Korea KF-X/ IF-X (KF-21) program

[Baljak]

(English subtitles are supported)
Video source: Defense Acquisition Program Administration

The first flight preparation process of the KF-21 revealed by the pilot of the flight test of the Korean fighter KF-21, which is about to fly for the first time. Check out KF-21's dignified appearance now, which will be on the runway after more than 2,000 simulations.

 

[Isa Khan]

 

[Baljak]

KF-21 successfully completed the engine test followed by the low speed ground run test (Ramp Taxi). Notice the KF-21 that emerged from the hangar.

KF-21 engine test

I'm sorry for the delay in updating the Korean military news. I'm so busy these days...

 

[TechNamu]

Thanks, mate. I appreciate it. However, I honestly don't think highly of KF-21.

KF-21 will

1) have about the same payload with F-16 (about 7,700kg / 17,000 lb)
2) probably have a high maintenance cost as the aircraft has two engines (vs. F-16)
3) have shorter Ferry Range than F-16V (2,900km with two drop tanks vs 3222km with two drop tanks)

Korea should have built a single jet engine, KFX-E (C501). It would have been more practical & cheaper to run & maintain only with 1000lb less payload which is not much anyway. I am baffled by ROKAF's decision of going for a twin-engine configuration for this size of aircraft.

 

[Windchime]

Not sure how obvious it was since you replied to this specific quote

Clearly I was talking about hypothetical KF-21 Block III, the 5th gen fighter aircraft and I plainly explained my reservation as KF-21's seemingly lack of internal fuel in contrast to F-35 will limit KF-21 Block III's role as a stealth multirole combat aircraft and that's why ROKAF is already considering a new platform, KF-XX.

If you were not interested in discussing the potential upgrade of KF-21 as a LO~VLO aircraft then I don't understand why you even bothered commenting on internal fuel as you and I both understand that non-stealth KF-21 will carry drop tanks & long-range missiles externally for those missions anyway.

I strongly implied the improvements that are required to evolve KF-21 into a true 5th gen fighter aircraft may need various structural changes and may be nearly impossible or too impractical for KAI/ROKAF to undertake. Meanwhile, avionics are also challenging, but they are doable and I doubt you'd disagree with this.

However, you claimed

That baffled me as things such as structural limitation are equally if not more challenging than implementing advanced avionics to turn KF-21 into a true 5th gen fighter.

However, I believe It was all due to a simple misunderstanding. I was talking about turning KF-21 into a 5th gen stealth combat aircraft. You were talking about maximising KF-21's capability as a 4.5 multirole combat aircraft.

Edit : I will stop here too as It is indeed getting irrevelant to the thread's topic.

I think moving the conversation to this thread makes sense as we both agree that it doesn't belong in the MMU thread.

No, you were not wrong with your assumptions, as in I was also talking about 5th generation iteration of the KF-21.

The biggest differences in our opinion lies on "if the fuel capacity is enough for a hypothetical 5th gen KF-21", or Block III as most of us call it. My answer is yes, I think it is, based on the missions fulfilled by current and future medium weight fighter fleets of the ROKAF - DCA, ground strike and SEAD, albeit being limited on which missions it could fulfill on full-stealth configuration.

Since the Block III, be it and upgrade to the existing Block II aircrafts or a completely new variant as a replacement for KF-16, is essentially a medium weight fighter, my best chance in predicting what this hypothetical Block III would do was to make an educated guess based on preceding medium weight fighters.

You on the other hand think the fuel capacity of current KF-21 is insufficient for it to become an effective 5th gen fighter, which also makes sense.

Now what we were really misunderstanding with each other's arguments was what needs to change.

For me, a 5th gen KF-21 is an aircraft using the same airframe with new avionics suite. It would retain some components like the AESA but would need to relocate or even add completely new avionics system like ICNI, internally. To get the EMC/EMI certification, this would effectively turn the Block III development program into a development of a quasi-new plane (although using the same airframe), since such extensive EMI/EMC change would better be done from scratch.

