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Korea's KF-X: News & Discussion

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    To end the OT digression, I Wonder how a nation so focused on new technologies still takes the burden of building a twin seat design.
    It depends on the operational concept. Considering how 4.5th Gen designs have twin-seat designs while 5th Gen aircraft do not, I may be a indicator of Korea's reduced ambitions in terms of technological complexity. It may be purely for conversion training. Or maybe if the rear-seater becomes a kind of dedicated UCAV/drone swarm controller, with the benefit of hindsight it may be recognised as a embryonic 6th Gen capability.

    On that point, as the advancement of UAV/UCAV capabilities causes the possible synergy between manned and unmanned systems to be explored, I think the concept of an 'Airborne Distributed Lethality' where sensors and weapons are shared between multiple platforms becomes viable. Instead of having a single (fighter) be a omni-role, jack-of-all-trades, one size fits all platform, why not have two separate, more economic platforms (manned and unmanned) work together? Distribute sensors and EOTS and stealthy 1k-lb,2k-lb bomb internal carriage to a more optimised platform. (Obviously Data-link, EW, Jamming vulnerabilities are an obvious weakness)

    While the F-35 and the US's future UCAV platform will undoubtedly be the most capable, Korea could have a combination of KF-X and K-UCAV platforms that leads to nearly F-35 level capabilities at a lower-risk and for a lesser economic burden.


      I don't see any reduced ambitions! The KFX is to date what looks like the most advanced and matured fighter aircraft project outside the US.

      Every items in the 5th Gen panoply is pursued relentlessly and they are the first on the line after the US.

      They might not succeed but, at least, ambitions they have!
      Last edited by TomcatViP; 15th July 2017, 12:03.


        I don't see any reduced ambitions! The KFX is to date what looks like the most advanced and matured fighter aircraft project outside the US.
        What about Pak-Fa, Shin shin???


          Don't take me wrong, the fog of war still means that a WSO or RIO is needed in some scenarios. But flight automation will soon end the need of a Front seater the time the operator focus on the tactical situation. IA will ensure the pilot build a relevant SA bubble until his full attention on the tactical picture is needed and advanced autopilot modes will guarantee flight safety and tactical manoeuvres.
          The merge of combat and flight software will alleviate the need of twin seats on fighter size aircraft (then complexity of systems on multi-sensored large platform is something else).
          On the other hand, networking with drones etc. May enhance work load and the need for a navigator.


            I may have this totally wrong but the entire point of AI and networking is to enable cross platform tactical coordination including controlling swarm behavior. Ths isn't about one person in the back controlling 2-3 unmanned trucks..This is more about 10-15 or more aircraft, manned and unmanned being able to seamlessly accomplish tasks with minimal labor intensive man in the loop tasking input.

            Old radar types never die; they just phased array


              KF-X fighter to have a two-seater version.

              From AW&ST

              SEOUL, TAIPEI—The Korea Aerospace Industries (KAI) KF-X fighter will have a two-seat version, developers have confirmed, following years of depictions of the indigenous aircraft with just one seat.

              The aircraft has again grown in size, with a notable increase in length, according to data released by the defense ministry’s procurement office this month.

              The latest design, C107, is descended from C103, a preliminary concept that was chosen as the basis of KF-X after Lockheed Martin won the separate F-X Phase 3 import competition in 2013 with the F-35 Lightning; the competition winner was required to support KF-X development.

              C103, prepared in 2012, featured tailplanes; an alternative concept with canard control surfaces would have been used had a European supplier won F-X Phase 3.

              Designs before C107 have been shown only as single-seaters, though a model of a two-seat version was glimpsed on a television report about KAI in 2016. With the discussion of C107 this month, the second seat is confirmed as an option.

              But it is unrelated to the increase in size. Rather, the aircraft has been enlarged to create more space and give it a better aerodynamic shape, officials from KAI and the procurement office, the Defense Acquisition Program Administration, said at a program briefing.

              Length has increased in C107 to 16.8 m (55.1 ft.) from 16 m in the C015 design of 2015 and 15.3 m in C103.

              C105, the last design before full-scale development began in late 2015, was longer than C103 but apparently only because the wing was enlarged in span, to 11 m from 10 m, and therefore in chord. Span has increased again in C107, but only to 11.2 m.

              C107 looks generally bulkier than its predecessors.

              The reason for the second seat has not been disclosed. Fighters designed before the 1990s routinely have two-seat versions. In some cases the second seat is now used not just for training but for carrying another crewmember in combat. But the Lockheed Martin F-22 Raptor and F-35 Lightning and Avic Chengdu J-20 have only single-seat versions, with advanced simulation used to prepare pilots for solo flights.

