Problem is that there is no engine in given thrust range of AMCA (110 KN), as all other 5th gen programs in the world are heavy weight and AMCA is the only one in medium weight range.
PAK-FA / Sukhoi Su-57 - Updates and Discussions
- Thread starter Ashwin
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Let’s take advantage of this free time to further critique the J-20 in this thread.
China possesses a vast territory, and its core historical military threat originated from the southeastern maritime vector. The primary threats included cruise missiles launched from bombers via optical/guided flight vectors, submarine-launched cruise missiles, and cruise missiles fired from the direction of Japan and the Philippines. Note that I say 'historical
'; today, the greatest vulnerability is actually the fragile maritime energy supply lines, though this is not something military hardware alone can salvage. The outcome of the Cold War thoroughly proved that even the US Navy—the most powerful maritime force on earth—cannot break a blockade enforced by Iran’s cheap, land-based guided weapons. But that’s a separate topic, so let’s not diverge.
Because of these maritime threats, China's fighter development has always prioritized the 'interceptor' doctrine—from the J-8 and J-10 all the way to the J-20. High-speed, high-altitude interception has consistently occupied the absolute top priority.
In the 1990s, when buying blueprints from a collapsing Soviet Union, a fatal error was made due to extreme budget constraints. Russia was actually willing to export the MiG-31 interceptor back then. However, crippled by severe fiscal hardship, the military ultimately chose to import the Su-27, primarily prioritizing its massive payload capacity as a crucial asset for taking Taiwan. Later, as China's economy improved, Russia's economy also recovered, and the window of opportunity to acquire the MiG-31 closed forever.
Thus, lacking a dedicated MiG interceptor in the inventory, China’s so-called fourth-generation fighter (classified under the framework modeled entirely after the US) was mandated from its inception to possess formidable interception capabilities. This aligns with the core, traditional mission assigned to the PLAAF since its decades-long inception—a deeply ingrained institutional mindset. Consequently, the aircraft was never designed for dogfighting. This explains why close-in combat configurations—such as internal cannons or thrust-vectoring engines—are practically non-existent. Even the IRST is mounted underneath the nose, creating a total blind spot for close-in dogfights. The reason for this downward placement is glaringly simple: it is optimized for high-altitude flight above 10,000 meters to look down and detect low-flying Tomahawk missiles over the sea. Furthermore, the PLAAF historically never trains for within-visual-range (WVR) dogfights anyway.
The J-20's fuselage is also noticeably more elongated than its spiritual predecessor, the MiG 1.44. This structural elongation deliberately sacrifices maneuvering agility to gain higher cruise and top speeds—a necessary compromise given that it was saddled with obsolete powerplants like the AL-31F or WS-10. Official narratives boast that it can achieve supersonic cruise. If so, it was undoubtedly bought at a catastrophic cost. Otherwise, why didn't the Russians achieve this with the AL-31F, or the Americans with the F110 (which is effectively the authentic version of the WS-10)?
In a genuine air-to-air engagement, there are ample grounds to suspect that the J-20 would lose to a Su-35. Once the four medium-range air-to-air missiles in its main belly bay are depleted without securing a definitive kill, the J-20 will inevitably find itself in a nightmare scenario: its escape velocity will be inferior to the Su-35's, leaving it to be hunted down, while in close-in maneuvering, it remains at an absolute disadvantage. Its downward-facing IRST will be completely useless in a dogfight, rendering the pilot functionally blind. To make matters worse, the Su-35 carries a far larger missile loadout than the J-20, This discussion assumes the Su-35S is not equipped with the R-37.
An aircraft like the J-20 is utterly suppressed by the Su-57. In the face of Russia's authentic, high-performance engines and straight-through intakes, raw kinetic dominance crushes all sophisticated gimmicks. All the desperate design compromises the J-20 made just to compensate for its woefully lagging powerplants will be exposed as a complete joke.
Compared to the Su-57, the J-20 suffers from the following fatal weaknesses:
1. Impoverished Sensor Suite: Its detection methods are far too limited, and it completely lacks L-band arrays.
2. Inferior Beyond-Visual-Range (BVR) Engagement: In a long-range missile duel, the J-20's four PL-15s are comprehensively overwhelmed by the Su-57's four R-37Ms. Beyond the well-known disparity in kinematics and range, the more critical vulnerability stems from the missile caliber, which dictates both terminal hit probability and seeker lock-on distance. Missile radar seekers follow the exact same physics rules: assuming identical electronic capabilities and detection thresholds, doubling the radar seeker’s aperture area increases the theoretical tracking range against the same target by 41%. Consequently, the 380mm diameter of the R-37M yields a staggering 260% increase in theoretical seeker tracking range compared to the 203mm diameter of the PL-15.