To you, any 5th gen development would first and foremost need an increased fuel capacity compared to KF-21. By your assertions, it is true that the biggest limitation of KF-21 is its airframe structure and change to it would be accompanied with extensive rework (or even clean sheet) from KF-21 to KF-XX, almost to the point of completely redesigning an aircraft (or in case of a clean sheet design, it is simply a new design), ala Super Hornet from Hornet or Hornet from Tiger. By that it is true that the aircraft structure, or a redesign thereof is also the biggest challenge.

 

[TechNamu]

I think moving the conversation to this thread makes sense as we both agree that it doesn't belong in the MMU thread.

No, you were not wrong with your assumptions, as in I was also talking about 5th generation iteration of the KF-21.

The biggest differences in our opinion lies on "if the fuel capacity is enough for a hypothetical 5th gen KF-21", or Block III as most of us call it. My answer is yes, I think it is, based on the missions fulfilled by current and future medium weight fighter fleets of the ROKAF - DCA, ground strike and SEAD, albeit being limited on which missions it could fulfill on full-stealth configuration.

Since the Block III, be it and upgrade to the existing Block II aircrafts or a completely new variant as a replacement for KF-16, is essentially a medium weight fighter, my best chance in prediciting what this hypothetical Block III would do was to make an educated guess based on preceeding medium weight fighters.

You on the other hand think the fuel capacity of current KF-21 is insufficient for it to become an effective 5th gen fighter, which also makes sense.

Now what we were really misunderstanding with each other's arguments was what needs to change.

For me, a 5th gen KF-21 is an aircraft using the same airframe with new avionics suite. It would retain some components like the AESA but would need to relocate or even add completely new avionics system like ICNI, internally. To get the EMC/EMI certification, this would effectively turn the Block III development program into a development of a quasi-new plane (although using the same airframe), since such extensive EMI/EMC change would better be done from scratch.

To you, any 5th gen development would first and foremost need an increased fuel capacity comoared to KF-21. By your assertions, it is true that the biggest limitation of KF-21 is its airfram structure and change to it would be accompanied with extensive rework, almost to the point of completely redesigning an aircraft, alla Super Hornet. By that it is true that the aircraft structure(or a redesign thereof) is also the biggest challenge.

I think we should evaluate the internal fuel capacity of KF-21 by comparing KF-21 with other 5th gen aircrafts that are already in service & development. Almost all of them have a large airframe to internally accomodate both a sufficient amount of fuel and weapons since engineers understand that the aircraft can't use drop tanks in a mission which requires a full-fledge stealth capability. Almost every single one of them is designed to carry more fuel than KF-21. If KF-21 could perform an aerial interception mission with seemingly little internal fuel, the engineers who design other 5th gen aircrafts have not done their job properly.

I will take HAL AMCA for example. Even though It is a slightly larger combat aircraft, It employs the same engine with KF-21 with the same twin-engine configuration. It is designed to carry 6,500kg of fuel internally. It is not much better than KF-21, but that's still a gap of almost 1,100kg of fuel and AMCA is designed to carry only 1500kg of weapon interally. That's not much and I believe HAL AMCA will be abale to perform a very limited role as an interceptor aircraft in the full stealth mode.

Now KF-21 is slightly smaller and carries significantly less fuel internally.

What would be a combat radius of KF-21 Block III? How much of payload that KF-21 could realistically carry internally?

Can we seriously argue that KF-21 could eventually evolve in a true 5th gen aircraft?

I believe ROK has made too many compromises and ended up with a 4.5th gen aircraft that is too small and no potential of becoming a practical 5th gen combat aircraft. Korean should be honest with themselves.

I concur that KF-21 Block II will be good enough for the future aerial warfare. Howeve, if the country is serious with building a true 5th gen combat aircraft, then she needs an entirely new airframe. Perhaps that's why ROKAF already considers moving to the KF-XX project.

