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

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.
El96ym6UcAASHPG.jpg


here is the cut away of the fueselage showing where the bays are. Of course, this current aircraft covers the bay with those semi-recessed panels.
But assuming those recessed areas are the size of a Meteor, it looks like 2 each bay, maybe 3


--

on another note
I hope Indonesia's future force would be something like
50 KFX (replace older F-16s, Flankers)
50 FA-50s (replace the hawks, form the lo part of a hi-low mix with KFX as the hi)
20 TA-50s (advanced training)
KT-1s (Primary training)

Korea likely to allow home production of all of them. good for the Indonesian industry
also reduce the many different types

but since I assume Indonesia's main security challenge in the future will be China trying to exerts its claims over the SCS and Natuna island
Indonesia likely needs to maintain a defense relationship with the US and Europe.
US P-8s for maritime warfare
French submarines

would Indonesia need a LHD/LPD capability to defend some islands? would they need something like an F-35B?

Not sure about Russian relations. IRC, the embargoes have made Russian spares a bit challenging
but on the other hand if going by Vietnam's scenario, Russian presence in Vietnam's SCS claims have scared off Chinese pressure for that area.
 
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.
Won't really go feelingly above M2 with those intakes either.
Raptor do fly above Mach 2 with a similar inlet profile. And it's probable that limitations, if there is any, are not coming from their design (Ram, canopy...).
 
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.
Won't really go feelingly above M2 with those intakes either.
Raptor do fly above Mach 2 with a similar inlet profile. And it's probable that limitations, if there is any, are not coming from their design (Ram, canopy...).
That's the point: there are questions about its ability to go significantly above M2. And there is no real info to disregard those sadly, aside some old and vague citations.
 
Mach 2 would give it a significant advantage in the context.
It also more probably indicates how fast it could supercruise. Think at the Gripen E and compare thrust and GW.
 
Oh, no question about M2 being good by itself and better than speed limitations of DSI. Was just specifically pointing at that M2.5 remark.
 
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?


Indeed interesting, but as you know and regardless all similarities, only the FC-31 is called a copy and F-35-clone, whereas the KF-21 is surely a marvel of an indigenous fighter design. ;)
 
I do not want to appear as if I have a great understadning of aircraft design, but, wouldn't all stealth aircraft have the same features? There is only a finite number of things and aircraft designer can do to make their design stealth. I find it's sort of like a teenager with clothing trends, when one wears something, the others will wear something similar, if not the same, very soon. The same goes for stealth aircraft design. One nation does one thing, the others follow.

Just my two cents

Wyvern
 
but, wouldn't all stealth aircraft have the same features?
Only at very basic level. Details might differ greatly. Can look at that as at high supersonic speed aircrafts: basic demands for reaching and sustaining those speeds is same for everyone, but there are numerous specific ways to achieve needed results.
 
I do not want to appear as if I have a great understadning of aircraft design, but, wouldn't all stealth aircraft have the same features? There is only a finite number of things and aircraft designer can do to make their design stealth. I find it's sort of like a teenager with clothing trends, when one wears something, the others will wear something similar, if not the same, very soon. The same goes for stealth aircraft design. One nation does one thing, the others follow.

Just my two cents

Wyvern
yes, many have faceted bodies and the zig zags..

but if we look at some designs like the X-32, that was pretty unique.
maybe Su-57 as well
the J-20, while the front half looks a lot like a Lockmart design, is unique in that it has a delta canard.

then there are the models and proposals that took a more unique route. the McD JAST had no horizontal tails, and the X-36 had a canard, but no vertical tails.
I honestly want to see a scaled up X-36 design one day. I thought the idea was cool.
 
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.
It will carry at least 4 Meteor sized AAM's in the Block 2 configuration which will have true internal bay.

It will yes.. limit the diameter of the possible air-to surface weapons. But well. I think GBU-39 can still fit. Maybe 2 Meteor and 8 GBU-39's.
 
but if we look at some designs like the X-32, that was pretty unique.
maybe Su-57 as well
the J-20, while the front half looks a lot like a Lockmart design, is unique in that it has a delta canard.

then there are the models and proposals that took a more unique route. the McD JAST had no horizontal tails, and the X-36 had a canard, but no vertical tails.
I honestly want to see a scaled up X-36 design one day. I thought the idea was cool.

F-23!
 
