Prosba Prokomentirovat' (RLS F15+AIM120)...

[EvilBivol-1]

Chizh,

 

Spasibo za otvet. Voobsheto, moi vopros zakluchaetso v drugom... Mne interesno kak realizovan etot effekt, v smisle, kak resko, ili naoborot, kak plavno snizhenie visoti nachenaiet vleiat' na RLS? Ia boius' shto effekt tipa, letish na 1300, nefiga ne nahodish, podnimaeshsa na 1520, tseli za gorizontom poiavliaiutsa na 'MFD'. Esli eta cherta nastolko rezkaia, kazalos' bi "ne realno". Hotelos' bi uslishat (prochitat') kak zdelano v sime i naskolo eto pohozhe na realnost (na skolko vi eio znaiete).

[EvilBivol-1]

Andrew!

 

You know, I swear I thought about "sidelobes" being the issue raising so much stink. But, having no real background in technical matters outside some popular aircraft readings, I decided to not bring it up. It is absolutely terrific to have it in the sim though.

 

Funny you should say that "Not only Russian pilots are angry!" here on lockon.ru, while on lo-mac.com I'm trying to tell them that not only westerners are angry! :) Poor Chizh indeed. Eagle Dynamic and certain individuals of Ubisoft...

 

YOU'RE GREAT :!:

[noir]

Andrew!

 

You know, I swear I thought about "sidelobes" being the issue raising so much stink. But, having no real background in technical matters outside some popular aircraft readings, I decided to not bring it up. It it absolutely terrific to have it in the sim though.

 

BTW i did a little research of my own and found out curious fact... All cassegrains, invariably have sidelobe reduction circa -18 dB. (although their amplification varies widely.) Quite good, but I bet Phased arrays can do much better...

[Gunn0r]

SwingKid, thx for the good read.

[Chizh]

Chizh,

 

Spasibo za otvet. Voobsheto, moi vopros zakluchaetso v drugom... Mne interesno kak realizovan etot effekt, v smisle, kak resko, ili naoborot, kak plavno snizhenie visoti nachenaiet vleiat' na RLS? Ia boius' shto effekt tipa, letish na 1300, nefiga ne nahodish, podnimaeshsa na 1520, tseli za gorizontom poiavliaiutsa na 'MFD'. Esli eta cherta nastolko rezkaia, kazalos' bi "ne realno". Hotelos' bi uslishat (prochitat') kak zdelano v sime i naskolo eto pohozhe na realnost (na skolko vi eio znaiete).

 

Нет ты плохо о нас думаешь. ;)

В игре смоделировано плавное уменьшение дальности обнаружения и захвата с высоты 1400 метров и ниже примерно на 40%.

[EvilBivol-1]

Нет ты плохо о нас думаешь.

 

:lol: Sovsem ne ploho... prosto vnematelno i ostorozhno ;). Dela takie, ponemaesh... blizko s serdsu kak-to :D Net, vi rebiata molodtsi koneshno. Ochen' priatno kogda sim razrobativaiut' liubiteli dela, da k tomu-zhe "svoi", i k vsemu esho ne leniatsa na forumah obshiatsa 'so vsiakimi tut...' :) Spasibo za trud.

 

No opros prodolzhaetsa! Oa tebe esho ne nadoel? :mrgreen:

1) Ia tak ponial shto

смоделировано плавное уменьшение дальности обнаружения и захвата с высоты 1400 метров и ниже примерно на 40%.

do patcha? A kak v radare F15 eto teper' izmenilos, esli ne sekret? Eto pravda chisto po liubopitnosti...

 

2) Kak vse eti dela deistvuiut na AI? Est' zhalovania shto AI ne teriaet effektivnos' radara na nizkih visotah, da i voobshe v raznih sluchaiah kogda radar virpila 'uhudshaetsa'. Ili eto i imelos' vvedu pod "dalneishei dorabotke AI" ?

[Chizh]

40% это сейчас так для F-15C. Т.е. будет в патче. Для Су-27 и МиГ-29 уменьшение дальности на 60%

На AI это также распространяется. Радар у них тотже.