 

[Windchime]

I think we should evaluate the internal fuel capacity of KF-21 by comparing KF-21 with other 5th gen aircrafts that are already in service & development. Almost all of them have a large airframe to internally accomodate both a sufficient amount of fuel and weapons since engineers understand that the aircraft can't use drop tanks in a mission which requires a full-fledge stealth capability. Almost every single one of them is designed to carry more fuel than KF-21. If KF-21 could perform an aerial interception mission with seemingly little internal fuel, the engineers who design other 5th gen aircrafts have not done their job properly.

I will take HAL AMCA for example. Even though It is a slightly larger combat aircraft, It employs the same engine with KF-21 with the same twin-engine configuration. It is designed to carry 6,500kg of fuel internally. It is not much better than KF-21, but that's still a gap of almost 1,100kg of fuel and AMCA is designed to carry only 1500kg of weapon interally. That's not much and I believe HAL AMCA will be abale to perform a very limited role as an interceptor aircraft in the full stealth mode.

Now KF-21 is slightly smaller and carries significantly less fuel internally.

What would be a combat radius of KF-21 Block III? How much of payload that KF-21 could realistically carry internally?

Can we seriously argue that KF-21 could eventually evolve in a true 5th gen aircraft?

I believe ROK has made too many compromises and ended up with a 4.5th gen aircraft that is too small and no potential of becoming a practical 5th gen combat aircraft. Korean should be honest with themselves.

I concur that KF-21 Block II will be good enough for the future aerial warfare. Howeve, if the country is serious with building a true 5th gen combat aircraft, then she needs an entirely new airframe. Perhaps that's why ROKAF already considers moving to the KF-XX project.

The thing is, those other 5th gen fighters are not primarily meant for DCA purposes but are either air dominance fighters or OCA deep strike capable. In that sense, I don't think a face to face comparison shows the entire picture.

Your point about AMCA makes more sense though and yeah, it's hard to argue against the fact that KF-21's internal fuel capacity is not enough for various multi-role missions in stealth configurations. But again, there were cases in the past like the pylon-drop tank of the F-22 which ejected not only the drop tanks but with them the pylons to retain stealth after using the external fuels. Similar practice could be employed for a stealth KF-21.

I personally don't agree on the "too many compromises" part to a full extent. Yes, they could've been a bit more ambitious, but current KF-21 as a 4.5th gen fighter is exactly what the AF asked for. KF-16 replacement for the future I think should be a separate matter.

 

[Baljak]

Thanks, mate. I appreciate it. However, I honestly don't think highly of KF-21.

KF-21 will

1) have about the same payload with F-16 (about 7,700kg / 17,000 lb)
2) probably have a high maintenance cost as the aircraft has two engines (vs. F-16)
3) have shorter Ferry Range than F-16V (2,900km with two drop tanks vs 3222km with two drop tanks)

Korea should have built a single jet engine, KFX-E (C501). It would have been more practical & cheaper to run & maintain only with 1000lb less payload which is not much anyway. I am baffled by ROKAF's decision of going for a twin-engine configuration for this size of aircraft.

Currently, the purpose of the development of the KF-21 Block 1 and Block 2 is to replace the aging F-5 fighter jets used by the Korean Air Force, and to avoid difficulties in maintenance during wartime by localizing aircraft parts. In 2011, 1500 parts for the F-16 were discontinued, and in a few years it will be difficult to supply and demand parts for the F-16 from the United States. As you know, the KF-21 Block 0, which is currently assembled, is shaped like a simple fourth-generation aircraft. When KFX's development began in 2015, research and development began based on the C103 configuration.

After KAI received the drawings for C103, C104, and C105 from ADD, each made an experimental model and conducted a wind tunnel test. Later, research and wind tunnel testing were conducted on the new design of the C107, which was larger in size and increased in max take-off weight. Finally, in 2018, the design configuration of the KF-21 was decided on the C109 proposed by ADD and KAI. The C109 has many advantages in changing its design to the fifth generation fighter, which will be named the C110 or C111.

The South Korean Air Force's decision to use twin engines for the KF-21 and its choice of Semi-Recessed Weapon Bay are for the fifth-generation fighter jets that will be redesigned after 2028. South Korean Air Force is currently considering redesigning the KF-21 Block 2 as a fifth-generation fighter, with the aim of developing a fighter jet capable of full stealth capability and joint operations with an unmanned fighter (KUS-FC) squadron.

