Boeing is Now T-X

 Boeing's proposal is now selected as T-X

https://twitter.com/search?q=boeing+t-x&ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Esearch

Aerodynamic Validation of Missile-SIM for Trajectory

Previous W.I.P Status 

 Recently, I have worked some Python Missile-SIM as shown in upper link. Before, simulation is performed in regular evaluation, I verify CFD method of the Simulation. 

 Although, there is some good reference related to aerodynamics of Missile for CFD (Star-CCM & Lockheed for JCM), due to the limited resource of my laptop, I cannot fully follow rule of thumb of the reference. 

 Following aerodynamic result is the best result in my resource
(Higher resolution mesh, Density based, and Implicit method requires too much calculation cost)

 My CFD setting reach maximum 20% discrepancy at M1.6 axial force, however, except that, M2.86 result seems reasonable. Prediction of normal direction force is reasonable for both M1.6 and 2.86. 

 Mach number contour at M2.86, AoA 12deg

Pressure contour at M2.86, AoA 12deg

Temperature contour at M2.86, AoA 12deg

Aeronautical Stuff in DX 2018 Korea

 I have visited DX 2018 in Ilsan of Korea at 15th Sep. 2018. I could see Apache, KF-X model, K-2 tank. And there is some demonstration of tank corps. 

 We could see updated feature of KF-X model, export version of K-2 tank (proposed status). 

Korean Apache helicopter with Surion (KUH-1)

Korean Apache helicopter with Hellfire, 2.75in rocket, and Stinger missiles

Standard armament load-out of Apache

Gurney flap with opposite direction is interesting

Best angle of Apache... probably

Updated feature of KF-X model after PDR

(separated control surface, extended fuselage)

Korean AAA with SRAAM (Biho) and Crotale Class SAM (Chunma)

Korean K-2 Tank

Korean K-1A2

Korean K-9 self-propelled gun with K-10 (ammunition supply vehicle)

Demonstration of Korean Army Corps

Initial Version of Missile-SIM for Performance evaluation

 Recently, I have worked some Python code for Missile-Rocket-Projectile Simulation having 2DOF.

 Because I could only simulate lift/drag characteristics of the missile body as shown in Fig. 5, my simulation is relatively simple. Full 6DOF simulation work have been developed for Matlab code when the full 6DOF data, inertia, center of gravity, moment coefficient, is available, however, in most cases, it is not available. 

 Most of my article in the past was relied on estimation of hunch or prediction from common sense, however, I realized better tool for estimation is required. Although, modification of past Matlab code is easier way, study of python code is also enjoyable. 

 As a future plan, I perform CFD for supersonic reference cases via ANSA + StarCCM while improvement for this code will be done. 

 After completion, analysis for Missile/SCRAMJET/Cruise Missile is on plan

Fig. 1. Part of code based on Python 3

Fig. 2. Sample of flight trajectory of missile

Fig. 3. Sample of output trajectory of Simulation

Fig. 4. Sample of output trajectory of Simulation - Plot of Speed, Altitude, Thrust, and Range

Fig. 5. Sample of CFD analysis plan

Hypersonic MIRV Air-to-Air Missile : 6th Gen. Fighter Killer?

* Related my previous articles for 6th Gen. Fighters (Also for Hypersonic MIRV Air-to-Air Missile)

   -> History of Air-warfare Part 2 (2017.04.21)
   -> French-German's proposal for replacement of Tornado jet (2018.01.28)
   -> USAF-2030 Commercial (2018.03.27)
   -> High AoA capability become useless in future air-warfare? (laser, stealth, hypersonic, etc) (2018.05.04)
   -> Current Technical Difficulties in Hypersonic MIRV Air to Air Missile (2018.05.10)
   -> Small-note-for-SRAAM and Their Futures (2018.05.23)
   -> French-German's proposal for replacement of Tornado jet (2) (2018.07.06)
   -> New-fighter-jet-for-UK:Tempest (2018.07.16)
   -> Example-of-booster-with-SRAAM : New Solution of Long-Range Air-to-Air Missile? (2018.07.20)
   -> More Information for UK's Tempest (2018.08.04)
   -> Small Note for Concept of 6th Generation Fighters : And Future Aerial-Warfare (2018.09.02)

