продувок будет наоборот +10, а здесь -10)))

Но что то не то, не дотягивала она до номограммы, как раз 10. 

 



Результаты "продувок"  - могут отличаться от реальности.
Пример: 

 


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BTW @Max1musI did run the DeltaV numbers for the DCS missiles, all based on lua numbers. Obviously. these numbers do ignore drag, and the affects that the burn profile has on the drag. But it gives a good comparison of the motors themselves.

 

AA-10A/B: 707 m/s
AA-10C/D: 736 m/s from boost, 441 m/s from sustain, total 1177 m/s
AA-12: 947 m/s
AIM-7M: 441 m/s from boost, 247 m/s from sustain, total 688 m/s
AIM-54 Mk47: 1227 m/s
AIM-54 Mk60: 1492 m/s
AIM-120B: 284 m/s from boost, 505 m/s from sustain, total 789 m/s
AIM-120C: 876 m/s

 

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At sea level the AIM-7 is losing speed when in sustain mode.  This profile provides some 1080lbf (490kg) thrust, the missile weights about 400lbs (180kg) at this point on average, so we're probably looking at 600-800kg drag force (no I didn't calculate the actual force, but it wouldn't be too hard, all the data for this is available) like at the particular top speed it reaches (M2.5 or so).   The force experienced by the R-27 will be much higher for two reasons:  A larger diameter increases the force a bit, and the high speed will increase it even more (relative to the square of the speed).


Edited by GGTharos

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2 hours ago, GGTharos said:

At sea level the AIM-7 is losing speed when in sustain mode.  This profile provides some 1080lbf (490kg) thrust, the missile weights about 400lbs (180kg) at this point on average, so we're probably looking at 600-800kg drag force (no I didn't calculate the actual force, but it wouldn't be too hard, all the data for this is available) like at the particular top speed it reaches (M2.5 or so).   The force experienced by the R-27 will be much higher for two reasons:  A larger diameter increases the force a bit, and the high speed will increase it even more (relative to the square of the speed).

 


Except that the AIM-54 achieves much more acceleration and flyoff despite a much larger diameter and higher speed. More thrust will mean better range at low altitude, but that advantage will diminish up high. You can see this right now in DCS, where AIM-54C (Mk47) severely outranges the AIM-120C down low, but is in kinematic terms (battery life gives 54C a bigger advantage) almost matched at altitude. With the even bigger MK60 motor, it continues to have a large advantage even up high, though the gap still decreases with higher altitude.

PS: Can someone test any AIM-7 graphs from IRL in DCS? There is a russian estimation, similar to the AIM-120A/B one posted by Chizh a while ago. If the russians underestimate american missiles in general (as suggested by EDs missile rework/research), the DCS AIM-7 should perform better by similar margin (11% at 5.000m, 23% at 10.000m). If no, then given the similar shape of AIM-7 and R-27, that would indicate a potential problem with software/game engine, favoring slicker missiles with a smaller rocket motor (AIM-120/R77), or not favoring missiles shaped like AIM-7/R-27, with a better rocket motor.

It would be interesting to know how heatblur modelled their long burning, not so slick AIM-54, since that one has easily 3-4x as much flyout as any of the missiles mentioned above.


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4 minutes ago, Max1mus said:


Except that the AIM-54 achieves much more acceleration and flyoff despite a much larger diameter and higher speed. More thrust will mean better range at low altitude, but that advantage will diminish up high. You can see this right now in DCS, where AIM-54C (Mk47) severely outranges the AIM-120C down low, but is in kinematic terms (battery life gives 54C a bigger advantage) almost matched at altitude. With the even bigger MK60 motor, it continues to have a large advantage even up high, though the gap still decreases with higher altitude.

PS: Can someone test any AIM-7 graphs from IRL in DCS? There is a russian estimation, similar to the AIM-120A/B one posted by Chizh a while ago. If the russians underestimate american missiles in general (as suggested by EDs missile rework/research), the DCS AIM-7 should perform better by similar margin (11% at 5.000m, 23% at 10.000m).

 

Didn't realize there were russian estimations of the AIM-7F/M out there.  Also its not just this the Russian F15 estimate was also low when you compare it to the F15 performance manual.