At this point, it still takes a lot of research and development to call the KF-21 the 4.5th generation fighter, and there is still a lot of time left to develop the KF-21 Block 2 with various hard points added. The KF-21 development program is undergoing a phased development process, and the ultimate goal is to develop a fifth-generation fighter jet with adequate economic feasibility and performance to operate in a Korean environment.

 

[Windchime]

Thanks, mate. I appreciate it. However, I honestly don't think highly of KF-21.

KF-21 will

1) have about the same payload with F-16 (about 7,700kg / 17,000 lb)
2) probably have a high maintenance cost as the aircraft has two engines (vs. F-16)
3) have shorter Ferry Range than F-16V (2,900km with two drop tanks vs 3222km with two drop tanks)

Korea should have built a single jet engine, KFX-E (C501). It would have been more practical & cheaper to run & maintain only with 1000lb less payload which is not much anyway. I am baffled by ROKAF's decision of going for a twin-engine configuration for this size of aircraft.

Twin engine was what the ROKAF really pushed for. If the end-user sees the point of going that way, I see no reason why not to. Also a single engine KF-X was supposed to use F110-GE-132 which is used by, you've guessed it, by and only by UAE. It's only logical twin F414 is a better choice.

 

[TechNamu]

The South Korean Air Force's decision to use twin engines for the KF-21 and its choice of Semi-Recessed Weapon Bay are for the fifth-generation fighter jets that will be redesigned after 2028.

As I said on the KF-X thread, I highly doubt the hypothetical KF-21 Block III will be an effective stealth combat aircraft with the current internal fuel capacity of 12000lb. It will carry about the same of even less payload than HAL AMCA which employs the same engines. KF-21 requires a complete strucutal change to be a full stealth aircraft and will be almost like designing a new aeroplane. It will be too impractical.

Twin engine was what the ROKAF really pushed for. If the end-user sees the point of going that way, I see no reason why not to. Also a single engine KF-X was supposed to use F110-GE-132 which is used by, you've guessed it, by and only by UAE. It's only logical twin F414 is a better choice.

I understand that ROKAF wanted the twin-engine configuration, so they pushed for KF-X C109 but their reasoning was completly asinine.
It seems like Korean Air force was not satisfied with payload of F-16 and required a higher thrust-to-weight ratio combat aircraft with the hope that the fighter jet could carry more payload.

However KF-21 is designed to carry about the same weight of weapons as F-16 does.

I am not sure why you claim was supposed to use "110-GE-132". KAI's suggestion of KFX-E was any engine with maximum thrust equal or more than 29,000lb, so any GE-F110-129 variants would have been sufficient. Even if ROKAF was to choose F110-GE-132, many parts of F110 are interchangable and It is objectively cheaper to service & maintain a single-engine fighter jet than a twin-engine fighter jet.

In my opinion, It was an illogical choice then and it is still an illogical choice now.

ROKAF will be stuck with a combat aircraft that has about the same payload with F-16, but more expensive to service and operate than F-16.

 

[Windchime]

As I said on the KF-X thread, I highly doubt the hypothetical KF-21 Block III will be an effective stealth combat aircraft with the current internal fuel capacity of 12000lb. It will carry the same of even less than HAL AMCA which employs the same engines. KF-21 requires a complete strucutal change to be a full stealth aircraft and will be almost like designing a new aeroplane. It will be too impractical.



I understand that ROKAF wanted the twin-engine configuration, so they pushed for KF-X C109 but their reasoning was completly asinine.
It seems like Korean Air force was not satisfied with payload of F-16 and required a higher thrust-to-weight ratio combat aircraft with the hope that the fighter jet could carry more payload.

I find their claim absurd as KF-21 is designed to carry about the same weight of weapons as F-16 does.