              Provision for a second seat in the KF-X may indicate that the type’s avionics will not be sufficiently advanced to support the most demanding strike missions without two crewmembers.



                Cobham to provide KF-X missile launchers



                  Korean 15W & 30W GaN X-Band HPA MMIC

                  Click image for larger version

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                  Further slides show the 15W HPA will be used in the KF-X's AESA T/R Modules. Assuming a Single Channel design and 1000 TRMs per Radar that's a peak power of 15kW. Not sure how that compares to other airborne AESAs.
                  Last edited by EagleSpirit; 26th August 2017, 18:51.


                    I tried to generate 3D model and then "calculate" the RCS of the C-107 configuration. The frequency used is 10 gHz.

                    The 3D representative

                    Polar plot

                    Linear plot

                    All plot indicates that at least. the C-107 configuration is capable of attaining 0.12 sqm RCS in 10 gHz. The assumption is of course, no RAM and flying clean. For me it looks promising, especially when some RAM and internal weapon bay provided.

                    Another plot of interest is what's KF/IF-X looks like in another frequency range. I generated a linear plot of frontal aspect of KF/IF-X in VHF straight to X-band.
                    Linear plot of frontal aspect in various frequencies (VHF to X band)

                    The result is wildly vary depending on frequency. Only specular RCS tho is considered in POFACETS. The contribution from creeping and surface wave are not considered.


                      Further slides show the 15W HPA will be used in the KF-X's AESA T/R Modules. Assuming a Single Channel design and 1000 TRMs per Radar that's a peak power of 15kW. Not sure how that compares to other airborne AESAs.
                      This process is 2013 for building those GaN MMIC. It will be obsolete by the time KFX enter service with obsolete engines.
                      In 2013, WIN demonstrated
                      their first 0.25 μ m GaN technology and transistor
                      performance operating in X-band [6~7] and thereafter a
                      program to develop high volume production capability in
                      terms of yield is being executed at WIN Semiconductor


                        Originally posted by JSR View Post
                        This process is 2013 for building those GaN MMIC. It will be obsolete by the time KFX enter service with obsolete engines.
                        1. The US had 0.25 μm tech long before 2013, obviously Korea isn't on the level of Qorvo
                        2.There is a difference between proving a tech and that tech having a good enough yield to be cost effective
                        3. Because Radars/Fighters take so long to develop and semiconductors improve so quickly there is no Radar that has been operational with the very latest processes.
                        4. Just because 0.25 μm gate-length isn't cutting-edge that isn't the same as being obsolete. It also doesn't make the Radar itself obsolete.
                        5. Just because the Radar doesn't have the very best technology doesn't mean it's not worth perusing to improve domestic industry.

                        I don't even know why I'm even replying to you when you will never change your mind.


                          the point I am making is atleast on paper you can aim for newer technology for some thing that will enter service 20 years down the road. by that time it will be equipped with 40 year old technology.

                          The PAK FA radar system consists of a prospective AFAR X-band in the nose, two side-view radars, and a L-band AFAR along the flaps.

                          Today CRET also works on the creation of a radio-optical radar for PAK FA. The concern intends to create a full-scale sample of the radar station of the future until 2018.

                          Photonic technologies will allow to expand the radar's possibilities - to reduce the mass more than twice, and to increase the resolution tens of times. Such radars with radio-optical phased array antennas are able to make a kind of "X-ray image" of aircraft located at a distance of more than 500 kilometers and give their detailed, three-dimensional image. This technology allows you to look inside the object, find out what technique it carries, how many people are in it, and even to see their faces.



                            Tango III already put this on Aviation News thread, but I put it again in this thread on pointed out that the difference need from ROKAF for internal bay (to make it more stealthly) and Indonesian TNI-AU to have more longer flight endurance, does not mean that definetely there're going to be 2 seperate version of KFX (with internal bay), and IFX (which use the space as additional fuel tanks for longger endurance), as the article stated.

                            The final design for Block 1 is not final yet, but from what I heard on unofficial report..the designers still try to find away to meet both ROKAF and TNI-AU need.


                              Indonesia factor may postpone KF-X project
                              By Kim Hyo-jin

                              Indonesia has failed to pay its annual share of expenses for a joint project with South Korea to develop high-tech fighter jets, an opposition lawmaker claimed Wednesday.

                              The claim prompted concerns the project, dubbed KF-X, could be suspended.




                                Video frm Air Recognition on Hanwha parts of KFX Avionics.