Su-27 high AoA flight curve
It has little to do with high AoA capabilities.
The standard Su-27 has a baffle in the air intake to block foreign objects. When the aircraft taxis, the baffle rises. The auxiliary air intakes on both sides and the bottom of the air intake are opened. The Su-27SM either cancels the baffle or only takes in air through the auxiliary air intakes on the side.
It is worth mentioning that the auxiliary air intake design was retained in the early PAK FA prototype.
1 Like
Вероятно, новые Су-27СМ изготовлены на основе остававшегося на КнААПО производственного задела по планерам самолетов Су-27СК от приостановленного лицензионного контракта с КНР. При этом машины оснащены новыми двигателями АЛ-31Ф-М1 (АЛ-31Ф серии 42) производства ММПП «Салют», отличающимися повышенной до 13 500 кгс тягой и увеличенным ресурсом, и новыми комплексами оборудования и вооружения – даже более совершенными, чем применяемые на поставлявшихся до сих пор модернизированных Су-27СМ.
Как рассказал в интервью нашему журналу минувшей осенью генеральный директор ОАО «НИИП им. В.В. Тихомирова» Юрий Белый, «в конце сентября состоялся первый успешный пуск с поражением цели модернизированной ракетой с борта опытного самолета Су-27СМ3. Для применения этой ракеты на повышенных дальностях модернизированы антенна, передатчик и канал передачи данных радиокоррекции штатной РЛС самолета. Модернизированный Су-27СМ3 передан на государственные испытания». По всей видимости, новые истребители выпущены как раз в таком варианте. Одновременно с доработками радиолокационного прицельного комплекса и введения в состав вооружения модернизированных ракет средней дальности усовершенствовано информационно-управляющее поле кабины летчика – она стала полностью «стеклянной».
http://take-off.ru/news/107-news-1-2-2011/561-su-27sm3-02-2011
According to this 2011 report, the first Su-27SM with the AL-31FM1 engine was delivered in 2011. Meanwhile, the Su-27SM3 entered the state acceptance phase. I worry that the gaijin will try to split the Su-27SM into two fighters - just like they did with the MiG-29G 9.12; or skip the Su-27SM with the AL-31FM1 and release the Su-27SM3 directly.
That is a vortex generator. 100%. It has everything to do with alpha flight. I am not talking about the baffle.
It has no bearing on the intake as you can see on the inside walls of the intake.
1 Like
В ходе испытаний в состав ОЭПС-27 была введена нашлемная система целеуказания (НСЦ) “Щель-ЗУМ”. Эта аппаратура, разработанная на киевском заводе “Арсенал” (главный конструктор А.К.Михайлик), включала нашлемное визирное устройство и блок оптической локации со сканерным устройством определения угла поворота головы летчика. НСЦ позволяла измерять координаты линии визирования при визуальном слежении за целью летчиком в зоне +60" по азимуту и от -15╟ до +60╟ по углу места при скорости линии визирования до 20╟/с, а также осуществлять наведение на цель зоны автоматического захвата ОЛС с одновременной передачей координат линии визирования цели в БРЛС и головки самонаведения ракет. Совместное использование НСЦ и ОЛС позволяло в ближнем маневренном бою сократить время прицеливания, осуществлять быстрый захват цели, обеспечивать целеуказание головкам самонаведения ракет до захода цели в конус возможных углов захвата цели головкой и тем самым осуществлять пуск ракет при максимально допустимых углах.
The HMD system directly controls the IRST, which in turn controls the radar… The OEPS-27 is integrated. This has nothing to do with whether the antenna can rotate.
1 Like
I see what you mean.
But it is also not a tool for increasing lift at high angles of attack. This is the azimuth antenna of the SPO-15 Берёза system.
3 Likes
BECAUSE its referring to IRs missiles.
if the IRST is providing designation to the homing heads directly. It is referring to the IR seekers which do not need reliance on any radar.
Yes, it is 100% even the Yak-141 has them.
They destabilize airflow for the elevators in high angles of attack.
It does not “increase lift”. That is not what destabilizers do. They delay the aircrafts point of stall.
These are SPO-15 RWR antennas
3 Likes
Antennas can be inside of aerodynamic designs. Its not exclusively one or the other. There is RWRs sensors in wings. Thats not a wing but an RWR?
It’s just SPO-15 antennas, all flankers with l-150 missing this
3 Likes
It can obviously be used to guide radar guided missiles. This is a simple membership problem (although complex to implement) but has nothing to do with the structure of the inverted Cassegrain antenna.
If you want to use the DCS Su-27 as an example, then you’d better know which parts of the DCS Su-27 module are close to reality and which parts are not. As a game, DCS also has many deviations from reality. Many features of the Su-27’s fire control system were not restored until 2.5.7 ob. And its flight control system is still using the wrong version. (Interestingly, they obviously know about this error in FM and point it out, but the game continues to use the wrong version.)
Yeah… many things have dual purposes. The Soviet Union in particular was heavily invested in simplicity & multipurpose designs. It’s kind of a cultural thing in communist society. Additionally they are the pioneers in high alpha flight. This is a standard Soviet doctrinal design in airflow destabilization again also found in the Yak-141.
I have never read any literature about the antenna fairing on the side wall of the air inlet providing lift and control gain at high AOA. Is it convenient to provide literature?
In fact, regarding the horizontal tail at high angles of attack, it should be remembered that its angle of attack is always smaller than the main wing. The control problems at high angles of attack are more from the ailerons (such as the roll reversal that often occurs in the F-14, which manifests as weak aileron control effect on fighters such as the MiG-29 and F-15). These problems can be alleviated by flaperon design, horizontal tail roll control and rudder roll control, which is also the solution used on aircraft such as the Su-27 and F/A-18.