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.

There was a presentation in 2014 that showed the weapon bay carrying either:
6 AIM-120
4 AIM-120 + 2 AIM-9
2 AIM-120 + 2 GBU-31

I don't know if that has changed over time.
 
The use of the caret style intake as opposed to DSI may be related to supercruise capabilities. Would be interesting to see the F414 show itself off as a "true supercruise" capable engine as opposed to the mild supercruise demonstrated with the Gripen E (Mach 1.2). Surely the intake plays a big role and the F414's low pressure section is apparently derived from the YF120.
 
how often do we see an unveiling of a new combat aircraft? 3 or 4 times per decade?

View attachment 654645


a few countries flags were flashed over it, i saw Turkey, Indonesia, US, Peru, Ghana, a few others
potential export?
View attachment 654646


View attachment 654647

Maybe a bit late to answer but those flags were just simply to thank the foreign representatives who have attended the ceremony. I've saw members of foreign forums speculating if its partners and potential export market but its not (directly) to do anything with export.

Given that they've unveiled it already and that at least superficially it looks finished - what are the chances we will see the first flight this year? As opposed to 2022, as various pundits predicted previously?

The manufacturing of the prototype was actually delayed for 6 months already during 2020 (I guess its unnecessary to explain why, as we all know the reason). Engineers and mechanics worked overtime to literally flip that to few weeks ahead of schedule somehow (the original timeline was roll-out on May). I don't think fast-tracking beyond what has already been achieved is possible.
 
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It seems like there are still wrong information floating around.

The block 2 of KF-21 will not have any IWB or anything, at least according to the current schedule. That plan of block 2 incorporating IWB was from the earlier days of the program, around 2014. Back then the block 1 was going to be the basic of the basic design without any RAS and other fancy stuff, just plain 4.5th gen aircraft. The block 2 was to incorporate RAS, fully conformal antennas, IWB, saw tooth panels and so on. Block 3 was going to be VLO but ADD didn't have a clue what's really needed for a fully VLO 5th gen aircraft so they left that field witha big "?"

Then once KAI and ADD actually got to the system development and EMD phase, they completely revised the schedule and came up with a new, more refined plan. They mixed what was formerly known as "block 1" and "block 2", which ended up with the current plan of block 1 and block 2. The new block 1 has RAS and some of its antennas integrated as a conformal design (from Cobham). Block 2 is the further development on the software side of things + armaments and operating mode certification. So the new Block 2 has nothing to do with major changes like an IWB but more to do with getting the A2S capabilities work + expanding some minor A2A capabilities. That's also the reason its only going to take 2 years (2026~2028) to develop the block 2 variant.

There are currently no "official" plans about the further development of the hardware side of things, also often called the "block 3" variant but the concrete plan regarding these matters will probably be announced upcoming August, as that's when the preliminary concept research for this "block 3" variant will be complete. (https://blog.naver.com/jhst3103/222045074204)

Some of the capabilities being mentioned are IWB, new radar and radome, highly directional and high bandwidth conformal antenna ala MADL, new higher-speed data bus that uses PCIe for the avionics architecture and the list goes on. I don't think that all of them are going to be included in the "block 3" package but most of them, hence the fact that most of those technologies are being researched with the aim to apply it on UCAV (flying wing aircraft currently being developed. TD already flew some years ago, even the footage of it being thrashed on the runway on an accident caused by software error has been made public.) and future variants of KF-21.

To sum it up, IWB in block 2 is the old plan. The current plans for the KF-21 block 2 doesn't have IWB. IWB along with currently missing sawtooth panels will probably be incorporated in block 3, although the details will not come out any sooner than the coming August. To think about it, ROKAF needs to replace KF-16 starting from mid-late 2030s (first KF-16 was handed over to ROKAF in 1994. With the life extension from the upgrades to Viper variant It would serve for another 15 odd years) so I expect the development of this "block 3" to be made official quite soon and to follow block 2 after 2028 without much downtime.
 
