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

[overscan (PaulMM)]

back to the Boramae,,
something I always wanted to ask

why are AESA radars usually facing at an angle?

So they don't present a large RCS spike pointing directly forward from the non-moving antenna.

 

[Sea_Vixen]

Something I just noticed, on the KF-21, all of the safety placards/decals are in English. Is that a requirement of the South Korean air force, or is it just they have many of those due to all of the U.S. equipment they own?

its just how a lot of KAIs stuff are
even Russian aircraft, when exported, have a lot of notices/decals in English
such as

back to the Boramae,,
something I always wanted to ask

why are AESA radars usually facing at an angle?

Reduce the aircraft's frontal RCS.

Large RCS aircraft such as the F-15 didn't bother.

 

[helmutkohl]

^ Thanks you two for the explanation
I had always thought the RCS relationship was with the exterior shaping of the aircraft.
did not take into consideration the internals as well

 

[Trident]

Most of the time the aircraft surfaces are deliberately treated to ensure it indeed is the outer mold line that's effectively relevant to RCS (or they form part of absorbent RAS anyway). For example, metal-plating the outside of canopy transparencies, so they act as a reflective surface to RF energy and shield the interior from view. This approach ceases to work for antenna radomes (including but not limited to the radar, nav, comm and EW are affected too) though which obviously have to be RF-transparent to perform their function. By using a frequency-selective surface it is possible to limit the problem to one particular frequency band (the operating frequency of whatever receiver/transmitter the radome is housing). But with RF energy in the same band some other solution has to be found, for the internals will necessarily have to be exposed to it. That may include shaping (e.g. canting the antenna to divert the RCS spike into a harmless direction) and RAM to shield the antenna mounting.

 

[sferrin]

Something I just noticed, on the KF-21, all of the safety placards/decals are in English. Is that a requirement of the South Korean air force, or is it just they have many of those due to all of the U.S. equipment they own?

its just how a lot of KAIs stuff are
even Russian aircraft, when exported, have a lot of notices/decals in English
such as



back to the Boramae,,
something I always wanted to ask

why are AESA radars usually facing at an angle?

Reduce the aircraft's frontal RCS.

Large RCS aircraft such as the F-15 didn't bother.

View attachment 695049

B-1Bs is angled down.

 

[Trident]

High-flyer vs. low-flyer (relative position of the enemy RF source).

 

[sferrin]

High-flyer vs. low-flyer (relative position of the enemy RF source).

Just pointing out that the B-1B also angles it's radar.

 

[VTOLicious]

back to the Boramae,,
something I always wanted to ask

why are AESA radars usually facing at an angle?

So they don't present a large RCS spike pointing directly forward from the non-moving antenna.

Hmm, what about other shapes? Pyramid, tetrahedron,...?

 

[stealthflanker]

Hmm, what about other shapes? Pyramid, tetrahedron,...?

Such shapes, were considered as fighter radar back in the day but there are difficulties in actually forming the beam and fabrication of the array. Flat plate provides convenient space to put not only the antenna elements but also cooling and structures.

 

[Maro.Kyo]

Something I just noticed, on the KF-21, all of the safety placards/decals are in English. Is that a requirement of the South Korean air force, or is it just they have many of those due to all of the U.S. equipment they own?

Most probably coming from their experience working with LM in KTX-II/T-50 program. As an engineer who worked for the program recalled in his book, it was a "complete overhaul" in terms of how KAI manage their programs and do R&D. They've (re)learnt almost everything from A to Z and essentially 'Americanized' the way they do things. It's no surprise they would work with English.

 

[AnonSB]

View: https://www.youtube.com/watch?v=gR-iZNp3TtQ


Night time flight test (done by prototype No. 003 and 004)

 

[Umigami]

View: https://youtu.be/8yZhL2ocec0

 

[Ainen]

High-flyer vs. low-flyer (relative position of the enemy RF source).

...and sacrificing AOR downwards on a bomber of all things doesn't exactly make much sense.

 

[aonestudio]

View: https://www.youtube.com/watch?v=XHot3ZN_ZZs

 

[mkellytx]

High-flyer vs. low-flyer (relative position of the enemy RF source).

Just pointing out that the B-1B also angles it's radar.

Indeed it does, it’s also on a swivel. ISTR that we called it LOA. Any guesses what the acronym is?

