KAI KF-21 Boramae (KFX Korean Indigenous Fighter program)

With the right sort of marketing the KF-21 will be an attractive purchase for countries put off from buying the F-35 for various reasons.
 
Scott Kenny said:
Agreed. The KF-21EX is going to dominate the market among those nations not buying F-35s.
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I wouldn't make that claim just yet, especially with the Turks moving quick with their KAAN, which may be a more attractive offer to countries who seek a heavier option.

Ultimately however the KF-21 is limited to the western aligned market, which has already been largely served with the F-35. And while I can imagine that some may opt for both to complement each other, I think the predominant market will be South and South East Asia, but many countries there are budget limited.

So while I think the KF-21 will find export customers, especially in Asia, I wouldn't go as far as predicting market dominance, especially with a rival design on the horizon. And it certainly won't break into the market consisting of countries that are historically aligned with the east, where Su-57, J-35 and in the future Su-75 will fill the niche.
 
Nx4eu said:
KF-21 in its current form still has strings attached to the US as well with the F414 engines.
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I assume that the South Koreans are working on an indigenous turbofan engine to replace the F414.
 
NMaude said:
I assume that the South Koreans are working on an indigenous turbofan engine to replace the F414.
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There is potential for this - see:

www.asianmilitaryreview.com

South Korea’s DAPA and MOTIE to collaborate on aircraft engine development - Asian Military Review

South Korea’s MOTIE and DAPA are collaborating to develop advanced engines for next-generation fighter jets and UAVs.
www.asianmilitaryreview.com www.asianmilitaryreview.com

That said, I wouldn't expect anything soon and fully expect the F414s to be used for now. In fact the above article says that any alternate engine won't be until the late 2030s.
 
Desertfox said:
The Koreans should team up with Mexico or Brazil and set up a Latin America focused production line.
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For what market? Brazil has just introduced the JAS-39E/F which will be their primary fighter platform for decades to come. I don't believe the Mexicans will be interested for the small number of aircraft they may select to replace their F-5E/Fs.
 
trose213 said:
Probably pick up what the Gripen would've got
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That doesn't make sense. If anything the Gripen is enjoying a resurgence with its E/F versions with Sweden, Brazil, Thailand and now Ukraine signing up. Arguably the KF21 falls into a gap whereby people who want something high end are going for the F-35 and those who want something simpler are going for the Gripen or other options including the F/T-50s or even second hand platforms.
 
NMaude said:
I assume that the South Koreans are working on an indigenous turbofan engine to replace the F414.
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There's far more than just GE's F414 engines in the KF-21. Collins Aerospace provides the electrical power generation system, the environmental control system, the engine starters. PTI provides the aerial refueling system. General Dynamics provides the 20mm gun. Eaton provides the hydraulics and stores management systems. Curtiss-Wright provides critical avionics systems etc.

Basically without US approval, KF-21 can't fly, can't fight and can't do much. You could rip it all out, but that would be starting almost from scratch.
 
how does Korea make the bulkheads for KF-21? Do they have an hydraulic press big enough to forge titanium for the airframe?
 
GTX said:
For what market? Brazil has just introduced the JAS-39E/F which will be their primary fighter platform for decades to come. I don't believe the Mexicans will be interested for the small number of aircraft they may select to replace their F-5E/Fs.
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The way I imagined the demand for KF-21 is that its for those countries that the US is generally friendly with but not close enough to want to sell the F-35 (but might be okay with selling US parts used in the KF-21.
i.e. Thailand, Indonesia, UAE, Qatar, etc

Some stretches might be Vietnam or some of the wealthier stan countries that are trying to diversify their inventory like Uzbekistan or Kazakhstan.

overall not a particularly large list, and the countries above likely to make rather small orders.
Kaan likely competes with those markets, even though it is a larger/heavier plane.
 
https://twitter.com/x/status/1980878798041280601
1761243240.jpg 1761243240 (1).jpg


Taurus Systems' Proposal:

The system will be manufactured in Korea. The entire missile, from the structure to the engine, will be developed and manufactured without ITAR restrictions. Furthermore, the initial design and analysis work has been completed, and ground launch testing is scheduled to begin within the next 18 months. Integration onto any aircraft is expected for three years thereafter.