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I want this thing to be powered by a pair of F414 EPEs. Is 2 x 26,500lbs too much to ask? :eek:
 
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.
El96ym6UcAASHPG.jpg


here is the cut away of the fueselage showing where the bays are. Of course, this current aircraft covers the bay with those semi-recessed panels.
But assuming those recessed areas are the size of a Meteor, it looks like 2 each bay, maybe 3


--

on another note
I hope Indonesia's future force would be something like
50 KFX (replace older F-16s, Flankers)
50 FA-50s (replace the hawks, form the lo part of a hi-low mix with KFX as the hi)
20 TA-50s (advanced training)
KT-1s (Primary training)

Korea likely to allow home production of all of them. good for the Indonesian industry
also reduce the many different types

but since I assume Indonesia's main security challenge in the future will be China trying to exerts its claims over the SCS and Natuna island
Indonesia likely needs to maintain a defense relationship with the US and Europe.
US P-8s for maritime warfare
French submarines

would Indonesia need a LHD/LPD capability to defend some islands? would they need something like an F-35B?

Not sure about Russian relations. IRC, the embargoes have made Russian spares a bit challenging
but on the other hand if going by Vietnam's scenario, Russian presence in Vietnam's SCS claims have scared off Chinese pressure for that area.

The big box that you could see right here is the ammo box for the gun. If you look at it more closely, you would notice that the space behind it is completely empty. KF-21 in its current form will be able to house around 500 rounds internally. Once they actually use that space for something more useful like an IWB, that number will shrink for quite a lot.

As you could see below, the geometry of the KF-21's bulkhead is almost identical to that of F-22, although smaller and structurally different.

1995_f22_airframe_turbine.jpg

Quoting the LM engineer, "It is impossible to make a 5th gen aircraft out of fundamentally 4th gen design. (I guess he kinda meant the F-15SE with this) If your aim is to develop a 5th gen aircraft, the fuselage itself at least needs to be of a 5th gen design" which is exactly what KAI is doing with KF-21. Guess that's what LM told them as well.

Tbh the avionics of this aircraft is completely and absolutely your typical 4.5th gen fighter. The level of data fusion is 4.5th gen, the application and usage of its sensors is 4.5th gen, its capabilities and operating environment is then obviously 4.5th gen. That's also the reason, quoting a KAI engineer "(KF-21's) fuselage design incorporates spaces within the airframe to internally house the antennas and sensors in the future" because it would need some huge modification to make this thing a fully 5th gen bird and the fuselage at least needs to be designed with such in mind, although I'm not so sure how true this statement is in reality. For example there is currently no MAWS in KF-21 and I don't think there will be any space for something like a DAS to be integrated in the future.
 
Talking about LM's participation, their main role is to give hints and guide KAI to a correct direction of development. I would say its very important task they've got, although unlike in the KTX-II program (resulted in T-50), they don't have direct input in the engineering side of things. For example, T-50's wings are heavily influenced by LM, as it derived from F-16's wing design, whereas the wing of KF-21 is designed completely in-house.

Another example is the cockpit design. as KAI have never designed a full-blown fighter jet (we all know that FA-50 is more of a light-attack jet), they don't have much experience on what's needed ergonomically and interface-wise for an actual fighter jet cockpit. LM was there to give some ideas how a fighter jet cockpit should look like. Then KAI with other sub-contractors designed the actual cockpit based on what LM taught them + their own research.
 
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in regards to the internal weapons bay
here is a pic from bemil showing the bay but its of the earlier C103-ia model (not sure how far behind the actual KFX model)


20130813170332.jpg

20130813170341.jpg


if this is applicable to the current FX, then it would seem the bays have more space than the F-35
 
in regards to the internal weapons bay
here is a pic from bemil showing the bay but its of the earlier C103-ia model (not sure how far behind the actual KFX model)


20130813170332.jpg

20130813170341.jpg


if this is applicable to the current FX, then it would seem the bays have more space than the F-35
This is purely fan-made. Nothing to do with KAI or anything official. If I could tell you anything, the author of this grpahics was one hell of a delusional retard.
 
Given the pictures of what has actually been built, i'm now even questioning whether 4 Meteors will fit internally. E.g. take image in 603 and move the lines of the weapon stations upwards so that the weapon fins and a thick door will fit and i'm really wondering how there isn't a clash with the side wall of the bay. Maybe 4 AMRAAMs with a bit of stagger?
From the pictures the bay sides don't seem to toe in/out at all to give extra width around the fins, and this would also be odd to do given the fuselage mounted landing gear is in this location.

Maybe the future block with internal bay includes a fuselage width increase? Sounds expensive
 
Most pessimistic prediction maybe internal bay setup of:

> 2x Meteor + 2 x IRIS-T
> 2x Meteor + small diameter bombs

(?)