[Sotka]

Акцент я ставил на то что выбрасывается моделирование РЛС со всеми особенностями и заменяется "однозначной" моделью как это можно было понять из:

 

"

Мы попытались придать больше реализма именно работе радаров и постарались смоделировать все известные ограничения, как то уменьшения дальности обнаружения и захвата по высоте и на фоне земли, зависимость от ракурса цели, ее скорости и ЭПР, срыв захвата по минимальной радиальной скорости сближения.

Похоже в этих начининиях нас не поняли, и для многих более простой и однознаный радар явно предпочтительнее.

"

23- Radar performance when operating at low altitudes has been greatly increased

 

 

Не знал что продюсер имеет полную власть - тогда всё понятно.

 

Кстати Р-77 сохранила то же преимущество по дальности что и до увеличения AMRAAM дальности на 13км ?

[Chizh]

А кто точно знает максимальную эффективную дальность пуска AIM-120 и Р-77?

[Sotka]

Ну дык кто точно знает тот не скажет. Для AMRAAMa никто же точно не говорил - поменяли после воя на буржуйском форуме - не было бы воя сомневаюсь что вы тронули бы свои данные.

В Вымпеле должны знать - Р-77 на экспорт продают, покупателям навеное должны говорить.

 

Насколько понятно, сейчас один из ваших тестеров написал простенькую программу моделирования ракет для оценки дальности. Эта пограмма даёт нижние и верхние ределы для ракет. Первоначально вы выбрали значения ближе к нижнему пределу для всех ракет. Но вот теперь AMRAAM получает оценку высокого предела в то время как остальные сидят на низах (иначе пришлось бы изменять для всех ракет и уравниловки для AMRAAMа не было бы).

 

Другой подход это использование публикуемых данных (на военных выставках могут быть более подробными) и уменьшение их по общему коэффициенту (ну может 0.7 для стрельбы навстречу) чтобы получить Rmax. Но и с этим подходом AMRAAM уступает (стрельба навстречу Р-27ЭР - 130км; Р-77 - 100км; AMRAAM - 42nm ~ 77.8км).

[SwingKid]

Sotka,

 

Всё не так просто и ясно.

 

AIM-120 is a very recent and secret missile. For other missiles, real data is available. An example: What is the maximum range of R-27R? Look on the internet. Some sources say 50 km, some say 80 km. But - 80 km = 50 mi. Maybe an American once made the mistake, changing km -> mi, and many people copied him? Then again, some books say the range is 70 km. What is the truth? In the real MiG-29 combat manual, it says, "50 km". But, in the same combat manual it also provides a graph with the conditions:

 

 

If the maximum launch range for R-27R is 50 km, or 70 km, or 80 km, then why does the graph show that for head-on target, 10 km altitude, 1100 km/h fighter speed, 900 km target speed, the maximum range is 35 km? It's a lie?

 

No, it's true. Simply, it is possible to launch the R-27R at higher altitudes and speeds than what is shown on the graph, and in such cases the range will be more than 35 km. But such cases can be special or very unusual for air combat. So, if the number of "maximum range" that is printed in a book is not accompanied by the details of the intercept - target speed, altitude, etc. then the numbers are not useful for comparison. When we say the maximum range of AIM-120 is "75 km," but for R-77 it's "100 km," what is the altitude? What is the geometry? What is the aircraft speed? These numbers are not sufficient to say the R-77 really has a longer range than AIM-120.

 

Where the numbers and conditions are available, Lock On uses the real numbers. But for a missile like the AIM-120, it's necessary to make a guess. For this reason, I made a mini-simulator. But even the mini-simulator is not perfect. The data used in the simulator is incomplete, and I often make corrections. Where the real data is known, the simulator should produce the real data. I have failed to satisfy even this simple criteria. Even for the KNOWN data, the simulator produces average 12% error. Who can say, what is the error for the unknown missiles? So, I am always making corrections and the numbers always change. The mini-simulator is only one source of information, among many other qualified people's opinions.

 

About the R-77, I don't know if it has a longer range than AIM-120. The R-77 has larger diameter and grid fins which make it slower. It has a one-regime engine, where the AIM-120 has two regimes. It flies straight to the target, where the AIM-120 flies a ballistic "loft" profile for less drag and more range. The R-77 uses "PATT" fuel, the AIM-120 uses HTPB fuel, which I think has higher energy. So, I can't say with confidence that the internet sources are correct.