We plan to propose and provide this product for the FA-50/KF-21, with initial integration planned for the FA-50 and subsequent integration onto the KF-21.
 
synetic said:
Taurus Systems' Proposal:

The system will be manufactured in Korea. The entire missile, from the structure to the engine, will be developed and manufactured without ITAR restrictions. Furthermore, the initial design and analysis work has been completed, and ground launch testing is scheduled to begin within the next 18 months. Integration onto any aircraft is expected for three years thereafter.

We plan to propose and provide this product for the FA-50/KF-21, with initial integration planned for the FA-50 and subsequent integration onto the KF-21.
Click to expand...

So Poland could also get Taurus capability quite soon. Distributed manufacturing also a plus.
 
Geo said:
I can't help it, but the Boramae is simply gorgeous and in the EX version with IWB and ideally Korean engines it will be just perfect.
A balanced machine that, conceptually speaking, will cover the needs of most air forces in the world for many decades to come.
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It looks nice, though visually it feels a bit like a chimera. Huge vertical stabilizers, smallish nose on a chubby front just don't really match on a boxy airframe.

I can't help but feel that "balanced" in case of KF-21 means lack of almost anything outstanding. Ability to mount 4 cruise missiles with 4 meteors is somewhat unusual, but in a "wtf??" way. Tactical ALBMs are also nice, but Israel fires (and exports) them in all directions for years.

Without bays, it's simply meh for its substantial size, without any good excuse: you can get similar enough performance from a much smaller aircraft. Like, very frankly speaking, replacing KF-16 with it is almost ironic, as modern F-16V (not even something thorough like F-16E/F) delivers more, on a single engine. And while that single engine was shared betweek KF-16 and F-15K, that won't be the case anymore. And this makes it more damning: what wa the point of introducing twin F414 in this case, when you operate and continue to expand on F404 aircraft fleet?

It's a bit hard to understand what currently existing tactical issue this plane actually solves as well, and level of details(pylon) optimization seems frankly lazy.
Ok, country may lack experienced store separation aerodynamists, but not to the point where, i don't know, central drop tank was beyond reach? Single-trick comb of meteors taking entire central plane is also weird - it is really just 1970s, mig-31 and tornado adf feature.
On a fighter that with empty not-a-bay isn't even optimized for drag at that.
And notion that South Korea doesn't need anything special, tailored for national situation seems a bit questionable. Surely a small country squeezed between North Korea and China could benefit from, i don't know, optimized dispersal performance?

With bays ... better, but it'll still mostly hold true. 2035-40 world isn't 2025 one, and frankly i am doubtful F-35 will remain a privilege plane 10 years into the future.
 
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Ainen said:
Without bays, it's simply meh for its substantial size, without any good excuse: you can get similar enough performance from a much smaller aircraft.
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The KF-21 has the highest thrust to weight ratio of any fighter in the world.

The KF-21 fuel fraction is second only to the F-35A.

KF-21
Thrust: 44,000lb Empty: 26,015lb Fuel: 13,227 lb
T/W: 1.69
Fuel fraction: 33.7%

F-22
Thrust: 70,000lb Empty: 43,340 lb Fuel: 18,000 lb
T/W: 1.61
Fuel fraction: 29.3%

Gripen E
Thrust: 22,000lb Empty: 17,637 lb Fuel: 7,480 lb
T/W: 1.25
Fuel fraction: 29.8%

Rafale
Thrust: 34,000lb Empty: 21,720 lb Fuel: 10,362 lb
T/W: 1.56
Fuel fraction: 32.3%

Eurofighter
Thrust: 40,400lb Empty: 24,251 lb Fuel: 9,900 lb
T/W: 1.67
Fuel fraction: 29.0%

F-15EX
Thrust: 59,000lb Empty: 35,500 lb Fuel: 13,550 lb
T/W: 1.66
Fuel fraction: 27.6%

F-16V
Thrust: 29,400 Empty: 20,300 lb Fuel: 7,000 lb
T/W: 1.45
Fuel fraction: 25.6%

F-35A
Thrust: 43,000lb Empty: 29,300lb Fuel: 18,250lb
T/W: 1.47
Fuel fraction: 38.4%

Ainen said:
Like, very frankly speaking, replacing KF-16 with it is almost ironic, as modern F-16V (not even something thorough like F-16E/F) delivers more, on a single engine.
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That is incorrect. It is vastly superior to the KF-16. The numbers above don't lie. The KF-21 performance is exceptional.