I am not sure why you claim was supposed to use "110-GE-132". KAI's suggestion of KFX-E was any engine with maximum thrust equal or more than 29,000lb, so any GE-F110-129 variants would have been sufficient. Even if ROKAF were to chose F110-GE-132, many parts of F110 are interchangable and It is objectively cheaper to service & maintain a single-engine fighter jet than a twin-engine fighter jet.

In my opinion, It was an illogical choice then and it is still an illogical choice now.

ROKAF will be stuck with a combat aircraft that has about the same payload with F-16, but more expensive to service and operate than F-16.

Well, it's an unfortunate case of effective payload being not only the equation of TWR but various other factors. Though I'd still argue the increased TWR is a great thing to have, even more so considering how the F-16 flies clean and with payloads; you know the difference is quite significant, even compared to other jets of its generation.

Talking about GE-132, I was talking from my memory and you are indeed right. The proposed C501 was supposed to be powered with GE-129 or other engines in the range. In the same time, what I recall is how GE-132 was repeatedly mentioned as the most viable option for KFX-E, which also makes considering the differences between C501 and F-16. Though come to think of it, there's also the case of F-2, so it might not have been that big of a problem to use GE-129, who knows.

 

[TechNamu]

The thing is, those other 5th gen fighters are not primarily meant for DCA purposes but are either air dominance fighters or OCA deep strike capable. In that sense, I don't think a face to face comparison shows the entire picture.

Your point about AMCA makes more sense though and yeah, it's hard to argue against the fact that KF-21's internal fuel capacity is not enough for various multi-role missions in stealth configurations. But again, there were cases in the past like the pylon-drop tank of the F-22 which ejected not only the drop tanks but with them the pylons to retain stealth after using the external fuels. Similar practice could be employed for a stealth KF-21.

I personally don't agree on the "too many compromises" part to a full extent. Yes, they could've been a bit more anbitious, but current KF-21 as a 4.5th gen fighter is exactly what the AF asked for. KF-16 replacement for the future I think should be a separate matter.

I don't think KF-21is designed to be equipped with the pylon-drop tank and I don't think KAI has any plan to do so in the future. Even ROKAF and KAI decide to implement the change, I don't honestly see any benefit. Korea is relatively a small country and surrounded by three marginal sea, yet potential adversaries operate a fleet of AWACS & many ground & naval radar systems that cover those areas. So when would this hypothetical KF-21 Block III have to drop its pylon-drop tank without being detected by any hostile radar system? If I remember correctly, North Korean's S-200 once even managed to identify a flying SR-71 and tried to shoot it down (of course it failed).

Citizens who are often swayed by nationalistic sentiment demanded the government to persue a 5th gen aircraft to compete with PRC and Japan and ROKAF wanted basically a Korean Rafale when reality was that KAI & ROK had no ability to build both a 5th gen fighter jet and a Korean Rafale. The most of the early project assessments concluded that KF-X had no financial merit, but politicians were pressured to persue the KF-X as a vote winner and the compromise was reached - a 4.5 gen combat aircraft that is designed to evolve into a full stealth aircraft in the future when any rational human being should have known the plan to upgrade the KF-X into a 5th gen fighter jet was just a lip-service and nearly impossible task.

 

[Windchime]

I don't think KF-21is designed to be equipped with the pylon-drop tank and I don't think KAI has any plan to do so in the future. Even ROKAF and KAI decide to implement the change, I don't honestly see any benefit. Korea is relatively a small country and surrounded by three marginal sea, yet potential adversaries operate a fleet of AWACS & many ground & naval radar systems that cover those areas. So when would this hypothetical KF-21 Block III have to drop its pylon-drop tank without being detected by any hostile radar system? If I remember correctly, North Korean's S-200 once even managed to identify a flying SR-71 and tried to shoot it down (of course it failed).

Citizens who are often swayed by nationalistic sentiment demanded the government to persue a 5th gen aircraft to compete with PRC and Japan and ROKAF wanted basically a Korean Rafale when reality was that KAI & ROK had no ability to build both a 5th gen fighter jet and a Korean Rafale. The most of the early project assessments concluded that KF-X had no financial merit, but politicians were pressured to persue the KF-X as a vote winner and the compromise was reached - a 4.5 gen combat aircraft that is designed to evolve into a full stealth aircraft in the future when any rational human being should have known the plan to upgrade the KF-X into a 5th gen fighter jet was just a lip-service and nearly impossible task.

