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

[helmutkohl]

With a maximum payload of 7,700 kilograms, the new warplane will have 10 pods for air-to-air missiles and other weapons, capable of flying at 2,200 kph with a flying range of 2,900 km.

The first flight test is scheduled for 2022, with the entire development set to be completed by 2026.

S. Korea unveils prototype of first homegrown fighter aircraft | Yonhap News Agency

By Choi Soo-hyang SEOUL, April 9 (Yonhap) -- South Korea on Friday unveiled a prototype ...

m-en.yna.co.kr

it puts it roughly in the same category as Rafale and Typhoon, but has less pylons and maybe less maximum payload
however it has the potential to use its internal bays for stealthier carriage. Based on the cutaway pics, the block 1 still has those bays (its just covered by the semi-recessed panels) and some one here said block 1 can be converted to block 2.

as for conflict with F-35 sales.. while I think there is some overlap in market.. overall I feel that the KF-21 could thrive in
(for the lack of a better word..) B-tier US allies.

Places where the US maintains good or working relations, but not super close, not enough to warrant selling the F-35 there.
So Iraq makes sense, Argentina (if they can get around UK parts), perhaps India?
Turkey would perhaps fit. maybe even Vietnam?

The problem isnt so much competition with F-35. its competition with advanced F-16 and F-15 models, which is what the US is likely to export to countries they don't quite trust with the F-35 but still wanna sell something.

and of course it potentially competes with Rafale, Gripen and Eurofighter too.

One disadvantage of KF-21 is that combat aircraft sales usually isnt just about the aircraft itself, but about defense ties and relations. This may be where KAI might be weaker when competing against US or European models.
But I do wish the KF-21 a successful career.

 

[Flyaway]

This article talks about its export potential.

South Korea rolls out the KF-21, joining elite group of global supersonic fighter jet makers | CNN

South Korea unveiled its homegrown supersonic jet fighter on Friday, joining an exclusive club of military aviation giants and setting the stage for a $5.2 billion program it hopes will be a top export driver and jobs creator.

www.google.co.uk

 

[helmutkohl]

much higher res version of the two pics from Bemil i posted earlier
and a third new one. you can see more details. may need to view the picture individually rather than through a browser

source

KF-21 º¸¶ó¸Å ½ÃÁ¦ 1È£±â µåµð¾î Ãâ°íµÇ´Ù! / ¹æ»çû Á¦°ø

< [Ãâ°í½Ä îñ ¸®Çã¼³ »çÁø] KF-X ½ÃÁ¦±â(45µµ) >< [Ãâ°í½Ä îñ ¸®Çã¼³ »çÁø] KF-X ½ÃÁ¦±â(30µµ) ><......

bemil.chosun.com

 

[RPO Rys]

I wonder how stealthy it would be, in term of fit and finish, from eyeballing it, imo this prototype looks to be close to Su-57 serial production level of fitting. I wonder if they can keep it / improve it later on during the mass production.

Is there any stealth mat/honeycomb/coating that'll be used on the block 1?

 

[Bounce]

There's no zig zagging anywhere, not even the the gear doors not a single one. I understand stealth is coming back but surely you'd have the gear doors initially?

Really good looking from most angles though, impressive.

 

[FighterJock]

There's no zig zagging anywhere, not even the the gear doors not a single one. I understand stealth is coming back but surely you'd have the gear doors initially?

Really good looking from most angles though, impressive.

That is exactly my view point as well, the lack of serrated edging is rather strange, will it be included in the full production aircraft?

 

[Combat-Master]

Interesting, didn't know that Turkish firm SDT has exported data-links to S.Korea for KFX. 19 units were exported, SDT is hopeful of follow-on orders.

 

[Frogfigther]

Wind tunnel miniature from KARI Instagram.

 

[_Del_]

Then there is the price tag and cost of sustainement.

Personal opinion is that it's going to be hard to beat the F-35 on cost (~$80 million) without several major customers. It may be slightly cheaper for procurement, but noone is going to be able to beat the combination of capability matched with advantages of a truly massive production run (and associated global logistics for sustainement). So the export market is probably limited to countries unable to get F-35.

Which is unfortunate, because from a US-centric perspective, would much rather poor money into a KFX buy-- perhaps with local production-- than throw more money at Bald Eagles (as some wit in the appropriate thread suggested) to recapitalize. And that sort of buy would be just the thing to drive the prices down for Korea and exports. I suspect between "not designed/made here" and the export-potential essentially killing legacy production/export, this would be stillborn in Congress. missed
This sort of intermediary step is exactly what the US should be looking at to recapitalize, and this was a missed opportunity to partner (as a customer beyond Lockheed design involvement).