  * Related my previous articles for Stealth Tankers (USN's MQ-25 and USAF's Stealth Tanker project)
   -> Boeing's-mq-25-candidate is revealed (2018.03.08)
   -> Lockheed's-mq-25-candidate is-revealed (2018.03.26)
   -> General Atomics'-mq-25-candidate is-revealed (2018.04.02)
   -> Additional-image-is-revealed-for MQ-25 of Boeing (2018.04.07)
   -> Additional-image-is-released-for MQ-25 of Lockheed (2018.04.09)
   -> Stealth-tanker-model-from-AFRL and Lockheed (2018.06.30)
   -> Boeing's design is Now MQ-25 (2018.08.31)
   -> Boeing MQ-25 - Additional Images (2018.08.31) 

1. Structure of Air-warfare prepared by Major powers
1.1. Basics of Tactics: Stealth / Network / Layering of Multiple Asset
 As described in my previous articles (links of foreword), concept of 6th generation fighter is hot issue recent days because it could be solution of countering J-20 and Pak-Fa, most dangerous threats for air superiority of western-world. Numerous concepts and their videos presented more-advanced-stealth, network capability, and usage of multiple platforms. 

First of all, the advanced stealth technology means broader range of stealth performance to consider counter-stealth technology, detecting old-stealth aircraft using L-band radar. More careful geometry design and RAM technology are adopted to make lower RCS of aircraft in broader range of radar frequency. In that aspect, aircraft become unavoidably larger because of size of radar wavelength. 

At last, network capability and usage of multiple asset are core of the 6th generation jet fighters; 6th generation fighters use not only their payload, information, reach, but also friendly asset’s. Gripen is regarded as one of the first aircraft to use that kind of concept in real-world; friendly aircraft guided launched missiles of others while launching aircraft could achieve higher probability of survival. Concept from Gripen gave impact on NATO-allies during training between Swedish force and other forces, and LINK 16 and other similar data-link system were developed to fight effectively. Network capability of 6th generation fighters will over the limit of the traditional capability; real-time data of all friendly air-space assets are integrated into 6th generation fighters. 

This kinds of integrated information make multi-layer tactics possible for 6th generation fighters, like air-fleet. Front line, relatively nearer to the enemy AD line, consists of relatively cheap and stealthy UCAV which could launch several type of ammunition or be eye of the fleet. In a second row, conventional 4.5th and 5th generation fighters are positioned to protect other high value assets or prepare close combat in a pinch; they also could command some part of UCAV fleet to accomplish the part of mission acting like small detachment from mother fleet. In the third row, final line of the air fleet, there are 6th generation fighters, some mother ship dispensing small UCAV or silver bullet type weapons, and stealth tanker for some cases. 


1.2. Perfect Picture of an Air-Strike Group : Combination of Tactics
Described components of forces in the previous paragraph consists air-strike group or air-fleet in the middle of the enemy air-space. It seems like concept of strike package of USAF, combination of attacker, fighter, bomber, SEAD, tanker aircraft, however, the new air-strike group targeted more flexible task than its predecessor. All of the components are well-stealthy to hide presence of their own, and well-connected to react quickly for un-expected situation change. Precise proportional ratio of the components could be changed by pre-determined mission plan. 

The air-strike group spread their ‘eye-asset’ to gather specific information for mission while rough area is already scanned by high performance sensors of the satellite, ISR aircraft, 5th and 6th generation fighters. The cheaper eye-asset is sometimes disposable and has lower performance sensors than that of high value platforms however, commander could deploy this cheaper one in relatively closer distance with some risks. 