 

One of the problems with the maximum range number is that it always includes the speed of the target. For example, the R-27R in the graph above. The range "35 km" - it's really 23.4 km that the missile travels, and 11.6 km that the target approaches, in the time of 54 seconds. If the target travels 1800 km/h instead of 900 km/h, it will pass 23.2 km in 54 seconds. 23.4 missile + 23.2 target = 46.6 km "maximum range" against an 1800 km/h encounter target, for the same R-27R missile!

 

So, if the target for a Russian missile is a non-maneuvering SR-71, and the target for an American missile is a non-maneuvering MiG-29, which missile will have the longer range? Is it a fair comparison? Is it possible for R-77 to have "100 km" and AIM-120 "75 km", when in reality the AIM-120 flies farther?

 

Eagle Dynamics must be very careful with the analysis of provided data. It is not "буржуйская воя" which causes them to change the numbers, but rather real evidence from real pilots.

 

-SK

[BP_Vos]

About the R-77, I don't know if it has a longer range than AIM-120. The R-77 has larger diameter and grid fins which make it slower. It has a one-regime engine, where the AIM-120 has two regimes. It flies straight to the target, where the AIM-120 flies a ballistic "loft" profile for less drag and more range. The R-77 uses "PATT" fuel, the AIM-120 uses HTPB fuel, which I think has higher energy. So, I can't say with confidence that the internet sources are correct.

-SK

 

 

Where are you getting your info on R-77's flight profile, SwingKid?

 

 

Also, we shouldn't forget that R-77 has a 2+ cm larger body diameter than AIM-120. This, among other things, allows for a bigger rocket motor with more fuel for longer burn times.

 

In addition to that, R-77 should be a better missile of the two when used in CAC, due to its grid fins and the advantages they bring.

 

A grid fin is a lifting and control surface that differs from a typical solid fin. The grid fin uses a honeycomb design that allows air to pass through the fin rather than bypass around it. Typically it has an outer frame supporting an inner grid of small intersecting planar surfaces. Grid fins have been used on some Russian Federation air-to-air missiles (see sidebar, "Other Grid Fin Applications," below) but have not been used on any fielded missile systems in the West. Interest in grid fins has increased in recent years due to their advantages over conventional planar controls. One advantage is the ability to maintain lift at higher angles of attack since grid fins do not have the same stall characteristics as planar fins. Another advantage is their very small hinge moment, which can reduce the size of control actuator systems. A third advantage is that their curvature has little effect on performance, so that folding the fins down onto the missile body is a storage design bonus. "These features allow grid fins to perform well at high angles of attack and high Mach numbers, making them well-suited for use on highly maneuverable munitions," explains James DeSpirito, aerospace engineer at U.S. Army Research Laboratory (ARL) in Maryland.

 

 

 

 

 

While we're on the subject of missiles here, can anybody tell me why the R-27EM in Lo-mac keeps homing in on the target after the radar lock is broken, as though it had an active seeker head? Isn't that supposed to be a SAR missile?

 

 

 

 

 

Sorry guys, can't use Russian. Got an English keyboard here.

[SwingKid]

Where are you getting your info on R-77's flight profile, SwingKid?

 

http://www.sistemasdearmas.hpg.ig.com.br/aam/r77.html

 

Sorry it's in Spanish, but you can see it has been very well-researched. I think the author spoke with someone from Vympel at aviasalon.

 

In addition to that, R-77 should be a better missile of the two when used in CAC, due to its grid fins and the advantages they bring.

 

I would agree that grid fins are an advantage in CAC and against a maneuvering target, because they have less induced drag with AOA. But for absolute maximum range with a non-maneuvering target, they have a drag penalty that is greater than that of conventional fins.

 

-SK

[BP_Vos]

Interesting article, thanks!