 

[Sundog]

Personal opinion .....

The reason they decided to do this is due to how long it takes them to get spares from the U.S for the F-15s and F-16s they already have. It can take up to a year for some component/assembly replacements to become available. Now they will have much better control of that and as a result, much better control of their own readiness..

 

[_Del_]

Personal opinion .....

The reason they decided to do this is due to how long it takes them to get spares from the U.S for the F-15s and F-16s they already have. It can take up to a year for some component/assembly replacements to become available. Now they will have much better control of that and as a result, much better control of their own readiness..

Oh, it's a great opportunity for Korea.They keep their aerospace sector thriving. Creates jobs. It represents a very fine feather in their cap without being too ambitious. Since the bulk of the money is staying home, it should be sustainable as a program barring some major hiccup occurring.

It was a missed opportunity for the US, imo.

 

[RPO Rys]

There's no zig zagging anywhere, not even the the gear doors not a single one. I understand stealth is coming back but surely you'd have the gear doors initially?

Really good looking from most angles though, impressive.

That is exactly my view point as well, the lack of serrated edging is rather strange, will it be included in the full production aircraft?

Imo, the basic stealth features like zigzagging panels & stealth mat, etc should be implemented as soon as block 2. I do not see the reason of putting complex, risky to develop, intensive to test & certificate, internal indigenous weapon bay, without already thinking of other proper stealth features in mind. (Unless block 2 will be mainly used for test demonstrator for a truer stealth on block 3.)

But I like the idea of Block 1 to be the low-risk, cheaper, and more achievable project which the main purpose is be completed, mass produced, and put in-service as soon as possible.

Imo, I think if someone wants to have affordable, cheap, and easy to maintain mass-produced planes, (while still having some reduced-observability / (semi) stealth features), semi-recessed/semi-hidden hardpoints (like 4 meteor hardpoints under the KFX fuselage) is the better way to go than full-fledged internal weapon bay.

For now, I think the complex mechanism (plus extra maintenance to monitor wear and prevent the failure of moving parts) of internal weapon bay is only worth it for premium high-end aircraft.

(maybe you can even have semi-hidden hardpoints + extra internal fuel tanks instead of full internal bay. that could be nice.)

 

[Blitzo]

There's no zig zagging anywhere, not even the the gear doors not a single one. I understand stealth is coming back but surely you'd have the gear doors initially?

Really good looking from most angles though, impressive.

That is exactly my view point as well, the lack of serrated edging is rather strange, will it be included in the full production aircraft?

The macro level stealth shaping of the aircraft is obviously quite notable -- the chines, the edge alignment, the intakes -- but the panelling of the aircraft whether it's for the radome, or the landing gear bay or just general panels as part of access/maintenance or part of the aircraft's airframe lack the characteristics visible on aircraft like those of F-22/35, J-20 or Su-57 to an extent.

There's nothing wrong with that -- from the outset the KFX block 1 was meant to be an aircraft with a loaded RCS similar to that of a 4+ generation aircraft like Super Hornet or Typhoon, which by the looks of KF-21 as it is, I think will be very achievable.
KFX block 2 in the past has been said will integrate a weapons bay, and seek F-117 levels of RCS reduction. I imagine integration of a weapons bay and some limited alterations in panelling and selective RAM application may achieve that.
KFX block 3 in the past has said will aim for F-35 levels of RCS reduction. I suspect all of the EO sensors, gun port, antennae, and all of the panelling, edges, etc, would have to be appropriately modified with more stealthy housings, and the panelling of the aircraft may appear more "traditionally serrated" that we expect out of current 5th generation aircraft.

All in all, it looks very sensible and consistent with what has been suggested for KFX in the past.

 

[trose213]

Not sure if there's really a market for a $65 million+ dual engine fighter with questionable avionics and ITAR. Would probably just be better off buying Gripens.

 

[stealthflanker]

On subject of KF-21's RCS.

KF-X RCS 관련해서 - 군사 마이너 갤러리

출처 : 항공우주를 향한 꿈과 도전 - 항공우주산업(주) 20년사 항공기 저피탐 해석 개념도에서 발췌한, 지금까지 한국항공우주산업에서 유일하게 공개된 전투기 RCS 해석 자료입니다. 2016년 6월 KF-X RCS/I

gall.dcinside.com

The link however seems not mentioning the frequency where it was measured/taken. Eyeballing it will only reveal that it has some -20 dB RCS across 0-60 degrees angle. But without frequency information Or disclosure from Korean Authority themselves on what kind of RCS they want to achieve. It would be difficult to draw any conclusion.

I do make my own estimates but i feel they're bit on the optimistic side and very limited.

