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

[TomcatViP]

What's to compare?

The J-31, first edition, was an hazard to its pilots (see my posts at the time).

Here we have a solid FBW and airframe design.

Could you please give a link to your post of "hazard to its pilots (see my posts at the time"?
otherwise I think the current J-35 surely also has a "FBW and a solid airframe design"! Or why not?

Of course, It was a keypub post related to the first appearance of the J-31 at an airshow in China.

Not even mine, but similar SH pilots comments of the events went to press.

 

[Deino]

What's to compare?

The J-31, first edition, was an hazard to its pilots (see my posts at the time).

Here we have a solid FBW and airframe design.

Could you please give a link to your post of "hazard to its pilots (see my posts at the time"?
otherwise I think the current J-35 surely also has a "FBW and a solid airframe design"! Or why not?

Of course, It was a keypub post related to the first appearance of the J-31 at an airshow in China.

Not even mine, but similar SH pilots comments of the events went to press.

Sorry, but that's just a bit of strange info without any link/source ... so you or this poster was claiming the FC-31 had no FBW and you noted it was "hazard to its pilots", but could you please explain why?
So far based on my understanding we have no information in regard to the FC-31's systems - and I cannot think it won't use a FBW-system - nor have we any reports, that there were issues mentioned from the pilots. As such a claim like being "hazard to its pilots" seems a rather unfounded claim ... if I'm wrong I would be happy to be corrected by an explanation.

 

[Sundog]

Congrats to KAI on this success.

 

[TomcatViP]

@Deino : I never said that the J-31 had no FBW! What I said is just that it was botched to the point that it's what the flight demo emphasized to any ppl having a sensible look in that domain.

 

[Umigami]

Notice the floating effect of the ctrl surfaces is really minored despite the size of the surfaces
Notice the firm pull-out resulting from deliberate pilot action
Notice the induced yaw (cross wind?) immediately corrected by an exaggerated deflection of the port stabilizer
Notice that that there is no aileron engaged
Notice the speed at which the tailplane deflects

Are those problems?

 

[rooster]

Notice the floating effect of the ctrl surfaces is really minored despite the size of the surfaces
Notice the firm pull-out resulting from deliberate pilot action
Notice the induced yaw (cross wind?) immediately corrected by an exaggerated deflection of the port stabilizer
Notice that that there is no aileron engaged
Notice the speed at which the tailplane deflects

Are those problems?

First flight happened

 

[TomcatViP]

@Umigami :Absolutely not! Those details just shows us how the FBW react, what give us a feeling of how sensitive the plane could be.

 

[Ainen]

Interesting comparison …

Btw, the comparison is indeed interesting in one aspect: vertical surfaces are just huge for the current generation of aircraft.
Interesting why.

 

[Umigami]

 

[Cjc]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

 

[helmutkohl]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

my eyeball estimates are

4m x 0.36m for each bay

 

[Maro.Kyo]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

Just big enough for 4 MRAAMs or 2 MRAAMs and 4 SDBs

 

[Umigami]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

Just big enough for 4 MRAAMs or 2 MRAAMs and 4 SDBs

Meteor?

 

[Umigami]

Gear up and it would have been perfect.

 

[Maro.Kyo]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

Just big enough for 4 MRAAMs or 2 MRAAMs and 4 SDBs

Meteor?

model used was AMRAAM iirc

 

[Cjc]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

Just big enough for 4 MRAAMs or 2 MRAAMs and 4 SDBs

I don't know, didn't the original requirement also have 1,000 lbs jdam as a requirement, like the f-22

 

[FighterJock]

Gear up and it would have been perfect.

Remember that this was only a first flight if anything went wrong during the flight say hydraulics failure they would have no way of bringing down the landing gear to make an emergency landing. I would think that all future flights would have the gear up.

 

[TomcatViP]

Let's appreciate how the first flight showed how mature were the FBW. No floating governs, no over correction from the pilot (except the cross wind lift-off), not much wobbling while rassembling on the chase plane (T-50) - and who the heck rassemble during a first flight (Isn't that a first?)). The pitch authority was noteworthy at liftoff. You would have to dial in advance an alpha nbr to get so much precision, really (akin only to Japanese drifting sequences in an Hollywood movie).

All in all, for us abroad, far away from the action, let's resume it to what it was to watch it: it was a GREAT first flight. Congrats!

 

[red admiral]

I don't know, didn't the original requirement also have 1,000 lbs jdam as a requirement, like the f-22

Possibly 1 X 1,000lb JDAM per bay?