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42 minutes ago, Max1mus said:

Except that the AIM-54 achieves much more acceleration and flyoff despite a much larger diameter and higher speed.

 

The AIM-54 rocket motor has about 4000lbs thrust, the  AIM-7 sustain has 1080 or so, so it will definitely top out above the AIM-7.  The diameter does make a difference, but not that much - the final force depends on the wetted area but not as much as it depends on speed.  With the AIM-7 losing speed at M~2.5, you can see that the AIM-54 will have a bunch of excess thrust there still.

 

Quote

More thrust will mean better range at low altitude, but that advantage will diminish up high.

 

Other way around.  At high altitude you have less drag, so you will achieve a higher top speed and keep it for longer.

 

Quote

You can see this right now in DCS, where AIM-54C (Mk47) severely outranges the AIM-120C down low, but is in kinematic terms (battery life gives 54C a bigger advantage) almost matched at altitude. With the even bigger MK60 motor, it continues to have a large advantage even up high, though the gap still decreases with higher altitude.

 

Not really.   There is a practical limit for any missile that depends on a lot of things.   The AIM-54 has a lot more impulse stored in its rocket and will top out at a might higher speed, meaning it can travel a longer distance in all cases.  At low altitude, the huge difference is made up by the fact that most other missiles burn their rocket motor for 10 sec and then glide, the AIM-54 is powered for 30 seconds.  That's enough time to see it fly powered all the way to a target that's head on at a bit over 10nm. 

At high altitude, the AIM-54 has much larger control surfaces and thus likely much better control as well - in other words there are altitude-g limits.

 

Quote

PS: Can someone test any AIM-7 graphs from IRL in DCS?

 

Nope, there are none in public.  There are certain very specific benchmarks which do fit (already tested them) that have to do with missile timing .

 

Quote

the DCS AIM-7 should perform better by similar margin (11% at 5.000m, 23% at 10.000m).

 

You can test that yourself.  The current AIM-7 when launched without loft basically conforms to the known timings/ranges.  I don't have them handy right now but you can consider the AIM-7 in DCS to be 'correct'.

 

Quote

If no, then given the similar shape of AIM-7 and R-27, that would indicate a potential problem with software/game engine, favoring slicker missiles with a smaller rocket motor (AIM-120/R77), or not favoring missiles shaped like AIM-7/R-27, with a better rocket motor.

 

They are not similar (much different fins) as well as running on different FM generations currently (the one AIM-7 is running on is more accurate for the drag/lift curves, but it won't make a significant difference anyway ).  There's no indication of a problem anywhere, the problem is that you're assuming the R-27 is wrong - you have to admit the possibility that it is correct, then you can actually do science.

 

And yes, the AIM-120 is very slick - when the CFD for it was made, the figures were surprising.  Slick gets you further than anything assuming similar rockets.

 

Quote

It would be interesting to know how heatblur modelled their long burning, not so slick AIM-54, since that one has easily 3-4x as much flyout as any of the missiles mentioned above.

 

You mean how they modeled a missile that runs its rocket for 30 sec with a specific drag profile?  ... Just like that? 🙂

The AIM-54 profile is the result of a CFD.  It's still using the previous generation FM IIRC (like the R-27) and the new FM would certainly make things more accurate, but this is in an academic fashion.  It wouldn't change the ranges much at all.


Edited by GGTharos

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10 minutes ago, GGTharos said:

 

Not really.   There is a practical limit for any missile that depends on a lot of things.   The AIM-54 has a lot more impulse stored in its rocket and will top out at a might higher speed, meaning it can travel a longer distance in all cases.  At low altitude, the huge difference is made up by the fact that most other missiles burn their rocket motor for 10 sec and then glide, the AIM-54 is powered for 30 seconds.  That's enough time to see it fly powered all the way to a target that's head on at a bit over 10nm. 

At high altitude, the AIM-54 has much larger control surfaces and thus likely much better control as well - in other words there are altitude-g limits.

 


Has nothing to do with G limits and they dont affect the AIM-54 up high in any meaningful way, in DCS.