 

[sferrin]

Any idea why the F-22 style intakes rather than diverter-less?

 

[zhuravlik]

Sferrin, I was asking myself the very same question: after all KAI implemented DSI onto T-50...

 

[overscan (PaulMM)]

It would make sense if optimised for Mach 1.8 - 2.5 as DSI is less efficient above Mach 1.6 - 1.8. Seems unlikely though.

 

[overscan (PaulMM)]

Sferrin, I was asking myself the very same question: after all KAI implemented DSI onto T-50...

????

 

[Blitzo]

Sferrin, I was asking myself the very same question: after all KAI implemented DSI onto T-50...

... Did they? AFAIK neither the T-50 and F/A-50 uses DSIs.

It would make sense if optimised for Mach 1.8 - 2.5 as DSI is less efficient above Mach 1.6 - 1.8. Seems unlikely though.

It could simply be that DSIs required additional R&D to get right and it wasn't yet ready and the fixed caret intake was adequate for their requirements.

 

[overscan (PaulMM)]

Quite possibly. It contributes to the strong impression that it's a mini F-22.

 

[Blitzo]

Quite possibly. It contributes to the strong impression that it's a mini F-22.

Indeed. The TAI TFX may also end up adopting an intake that is caret fixed rather than DSI.


I for one am somewhat pleased that there will be multiple aircraft designs in the near future that will have similar configurations to each other.

I think defense watchers have been too spoiled in recent decades in their understanding of what differentiates aircraft from one another -- seeing multiple aircraft of similar superficial appearances means they have to put more effort into truly differentiating the different capabilities each aircraft offers in the same way that people in the WWII era would have had to differentiate between the many types of "single propeller engine driven monoplane" combat aircraft.

 

[zhuravlik]

D'oh, what a blunder, confused T-50 with JF-17. Also the barn door verticals contributes to the strong impression that it's a mini F-22. I wonder what its abilities are with regards to AoA.

 

[quellish]

stealth mat

I am curious, what is "stealth mat"?

 

[_Del_]

Any idea why the F-22 style intakes rather than diverter-less?

Probably the same reasons variable geometry of various forms have been used for wings beyond fixed geometry. Greater efficiency across a wider envelope than the fixed DSI tailored to a specific regime.

 

[overscan (PaulMM)]

stealth mat

I am curious, what is "stealth mat"?

Stealth materials for millennials short on time?

 

[Frogfigther]

In KAI's RFI,
RAM will be applied to wing skins and vertical/horizontal tail skins, and RAS to S-Duct, leading edges, and flaperons, rudders.
Their performance would be -30 db for center frequency in X-band, and -10db for >4.2 Ghz bandwidth including X-band. Also, it is required to have -7db for some segment of C-band and Ku-band.
ITO coating will be applied to KF-21's canopy, and FSS Radome to its radome.

Source

쉘든의 밀리터리 : 네이버 블로그

blog.naver.com

전투기 적용 RAM 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 캐노피 물질 및 코팅기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 Material Transition 물질 및 적용기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기 적용 RAS 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모

 

[helmutkohl]

Sferrin, I was asking myself the very same question: after all KAI implemented DSI onto T-50...

actually I had the reverse question.
rather than thinking why there's no DSI on the Korean aircraft
why did the Chinese decide to put DSI on just about anything? J-10S? J-20, FC-31, etc
as far as future fighter goes.. most of the US 6th gen proposals don't have DSI
Airbus FCAS doesn't, Dassault FCAS does
BAe Tempest seems like it doesnt (it has that forward angle intake but doesnt have the bump)
TFX doesnt

 

[TomcatViP]

I would regard the KF-21 intakes as some of the most sophisticated among non-US airframe. IMOHO for example they have embedded effectors.
They really put the focus on it to have high Mach and frontal stealth. That inherent A2A potential could well be a market magnet.

 

[tequilashooter]

-20 -30 decibels guesses, considering the source I received on PAK-DA I will go with a lower than -50 decibel guess.

 

[helmutkohl]

on a random note

I've seen all kinds of translations of Boramae like flying hawk, leaping hawk, etc

it should really be Goshawk. if you google 보라매, you will get mostly these

 

[Deino]

on a random note

I've seen all kinds of translations of Boramae like flying hawk, leaping hawk, etc

it should really be Goshawk. if you google 보라매, you will get mostly these

At Twitter I got a very kind correction and explanation where someone told me that "Boramae is not Young Eagle. It's kind of falcon but trained to be Hunting Falcon from young. But also referring Young Falcons as well."

via

https://twitter.com/x/status/1380302701041307653

View: https://twitter.com/netchan1129/status/1380302701041307653

 

[helmutkohl]

on a random note

I've seen all kinds of translations of Boramae like flying hawk, leaping hawk, etc

it should really be Goshawk. if you google 보라매, you will get mostly these

At Twitter I got a very kind correction and explanation where someone told me that "Boramae is not Young Eagle. It's kind of falcon but trained to be Hunting Falcon from young. But also referring Young Falcons as well."

via

https://twitter.com/x/status/1380302701041307653

View: https://twitter.com/netchan1129/status/1380302701041307653

uh oh, the Swiss Bank is on to you!