Gathered information is collected and organized in real-time and re-spread to all friendly assets. Commander could choose optimized path for suppressing enemy air-defense system. In order to destroy or suppress high value air-defense system asset, like radar, command center, AWACS, or high end jet fighters, silver-bullet type weapons, high stealth cruise missile, long-range air-to-air missile, and hypersonic strike missile, are used because enemy air-defense system is still alive. Some conventional weapons could be deployed for distraction purpose hiding true purpose of hunting high value asset or giving additional burden for the system. 

After, the success of destroying back-bone of the enemy air-defense system, the separated enemy stealth jet and SAMs should be out of the game to degrade entire defense capability. Due to the effort of previous work, air-fleet has advantage in situation-awareness, and enemy stealth jet fighter just avoid the missile lock to be destroyed. However, as time left, friendly asset detour dead zone of enemy jet and finally locked on. At the final stage of the fight, enemy jet realized that they are under attack and try to counter attack. Enemy missiles for counter attack is intercepted by MDSM or DEW to block any possibility of loss of friendly asset. 6th generation fighter takes large part in the role of information integration, commanding, deploying silver-bullet weapon, and defense of other friendly assets via soft-kill and hard-kill of enemy projectile. 

While 6th generation fighters act like Aegis ship of the naval fleet, small UCAVs start their role as punch of the fleet, carrier borne aircraft. After, high-end air-defense system is collapsed, every miscellaneous asset is targeted by fleet components. At this stage, conventional ammunition could be used by every platform in the fleet, and loitering time of the fleet is extended by stealth tanker in the area without taking risk. Actually, previous (hard) stage of war is only shown in day 1 or 2 for most of the country except few major countries of air-warfare. Indeed, in some perspective of view, most components of the air-fleet are very expensive, however, problem is that it is the cheapest way for suppressing advanced air-force armed with 5th generation fighters. 

If air-force try to overwhelm other well-armed air-force in day 1 mission, air-force requires a lot of overwhelmingly well-armed fighter which could beat enemy air-force’s top jet fighter. However, this fleet strategy mechanism minimize number of required expensive jet fighters in their inventory. Due to the effort of network capability, 6th generation fighters and their fleet do not have to massive number of aircraft; part of fleet, stealth tankers compensate small number problem of 6th generation fighter. 

Fig. 1.1. Concept of 6th generation fighters with their friendly assets; they consist of UCAV, 5th and 6th generation fighters, mother ship of UAV while AWACS or satellite can be used to give better situation awareness. 


 
2. New Counter for Major powers
The air-fleet tactics described above seems to be hard to resist without having similar fleet, however we always have to find answers to counter the new armada of 21st century. Basic idea of countering any concepts could be shown in Fig. 2.1. Most dangerous aspect of the fleet tactics is their superiority in information; they hide their presence and attacking direction. Based on this superiority, they could focus on their asset and defense easily. In the following paragraph, I attempt to idea for countering air-fleet strategy. 

Fig. 2.1. Brain-Storming of counter-air-fleet; problem of sensing stealth fleet, giving massive burden on their defense line, separating fleet are major task to encounter the fleet. 


2.1. Sensing Presence of Air-Strike Group
Probably it is the most difficult work among countering task; most of the fleet components will have good stealth performance and try to search and destroy any counter-stealth sensors. Some kinds of IR sensors, L-band, optical-path radars are proposed. However, performance of these are limited, and platform of these cannot guarantee survival from the fleet. 

The best way to sense the presence of the fleet could be image from optical, radar, and multi-spectral payload of satellite. For radar, velocity components of the aircraft in the atmosphere is almost vertical to the line of sight of the satellite, and aircraft is not easy target by using Doppler method. In most case, high speed image integration for multi-spectral range is required to sense the presence of the fleet. Fortunately, size of some sort of fleet is relatively large like 6th generation fighters and stealth tankers; their size help sensors to find their position from the space. 