Not really related but I once saw some graphic of F-35B/A carrying 2x bvr/mraam + 2x asraam setup internally sometime ago if i am not mistaken.

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Max Speed: Mach 1.81 (2,200km/h / 1,400mph)
Engine thrust: 2 x 22,000lb F414
Range: 2900km / 1550nm
Length: 16.9 m / 55.4ft
Wingspan: 11.2 m / 36.7ft
Height: 4.7 m / 15.6ft
Wing area: 46.5 m2*
Empty weight: 11,800 kg*
Max Payload: 7,700kg / 17,000lb
Gross weight: 17,200 kg*
Max takeoff weight: 25,400 kg / 56,400lb

* Figures from media sources - may not be accurate. Metric and imperial figures don't always match.
 
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Ah right, there are some graphics on a more compact, cropped fin meteor. How's its development going?

Could they potentially be considered for future KF-21s with IWB?
I'd think so, but it still looks really tight to fit 4 in that bay. The cropped fins on Meteor don't reduce the size as much as AMRAAM.
 
Max Speed: Mach 1.81 (2,200km/h / 1,400mph)
Engine thrust: 2 x 22,000lb F414
Range: 2900km / 1550nm
Length: 16.9 m / 55.4ft
Wingspan: 11.2 m / 36.7ft
Height: 4.7 m / 15.6ft
Wing area: 46.5 m2*
Empty weight: 11,800 kg*
Max Payload: 7,700kg / 17,000lb
Gross weight: 17,200 kg*
Max takeoff weight: 25,400 kg / 56,400lb

* Figures from media sources - may not be accurate. Metric and imperial figures don't always match.
That max Mach relative to 1400 MPH already doesn't match up based on the altitude where modern combat tend to achieve their fastest speeds, generally around 35 to 45k ft. Standard conditions for Mach 1.8 at 35k would be just under 1200 MPH. 1400 MPH at the same altitude would about Mach 2.1. If it really is a 1400 MPH design, I imagine it's a credible supercruiser.

I kind of can't help but view the KF-X as a sort of semi-5th gen design like the Su-57. Clearly close but lacking in some manners to fully match what I would consider true 5th gen traits. It's a very good start and perhaps where SAAB could've gone if they still plan on developing a stealth successor to the Gripen.
 
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Max Speed: Mach 1.81 (2,200km/h / 1,400mph)
Engine thrust: 2 x 22,000lb F414
Range: 2900km / 1550nm
Length: 16.9 m / 55.4ft
Wingspan: 11.2 m / 36.7ft
Height: 4.7 m / 15.6ft
Wing area: 46.5 m2*
Empty weight: 11,800 kg*
Max Payload: 7,700kg / 17,000lb
Gross weight: 17,200 kg*
Max takeoff weight: 25,400 kg / 56,400lb

* Figures from media sources - may not be accurate. Metric and imperial figures don't always match.
That max Mach relative to 1400 MPH already doesn't match up based on the altitude where modern combat tend to achieve their fastest speeds, generally around 35 to 45k ft. Standard conditions for Mach 1.8 at 35k would be just under 1200 MPH. 1400 MPH at the same altitude would about Mach 2.1. If it really is a 1400 MPH design, I imagine it's a credible supercruiser.

I kind of can't help but view the KF-X as a sort of semi-5th gen design like the Su-57. Clearly close but lacking in some manners to fully match what I would consider true 5th gen traits. It's a very good start and perhaps where SAAB could've gone if they still plan on developing a stealth successor to the Gripen.
KAI has stated its not a 5th gen aircraft but a 4.5 gen one.
only the LATER versions have the possibility of receiving a full modification to 4.5 gen i.e. internal weapons bay, better paneling and avionics.
 
