Darth

Andrew: Well, theoretically, one can preset the coordinates of target intercept point, so having command update capability here is not mandatory. But INS is, and that's what I meant – capable of realizing ballistic trajectory are only the AAMs with INS installed. (But since we discussed R-27 and R-77 anyway, I omitted to specify this.) But that's when the missile has switched to homing. What prevents from making use of a ballistic trajectory during the inertial phase of the flight? Oh yes, that's a perfectly valid question :). The introduction of the term "lifting body" ("несущий фюзеляж") or "lifting cone" ("несущий конус") when applied to S-300P SAMs was surely the designers' idea, purporting simply to say that these missiles have no wings :) (therefore the only thing capable of generating lift at a non-zero angle of attack is their fuselage). Yes, that's for sure Rmax1, which is described in the Russian textbooks as "the maximum range at which the missile is able to intercept the target with a probability not lower than required". Rmax2 is a guaranteed range, which is "the maximum range at which the missile is able to intercept the target with a probability not lower than required, regardless of the type and parameters of the target's defensive manoeuvres". I've never encountered the Russian equivalent of Raero, though. True, but the radiated power level drops exponentially from the mainlobe to sidelobes, therefore I phrased it like "the missile cannot afford to fly very far [in angular coordinates] outside of our radar's mainlobe, for fear of losing the command link". BTW, don't you find that the fact that the manual keeps referring to guidance through sidelobes itself suggests that in inertial stage of the flight the missile can be using loft trajectory? (otherwise it would have probably said "radar mainlobe" which is always directed at the acquired target anyway) How is it possible? It's true for close air combat, when you can estimate the target's trajectory, but in BVR you don't even have an intercept point mark on the HUD. Yes, try telling that to "Tor" and "Tunguska" designers :D (Particularly those of "Tor" – these guys have installed a relatively wide-angle phased array in it, yet implemented command-to-LOS. Doesn't seem a smart choice…) I didn't say command-to-LOS was the guidance method for R-27 (one must be "slightly off" to allege that :)), I said that during the inertial stage of the flight (i.e. before switching to homing) its trajectory "should resemble that of a missile employing command-to-LOS method", for reasons already outlined supra :).

And still one more thought :) When talking about SAM system characteristics, what is the "maximum target speed" there for? :) Should we accept the thesis that in forward-quarter engagements the missile can slow down indefinitely until it stalls, i.e. that at the intercept point the missile-to-target speed ratio can be as low as zero, what difference does the target speed make? E.g., why Buk's 9M38 isn't expected to successfully intercept targets closing on SAM position at, say, 1500 m/s? Ideas? :)

В смысле "Ульяновск"? :)

Yet another thought on the engagement zone not being circular. Above I supposed that the missile uses proportional navigation method for guidance all the way to the target, while in fact it obviously does that only after switching to homing. Prior to that its trajectory should resemble that of a missile employing command-to-LOS method, because the missile cannot afford to fly very far outside of our radar's main lobe, for fear of losing the command link. Therefore it becomes perfectly understandable now that the higher the initial target aspect angle is, the less optimal the trajectory (hence we get a lateral deviation function maximum shifted towards the target, as in our example above – 15 km vs. 11). If this is the case, the engagement zone for longer range missile, all other factors being equal (say, R-27RE vs. R-27R), should be elliptical with even higher eccentricity. This theory can be indirectly supported by the following reasoning. 48N6E SAM is reported to be able to kill targets 150 km away from the launcher. It is also reported to be able to engage targets whose trajectory has a lateral deviation ("target parameter" in Russian, what's the correct English for it?) of the same 150 km (meaning that the engagement zone is a circle with it's center shifted towards the incoming target). In S-300 case this is nothing extraordinary, for the SAM is from the very start guided directly to the projected collision point, at least as long as the radar can track both the target and the missile. But now let's remember the numbers for other SAM systems not equipped with phased array engagement radars. Here goes: "Krug" – Max range: 50 km; Max parameter: 18-20 km. "Kub" – Max range: 22-25 km; Max parameter: 15-18 km. "Buk" – Max range: 25-35 km; Max parameter: 18-22 km. "Osa" – Max range: 9-10 km; Max parameter: 5-6 km, and so on… So, I think this can explain the elliptical nature of the R-27 engagement zone. P.S.: At the moment I am ill with some cold, I got a terrible headache, my reasoning powers are weak, so if the above doesn't make much sense, don't blame it on me! :D калоян стоев: Да, В.Н. Кондауров это тоже отмечал. Что ж, приятно сознавать, что хоть здесь "Военный парад" не наврал :)