Sensing the jet fighter from the space altitude means it requires several satellite with expensive payloads to monitor their air-space in anytime. Indeed, in cost perspective, it could not be ideal solution, however, notification method in air-space for air-fleet become almost impossible. Sensor from diagonal or side direction could another option however, knowing exact angle for the air-fleet itself is also not easy. 


2.2. Sudden Strike of Hypersonic EMP/MIRV Air-to-Air missiles
After the sensing the air-fleet via sensor payload in the space, counter force should move quickly before their system is under attack. As shown in Fig. 2.2, multiple shot of hypersonic MIRV and EMP missile should be used; it is the core of this tactics which can break defense system. Hypersonic air-to-ground missiles are recently introduced; there is no hypersonic MIRV type air-to-air missile yet. However, break of multi-layered air-defense system could be only done by a brand new hypersonic MIRV air-to-air missiles. 

Usage of the new missiles concept is shown in Fig. 2.2; ballistic trajectory of the missile allows multi-directional attack from the top altitude which cannot be covered easily by current technology of the air-fleet. It means re-action time of the defense system is significantly reduced while re-action time of the hypersonic projectile is already much shorter than that of conventional supersonic missiles. 

1st group of the missile is EMP warhead which neutralize electromagnetic devices back-bone of the air-fleet system and UCAVs. 2nd wave of the missile should be hypersonic MIRV air-to-air missiles targeting separated assets. MIRV type warhead save the cost per kill and reduce the chance of interception via DEW and MDSMs. It is definitely similar to implementation of supersonic anti-ship against Aegis ship in the 80’s; reducing re-action time using speed and multiple shot of missile are adopted in this concept. Difference between the concept of the 80’s and the hypersonic MIRV is separated warhead from one unitary missile for saving. 

Fig. 2.2. Usage of Hypersonic MIRV missiles; as the first stage of sudden attack, multiple shot of hypersonic MIRV missiles are required to distract attacking direction and give maximum burden for defense system of the fleet. 



2.3. Hunt of Separated Assets
After downing some important assets like 6th generation fighters, AWACS, or stealth tankers capable of commanding other air-asset and giving DEW/MDSM umbrella, the air-fleet is degraded as individual sum of the jet fighters from 5th generation to remained UCAV. Counter-force should care about the fact that the sum of individual is still stronger than most average air-force fighters. 

It is the time to dispose cheap UCAV from the counter-force to treat the air-fleet; fortunately, in that stage, out-numbering of cheap weapon could be effective. Some 5th generation fighter still fight effectively against the counter-force, however, amount of ammunition in 5th generation fighter is limited. In order to save the cost, low-speed stealth UCAV cruiser launches missiles, and this cannot be profitable game for air-fleet. 

Fig. 2.3. Summary of counter for air-fleet concept driven by 6th generation fighters. 

Fig. 2.4. Hunting of separated fighters are relatively easier than that of entire air-fleet, but still, it is not easy. 


 
3. Consideration of Technologies and Logic
3.1. Technical Difficulties and Requirement for Hypersonic Air-To-Air MIRV Missiles
Contents of this part is basically same as the previous articles as shown in below. 
Link for [http://jaesan-aero.blogspot.com/2018/05/small-note-for-1-131-current-technical.html]


3.2. Decision Logics and Required Data Base for New Generations 
Contrary to the idea described above, we could assume that 6th generation fighter integrates the hypersonic MIRV missiles as their new silver bullet. Maybe this is the most fearful advantage of the 6th generation fighter because it can integrate almost anything using its massive payload capability. At that stage, now no one argues the aerodynamic performance of the platform itself; for example, after WWII, no one argues hydrodynamic performance of the ship. Only concern is what and how many weapon they load for ship with reasonable range and sensor capability. As shown in the air-fleet concept, focus for performance of the fleet is now gone from aerodynamic to payload, sensor, and self-defense capability. 