KAI did CFD research using C107 model w\ IWB in 2017. In the research, four AMRAAMs/two AMRAAMs&four GBU-30 are considered as internal weapon.

source
내부 무장 안전분리 특성 연구 연구에 대한 참여 기관(업체) 공모
내부무장창 비정상 유동해석 연구에 대한 참여 기관(업체) 공모
 
KAI did CFD research using C107 model w\ IWB in 2017. In the research, four AMRAAMs/two AMRAAMs&four GBU-30 are considered as internal weapon.

source
내부 무장 안전분리 특성 연구 연구에 대한 참여 기관(업체) 공모
내부무장창 비정상 유동해석 연구에 대한 참여 기관(업체) 공모
GBU-30 is a typo btw. It should be GBU-39 aka SDB-1
 
in regards to the internal weapons bay
here is a pic from bemil showing the bay but its of the earlier C103-ia model (not sure how far behind the actual KFX model)


20130813170332.jpg

20130813170341.jpg


if this is applicable to the current FX, then it would seem the bays have more space than the F-35
This is purely fan-made. Nothing to do with KAI or anything official. If I could tell you anything, the author of this grpahics was one hell of a delusional retard.

Thanks for clarifying - that was the source I was referring to. I thought it wouldn't make much sense to replicate F-35 capabilites regarding the carriage of Mk 84 class weapons.
The 6 AAM loadout would be nice to have though.

So, any official sources for future weapon bay capacity?

Regarding (EO)DAS or MAWS respectively, this is something a 4.5 gen fighter should have imho. It would be a shame if KF-21 has no provisions for MAWS...
 
Max Speed: Mach 1.81 (2,200km/h / 1,400mph)
Engine thrust: 2 x 22,000lb F414
Range: 2900km / 1550nm
Length: 16.9 m / 55.4ft
Wingspan: 11.2 m / 36.7ft
Height: 4.7 m / 15.6ft
Wing area: 46.5 m2*
Empty weight: 11,800 kg*
Max Payload: 7,700kg / 17,000lb
Gross weight: 17,200 kg*
Max takeoff weight: 25,400 kg / 56,400lb

* Figures from media sources - may not be accurate. Metric and imperial figures don't always match.
Max speed error was already deciphered (see above)
Range is probably wrong also and looks like to be more related to a maximum ferrying distance than a combat range.
 
KAI did CFD research using C107 model w\ IWB in 2017. In the research, four AMRAAMs/two AMRAAMs&four GBU-39 are considered as internal weapon.

source
내부 무장 안전분리 특성 연구 연구에 대한 참여 기관(업체) 공모
내부무장창 비정상 유동해석 연구에 대한 참여 기관(업체) 공모

Thanks, I can believe that. Assume two AMRAAMs in one bay and a quad pack of SDBs in the other? Or maybe a new low profile twin SDB launcher?
 
Max Speed: Mach 1.81 (2,200km/h / 1,400mph)
Engine thrust: 2 x 22,000lb F414
Range: 2900km / 1550nm
Length: 16.9 m / 55.4ft
Wingspan: 11.2 m / 36.7ft
Height: 4.7 m / 15.6ft
Wing area: 46.5 m2*
Empty weight: 11,800 kg*
Max Payload: 7,700kg / 17,000lb
Gross weight: 17,200 kg*
Max takeoff weight: 25,400 kg / 56,400lb

* Figures from media sources - may not be accurate. Metric and imperial figures don't always match.
Max speed error was already deciphered (see above)
Range is probably wrong also and looks like to be more related to a maximum ferrying distance than a combat range.

Range is from the KAI website, but yes most likely ferry range.
 
on a related note, since we talked about exports and korean aircraft.


JF-17 vs FA-50 in Malaysia!!!
they narrowed it down to those two, but the JF-17 is in the lead due to better medium range weapons

i thought FA-50 was cleared for AMRAAM no?
 
on a related note, since we talked about exports and korean aircraft.


JF-17 vs FA-50 in Malaysia!!!
they narrowed it down to those two, but the JF-17 is in the lead due to better medium range weapons

i thought FA-50 was cleared for AMRAAM no?

There are currently two upgrade programs regarding FA-50, namely block 10 and 20 respectively. What's currently under works is the block 10, which aims for the integration of LGBs and Sniper pod (a photo of FA-50 flight testing with a pod hanging on the center pylon has recently been revealed, although there seems to be no high-res photo made public). Block 20 is when the AMRAAM will be integrated (probably the C5/7 variation?) although it is not clear if such upgrade program is actually under development or only being planned on. I would lean towards the latter unless there are some clarification from KAI. KAI seems to even be considering ways to enhance the power output of the existing EL/M-2032 radar once they are done with AMRAAM integration program, probably due to the small antenna aperture, although I'm not so sure how they would be able to achieve such.
 

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