The F-16 has a very low fuel fraction. It would need two external fuel tanks just to match the KF-21 with only internal fuel. The F-16 with two wing tanks and a four missiles can't even break the sound barrier. While the KF-21 with 4 meteor and not needing the external tanks can go TWICE as fast.

The KF-21 has a higher thrust to weight ratio than both the supercruising F-22 and Eurofighter. The F414 engine is a supercruising engine being selected for the Lockheed supercruise demonstrator. The F414 has a lower bypass ratio than both the EJ200 and F119.

It is pretty funny when people say the KF-21 can't supercruise.

The KF-21 photos already show the space for the internal weapon bays. No major redesign is needed. Add 1,000lb to the empty weight for the doors and the number are still exceptional.

Ainen said:
And while that single engine was shared betweek KF-16 and F-15K, that won't be the case anymore. And this makes it more damning: what wa the point of introducing twin F414 in this case, when you operate and continue to expand on F404 aircraft fleet?
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You highlight the advantage of the KF-16 and F-15K sharing engines. Korea is thinking long term. Fast forward 20 years and both the FA-50 and KF-21 will use the same Korean indigenous engine. They will have similar cockpit layouts creating a nice high-low combination. The Gripen and Tejas have both moved from the F404 to F414. I can see the FA-50 moving from the F404 to the Korean F414 replacement.

A small air force might have T-50 and FA-50 combo, a larger air force might have a T-50 and KF-21 combo. Having the same engines and cockpits helps with training.

I still think Korea needs a major European partner and this would help gain access to an ITAR free engine. This would then rapidly increase the export potential.
 
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insidersource said:
The KF-21 has the highest thrust to weight ratio of any fighter in the world.

The KF-21 fuel fraction is second only to the F-35A.
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It's more informative to compare Thrust/Weight ratios at combat mass with payload. Similar with fuel fraction.

I've been very skeptical of the published 11,800kg empty mass for KF-21 and what it includes. Comparing with Rafale/Typhoon/Super Hornet as other fighters with twin F414 class engines then there really isn't much extra mass in KF-21 despite the fact that it has a much larger fuselage. I wouldn't be surprised if a like with like comparison ended up adding another 1,000kg onto the empty mass.

At the same point then T/W comparisons only go so far. Many air vehicle performance metrics come down to Thrust minus Drag. There's a lot more drag from the larger fuselage of KF-21 (profile and skin friction). This will be particularly the case in the supersonic flight regime given the much larger cross sectional area and hence lower fineness ratio leading to higher wave drag.
 
insidersource said:
The KF-21 has the highest thrust to weight ratio of any fighter in the world.

The KF-21 fuel fraction is second only to the F-35A.
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We probably should operate the first number at combat weight, not at empty, and overall - giving fuel/engine, adding TSFC, is more relevant.
Though it's more of a hindsight, it's not something we are in disagreement in, rather that i see overly high T:W outside of context exactly as a downside. I see KF-21 as significantly overengined - i.e. expensive to operate, - for what it is. It is most certainly not a purpose made interceptor, and it isn't a carrier aircraft either, at least per original intention. What for is so much thrust if there is no way to use it?
Achieving same results on F404s, together with doing more pylon optimization, would've been more acceptable.

For fuel fraction - very careful choice of fighters; it will only truly apply to F-22 (which is notably known for insufficient range).
Gripen E, while less to empty (as if that matters), carries more per same engine. And really all others carry way more through drop tanks (and conformal tanks as well, for americans). F-35A (the only one on the list which is indeed intented to operate mostly w/o drop tanks) - has far more both per weight and per engine, and as such it somehow has more pylon flexibility as well (against non-lo aircraft this is bonkers).
All - including F-35! - are more flexible with their outer suspension points, too; KF-21 really suffers because of that meteor-specific conformal suspension, which takes all the centerplane (good 1/3 of available store real estate) and doesn't let anything else.