 

[helmutkohl]

A comparison of the FC-31/J-31 and KF-21

couldn't find a good side pic of the revised FC-31, so using a mock up.
just to compare the basic design as these two aircraft are most likely the most similar to each other

likely same weight class, same engine class, likely same bay size, etc

which would you choose?

 

[Archibald]

View attachment 654718

A comparison of the FC-31/J-31 and KF-21

couldn't find a good side pic of the revised FC-31, so using a mock up.
just to compare the basic design as these two aircraft are most likely the most similar to each other

likely same weight class, same engine class, likely same bay size, etc

which would you choose?

Oh boy... remember in Red storm rising when, in the fight to retake Iceland, MiG-29s tangle with Hornets ? the two of course being so similar in shapes... weird things happen.
Those two are headed the same way !

 

[overscan (PaulMM)]

View attachment 654718

A comparison of the FC-31/J-31 and KF-21

couldn't find a good side pic of the revised FC-31, so using a mock up.
just to compare the basic design as these two aircraft are most likely the most similar to each other

likely same weight class, same engine class, likely same bay size, etc

which would you choose?

KF-21 has better engines...

 

[stealthflanker]

In KAI's RFI,
RAM will be applied to wing skins and vertical/horizontal tail skins, and RAS to S-Duct, leading edges, and flaperons, rudders.
Their performance would be -30 db for center frequency in X-band, and -10db for >4.2 Ghz bandwidth including X-band. Also, it is required to have -7db for some segment of C-band and Ku-band.
ITO coating will be applied to KF-21's canopy, and FSS Radome to its radome.

Source

쉘든의 밀리터리 : 네이버 블로그

blog.naver.com

전투기 적용 RAM 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 캐노피 물질 및 코팅기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 Material Transition 물질 및 적용기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기 적용 RAS 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모

Thanks. That's really enlightening. Seems my estimate looks reasonable for the KF-21's Then

this assumes no engines, no RAM's and no multiple reflections and those phenomenon observable in lower frequencies and i havent put the IRST's. This is from X to VHF. tho the exact frequencies might be different.





The table (median is used for simplified presentation)

just to compare the basic design as these two aircraft are most likely the most similar to each other

They do. the J-31 is basically what KFX Block-2 and potentially AMCA would be. Improved shaping and stuff but unlikely to use DSI.

 

[Frogfigther]

In KAI's RFI,
RAM will be applied to wing skins and vertical/horizontal tail skins, and RAS to S-Duct, leading edges, and flaperons, rudders.
Their performance would be -30 db for center frequency in X-band, and -10db for >4.2 Ghz bandwidth including X-band. Also, it is required to have -7db for some segment of C-band and Ku-band.
ITO coating will be applied to KF-21's canopy, and FSS Radome to its radome.

Source

쉘든의 밀리터리 : 네이버 블로그

blog.naver.com

전투기 적용 RAM 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 캐노피 물질 및 코팅기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기의 RCS 감소를 위한 Material Transition 물질 및 적용기술 개발에 대한 참여 기관 ( 업체 ) 공모
전투기 적용 RAS 개발 및 전투기 운용 시 유지보수기술 개발에 대한 참여 기관 ( 업체 ) 공모

Thanks. That's really enlightening. Seems my estimate looks reasonable for the KF-21's Then

this assumes no engines, no RAM's and no multiple reflections and those phenomenon observable in lower frequencies and i havent put the IRST's. This is from X to VHF. tho the exact frequencies might be different.



View attachment 654719

The table (median is used for simplified presentation)

View attachment 654720

just to compare the basic design as these two aircraft are most likely the most similar to each other

They do. the J-31 is basically what KFX Block-2 and potentially AMCA would be. Improved shaping and stuff but unlikely to use DSI.

Ah, there might be some misunderstanding. The requirement is applied to RAM&RAS, not the fighter itself.

 

[tequilashooter]

hmm is the RCS graph more of a I designed it myself or from an official KFX source?

 

[red admiral]

On the comparisons with F-35 and other aircraft, does anyone know what the internal payload bay capacity is? They look pretty small to me i.e. maybe 4 x AMRAAM-size weapons, but looks challenging to carry air-to-surface weapons or much of a mixed load.