3. Defenceless Close-In Combat: It cannot win in a close-range dogfight.
4. Zero Escape Velocity: If it tries to run, it simply cannot escape.
5. Lacking Multi-Role Versatility: The Su-57’s robust anti-ship and land-attack strike capabilities are entirely beyond the J-20's reach.
6. Inferior Operational Readiness: In terms of daily sortie rates, the Su-57 will naturally reign supreme.
If you dare to say these things on Chinese forums, you’ll be labeled a "dog raised by the Russians"、"5-ruble dog" (analogous to China's "0.5-RMB dog"—referring to the 5-ruble wage earned for each post).
or "Gangyi’s house slave" (Gangyi刚毅----referring to a well-known Chinese fan of the Russian military).
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Why would 4 BVR missiles of J20 be depleted without securing a confirmed kill? Is this a normal occurrence in modern air combat?
Well, perhaps you can elaborate on that a bit.
Aerodynamics would be used by all jets to compensate thrust via C-D duct, ramps, speed, ram effect, etc.
Higher spool RPM = higher OPR = higher temp.
When TET & other parts temp limits are approached then spool RPM is limited.
IDK if their version of FADEC would increase spool RPM or add more fuel, but temperature, pressure, density, speed, all are inter-connected, depicted by Isentropic formulas.
But as per Brayton Cycle, temperature should as high as possible, limited only by materials.
So if Russians improved on materials then they should not have problem to thermodynamically compensate the thrust.
Air-to-air missiles are by no means guaranteed killers.
In 2024, in Ukraine, there was a case where an Su-34, carrying four FAB-500 bombs and operating under Russian ground command, performed aggressive evasive maneuvers and successfully dodged three Patriot missiles. When the first Patriot was detected, it was 80 km away from the Su-34, flying at an altitude of 25,000 meters and a speed of 4,000 km/h. In the end, the Su-34 returned to base with only proximity blast damage, while the Patriot's hit probability, blast radius, and speed are all greater than those of missiles like the PL-15.
俄军苏34成功规避乌军三枚爱国者导弹拦截
2024年7月，俄军一架苏34战斗机被乌军发射三枚爱国者防空导弹拦截，在地面和空中指挥下，最终苏34通过机动，成功躲避了这三枚导弹的追杀，整个过程惊心动魄，堪称经典。（抖音：普雷恩知识说） #俄乌战争##武器装备##国际军事#
k.sina.com.cn
For standard air-to-air missiles with calibers between 150 and 203 mm, against targets with a radar cross-section of 3 to 5 square meters, the officially claimed lock-on range is only 15 to 20 kilometers — this provides ample conditions for evasion.
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This is anecdotal evidence, not empirical evidence. You have made an empirical conclusion that 4 Pl15s will be depleted without making a kill in most cases. Hence you need to present empirical evidence. Please share any source for lock on range of 15-20 km for targets with 3-5 sqm RCS. Are you referring to aircraft radar lock on range, or missile terminal seeker lock on range? Missile terminal seeker lock on range of 20 km is not bad, and is expected too. It doesn't mean in anyway that Su57 will be able to dodge 4 PL15s.Air-to-air missiles are by no means guaranteed killers.
In 2024, in Ukraine, there was a case where an Su-34, carrying four FAB-500 bombs and operating under Russian ground command, performed aggressive evasive maneuvers and successfully dodged three Patriot missiles. When the first Patriot was detected, it was 80 km away from the Su-34, flying at an altitude of 25,000 meters and a speed of 4,000 km/h. In the end, the Su-34 returned to base with only proximity blast damage, while the Patriot's hit probability, blast radius, and speed are all greater than those of missiles like the PL-15.
This consists of the live recording combined with a post-event breakdown created by a netizen.俄军苏34成功规避乌军三枚爱国者导弹拦截
2024年7月，俄军一架苏34战斗机被乌军发射三枚爱国者防空导弹拦截，在地面和空中指挥下，最终苏34通过机动，成功躲避了这三枚导弹的追杀，整个过程惊心动魄，堪称经典。（抖音：普雷恩知识说） #俄乌战争##武器装备##国际军事#
For standard air-to-air missiles with calibers between 150 and 203 mm, against targets with a radar cross-section of 3 to 5 square meters, the officially claimed lock-on range is only 15 to 20 kilometers — this provides ample conditions for evasion.
This is a spreadsheet I made a few years ago; just ran a quick machine translation on it.↑
Furthermore, this so-called "20 km search range" refers to a 50% acquisition probability within a narrow conical sector. It does not mean you can simply draw a 20 km circle on a 2D map, like in a video game, and achieve a 100% lock-on.