E.g. 2 X AMRAAM in one bay + 1 X JDAM in the other?

 

[Deino]

Well senses we know the internal bay is in the design (gust not in use from the first blocks for some reason) do we have any idea about the dimensions of the weapon bay?

Just big enough for 4 MRAAMs or 2 MRAAMs and 4 SDBs

Meteor?

model used was AMRAAM iirc

No, clearly Meteors

 

[stealthflanker]

Should update my Boramae model soon.

 

[Maro.Kyo]

No, clearly Meteors

No, I was talking about computer simulations ran by KAI to calculate IWB development and implementation requirements to the existing KF-21 fuselage design. They've used 2 configurations of 4 AMRAAMS and 2 AMRAAMS accompanied by 4 SDBs on various altitudes, speed and AOA.

 

[Hydroman]

Let's appreciate how the first flight showed how mature were the FBW. No floating governs, no over correction from the pilot (except the cross wind lift-off), not much wobbling while rassembling on the chase plane (T-50) - and who the heck rassemble during a first flight (Isn't that a first?)). The pitch authority was noteworthy at liftoff. You would have to dial in advance an alpha nbr to get so much precision, really (akin only to Japanese drifting sequences in an Hollywood movie).

All in all, for us abroad, far away from the action, let's resume it to what it was to watch it: it was a GREAT first flight. Congrats!

I agree with you, I assume KAI used the FBW experience gained from the T-50 (I am very familiar with the T-50 flight control servoactuators). Also, KAI did an excellent job moving this program along very quickly when they began building the first vehicle, through taxi testing and of course to this successful first flight. The aircraft was very stable and looked to fly very well, kudos to the KAI team.

 

[Umigami]

No, clearly Meteors

No, I was talking about computer simulations ran by KAI to calculate IWB development and implementation requirements to the existing KF-21 fuselage design. They've used 2 configurations of 4 AMRAAMS and 2 AMRAAMS accompanied by 4 SDBs on various altitudes, speed and AOA.

Yeah, latest Amraam is good too. Not necessarily a downgrade from Meteor.

Air Force Successfully Tests Redesigned AMRAAM AIM-120D3 - Air Force Magazine

The Air Force successfully tested its redesigned AMRAAM F3R, firing the AIM-120D3 missile June 30 from the F-15E Strike Eagle.

www.airforcemag.com

 

[AnonSB]

Reportedly, the plane's second test flight with the landing gears up was successfully completed :

KF-21 '보라매' 이번엔 랜딩기어 접고 40분간 2차 비행

국산 4.5세대 초음속 전투기 KF-21 1호기가 지난 19일 오후 경남 사천 공군 제3훈련비행단에서 활주로를 박차고 이륙하고 있다.윤석열 대통령과 조코 위도도 인도네시아 대통령은..

news.tf.co.kr

 

[Umigami]

Reportedly, the plane's second test flight with the landing gears up was successfully completed :

KF-21 '보라매' 이번엔 랜딩기어 접고 40분간 2차 비행

국산 4.5세대 초음속 전투기 KF-21 1호기가 지난 19일 오후 경남 사천 공군 제3훈련비행단에서 활주로를 박차고 이륙하고 있다.윤석열 대통령과 조코 위도도 인도네시아 대통령은..

news.tf.co.kr

Waiting for photo or video here

 

[Umigami]

 

[AnonSB]

Reportedly, the plane's second test flight with the landing gears up was successfully completed :

KF-21 '보라매' 이번엔 랜딩기어 접고 40분간 2차 비행

국산 4.5세대 초음속 전투기 KF-21 1호기가 지난 19일 오후 경남 사천 공군 제3훈련비행단에서 활주로를 박차고 이륙하고 있다.윤석열 대통령과 조코 위도도 인도네시아 대통령은..

news.tf.co.kr

Waiting for photo or video here

Can't find any

 

[Umigami]

Even after Indonesian President visit to Korea recently, I still didn't hear any news regarding Indonesian commitment in this program.

 

[Hanz2k]

I think there will be polish commitment after buying FA50. The plan is to buy FA50 to replace Mig29 and Su22, then buy additional F35 - I think another 32, then we need to start looking for F16 replacement that were delivered in 2007-2008. So still at least 10 years ahead with potential contract in 5-6 years from now.

 

[GTX]

I think there will be polish commitment after buying FA50. The plan is to buy FA50 to replace Mig29 and Su22, then buy additional F35 - I think another 32, then we need to start looking for F16 replacement that were delivered in 2007-2008. So still at least 10 years ahead with potential contract in 5-6 years from now.