More importantly, un-seen capability, decision logic of the behavior of asset become crucial factor of the air-force. As air-warfare become complex and time-shortening environment, decision speed of the human cannot track all of the situation change. Even full-integrated 6th generation fighters with one additional crew is hard to analyze whole battle field picture. Major countries will not make mistake of Vietnam war that how complex electric equipment became ineffective in unexpected situation. Indeed, careful design will focus on reduction of decision burden for human pilots. Then, most part of the air-combat will be automatic like recent weapon system of the ship or submarines. Pilots will only command the rough direction of the asset like command RTS games. 



4. Conclusion and Further Development of Air-warfare
 In the article, I showed concept of the 6th generation fighter as an air-fleet and possible counter concept using hypersonic MIRV air-to-air missiles. Current situation seems like end time of the warship at the end of WWII; focus is changed from platform to its payload including weapon and sensor. Air-warfare become more complex and fast in temporal aspects; automation of specific air-combat action should be important in near future. 

 In further future, boundary between space and air is blurred. As already described in the counter tactics, integrated sensing from the space is essential in the near future. Furthermore, projectile from space could affect outcome of the atmosphere. Big mothership like jet provide almost unlimited energy for their asset via wave energy transfer and ammunition via DEW. All of these expectation is possible to be realized. 

Small Note for Concept of 6th Generation Fighters : And Future Aerial-Warfare

* Related my previous articles for 6th Gen. Fighters (Also for Hypersonic MIRV Air-to-Air Missile)

   -> History of Air-warfare Part 2 (2017.04.21)
   -> French-German's proposal for replacement of Tornado jet (2018.01.28)
   -> USAF-2030 Commercial (2018.03.27)
   -> High AoA capability become useless in future air-warfare? (laser, stealth, hypersonic, etc) (2018.05.04)
   -> Current Technical Difficulties in Hypersonic MIRV Air to Air Missile (2018.05.10)
   -> Small-note-for-SRAAM and Their Futures (2018.05.23)
   -> French-German's proposal for replacement of Tornado jet (2) (2018.07.06)
   -> New-fighter-jet-for-UK:Tempest (2018.07.16)
   -> Example-of-booster-with-SRAAM : New Solution of Long-Range Air-to-Air Missile? (2018.07.20)
   -> More Information for UK's Tempest (2018.08.04)

  * Related my previous articles for Stealth Tankers (USN's MQ-25 and USAF's Stealth Tanker project)
   -> Boeing's-mq-25-candidate is revealed (2018.03.08)
   -> Lockheed's-mq-25-candidate is-revealed (2018.03.26)
   -> General Atomics'-mq-25-candidate is-revealed (2018.04.02)
   -> Additional-image-is-revealed-for MQ-25 of Boeing (2018.04.07)
   -> Additional-image-is-released-for MQ-25 of Lockheed (2018.04.09)
   -> Stealth-tanker-model-from-AFRL and Lockheed (2018.06.30)
   -> Boeing's design is Now MQ-25 (2018.08.31)
   -> Boeing MQ-25 - Additional Images (2018.08.31) 

1. Background of 6^th Generation fighter

1.1. Big ice age for jet fighters: Collapse of Soviet Union and War on Terror

 As described in the previous articles or numerous phenomenon in aerospace industry, after collapse of Soviet Union in 1990’s, development of a new air-warfare weapon became sluggish or even cancelled like A-12 of USN or RAH-66 of Army as shown in Fig. 1.1. This event made USN, USAF and air-borne of US army concentrate exhausted CAS missions; fancy maneuverability or acceleration/speed was no longer required for Afghanistan or Iraq. Russia, descendant of Soviet, lost their willing for new fighters because of their economic chaos; only demonstrators like MiG-1.44, Su-37, or 47 were in show-window.