It, together with excessive T:W, could've been alright if KF-21 was designed primarily as an interceptor (again, mig-31 and tornado ADV), but it is just not the case.

insidersource said:
That is incorrect. It is vastly superior to the KF-16. The numbers above don't lie. The KF-21 performance is exceptional.

The F-16 has a very low fuel fraction. It would need two external fuel tanks just to match the KF-21 with only internal fuel. The F-16 with two wing tanks and a four missiles can't even break the sound barrier. While the KF-21 with 4 meteor and not needing the external tanks can go TWICE as fast.
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But it also has just one engine. And there is nothing wrong with going conformal and/or supersonic tanks (and dropping them).
This is often treated as some significant downside, when it's a flexibility point, which exactly lets aircraft in KF-21 class(medium) to reach out into heavy fighter task area. Or, alternatively, light-medium class - into medium (KF-21) area.
insidersource said:
The KF-21 has a higher thrust to weight ratio than both the supercruising F-22 and Eurofighter. The F414 engine is a supercruising engine being selected for the Lockheed supercruise demonstrator. The F414 has a lower bypass ratio than both the EJ200 and F119.
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Static thrust? Sure.
Again, we already talked about it. No, bypass by itself isn't measure of supercruise, it's measure of exactly that - bypass (in case of F414 - size to fit F-18E/F the supercruiser).
F414 isn't chosen for "Lockheed supercruise demonstrator", it's chosen for NASA quiet supersonic flight demonstrator, and it will operate at full reheat. "Cruise" doesn't just mean supercruise.
insidersource said:
It is pretty funny when people say the KF-21 can't supercruise.
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I think we already have a su-57 thread where people fight against windmills and fighter OEM statements. KF-21 was never even claimed to supercruise...
It is indeed optimized for a low drag configuration, not unlike Typhoon. But for some reason it's done in such a cruel way, that lets even Typhoon look efficient at stores management. And of course, typhon comes without a 0.4x1.0x4.2m box of useless parasitic drag, which isn't even used to carry fuel...
insidersource said:
You highlight the advantage of the KF-16 and F-15K sharing engines. Korea is thinking long term. Fast forward 20 years and both the FA-50 and KF-21 will use the same Korean indigenous engine. They will have similar cockpit layouts creating a nice high-low combination. The Gripen and Tejas have both moved from the F404 to F414. I can see the FA-50 moving from the F404 to the Korean F414 replacement.
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The problem is time; KF-21 is already going to be in this state for the first... 1/3, at least, of its effective lifecycle. At worst it can be half.
In blk 1/2 form, it has severe pylon limitations: out of 11 points, 1 is targeting poid only; 4 are single trick meteor ponies; outer 2 are light(WVR); internal fuel carriage is better than some competition, but nowhere near enough to consistently work without drop tanks).
Which means, that for anything but PD intercept/air superiority profiles/direct proximity strike, it has effectively two available payload pylons.
Which is effectively a Gripen E/Tejas 2 - or, indeed, F-16 territory, and these actually get more flexibility in this arrangement.

All of this will change into a right direction when bays go online, yes. And yes, Korea is certainly very prudent in moving carefully, especially with KAF being quite comfortable with "good enough" capability bar (which it indeed certainly achieves, and it overall isn't a low bar for 2025-35 timeframe). But how carefully and meticuously? It's ultimately public money and a long period, in a very combustible neighborhood which can explode within these 5-10-15 years; this isn't just due dilligence.

Final, competitive product will be effectively a different airplane, many years and whole cycle of development(and, quite possibly, delays) later. Expectation of future engines moves the goalpost of target efficiency even further still(and, of course, it comes with additional risks).
Honestly, in more communist countries this pace of progress and return per money would arguably lead to high treason charges.
 