2 Likes
Interestingly, the Chinese Su-27 variants did not remove them until the J-16. The J-11B and J-15 still use these antennas as the RWR’s goniometric antennas.
1 Like
Because they’re using their own RWR system. And decided to keep such antennas placement.
3 Likes
I do not want to use another video game.
It’s not obvious. Its rather silly when actually carefully reading the Su-27SK flight manual & carefully understanding the technology involved and the history of it.
The radar dish does not move. There is a single reflector plate enclosed inside the radar that pivots. it is reliant directing reflection of a plate at the front of the radar that is fixed & back to the main plate that moves at outward in a limited range of motion. That is why the Mig-23, Mig-29 & Su27 are severely limited in ability to scan.
These radars do not have any ability to follow the line of sight of a human being. All actual sources state that only IR missiles are utilized with the sighting rings of the HMS.
You must point the radars nose at the target so that it may be captured by the radar. There is no high off boresight radar missile capability. I am so sorry that was not a thing for the Soviet Union. It’s made up.
If you have radar weapons selected. The radars will switch on & stand-by until the target enters its FoV. All the OEPS does, if communicates the direction or angular position of the target so that the moment it crosses its view, it will track it. Then you must look at your HUD for verification & further aiming. There no frequency growl or tone like IR missiles or flashing light in the sight rings for radar missiles.
You cannot use radar weapons as if they IR missiles with the HMS. The HMS does not communicate with any radar weapons.
Because they rely entirely on the radar for guidance. Not the opto-electronic pointing station
They do not provide lift bro.
all they do besides be an antenna is provide wingtip vortices which are caught along the fuselage through the middle and right where they are caught by the elevator. They are the same fan like shape of the Yak-141. I am trying to find which other designs had them too. I will let you know.
These destabilized, energized airflows will stick to the surface of the aircraft, elevators & maintain the boundary layer allowing the elevators to continue to provide pitch at angles of attack beyond lift. This is one of many reasons the Flanker can be controlled in situations where most aircraft will deep stall & become unrecoverable.
The Su-27 & Mig-29 have numerous technologies throughout that when added together make it supermaneuverable. Of course, the Mig-29 is not the Su-27 (only because the Mig-29 did not get the same digital design treatment). But it is still the only other aircraft in the world considered supermaneuverable without the use of thrust vectoring.
It’s a fascinating aircraft. Literally nothing like the Su27 in the world.
For example the 9-15 utilized different vortex generators for its elevators. these are dogtooth extensions. The F-15 uses them too.
As for the Su-27 they are called intake strakes which are found on other aircraft such as the Mirage 2000.
Here’s some literature on the use and placement of strakes
Aircraft Vortex Generators - The Nacelle Strakes - GridPro Blog
These application are for commercial but of course gives you an idea how they apply in conbat aviation. I will bring up some more specific to the Flanker when I get the chance.
1 Like
The vortex generators of the Mirage 2000 are located above the main wing, overlapping with the main wing in projection, which can effectively delay the airflow separation on the upper surface of the main wing when flying at a high angle of attack. On the Su-27 and MiG-29, this task is completed by the wing strips.
In fact, the later Su-27 and MiG-29 families also adopted some unique ways to increase the lift at a high angle of attack to slow down the stall, such as the spoilers used by the MiG-29K and MiG-35. However, the pair of antennas of the Su-27 are too far away from the horizontal tail and their installation position is lower than the horizontal tail, so it is difficult to have much actual impact on the horizontal tail.
In my limited communication with real VKS pilots, I believe that thanks to its substantial increase in thrust and slight increase in weight, the Su-27SM/SM3 equipped with AL-31F series42 is one of the most difficult Su-27s to defeat in BFM. Perhaps only the Su-35 with greater thrust and vector thrust function has the conditions to surpass them in hardware. In Akhtubinsk, the Su-27SM piloted by experienced “Blue Army” instructors was responsible for imitating the imaginary enemy of the NATO Air Force, and conducting BFM training with more advanced fighters such as Su-30SM and Su-35. Almost no one could detect the impact of the missing antenna on the flight (of course, at least in my limited communication, they told me so). Of course, we all know that there are some problems with the gaijin’s Su-27 FM. But this is not the main point we are going to discuss.
2 Likes
The paraboloid transreflector is fixed. The twist reflector moves without feed horn. The Mech radar does not need the paraboloid transreflector to move when choosing the direction of its radiation, so it is displayed as a “hood”. In practice, it achieves this function by rotating the twist reflector on a universal joint.
In addition, in the Su-27 tactical manuals of the VVS and the PLAAF, “tactical lapel” (the action of a two-plane formation turning 45-60 degrees to the opposite side to keep the enemy aircraft on the edge of the radar STT tracking after launching SAR missiles at the enemy aircraft) is a standard tactical operation.
In addition, the Mirage 2000C’s RDM/RDI radar is an inverted Cassegrain antenna like the N001/N019. In terms of antenna composition, they have similar features. This technology is not exclusive to Soviet fighters, and the Mirage 2000 is no better (or worse) than them - one of the few things worth discussing is the Mirage 2000’s ground mapping function, which the N001 series upgraded in VP/VEP (equipped with Su-30MKK/MKK2/M2). There are reports that the Su-33’s radar has basic sea mapping capabilities, but I have no information to confirm it.
3 Likes