 Frankly, about for 25 years after the collapse, there was no equivalent rival for F-15 with AIM-120C, and this had been proved by record; most of the Su-27 series were limited in usage of R-27. War on Terror and sub-prime mortgage consumed certain part of the defense budget, and there was no room for ‘already-the-best-area-of-USAF’; amount of production for F-22 was also reduced. USN should adopt F/A-18E/F as replacement of glory F-14 and A-6 for cost reason; Congress did not allow expensive stealth jet for ‘GBU-truck’ missions.

 F-22 and F-35 was the latest jet fighters developed by US just before end of the Cold War; F-22 pursued for countering-all-imaginable-threat while F-35 tried to make entire air-fleet as sum of F-16 and F-117 with reasonable(?) cost. This kind of approach still showed glimpse of Cold-War age idea which try to overwhelm rival Russia in every aspect. Naturally, these had been criticized by internal enemies arguing their cost. It looked reasonable that special ability for day-1 strike was no-longer represented in Pax-Americana, and all-stealth of entire air-fleet is still argued topic for constitute of high air-command. So, it is not surprising that proliferation of unmanned concept for reducing ‘human-exhaust or risk’ and cost was fancy at that time. Mission of ISR or police type patrol could be replaced by relatively simple platforms, and few of them bear fruit like MQ-1, 9 or Global Hawk.

Fig. 1.1. Two typical example of “Cancelled as Collapse of Soviet Union”, A-12 and RAH-66; Cost is not only problem for these, also ‘too-strong-or-expensive’ for War-on-Terror. They lost their primary adversary at early 90’s.

Fig. 1.2. The two latest jet fighter projects of US, F-22 and 35, were criticized for its in-effectiveness in cost for Ice-age, however is it right again for new Cold-War age?

1.2. Advent of T-50 and J-20

As the US have struggled in desert, global power of Russia was partially restored, and Chinese pursued regional power in western Pacific. Aspiration of the two countries was proved by prototype of T-50 and J-20 as shown in Fig. 1.3, challenging air-superiority of US. Two aircraft is similar or larger than F-22; clearly they pursue super-cruise, stealth, and high maneuverability performance like that of F-22. Still, exact performance of the two are in fog via unfinished development of them, however it clearly showed long-lived high teen series will face end of their prime time. If we changed our focus from ‘common between F-22 and its rivals’ to ‘differentiation’, physical size of the two fighters are noticeable. They prepare long range missions to cover their deep territory or have intention to penetrate air-space.

Penetration of air-space with long range is essential for 1^st class of air-superiority fighters requiring sniping of prime assets guarded by their own escort fighters like AWACS, Tankers, and Bombers. That kinds of mission profiles were limitedly supported by Su-27 class fighters in Cold-War age with specially designed air-to-air missiles, Kh-31A/P or KS-172. Proof of the intention is clearly shown for these fighters; both fighters have deep internal weapon bays for long range missiles like new R-37M class as shown in Fig. 1.3. With combination of enhanced long range missiles and stealth performance of them, threat for US air-superiority is not only for front-line fighters also for the prime assets.

Contrary to Chinese and Russian, European did not show any noticeable movement related to development of fighters like F-22, J-20, or T-50. They have struggled much time for Eurofighter and Rafale, and satisfied a few number of F-35 during the Ice Age of jet fighters. They have concentrated development of cruise missiles and UCAV projects for Day-1 Strike missions.

Fig. 1.3. J-20 (Top) and T-50 (Middle) are result of two countries challenging air-superiority of USAF and USN. Bottom view of T-50 (Bottom) shows R-37M class long range missiles (blue) could be carried internal bay of the T-50.

1.3. Current Limit of 5^th Generation fighters: Range/Loitering of Current Platform

USAF and USN are the most sensitive forces in the world for the range and payload of their platform because they always did offensive role in the air-warfare. So it is not strange that size of US jet fighters is mostly bigger than their counter part except few bizarre Soviet interceptors, Yak-128, MiG-25 and 31. As shown in the Fig. 1.4, F-22 and F-35 invest much of their internal space for fuel, however, basically, stealth performance requires limitation of external fuel tank and consume internal space as weapon bay, then, leads to short range.