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GTX said:
That doesn't make sense. If anything the Gripen is enjoying a resurgence with its E/F versions with Sweden, Brazil, Thailand and now Ukraine signing up. Arguably the KF21 falls into a gap whereby people who want something high end are going for the F-35 and those who want something simpler are going for the Gripen or other options including the F/T-50s or even second hand platforms.
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The Gripen "resurgence" will be more impressive when there is a sale to a new customer (not already a Gripen user) or someone not desperate for anything they can get.
 
Vanessa1402 said:
Is it just me or KF-21 seem to have smaller radar than F-35 despite being the bigger aircraft?
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The KF-21 is the smaller aircraft. The F-35A has a 13% heavier empty weight, 17% heavier MTOW and has 38% more internal fuel volume.

A 6 foot tall 80kg track and field athlete is smaller than a 120kg 5 foot 10 tall body builder.

The KF-21 is a skinny aircraft compared to the F-35. The aircraft length of KF-21 will provide better transonic performance. This combined with Being "overengined" with "excessive T:W" makes it the closest aircraft to the F-22.
 
insidersource said:
The F-16 with two wing tanks and a four missiles can't even break the sound barrier.
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In that configuration, an F-16C Block 52 i.e. the same engine Korea uses, has a drag index of 85. Weight fully fuelled is 30k lbs (Greek version, but Korean is probably very close).
In my excel file, I have noted a top speed of 1.72 Mach for such an F-16. Might not be 100% accurate, but clearly very much supersonic. ;) Btw. the Block 50 reaches M1.8 in the same configuration.

Maybe you confused the F-16 with the F-18. Vipers are not Hornets, they're actually supersonic fighters. :p
 
insidersource said:
The KF-21 has the highest thrust to weight ratio of any fighter in the world.

The KF-21 fuel fraction is second only to the F-35A.

KF-21
Thrust: 44,000lb Empty: 26,015lb Fuel: 13,227 lb
T/W: 1.69
Fuel fraction: 33.7%

F-22
Thrust: 70,000lb Empty: 43,340 lb Fuel: 18,000 lb
T/W: 1.61
Fuel fraction: 29.3%

Gripen E
Thrust: 22,000lb Empty: 17,637 lb Fuel: 7,480 lb
T/W: 1.25
Fuel fraction: 29.8%

Rafale
Thrust: 34,000lb Empty: 21,720 lb Fuel: 10,362 lb
T/W: 1.56
Fuel fraction: 32.3%

Eurofighter
Thrust: 40,400lb Empty: 24,251 lb Fuel: 9,900 lb
T/W: 1.67
Fuel fraction: 29.0%

F-15EX
Thrust: 59,000lb Empty: 35,500 lb Fuel: 13,550 lb
T/W: 1.66
Fuel fraction: 27.6%

F-16V
Thrust: 29,400 Empty: 20,300 lb Fuel: 7,000 lb
T/W: 1.45
Fuel fraction: 25.6%

F-35A
Thrust: 43,000lb Empty: 29,300lb Fuel: 18,250lb
T/W: 1.47
Fuel fraction: 38.4%


That is incorrect. It is vastly superior to the KF-16. The numbers above don't lie. The KF-21 performance is exceptional.

The F-16 has a very low fuel fraction. It would need two external fuel tanks just to match the KF-21 with only internal fuel. The F-16 with two wing tanks and a four missiles can't even break the sound barrier. While the KF-21 with 4 meteor and not needing the external tanks can go TWICE as fast.

The KF-21 has a higher thrust to weight ratio than both the supercruising F-22 and Eurofighter. The F414 engine is a supercruising engine being selected for the Lockheed supercruise demonstrator. The F414 has a lower bypass ratio than both the EJ200 and F119.

It is pretty funny when people say the KF-21 can't supercruise.

The KF-21 photos already show the space for the internal weapon bays. No major redesign is needed. Add 1,000lb to the empty weight for the doors and the number are still exceptional.


You highlight the advantage of the KF-16 and F-15K sharing engines. Korea is thinking long term. Fast forward 20 years and both the FA-50 and KF-21 will use the same Korean indigenous engine. They will have similar cockpit layouts creating a nice high-low combination. The Gripen and Tejas have both moved from the F404 to F414. I can see the FA-50 moving from the F404 to the Korean F414 replacement.