Test AIM-54C (heatblur) against AIM-120C down low and up high. Check difference. You will see that im right. It comes down to the lofting AIM-120C practically not loosing much energy at all up high in DCS, as such it will still maintain mach 2.5-3 even after 100 miles of flight. The DCS AIM-54 will continue to loose energy, especially on a target diving into thicker air.

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19 minutes ago, Max1mus said:

Has nothing to do with G limits and they dont affect the AIM-54 up high in any meaningful way, in DCS.

 

Has plenty to do with g limits (or more strictly with control surface AoA limits) which are modeled in the new FM.  Basically the IAS up high is quite low, despite supersonic speed and missile maneuver is limited.  The old FM models this, the new one does it much better.

Like I said, you could shoot the missile into orbit, but it won't do you much good if it can't maneuver.

 

Quote

Test AIM-54C (heatblur) against AIM-120C down low and up high. Check difference. You will see that im right. It comes down to the lofting AIM-120C practically not loosing much energy at all up high in DCS, as such it will still maintain mach 2.5-3 even after 100 miles of flight. The DCS AIM-54 will continue to loose energy, especially on a target diving into thicker air.

 

I've never been able to get the 120 to go 100nm, but I'm really not surprised that it could do so on a ballistic trajectory.


Edited by GGTharos
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10 hours ago, Hoarfrost said:

Как тогда такое возможно, что изменения ракет противоборствующей стороны на столько затянулись? И опять же сроки откладываются до лучших времён, так как в приоритете другие проекты, вы представляете сколько было бы критики если р77 получила лофт и большую дальность, р27 Эр доведена, а у другой стороны была чуть изменена аим-7, а об изменениях аим-120 говорилось что есть в планах, когда будет время? 

Хорошо что вы об этом говорите внутри, и знаете об проблеме, но скажите уже конкретные сроки, когда ждать изменений или что просто изменений не будет, и все. Как в теме Су 27. И мы не будем здесь писать тысячу постов и заходить с надеждой, когда же изменения. 

Not just each individuals desire drives development direction and timelines, there are many factors that push things back, or pull them to the front.

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20 минут назад, NineLine сказал:

Not just each individuals desire drives development direction and timelines, there are many factors that push things back, or pull them to the front.

Вы ответили как отличный политик - вроде все хорошо, но никакой ясности) 

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27 минут назад, Hoarfrost сказал:

Вы ответили как отличный политик - вроде все хорошо, но никакой ясности) 

Да все тут ясно: эффективный менеджмент.

Смиритесь и отстаньте от "художников" наконец. Не мешайте людям делать деньги.

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3 минуты назад, KBAC сказал:

Да все тут ясно: эффективный менеджмент.

Смиритесь и отстаньте от "художников" наконец. Не мешайте людям делать деньги.

Давно хотелось этой честности и на самом деле, если бы они честно это сказали сообществу) я думаю все бы сделали свои выводы и отстали бы от этой темы.

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2 минуты назад, jager_jager сказал:

Давно хотелось этой честности и на самом деле, если бы они честно это сказали сообществу) я думаю все бы сделали свои выводы и отстали бы от этой темы.

Да, конечно же! И не было бы тех, кто просит/требует лучшей симуляции того или иного.

Не то "у нас всё правильно" да всякое такое в грудь себя пяткой битьё... Начитался каждый уже вдоволь.
Зачем обманывать клиентов...

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That’s why I uninstalled DCS World 5 months ago. I have been waiting for 2-3 years for Deka J 11A MFI 55 update. The R 27 and R 77 missiles will not be special. With the MFI 55 update, you could even build a 2-seater Su 30KN for the Flaming Cliffs. There are plenty of options in this simulator and we can only be targets for NATO planes! There's no point in coming back yet! If you were to take steps that would delight us Flanker pilots you could make money to ED and please those who are still here don’t torture them! 😟

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Я вот пока не удалил. Захожу раз в месяц полетать на пол часика - часок на несчастном МИГе. Потом плюю и забываю еще на месяц - другой. Иной раз думаю, стоит ли это вваленого бабла. Ну да ладно, пусть своими Fками и Апачами развлекаются. Помятую хорнет, будут еще года 2 к нему хелферы - радары пилить, а там может за гриппен возьмутся. Так что здесь можно прорывов не ждать. Все после...

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