The avionics shop at Dyess was in the same squadron as the engine shop, I may have seven a few of those…

 

[apparition13]

High-flyer vs. low-flyer (relative position of the enemy RF source).

...and sacrificing AOR downwards on a bomber of all things doesn't exactly make much sense.

B-1B was designed for low level penetration. It's a tree-top flyer. A really big Tornado, if you will.

 

[sferrin]

High-flyer vs. low-flyer (relative position of the enemy RF source).

Just pointing out that the B-1B also angles it's radar.

Indeed it does, it’s also on a swivel. ISTR that we called it LOA. Any guesses what the acronym is?

The avionics shop at Dyess was in the same squadron as the engine shop, I may have seven a few of those…

I knew it could move (because I'd always thought it strange that a phased array would need to) but have never known the envelope.

 

[mkellytx]

I knew it could move (because I'd always thought it strange that a phased array would need to) but have never known the envelope.

Memory fades, but it’s behind the 3-9 line. The side stare is pretty good for SAR, and pretty useful if you want to map something beyond a 90-120 degree arc pointed forward.

 

[Deltafan]

South Korea Eyeing Larger Aircraft Carrier for its CVX Program - Naval News

South Korea’s Ministry of Defense will soon begin working on preliminary policy research on the feasibility of building a 50,000-tons CVX aircraft carrier.

www.navalnews.com

(...)
This decision from the MoD has been made after carefully reviewing the research from DAPA (Defense Acquisition Program Administration) completed in January this year. In that research, DAPA concluded that developing the naval variant of KF-21 (referred to as KF-21N) is fully achievable with sufficient budget allocation and time invested into development, which accounted for 1.8 trillion KRW (roughly $1.3B) and a long ten years respectively.
This change of plans is especially important, as MoD turning towards a medium-sized carrier than current design would involve major modifications to aircrafts that are to be operated on the ship once it has been commissioned. As it turns out, it is most likely that MoD will drop the original plan of acquiring sixteen F-35B’s but rather wait for the naval variant of KF-21 보라매 (meaning ‘Falcon’ in English), an indigenous fighter jet currently in a critical testing phase.
(...)

 

[helmutkohl]

well that was really unexpected.
I think most people thought the MoD would either get F-35s to save costs, or not go with carriers complete (a reasonable choice given Korea's defense needs).

If they do go ahead, I hope this is something India can consider in the future

 

[snne]

well that was really unexpected.
I think most people thought the MoD would either get F-35s to save costs, or not go with carriers complete (a reasonable choice given Korea's defense needs).

If they do go ahead, I hope this is something India can consider in the future

If the US eases approval for possible sales to non-aligned countries, then Boramae may be the go-to aircraft choice for naval aviation-aspiring countries. It really has a relatively big sales potential.

 

[helmutkohl]

well that was really unexpected.
I think most people thought the MoD would either get F-35s to save costs, or not go with carriers complete (a reasonable choice given Korea's defense needs).

If they do go ahead, I hope this is something India can consider in the future

If the US eases approval for possible sales to non-aligned countries, then Boramae may be the go-to aircraft choice for naval aviation-aspiring countries. It really has a relatively big sales potential.

My questions regarding the Naval Boramae for export would be

• How much would it cost? I think for it to be competitive against the F-35B/C and even Rafale, it will need to be a bit cheaper. I dont even know how much the regular Boramae is estimated to cost
• Should an aspiring country that wants naval aviation capabilities even go for the Boramae, let alone the F-35B/C and Rafales? Or should it instead, consider drones. I feel by the time a naval Boramae makes it into production.. it'll be in the 2030s? There's been lots of serious push towards naval drones in recent years, and it could be more appealing due to lower costs, and easier fit on smaller carriers.

 

[kaiserd]

Which specific countries (other than South Korea itself) intends to field a CTOL carrier and would actually be in the market for a navalised KF-21, rather than having their own national aircraft or go with an buy of an existing aircraft from the US or France?
And how many aircraft would they actually wanted?
This is clearly not going to be a massive market.?

 

[helmutkohl]

Which specific countries (other than South Korea itself) intends to field a CTOL carrier and would actually be in the market for a navalised KF-21, rather than having their own national aircraft or go with an buy of an existing aircraft from the US or France?
And how many aircraft would they actually wanted?
This is clearly not going to be a massive market.?