Chizh: Ну так кто бы спорил :) Здесь вопрос несколько в другом (см. далее). Как-то раз мне посчастливилось одну работу почитать в И-нете, про ЗУР вообще и С-300П в частности. Потом правда оказалось, что выложили ее по глупости (секретная, видимо, оказалась), начался небольшой переполох, файл быстро убрали, но вокзал уже ушел :). Не знаю, самому интересно. Дело не в маневренности цели – пока мы для удобства вообще предполагаем, что она всю дорогу прямо летит. Дело в возможностях ГСН по ее своевременному обнаружению и вычислению ее фазовых координат (x, y, z, векторы скорости, ускорения, ...). Понятно, что для ракет с самонаведением (в противоположность радиокомандным, так что про 5В55К выше – это я загнул :)), точность определения последних обратно пропорциональна расстоянию до цели. В некоторый момент времени ГСН может точно определить величину промаха, и возникает необходимость "совершения маневра для ликвидации (выбора) промаха на конечном участке" (клише из книжек про ПВО :)). Вот тут-то нам и пригодятся маневренные возможности ракеты. Отсюда же видно, почему в этих условиях для обеспечения требуемой вероятности поражения нам выгоднее иметь дело с малоскоростной целью – относительная угловая скорость меньше. В случае маневрирования цели все вышесказанное остается в силе, а наше (ракетное) положение еще более усугубляется :) Собственно, за сим нам и нужно преимущество в скорости, следовательно, располагаемых перегрузках. А, как я уже говорил, дальность устанавливается в ТТЗ для определенной вероятности поражения цели. Вот вам и ответ на вопрос "как может уменьшится дальность из-за более скоростной цели" :) Ну да, там глупая таблица зашита. Удачи! ;) Andrew: Interesting, I was under the impression that all AAMs use loft trajectory. Flying straight to target is, well, unwise :), particularly for one-regime motors. I guess all medium- and long-range SAMs nowadays use optimised flat trajectory in vertical plane, why should AAMs act differently? No, we shouldn't. It is for this reason that I specified which missiles this standard applies to – S-300 SAMs. With their "lifting body" layout they are inherently less manoeuvrable than the missiles with wings (particularly R-27, just look at its fins :)) Therefore, higher speed advantage is necessary to be able to pull sufficient Gs. What the case is for something like R-27, I don't know. But that should be expected :). Really, for purely geometrical reasons, the maximum allowed lateral deviation of the target's path from the attacker should appear on our graph at 13-(35+13)/2 = 13-24 = -11 km (which corresponds to target aspect angle of about 70 deg head-on), not at 0 (90 deg). But, good point, instead the graph shows the maximum somewhere near -15 km, and lateral deviation of only about 21-22 km instead of the expected 24. Well, yes, the engagement zone is not a circle, and you could be right about the reasons for it. Perhaps, our Air Defense pays more attention to hit probabilities than the Air Force does? :)

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 :)

Andrew: > I don't believe the MiG-21 has higher RCS than Su-27 Oops, I haven't even noticed THAT! What kind of a source could claim this, I wonder? :) By the way, it's somewhat atypical to see Su-27's average RCS stated to be as low 3 sq. m. Russian radioelectronics manuals usually propose the following average RCS standards for fighter-class targets in 3 cm wavelength: 3 sq. m. for a "light fighter" (MiG-29), 5 sq. m. for a "heavy fighter" (Su-27). Naturally, these values are nothing more than "standards" used to calculate radar ranges in comparable conditions, however, they are meant to at least be illustrative of the reality (or so I suppose :)).

Павел> Во всех источниках по ТТХ Су-27 может одновременно захватывать и атаковать 2 воздушные цели, а в игре только одну Да где ж вы такие "источники" берете-то?! :)

Liosha> а вот сильный МиГ-31 - значительно повысит наш рейтинг в столь важном сейчас - дальнем в. бою Liosha, появление на стороне российских ВВС пилотируемого МиГа-31 приведет к серьезному дисбалансу в игре, для компенсации которого необходимо будет моделировать летабельный F-14. А это сами знаете во что выльется (потом ведь Су-35 и F-22 захотят :)). Я сам Lock-On’а пока не видел, но судя по отзывам здесь, продукт вышел сырым и в некотором роде сохранил аркадность своего предшественника. В связи с этим считаю первостепенной задачей разработчиков по мере возможности устранить выявленные недостатки и в дальнейшем изыскать возможности для кардинального повышения реализма при сохранении приемлемой производительности программы. А новые летабельные самолеты – это от лукавого :D P.S.: Кстати, в качестве компенсации можно предложить разработчикам сделать возможность выбора игроком в редакторе любого самолета. Такой самолет будет иметь какую-нибудь стандартную кабину, или даже не иметь ее вовсе, и такую динамику полета, как если бы он управлялся AI. А чтоб такие как я не возникали (типа, "чё за ацтой?!" :)), в меню вставить "элемент управления типа check-box", вроде "Allow user to fly any aircraft", сопровождаемый примечанием "Warning: the flight model and avionics may be grossly unrealistic!!!" :)

Noir, но не забывайте, однако, про несущий фюзеляж Сушки. У F-15 эта "фича" просматривается в значительно меньшей степени.

А почитайте :) Очень ценный материал. Заодно и про МиГ-21 в сравнении с F-5 много интересного узнаете :)

RCS: F-111 vs. Su-27 Hi Chizh, Andrew! Remember me? :) Glad to hear from you all! Guys, don’t you find it a little bit odd that F-111’s RCS is said to be 2 times greater than that of Su-27? Something just doesn’t seem right about this :)

noir> Вот всегда интересовало, почему американцы так мало применяли неплохой в общем-то самолет, который если и был хуже МиГ-21, то ненамного А вы Кондаурова внимательно читали? :)

Круто! Чиж, а "Базальт" с "Малахитом" уже переделали?

Круто!!! Народ, ну вы даете! Офигеть, даже не верится! ЗЫ: И все же вопрос есть. А все уверенны, что у Су-25 на ИЛС только прицел отображается? Странно как-то...