Obviously I'm talking about the case of "if they need the capability, there's a precedent". Also drop tanks coupled with ejecting pylons are still a great feature to have, considering CAP situations and such. What matters is the signature in combat range of BVR. Once they're coordinated into combat airspace by GCI or AEW&C, they could drop it and still enjoy the same benefits as to taking off without any drop tanks in the first place; Unless you're shooting it maddog, the adversary still has to lock you with their FCR anyways regardless of if they detected those KF-21s.

Calling KF-X a result of purely political decision sounds a bit to far off I'd say. Most importantly, said plan(by ADD) of evolving this jet into 5th gen was officially dropped just as/before the development started.

 

[TechNamu]

Well, it's an unfortunate case of effective payload being not only the equation of TWR but various other factors. Though I'd still argue the increased TWR is a great thing to have, even more so considering how the F-16 flies clean and with payloads; you know the difference is quite significant, even compared to other jets of its generation.

Talking about GE-132, I was talking from my memory and you are indeed right. The proposed C501 was supposed to be powered with GE129. In the same time, what I recall is how GE-132 was repeatedly mentioned as the most viable option for KFX-E, which also makes sense to me, considering the differences between C501 and F-16. Though come to think of it, there's also the case of F-2, so it might not have been that big of a problem, who knows.

I agree that TWR is a great thing to have, but It is not much important as payload & combined fuel capacity (internal + external) as the most of aerial combat between fighter jets is taken in BVR and I am sure you know that. I wouldn't have minded if ROKAF & KAI had sacrificed a bit of "stealth capability" & TWR in exchange for increasing effective payload & combat range of KF-21.

 

[TechNamu]

Obviously I'm talking about the case of "if they need the capability, there's a precedent". Also drop tanks coupled with ejecting pylons are still a great feature to have, considering CAP situations and such. What matters is the signature in combat range of BVR. Once they're coordinated into combat airspace by GCI or AEW&C, they could drop it and still enjoy the same benefits as to taking off without any drop tanks in the first place; Unless you're shooting it maddog, the adversary still has to lock you with their FCR anyways regardless of if they detected those KF-21s.

Calling KF-X a result of purely political decision sounds a bit to far off I'd say. Most importantly, said plan(by ADD) of evolving this jet into 5th gen was officially dropped just as/before the development started.

I can see your argument. However, I'd imagine you are talking about a hypothetical situation that ROK has better surveillance assets than potential hostile countries and Korean AWE&C and radar systems detect a fleet of enemy aircrafts before the engagement and pass over the information to KF-21 pilots so they could jettison drop tanks and start a BVR aerial combat. Is this correct?

 

[Windchime]

I can see your argument. However, I'd imagine you are talking about a hypothetical situation that ROK has better surveillance assets than potential hostile countries and Korean AWE&C and radar systems detect a fleet of enemy aircrafts before the engagement and pass over the information to KF-21 pilots so they could jettison drop tanks and start a BVR aerial combat. Is this correct?

Yes, it is indeed correct. And judging by your post that I'm replying to, I guess you are talking about the potential situation where the PLAAF is attacking across the Yellow Sea or from the North with J-20 or the next generation Chinese naval fighter?

 

[TechNamu]

Yes, it is indeed correct. And judging by your post that I'm replying to, I guess you are talking about the potential situation where the PLAAF is attacking across the Yellow Sea or from the North with J-20?

Yes, as well any potential mission in against JASDF in East Sea of Korea. You know PLAAF and JASDF have better aerial & naval surveillance and reconnaissance assets than Korea both in qaulity and quantity.

I am curious if KF-21 is designed to safely take-off & land with max. payload at Ulleungdo & Heuksando Airports which are currently in construction. Moreoever, is there any maritime patrol aircraft that has a take-off & landing distance less than 1,200m?