I cant think of too many countries wanting a CTOL carrier, although this one looks like it will be a STOBAR, but either way lets list some possible ones

India - Best possibility outside of Korea. Already has 2 Stobar carriers, and based on recent reports, they may opt for another Vikrant class rather than building another new class as they've been satisfied with its trials so far. Also Vikrant is close in size to what South Korea wants to operate based on the new report (50,000 ton). India however wants TEDBEF to replace the MiG-29Ks. While I support India's initiatives to make things on their own, I think in this case, it would be better India just works with KAI and get the KF-21N. Would save time and money. HAL is already quite strained with many projects and I'd rather they focus on getting AMCA out soon. KF-21 engines should be the same as their Tejas Mk2?

Indonesia - mid possibility. Indonesia is already a partner with the KF-21 program and began resuming payments. Its a rising economy and quickly becoming a very major Asian power. Given its vast area and maritime importance, there is some possibility they may consider a carrier. I don't think its very high, but its there.

Turkey - Low possibility. Their LHD might be too small to operate it, but they may have future plans for an actual carrier. Their TFX might be too large for something a lilttle bit larger, but the KF-21 could work. They have issues with the F-35 and France will never sell them the Rafale, so KF-21 has an advantage here

Australia - Very low possibility. They've been trying to update their navy plans, and want to keep up with China's rising maritime might. They have an LHD that can accept planes.. However they seem to have significant manpower issues, and a larger carrier, or using the existing LHD plus more aircraft, would just add to that burden. But at the end of the day, I suspect that if they do end up buying naval combat aircraft, it will be the F-35B.

Singapore - Very low possibility. They are also trying to expand their navy and are even building ships that can accomodate some fixed wing aircraft. But I don't see them going any larger, and if they do.. they will go F-35B because they already have some on order.

Brazil - very low possibility. they had a carrier recently, may have an interest in restarting one in the future if funding permits. I dont see the US selling the F-35, so the Rafale or KF-21 could be viable. But given the state of the economy, probably unlikely for a while.

ultimately, I only see India as being one viable place the KF-21 could be exported to.

 

[snne]

Turkey - Low possibility. Their LHD might be too small to operate it, but they may have future plans for an actual carrier. Their TFX might be too large for something a lilttle bit larger, but the KF-21 could work. They have issues with the F-35 and France will never sell them the Rafale, so KF-21 has an advantage here

I agree with everything else (to the point that I actually wrote exactly what you said but then deleted it later) except the Turkey example.

The problem within Turkey's case is, they don't plan on buying anything except a stop-gap fighter from abroad anymore. The current planning is such that they're planning to equip the future fully fledged Trakya carrier with Kızılelma-B/-C UCAVs and maybe network them with a possible naval Hurjet. Mind you that KE is developed by a private company and they've always advertised it from the very start as an unmanned fighter, not a loyal wingman.

(If the Navy's carrier ambitions materialise) KE operating from a STOBAR deck is a given, what's not yet certain is whether it's going to be single or twin engined.

 

[snne]

How much would it cost? I think for it to be competitive against the F-35B/C and even Rafale, it will need to be a bit cheaper. I dont even know how much the regular Boramae is estimated to cost

I think in order to compete better, they'd probably offer some local assembly or production as in Poland's example. Also although it's now sold to allies like hotcakes, not everyone has access to F-35 which is one of the main selling points of this jet for foreign customers.

Think of it as a carrot to countries like the Emirates which cannot buy the F-35. The same case can be applied to Egypt, SA, possibly Pakistan, Malaysia, etc...

India - Best possibility outside of Korea. Already has 2 Stobar carriers, and based on recent reports, they may opt for another Vikrant class rather than building another new class as they've been satisfied with its trials so far. Also Vikrant is close in size to what South Korea wants to operate based on the new report (50,000 ton). India however wants TEDBEF to replace the MiG-29Ks. While I support India's initiatives to make things on their own, I think in this case, it would be better India just works with KAI and get the KF-21N. Would save time and money. HAL is already quite strained with many projects and I'd rather they focus on getting AMCA out soon. KF-21 engines should be the same as their Tejas Mk2?

Apparently they're now also planning a naval AMCA which is already concept and design-wise super similar to this aircraft.

Man, sometimes it is really hard to understand what the Indians are trying to achieve...