If I was Poland I would just get additional F-35s rather than increase support costs even further with a new type that offers less capability.

 

[CV12Hornet]

Agreed. KF-21 future sales are for countries that aren't able to cozy up to Uncle Sam. Poland is not one of those countries.

 

[Bounce]

I still think this would be perfect to compliment our RAAF F-35's, just love it! If someone does it in 1/48 or 1/32 I might even get back into modelling.

 

[helmutkohl]

Agreed. KF-21 future sales are for countries that aren't able to cozy up to Uncle Sam. Poland is not one of those countries.

Given the high number of US parts in the KF-21, I feel if a country isn't on good terms with the US, then it likely won't be able to get the KF-21 either.
the FA-50's exports to Uzbekistan and Argentina were halted by opposition by the US and UK respectively.

I also think that the KF-21 might offer some significant performance differences from the F-35 (perhaps better supersonic performance) that may push some F-35 operators to operate both types. More logistical headaches indeed, but at least they will more or less share the same weapons.

 

[CV12Hornet]

Given the high number of US parts in the KF-21, I feel if a country isn't on good terms with the US, then it likely won't be able to get the KF-21 either.
the FA-50's exports to Uzbekistan and Argentina were halted by opposition by the US and UK respectively.

I also think that the KF-21 might offer some significant performance differences from the F-35 (perhaps better supersonic performance) that may push some F-35 operators to operate both types. More logistical headaches indeed, but at least they will more or less share the same weapons.

KF-21 is currently, IIRC, 65% Korean, and the big-ticket foreign item are the engines. Full indiginezation is currently an ongoing goal for the Koreans.

 

[GTX]

I still think this would be perfect to compliment our RAAF F-35's

How exactly?

 

[GTX]

I also think that the KF-21 might offer some significant performance differences from the F-35 (perhaps better supersonic performance) that may push some F-35 operators to operate both types. More logistical headaches indeed, but at least they will more or less share the same weapons.

I doubt the performance will be any better but the logistics headaches will certainly be there…

 

[Maro.Kyo]

Agreed. KF-21 future sales are for countries that aren't able to cozy up to Uncle Sam. Poland is not one of those countries.

Given the high number of US parts in the KF-21, I feel if a country isn't on good terms with the US, then it likely won't be able to get the KF-21 either.
the FA-50's exports to Uzbekistan and Argentina were halted by opposition by the US and UK respectively.

I also think that the KF-21 might offer some significant performance differences from the F-35 (perhaps better supersonic performance) that may push some F-35 operators to operate both types. More logistical headaches indeed, but at least they will more or less share the same weapons.

Guess by "countries that can't cozy up" he meant 'countries close enough to Washington for the US to sell fighters, but not close enough to sell F-35s'. Sounds like your typical ASEAN or ME countries to me.

KF-21 is currently, IIRC, 65% Korean, and the big-ticket foreign item are the engines. Full indiginezation is currently an ongoing goal for the Koreans.

Apart from the engines, IFF, TDL and IRST(HW) are or will be imported. Not to mention several key avionics as well. Some of them are set for long-term development but a full indigenization is at least a decade or two away, if it is to ever happen. Also to my knowledge, maximum, not full, indigenization is the focus. Those imply very different things.

I still think this would be perfect to compliment our RAAF F-35's, just love it! If someone does it in 1/48 or 1/32 I might even get back into modelling.

Tbh, if the RAAF does not opt for a fully F-35 air force, which in my opinion would be a wrong choice to make in the first place, I still don't think the mix of F-35s and KF-21s is the second best option in terms of both the military and industrial implications.

 

[Maro.Kyo]

Moving the thread since it's more appropriate here.

While i don't read Korean, isn't it reasonably safe to assume that KFX will aim for the same fusion/interlinking standards?
They were industry-leading half a decade ago when F-35 was entering service, but now they're becoming pretty much standard.
While they are by no means simple - there is no technomagic there, neither in soft- nor in hardware.

I simply doubt a new late 2020s fighter from a country without hard technical limitations will come out without it.

The difference between KF-21 TDL and data fusion capabilities compared to other 4.5th gen fighters in their latest versions between late 20s and early 30s comes down to two things : One is the data link terminal it is going to use (MIDS JTRS) and the other is the Korean goals on data integration depth.