A small air force might have T-50 and FA-50 combo, a larger air force might have a T-50 and KF-21 combo. Having the same engines and cockpits helps with training.

I still think Korea needs a major European partner and this would help gain access to an ITAR free engine. This would then rapidly increase the export potential.
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Internal fuel fraction is fine but KF-21 is lack of central fuel tank pylon

ex) KF-21 : Internal fuel + 2 X 480Gal

other 4 and 4.5th gen fighters : Internal fuel + 3 X EFT
 
Ainen said:
Like, very frankly speaking, replacing KF-16 with it is almost ironic, as modern F-16V (not even something thorough like F-16E/F) delivers more, on a single engine.
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I don't know how many times I have to reiterate this, but the main fleet the KF-21 is replacing is ROKAF's F-5s. not KF-16s. There are a handful of F-16 PBs in the mix, but the actual replacement of KF-16s will come in the late 2030s, ie EX, KF-XX, of whatever it will be called then
 
yes, but looks legit:

iu
 
Concerning the weapons bay, I thought I saw it somewhere in this thread (but perhaps not) that the bay dimensions were 4 m long (or was it 4.25 m) and 50 cm wide. (The image was a shot of the plane with someone painting dimensions underneath it in comparison to known dimensions). But then I saw the below Jane's link earlier today suggesting that a missile with a length of 4 m but a width of 95 cm would be for internal storage.

That makes me wonder if it's a single bay like the F-22 vs. the individual bays (like the F-35) that we seen in the graphics images.

Or perhaps is the 50 cm figure perhaps the height and each individual bay is closer to a meter.

On weight measurements 2,000 kg would fit the idea of 2 x GBU-31 JDAMs, but I imagine they'd want 2 of these cruise missiles in there, not 1?

Am I just overthinking it, has anyone else got any thoughts?


www.janes.com

ADEX 2025: Taurus unveils new missile for internal weapons bays of stealth aircraft

Taurus Systems has unveiled a new air-launched cruise missile that is capable of being carried internally in a future variant of the Korea Aerospace Industries (KAI)...
www.janes.com www.janes.com

Taurus Unveils New Missile for Internal Weapons Bays of Stealth Aircraft - DEFCROS News

Taurus unveiled its KASOM missile, designed for Korea's KF-21 fighter, at ADEX 2025, featuring a reduced size and weight.
news.defcros.com news.defcros.com

www.edrmagazine.eu

ADEX 2025 – Taurus advances KASOM development - EDR Magazine

Taurus Systems showcased at ADEX a mock-up of the KASOM, a scaled down version of the original Taurus, providing details on the programme
www.edrmagazine.eu www.edrmagazine.eu
 
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Quite frankly and looking at another well known east asian stealth fighter, I don't think dropping the gun further down the line would be overly controversial. It's certainly an option that's not fully out of the question, if that's what needs to be done to make room for more effective payload.
 
EmoBirb said:
Quite frankly and looking at another well known east asian stealth fighter, I don't think dropping the gun further down the line would be overly controversial. It's certainly an option that's not fully out of the question, if that's what needs to be done to make room for more effective payload.
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Given how...unnatural this bag looks in this structure, i think it was always the plan.
 
Ainen said:
Given how...unnatural this bag looks in this structure, i think it was always the plan.
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That is not the plan at all.

The current ammunition magazine is simple, reduces development time, eliminates jamming as the bullet feed is straight and uses the empty space perfectly.

The KF-21 also has 480 rounds while the FA-50 has only 205 rounds. The KF-21 is replacing the KF-5 fleet so it needs lots of bullets and doesn't need stealthy weapons bay.

The KF-21 has plenty of space to fit 200+ rounds and still have two 2,000lb bombs. People are trying to find ways of hating on the KF-21. The F-35A only carries 180 rounds. The Gripen only 120 rounds.

The ammunition feeds often twist, change direction and go into a circular barrel. With the KF-21 instead of going across the bay there are multiple of obvious solutions to this problem.
 

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