 

[helmutkohl]

I found a Korean article about this, and it explains a bit more detail

"KF-21N 독자개발 가능"…'한국형 항모' 막힌 혈 뚫는다 [취재파일]

방사청이 발주해 국방기술진흥연구소가 수행한 '함 탑재용 전투기 국내 연구개발 방안' 연구용역의 결과, 개발과 양산 포함 4조 1천억 원을 투입해 10년 반 만에 전력화가 가능하다고 분석된 것입니다.

news.sbs.co.kr

Basically some key points

• Total costs, including the research, development, and mass production is closer to 8 trillion won, or 6 billion USD
• They think they can do it in 10 years
• Reason is because F-35B is too expensive, and there's some issues with the Air Force being reluctant to get the B version, so this is supposedly a way around these hurdles
• Supposedly the public also supports a larger/heavier carrier
• Carrier is intended to be 50,000 tons (roughly similar to Vikrant and CdG, maybe a bit heavier), 28 KF-21N, 2 AEW aircraft, 2 Helicopters (seems a bit light on non combat aircraft)
• It sounds like they want EMALS, and will purchase one abroad (I guess this is more or less the US). The rationale is they want greater payload capabilities.

 

[Maro.Kyo]

(translated and edited by myself from the original KAI presentation slide)

There was a KAI presentation regarding business models and near-future investment plans. One of the covered topics was the KF-21 Block III and future 6th gen fighter development for KF-16U replacement.

As I've mentioned before, the ROKAF's preliminary plans for replacing the upgraded Vipers is not to go with KF-21 Block III but instead with an enlarged, 6th gen figher jet. Nothing much to talk about regarding this program since its too early. They've also disclosed what they are envisioning for the KF-21 upgrade (Block III); to some people's disappointment, ROKAF wasn't looking for internal weapons bay or VLO-ization of KF-21 but instead their main focus lay on NCW.

What's interesting is that this new presentation from KAI is pointing otherwise. KAI's vision of KF-21 block III seems closer to a full-fledged 5th gen fighter based on the existing KF-21 block II, as it was promised from the beginning. I'm not sure in which direction the project will proceed, but a few things are clear. For one both the military and the industry are already preparing the block III upgrade program for KF-21 to follow up on Block II program that will end by 2028. On the other hand there seems to be different proposals regarding what this Block III should be and as I've mentioned before, a 5th gen VLO model isn't abandoned just yet it seems. We'll see where it goes.

Another thing to point out is KAI's own UCAV project fueled with corporate funding. As some of you'll know, there are currently two stealth UCAV programs, the KUS-FC (VLO flying wing reconnaissance and strike, X-47B/nEUROn/Taranis lookalike) and KUS-LW (tactical wingman drone, Ghost Bat/Valkyrie lookalike). They are both KAL project since KAI lost out on the bid for the preceding program called the KUS-X. Though I don't think it's a given that they really will actually proceed with corporate funded programs, though several cases around the world may have helped making them think that there's a business case here.

 

[Maro.Kyo]

View: https://youtu.be/hPvF7UrtpVU

Meteor test round released and around 100 20mm rounds fired.

 

[FighterJock]

Well done for the first test firing of the Meteor from the Boramae.

 

[timmymagic]

Meteor test round released and around 100 20mm rounds fired.

Didn't realise they'd gone for 20mm (presumably 20mm Vulcan?).

Seems a weird choice, its pretty much accepted that 25-30mm autocannon rounds are the sweet spot for aircraft, hence why the BK-27 is 27mm. US is switching to 25mm etc.

 

[TomS]

Meteor test round released and around 100 20mm rounds fired.

Didn't realise they'd gone for 20mm (presumably 20mm Vulcan?).

Seems a weird choice, its pretty much accepted that 25-30mm autocannon rounds are the sweet spot for aircraft, hence why the BK-27 is 27mm. US is switching to 25mm etc.

Korea uses a lot of 20mm -- it's on their F-15s, F-16s, and FA-50s. It's not inherently unsat, especially with the newer ammo. And it's probably lighter than fitting the other alternative, some version of 25mm Gatling for commonality with the F-35.

The US 25mm in the JSF is a bit of an excursion. If NGAD has a gun at all (not a given) I'd not be surprised if it turns out to be 20mm.

Well done for the first test firing of the Meteor from the Boramae.

Just a separation test this time. Looks like they were dropping an inert shape, not a real live missile.