 

[Windchime]

Yes, as well any potential mission in against JASDF in East Sea of Korea. You know PLAAF and JASDF have better aerial & naval surveillance and reconnaissance assets than Korea both in qaulity and quantity.

I am curious if KF-21 is designed to safely take-off & land with max. payload at Ulleungdo & Heuksando Airports which are currently in construction. Moreoever, is there any maritime patrol aircraft that has a take-off & landing distance less than 1,200m?

Their C4ISR capabilities being better than ROKA's as well as their stealth fleet being bigger than ROKAF's is surely a problem, but I'd still say there's a viable case against their legacy fleet, especially the Chinese J-10s and Flankers, in which a stealth KF-21 with drop tanks could be coordinated accordingly to engage in favorable conditions.

Talking about their stealth assets, or more specifically the Chinese J-20s and stealth naval fighters, well I couldn't say much other than that the ROKAF should rely on their own counter-stealth assets, most notably the F-35 or the L-band MESA on Peace Eyes, etc. Let's hope those assets could provide enough early warning, though I should say I'm quite confident at least based on known information.

Talking about KF-21 operations from Ulleungdo and Heuksando on their respective airports, I'd say it's going to be hard, especially in terms of landing the plane. Since I don't have any take-off or landing distance related information concerning KF-21 in hand, I've used Super Hornet data from NATOPS. SH notably has heavier MTOW and a different wing area but it's still a good comparison imo. Take off on MTOW with moderate condition is already going to be impossible; the runway is a bit too short, even on an attempt to take off from end to end. I'd guess it ain't gonna be much of a different tale for the KF-21. It'll need to forgo of some payload or fuel. Landing is even harder - borderline impossible in most cases, especially with munition. Add to that, we need a longer runway than the required take-off and landing distance to cope with varying conditions. Since these are islands, there's always going to be the case of a tailwind. The most important problem would be to have an infrastructure on those airports to support tactical operations. That would be another kind of a problem apart from the physical limits.

Talking about MPAs that could operate on those airports, I'm not sure, but to my knowledge, those airports are not really suitable to support any military operation unless it's STOL, STOVL or VTOL anyways.

 

[Isa Khan]

<KF-21 Boramae's first flight was successful! >

Today (19th) at 16:13 a Korean-style fighter (KF-21, Boramae) succeeded in its first flight! The test flight was conducted by Major General Ahn Jun Hyun, a test flight pilot of the Air Force 52nd Test Evaluation Unit. Since the release of April 1, the Korean-type fighter aircraft in April 2021, through various ground tests and the June 2022 First Flight Preparation Review Meeting (FFRR), confirmed that the first flight was ready. The first flight took off from the base at 15:40 and landed at 16:13.

 

[Baljak]

I agree that TWR is a great thing to have, but It is not much important as payload & combined fuel capacity (internal + external) as the most of aerial combat between fighter jets is taken in BVR and I am sure you know that. I wouldn't have minded if ROKAF & KAI had sacrificed a bit of "stealth capability" & TWR in exchange for increasing effective payload & combat range of KF-21.

KF-21 is not a stealth fighter. Although several technologies have been applied to the current prototype for limited stealth functions, KF-21 is to develop a Middle-class or Middle-high-class fighter that can completely replace the F-16 of the Korean Air Force.

The KF-21 research and development project also aims to build technology for the 5th generation fighter jets to be developed in the future, and if it was simply economical or inexpensive, it would have been better to improve the F-16.

What the Korean Air Force wants now is a fighter jet that can freely supply and demand parts during wartime without being obsessed with operating costs. Currently, even the simple maintenance of the F-5 and F-16 fighter jets of the Korean Air Force cannot be done without the participation of American engineers or the permission of the U.S. government. The development of the KF-21 is one of the independent fighter development processes for Korea to escape technology dependence on U.S. parts.

There is a possibility that the problem with the design and performance of KF-21 that you mentioned will not be improved in Block 2 or 3. Currently, only Block 3 exists in the Korean Air Force's plan, and after that, it is considering developing 5th or 5.5th generation fighter.