 

Here's a link to a translated version:

 

http://translate.google.com/translate?hl=en&sl=pt&u=http://www.sistemasdearmas.hpg.ig.com.br/aam/r77.html&prev=/search%3Fq%3Dhttp://www.sistemasdearmas.hpg.ig.com.br/aam/r77.html%26hl%3Den%26lr%3D%26ie%3DUTF-8%26oe%3DUTF-8%26safe%3Doff%26sa%3DG

 

 

The first part of it seems strangely familiar.

 

Ah, yes...

 

http://www.bharat-rakshak.com/IAF/Aircraft/Missiles/R-77.html

 

 

 

 

 

About your program for calculating missile ranges.

 

Does it take into account the weight of the rocket fuel and the fact that a missile itself will be much lighter by the time the rocket motor burns out?

[SwingKid]

About your program for calculating missile ranges.

 

Does it take into account the weight of the rocket fuel and the fact that a missile itself will be much lighter by the time the rocket motor burns out?

 

Конечно да! :)

 

It even takes account of two-regime boost-sustain motors and the fact that in pursuit, the missile may decelerate to the speed of the target but no further before the intercept. But in head-on encounter, it may fully decelerate until it stalls from lack of lift.

 

One feature that it does not account for is the "loft" ballistic flight path of some missiles - it assumes constant altitude flight to the point of intercept. Therefore according my mini-simulator, the R-77 has some range advantage over AIM-120. In order to estimate "loft", I must simulate the missile range at two different altitudes and take the average. But even then it's difficult to know - do I have the correct answer? Because I don't know what is the real missile flight path loft altitude. Maybe I chose too high or too low.

 

And, even with all these features, to obtain agreement with all known data, it never happens regardless my efforts. I don't know why. :cry:

 

-SK

[SwingKid]

While we're on the subject of missiles here, can anybody tell me why the R-27EM in Lo-mac keeps homing in on the target after the radar lock is broken, as though it had an active seeker head? Isn't that supposed to be a SAR missile?

 

Is the target using active jamming ECM/РЭБ? If yes, then the missile is following the jammer with or without a lock ("home on jam"). If no, then it may be an error in the game.

 

-SK

[BP_Vos]

While we're on the subject of missiles here, can anybody tell me why the R-27EM in Lo-mac keeps homing in on the target after the radar lock is broken, as though it had an active seeker head? Isn't that supposed to be a SAR missile?

 

Is the target using active jamming ECM/РЭБ? If yes, then the missile is following the jammer with or without a lock ("home on jam"). If no, then it may be an error in the game.

 

-SK

 

 

Hmm... I retested it and, indeed, it appears to be the case of HOJ homing.

[Sotka]

Конечно дальность зависит от многих параметров и конкретной ситуации. Наверняка производится много испытательных пусков чтобы получить графики зон.

Но - дальности заявленные фирмами сопоставимы тк отражают лучшую ситацию которую удалось достичь. Да это всего лишь одна точка, но если учитывать что ни одна из фирм не стреляет себе в ногу а старается дать лучший полученный результат, то эти максимальные дальности всё же сравнимы и дают представление об относительной дальности в другой ситуации.

 

Статья Вымпела (Геннадий Соколовский) указывает дальности 100км для Р-77 и 130км для Р-27ЭР. Тов. Соколовский пишет о Р-77:

 

"

The missile has a combined guidance system. At the initial leg, which accounts for up to 80% of the flight path, the missile is inertially guided. Once the target is locked on by the homing head, the missile enters the self-homing phase. The use of a compact missile motor with a high power-to-weight ratio assures a maximum launching range of 100km. The missile can kill targets maneuvering with accelerations of up to 12g at altitudes of 0.02 to 30km.

"

 

В другой статье тов. Соколовский описывает некоторые конструктивные особенности Р-77:

"

The missile's parabolic nose increases its total lift. The most remarkable feature of the missile's aerodynamic configuration is its latticed control surfaces which, despite insignificant increase in drag and radar signature, provide several important advantages. They have a low (about 1.5kgm) hinge moment which remains stable within the wholerange of Mach numbers, flight altitudes, angles of attack, and angles of orientation of the plane of symmetry relative to plane of attack. This feature enabled designers to use a small-size low-power electric drive to manipulate the control syrfaces. Such a design of the control surfaces provides for a stall-free flow-past up to angles of attack as high as 40deg, the aerodynamic efficiency remaining unaffected. Provision is made for changing the characteristics of the missile's empendage by varying the number of control surface meshes which are almost independent aerodynamically from one another and from the missile's body. Compared to traditional designs, these control surfaces feature better strength and aeroelastic characteristics.