 

[FighterJock]

Even though the missile was inert it is a good step forward for the Boramae, I am looking forward for the first real test firing of the Meteor missile and other weapons.

 

[Deino]

Congrats ...

 

[AnonSB]

View: https://www.youtube.com/watch?v=jR0jabs34Wo


Firing dummy IRIS-T round (not an actual test firing; just ejecting)

 

[FighterJock]

Well done again Boramae. No doubt it will be air to ground munitions that will be getting tested next at this rate.

 

[fighterman]

View attachment 695901
(translated and edited by myself from the original KAI presentation slide)

There was a KAI presentation regarding business models and near-future investment plans. One of the covered topics was the KF-21 Block III and future 6th gen fighter development for KF-16U replacement.

As I've mentioned before, the ROKAF's preliminary plans for replacing the upgraded Vipers is not to go with KF-21 Block III but instead with an enlarged, 6th gen figher jet. Nothing much to talk about regarding this program since its too early. They've also disclosed what they are envisioning for the KF-21 upgrade (Block III); to some people's disappointment, ROKAF wasn't looking for internal weapons bay or VLO-ization of KF-21 but instead their main focus lay on NCW.

What's interesting is that this new presentation from KAI is pointing otherwise. KAI's vision of KF-21 block III seems closer to a full-fledged 5th gen fighter based on the existing KF-21 block II, as it was promised from the beginning. I'm not sure in which direction the project will proceed, but a few things are clear. For one both the military and the industry are already preparing the block III upgrade program for KF-21 to follow up on Block II program that will end by 2028. On the other hand there seems to be different proposals regarding what this Block III should be and as I've mentioned before, a 5th gen VLO model isn't abandoned just yet it seems. We'll see where it goes.

Another thing to point out is KAI's own UCAV project fueled with corporate funding. As some of you'll know, there are currently two stealth UCAV programs, the KUS-FC (VLO flying wing reconnaissance and strike, X-47B/nEUROn/Taranis lookalike) and KUS-LW (tactical wingman drone, Ghost Bat/Valkyrie lookalike). They are both KAL project since KAI lost out on the bid for the preceding program called the KUS-X. Though I don't think it's a given that they really will actually proceed with corporate funded programs, though several cases around the world may have helped making them think that there's a business case here.

What does Block III upgrade exactly mean? retrofitting existing Blkoc I & II airframes with internal weapon bays? or buidling brand new block IIIs?

 

[Maro.Kyo]

What does Block III upgrade exactly mean? retrofitting existing Blkoc I & II airframes with internal weapon bays? or buidling brand new block IIIs?

It's the former. The goal of the block III program is to stop the pre-existing KF-21 block II aircrafts from becoming technologically obsolete in the adverse environement of the 2030s and 40s and therefore the most important part of the block III program would be if it is applicable to pre-existing airframes. Apart from that, as I've said, after KF-21 the only ROKAF demand for new fight jets are the KF-16 replacement, which will be fulfilled with a new design. For that reason there are no demands for a newly built block III aircrafts within the ROKAF and any newly built block III aircraft will be for export.

Also, the internal weapons bay, if implemented, will only be a part of the vast block III programme. Although not concrete, preliminary concepts for the block III aircraft is about fundamentally changing the way KF-21 will operate as a fighter jet. Other block III features include the conformalization of sensors and antenni which are currently protruding from the airframe, as well as integrating new capabilities that are currently not present both on the HW and SW sides. It's quite a huge addition especially on the avionics side.

One thing I'm worried about is the funding. I'm not exactly sure on how they are going to fund both the block III programme and KF-XX simultaneously in 2030s. There are even more reasons to find international partners for the KF-XX programme but there aren't much options when it comes to suitable partners that will also be willing to participate in a programme not led by the traditional leaders in the aviation field, which already have their own next generation fighter programmes. It's a difficult question afterall.

For such reason I think that there's still a chance that the ROKAF opts for the block III instead of the new design for KF-16 replacement and introduce foreign 6th gen design for the F-15K replacement, which will start around mid-late 2040s. Everything is possible as of now, since there's still some time for ROKAF future decisions.

 

[AnonSB]

Cant find the exact source

Possible IWB (with 6 MRAAMs) in the future?

 

[VTOLicious]

Wouldn't surprise me if it is designed to carry up to 6 internally.