By the way, the R-77-1 has a minimum detectable target RCS of 0.05 square meters. That's why I said before, I can't help but laugh when I think of some people boasting that the F-22 has an RCS of 0.00000x. Of course, I didn't post the chart at the time — does that mean the ancient S-125 that shot down the F-117 had a higher detection rate than the R-77-1? Is Russia regressing technologically?
An AK magazine holds 30 rounds, but that doesn't mean it can kill 30 people.
A fighter jet carrying four missiles doesn't mean it can shoot down four enemy aircraft.
In an encounter battle between a 12-aircraft Su-27 flight and a 12-aircraft F-15 flight, the combined mathematical expectation of losses on both sides would be less than five aircraft (based on 1992 technological levels).
Going on a rampage in the skies only exists in video games.
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Ok fine, even if we agree with this, I think this is under ideal conditions of no networked warfare. Real world combat conditions, especially the Ind-Pak or Ind-Sino encounters won't be like that. The fighter will be able to launch their missiles at much longer ranges as they get guidance from other fighters, AWACS and ground based radars. Thats why Pakistanis were able to launch their AMRAAMs at 100+ KM range back in 2019.
In real combat situations, a fighter will be able to launch and guide its missiles at much longer range. I fail to understand how a Su57 will be able to dodge 4 PL15s, when, with all its supermanuverability, it is less manuverable than the missile, and that gap between the maneuverability of fighter and missile is only going to increase.
My interpretation of the data is entirely different from yours. Look at your air conflict with Pakistan last year: both sides mobilized anywhere from 100 to 200 combat sorties combined—excluding support aircraft—pulling every tactical maneuver in the book for 1 hour and 20 minutes straight. God knows how many missiles were spammed into the sky, yet the final confirmed aerial kills didn't even hit double digits. To make it worse, over half of those downings were actually the handiwork of ground-based air defense systems. these loss rates do not even account for the Western nations, nor do they factor in the massive, inevitable fratricide rates experienced by Russia in the ongoing Ukraine war. Even under the most meticulous command and control coordination, this friendly-fire ratio has historically never dropped below 20%.
That alone speaks volumes.
The cold, hard reality is that the actual probability of kill (PK) for air-to-air missiles against modern fighter jets is notoriously abysmal.
Furthermore, look at the Ukraine theater. There is an abundance of footage showing Su-35s conducting 4-missile ripple fires. Have you ever seen a single one of those salvos successfully taking down an F-16 or a MiG-29 in one go? By your logic, is the Su-57’s survivability somehow inferior to an F-16?
This is exactly what I mean by the 'dialectical thinking' .
This is an official Soviet Air Force combat attrition study. Since the original document is in Russian, the literal translation can be quite dry and heavily nuanced, but you're welcome to feed it into an AI to decipher the technical jargon yourself.
To sum it up, the study models a 12-aircraft Su-27 regiment deployed entirely in an interceptor configuration. Their mission is to intercept a strike package consisting of 4 pure-air-combat configured F-15As and 10 F-15Es (carrying 1/3 air-to-air payload and 2/3 air-to-ground payload), all operating under the tactical superiority of an E-3 AWACS (which provides a 20% baseline advantage over the Soviet command network).
The 12-aircraft Su-27 regiment splits into a 6+6 formation to simultaneously engage the 4 F-15As and 10 F-15Es. According to the final mathematical expectation, the Soviet forces will destroy 4.13 combat potential units of F-15s (which, according to Table 2.2, converts to actual airframes based on specific range profiles, translating to roughly 1 to 2 F-15s shot down). In return, the Soviet side suffers a loss of 1.84 combat potential units of Su-27s (referencing Table 2.2, meaning no actual airframes are completely destroyed, but rather damaged).
This data alone is more than enough to expose the abysmal real-world lethality of air-to-air missiles
If this kind of internal military simulation were ever turned into a video game, it would undoubtedly flop and go completely unnoticed—simply because it would be too incredibly boring. You have 12 Su-27s clashing with 14 F-15s, and the final attrition expectation turns out to be that minuscule? It fails completely to deliver that dopaminergic rush of single-handedly dominating the skies. Yet, the tragic reality is that the vast majority of people form their entire understanding of military aviation from these high-octane video games and cinematic blockbusters
My point is that missile maneuverability has significantly improved from the time this document was written. Aircraft maneuverability hasn't improved that much and can't improve that much. So such documents aren't relevant today.
But I don't think we have an updated document from the current decade.