...

The guidance system combines command/inertial navigation in the initial phase and active radar homing in the terminal phase. The terminal phase begins upon application of a command generated by the onboard computer. The computer calculates the distance of target acquisition by the missile's homing head. When the homing phase begins, the onboard computer conitnues providing a mathematical model of the target. If the target is lost, this model is used again to initiate the new search.

 

The missile uses a modified proportional guidance technique in all application modes. Under jamming conditions, the carrier's radar cannot supply the target range and close-in data to the missile and, therefore, its guidance is accomplished with use of specific trajectories. The homing head is equipped with a facility for passive guidance towards a jamming source that masks the target.

 

The missile is equipped with a laser fuze which illuminates the target and, using return signals, determines the optimal distance for warhead detonation. The operating parameters of the fuze are adaptable to the target's size. There is also an impact fuze designed for direct target hits or for self-destruct purposes when the missile hits the ground or water surface.

 

The warhead has a rod-type design with microcumulative elements. The rods are assembled in such a way that at the moment of detonation they form an expanding ring which actually cuts the target. The microcumulative elements can destroy precision-guided weapons when the carrier-aircraft executes missile defense missions.

"

[Gunn0r]

And, even with all these features, to obtain agreement with all known data, it never happens regardless my efforts. I don't know why. :cry:

 

Well, you gotta leave something for the nerf brigade to "cry wolf" over ;)

 

With all due respect, can one really completely simulate what is going on IRL on a computer? I have been playing World War II Online for 3 years now, and that sim's dev team is trying to keep it as real as it gets, but even they are forced to make concessions, due to the fact that one can hardly account for ALL the possible variables that can affect a unit in a simulated environment, and that even if the manhours are put into making it as real as it gets, hardly any modern (home) computer will be able to do all the calculations without dropping the framerate to 0.

[калоян стоев]

In real life in high altitudes (9-13 km) the max range for R-27R is about 41 km, for R-27T - 32 km

 

R-27ET - 53 km

R-27ER - 66 km

R-27AE - 70 km

 

These are the max distances for real battle use at which maneuvering air-targets could be destroyed.

 

At low alt, low speed and high-G maneuvering target the distances are much lower - hardly exceeding 10-15 km

 

The same goes for AIM-7 modifications, but their range is even lower.

 

R-77 (RVV-AE) has max range about 55-60 km which is about 5% more than AIM-120C`s range

 

R-77M (RVV-AE-PD) was succesfuly tested at targets at 115 km

[Darth]

Andrew:

 

> If the target travels 1800 km/h instead of 900 km/h, it will pass 23.2 km in 54 seconds. 23.4 missile + 23.2 target = 46.6 km "maximum range" against an 1800 km/h encounter target, for the same R-27R missile!

 

So, if the target for a Russian missile is a non-maneuvering SR-71, and the target for an American missile is a non-maneuvering MiG-29, which missile will have the longer range?

 

Andrew, but there is another important factor involved in the computation of maximum intercept range, namely the target hit probability being "not lower than required by the specifications". Usually the closer the missile is to the target, the higher is the precision of estimation of their relative position. At some moment the seeker becomes able to tell exactly what the miss would be if the missile continues on without course correction, so the final closure manoeuvre is performed the effectiveness of which depends largely on the missile's available (capable of being realised) load factor. Naturally, the required load factor is lower for low speed targets and higher for high speed ones. In turn, the load factor is itself the function of missile's own airspeed.

 

Conclusion: in order to meet the hit probability specification, at the terminal phase of the missile's flight we must have a certain ratio between missile and target airspeeds. For example, for "wingless" S-300P family SAMs (5V55K, 5V55R, 48N6, etc.) this required speed advantage is estimated to be 1.5 times.