Firstly, I am by no means trying to argue that MIDS JTRS is a lacking system, but quite the opposite. It is THE standard when it comes to modern airborne comms/data link SDR with its variety of features and waveforms. The biggest problem is that we don't know if the Koreans are planning to implement CMN-4 model or TTNT model, but it seems very likely that they would go with CMN-4(reason I'll explain below). Other problems are its interoperability with Korean waveforms and integration of future Korean waveforms into the system. So if they are not acquiring TTNT capabilities, they are going to be limited to Link-16 for quite a while, which is a great TDL, but lacks several technical aspects when compared to dedicated intra-flight TDLs like the MADL or TIDLS.

They are currently developing the second gen JTDLS, a Korean MIDS/EMIDS/CONTACT equivalent system. It is (probably a SCA based SDR system and is) going to be fitted with the Korean Link K and KVMF, as well as have interoperability with Link-16 and 22, just like the European ESSOR based terminals. Problem is, firstly, this system is not going to be ready any sooner than 2026 and secondly, there are currently no plans to develop a dedicated intra-flight data link waveform OFP for this system since the priorities lies on integrating other waveforms as mentioned above (though I should note that there's a similar development with reagrds to MUM-T and the necessary CDL in work. Underlying technologies are also under research but the problem is how and when exactly this is gointg to be implemented).

TTNT is also not being mentioned as a planned waveform and frankly, I doubt that the US would allow foreign countries to integrate TTNT with their own terminals in the first place. Due to such reasons, I highly doubt that Korea would acquire TTNT capabilities at all, at least in the mid-term.

So, be it with MIDS JTRS or with JTDLS, the KF-21 will not be equipped with dedicated intra-flight TDL, at least until mid 30s or in other words, for the first 10 or so years in service.

Rafale on the other hand will be fitted with FO3D. From what I've heard, it's also directional and is high-throughput, low latency system. Quite a significant difference.

Talking about data fusion itself, KF-21 and other 4.5th gens, or more specifically the newest Eurocanard variants like the Tranche 4/5 or Standard F4 and MS21(?) are all working on an object assessment level. Now the question is in which depth. KF-21 fuses its data on a individual unit basis. It processess its signals/data from onboard sensors and the track it receives from Link-16. Then it shares the improved track on Link-16 and the cycle continues. The problem is that Link-16 has a 12 sec. time frame and therefore the latency and shared track quality is not suitable to fuse the shared data into a single unified air space picture amongst flight-members.

Eurocanrds on the other hand does this differently. Gripen for example has a separate radio terminal(TARAS) apart from the MIDS and conducts intra-flight data linking(TIDLS) and fusing on the basis of said platform. The Swedes are planning to upgrade this capability on the next version of Gripen, which I think will probably be called the Vs or MS21. Rafale currently works with Link-16 but as I've said, will obtain a dedicated intra-flight TDL and an improved TRAGEDAC system to fuse and create unified airspace picture/track. I wasn't able to find much with reagrds to the Eurofighter, but at least the operators apart from Britain will fit their Eurofighters with F-EMIDS that has a dedicated waveform (IFDLWF) for the aforementioned purposes. It is not hard to imagine that they would also be fitted with flight-level data fusion capabilities. The British Eurofighters are a bit out in blue, but I presume they are also planning on comparable capabilities. Else, they could be pursuing similar paths as to the US (focusing on 5th gen to 4th gen connectivity with gateway platforms, eg. Freedom 550 fitted relay aircrafts) since they are going to operate a vast amount of F-35Bs and is the only tier-1 partner in JSF.

So overall, maybe to your surprise, there are a few known "obsolescences" of KF-21 avionics when compared to other 4.5th gen fighters. Obviously, there are also a few fields in which the KF-21 excels when compared to other 4.5th gen aircrafts, as I've mentioned in my last post, which is the reason I think that KF-21 is going to be largely comparable/equivalent to other 4.5th gen fighters.

 

[Maro.Kyo]

Also, since I've shortly mentioned MUM-T, the development of a wingman drone that is to perform air to air and air to ground roles alongside KF-21 has been revised and is now a two-track program.

The flying-wing reconnaisance-strike drone, dubbed the KUS-X, that was known for a while will now operate independently (although it could also operate with) from the KF-21. Accompanying the KF-21 is a more conventional tailed LO design that looks like a mishmash between GA Longshot and Boeing Aus. Loyal Wingman, dubbed the KUS-LW. The reason for such change was apparently considerations concerning maneuverability in air to air combat.

The bid for the latter was recently ended in which KAL was seleceted over KAI, meaning that KAL is now responsible for both stealth UCAVs in development.


KUS-X technology demonstrator in flight.

KAL KUS-LW rendering.