The improvement of a missile's maneuverability depends primarily on its 'specific impulse' (Isp). Specific impulse essentially defines the theoretical chemical energy density of the rocket motor's propellant. Regrettably, the specific impulse of solid fuels is notoriously low, with tactical and strategic missiles alike—ranging from portable man-portable systems to the Topol-M ICBM—stuck between 230 and 290 seconds. In sharp contrast, liquid kerolox engines routinely exceed 320 seconds, while hydrolox fuels can soar past 450 seconds.
This is a hard boundary governed by the laws of physics. It is a fundamental bottleneck in chemical engineering that has remained unbroken for nearly forty years.
In other words, without massively increasing the missile's launch weight, it is physically impossible to achieve greater throwing capacity (payload \times range). This capacity can be converted into enhanced maneuverability through structural design—for instance, adopting a star-grain or cone-shaped solid propellant geometry to maximize the burning surface area, thereby sacrificing raw range in exchange for explosive terminal speed and acceleration. Furthermore, generating higher lateral g-forces requires strengthening and thickening the missile airframe, which further penalizes the dry mass fraction.
Ultimately, because propulsion technology has stagnated, a missile's true kinetic maneuverability and effective range have seen no material breakthroughs. In reality, the heavily marketed 'extended ranges' of modern missiles rely almost entirely on dual-pulse or multi-pulse rocket motors—which actually reduce initial launch and cruise velocities to prolong burn time—or by utilizing highly lofted ballistic trajectories
Yet, none of these methods fundamentally enhance a missile's true kinetic range or maneuverability. At the end of the day, when it comes to missiles, bigger is always better.
A larger diameter directly translates to a superior radar aperture, a maximized propellant burning surface area, and explosive acceleration. Consequently, the highly advertised '150+ km' ranges of missiles like the PL-15 or the AIM-120D—including ramjet-powered variants like the Meteor—are largely kinematic illusions built on data manipulation.
Under real-world combat conditions, these numbers possess a massive element of technical deception
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Then, in subsequent mass-produced variants, they switched to a lower-grade copycat version of the F110, and continued to use it on the so-called sixth-generation prototype.
The Chinese use the al 31FM2 and used for atleast 4+ years. From what I know the initial versions of the ws-10 were trash so the al-31 has been reliably used for atleast a full decade for j-20 testing and production. The rd-33 very similar(slightly bigger) than the ge-414. Let's not forget that ge-414 is not a stealth engine either.
Now for all purposes it is good enough especially the sea wasp Rd-33mk. Both the AMCA and TEDBF can be built on the rd-33mk. Apart from the f-22's f-119 there's not a single engine that is truly fifth gen or aircraft that is fifth gen.
Also we are not US, China or Russia. We are stuck at 2000-3000$ gdp per capita. Our baseline capabilities don't allow us to make a fifth gen engine. War is fought on economics we don't have the money of technical capabilities right now. Even Iran is a richer economy than us so is Turkey and SoKo.
Use the rd-33 mk till Kaveri 2 or ge-414 gets online you can make TD's based on both Kaveri and Ge-414 once the deliveries start.
Modern Air warfare basically is having the biggest radar and the longest range missile that you can lob into enemy airspace. We saw the same in Russia-Ukraine we saw the same in Op Sindoor and the same thing has happened in Iran.
When Iran can use f-5's to bomb American airbases what is stopping us from using rd-33mks to make AMCA or MCA or TEDBF.
The mig 29 pretty much has the best kinematics in the IAF after the MKI. The IAF kebabkhors actually think they will get top of the line American tech to shove in the AMCA and take 2 decades to pump one aircraft out of the production line per year.
Having the rd-33 mk allows us to lower cost and speed up or delivery speed. In fact the rd-33mk has fadec like the ge-404(which was the primary reason IAF didn't want Russian engines the mig 29upg RD-33 series 3 doesn't have fadec but the IN mig 29k rd-33mk has fadec)
What kind of silo the IAF is living in only God knows.
We are an enemy state for the Americans. It must now become a priority to de link every major defence program from the Americans.
The MiG‑35 actually has the strongest thrust‑to‑weight ratio among all active‑duty fighter jets, and the J‑35’s prototype, the FC‑31, also uses the RD‑33, but the production version is an inferior copy (the WS‑13).
But isn't the CFM-56 superior in terms of efficiency than Russian engines. It's so ironic that US ,France and China have there entire aerospace industry based on this one single engine.
How are they inferior? We know that Chinese mtbf is between 300-600 hours as compared to rd-33's 3000-4000 hrs.
Its around 40G for all modern BVR missiles. You can't change physics, and there is no breakthrough to maintain the structural integrity of missiles.