 

Similarly, altitude works both ways. True, drag is reduced at high altitudes, but so are the available load factors. :)

 

Now, the maximum launch range is specified for a certain hit probability (as far as I know, 0.7 for R-27 against a non-manoeuvring target). Should the target move faster, this range would not necessarily increase, but instead, as you can see from the above, it can actually even decrease. At certain speeds (or altitudes) the target cannot be hit with the specified probability at all.

 

So all this actually means one thing for us – that we are stuck once again :). I think, now it's all up to ED's educated guessing abilities.

 

P.S.: By the way, that article on R-77 – what language is it in? :) Seems Catalon to me. But definitely not Spanish :)

[Chizh]

In real life in high altitudes (9-13 km) the max range for R-27R is about 41 km, for R-27T - 32 km

 

R-27ET - 53 km

R-27ER - 66 km

R-27AE - 70 km

 

These are the max distances for real battle use at which maneuvering air-targets could be destroyed.

 

At low alt, low speed and high-G maneuvering target the distances are much lower - hardly exceeding 10-15 km

 

The same goes for AIM-7 modifications, but their range is even lower.

 

R-77 (RVV-AE) has max range about 55-60 km which is about 5% more than AIM-120C`s range

 

R-77M (RVV-AE-PD) was succesfuly tested at targets at 115 km

 

В общем правильно. Но вот меня всегда интересовало, за счет чего ракета Р-27АЕ имеют большую дальность при том же двигателе и абсолютно той же геометрии?

 

Кто скажет дальность AIM-7M? ;)

[Biker]

 

Кто скажет дальность AIM-7M? ;)

approximately 30 nm

[Chizh]

Andrew, but there is another important factor involved in the computation of maximum intercept range, namely the target hit probability being "not lower than required by the specifications". Usually the closer the missile is to the target, the higher is the precision of estimation of their relative position. At some moment the seeker becomes able to tell exactly what the miss would be if the missile continues on without course correction, so the final closure manoeuvre is performed the effectiveness of which depends largely on the missile's available (capable of being realised) load factor. Naturally, the required load factor is lower for low speed targets and higher for high speed ones. In turn, the load factor is itself the function of missile's own airspeed.

Дальности которыми мы оперируем обычно являются идеальными для конкретного случая. Т.е СУВ самолета Су-27 выводит признак ПР на дальности 60 км для ракеты Р-27ЭР с истребителя летящего со скоростью 900 км/ч по неманеврирующей цели летящей навстречу с такой же скоростью. Также есть другая меньшая засечка по дальности символизирующая дальность пуска с учетом маневра цели которая примерно на 2/3 меньше максимальной. СУВ сама не расчитывает возможности ракеты т.к. не может предсказать маневр цели и оставляет решение о пуске на летчика. А возможность маневра сильно зависит от алгоритма наведения ракеты или коэффициантов в алгоритме пропорционального сближения.

 

Conclusion: in order to meet the hit probability specification, at the terminal phase of the missile's flight we must have a certain ratio between missile and target airspeeds. For example, for "wingless" S-300P family SAMs (5V55K, 5V55R, 48N6, etc.) this required speed advantage is estimated to be 1.5 times.

Откуда эта информация? Какая минимальная эволютивная скорость для ракет В-В, например Р-27?

 

Similarly, altitude works both ways. True, drag is reduced at high altitudes, but so are the available load factors. :)

Логично. ;)

 

Now, the maximum launch range is specified for a certain hit probability (as far as I know, 0.7 for R-27 against a non-manoeuvring target). Should the target move faster, this range would not necessarily increase, but instead, as you can see from the above, it can actually even decrease. At certain speeds (or altitudes) the target cannot be hit with the specified probability at all.

Могу возразить, что более скоростной самолет все равно упирается в предельную перегрузку по прочности или по "прочности летчика" и для меня не совсем очевидно как может уменьшится дальность из-за более скоростной цели если на сверхзвуке она становится менее маневренной.

ИМХО. СУВ самолета такие сложности не вычисляет. ;)

 

So all this actually means one thing for us – that we are stuck once again :). I think, now it's all up to ED's educated guessing abilities.

Пытаемся раскопасть больше информации и вникнуть. ;)

[Chizh]

 

Кто скажет дальность AIM-7M? ;)

approximately 30 nm

Сейчас так и есть. ;)