Advent of enemy’s advance air-defense system including fighters (J-20, T-50, and J-31) and SAMs (S-300, 400, and 500) aggravate the situation worse as it limits ‘safe-range’ from enemy territory for aerial refueling or external fuel tank. Also it is bonus that Russia and China has very deep offensive depth via size of their land. For F-22, 1^st capable super cruiser, problem is not negligible; advantage of super-cruise is unavoidably consuming a lot of fuel.

Fig. 1.4. Internal fuel tank layout or cutaway of F-22 (Top), F-35 (Middle), and T-50 (Bottom). As attachment of external fuel tank is limited by stealth, space for internal tank become more important.

2. Concepts of 6^th Generation fighters

After advent of J-20 and T-50 for 10 years, whether western countries developed 5^th generation fighters or not, western counter parts showed their plan for the jet fighters breaking the ice age. Fortunately, their plan is well summarized in Fig. 2.1 with uncertainties; political, technical, or budget issues always changed what they planned. Among the planned fighters, T-50 and J-20 are the initial triggers for the other jet fighters; from the plan, absolute advantage of US’ F-22 and F-35 will be challenged by Russian and Chinese at 2020, and US’ answer will be prepared at 2030.

Plan for other fighters like India, Korea, Turkey, Japan is uncertain to ‘overwhelm’ the Chinese and Russian due to lack of experience for leading air-warfare technologies. Even in the Korean case, target of the jet fighter performance is limited in 4.5^th generation fighter for Block I; full performance of Block III is expected to be slightly worse than 5^th generation fighters. Project of India always suffers long delay as shown in the project of Tejas. Turkish has lack of experience in full-scale jet fighters like Korean while Japanese has possibilities of conducting better fighter than others. However, willing to develop Japanese fighter is still uncertain.

Indeed, this article focuses on 6^th generation fighter projects related to US, French-German, and UK having possibility to overwhelm J-20 and T-50.

Fig. 2.1. Plan/situation of jet fighter development; about 2030, picture of air-warfare will be changed.

2.1. Common Goals presented in Concepts

Few pictures of known projects, F/A-XX, F-X, FCAS, and Tempest are shown in below from Fig. 2.2 to Fig. 2.5; all of these are still in CG concept level. We could speculate some common characteristics from these eye candies. All of them targeted extremely large platform size as fighter. Although few of them has same physical size of conventional fighters for length and span, expected payload and internal volume is much bigger than current 4^th and 5^th generation fighters; huge delta wing with or without tails committed it. That kind of external configuration of the jets means more loitering time/range/payload is emphasized rather than conventional dog-fighting or maneuvering. Actually, that kinds of tendency for maneuver in transonic region was already in the road of decline as R-73 emerged. Advanced SRAAMs including MICA-IR, ASRAAM, IRIS-T, R-74, Python-5, and AIM-9X already overwhelmed maneuverability of human-driven jet vehicle limited by physical condition of human (http://jaesan-aero.blogspot.com/2018/05/small-note-for-short-range-air-to-air.html).

Fig. 2.2. Few concept CG related to 6^th Generation fighters for F-X of USAF from Northrop (Top), Lockheed (Middle), Boeing (Bottom)

Fig. 2.3. Few concept CG related to 6^th Generation fighters for F/A-XX of USN from Boeing

Fig. 2.4. Few concept CG related to 6^th Generation fighters for France-German (FCAS)

Fig. 2.5. Few concept CG related to 6^th Generation fighters for UK Tempest

Indeed, all of the published concepts seems to focus wide range of weapons including DEW to cover short range engagement; combination of short range missiles and DEW act like RAM and CIWS of modern destroyers. It means new generation of fighters did not act like individual vehicle also take role of modern ship having complex layer of defense and offensive payloads. In order to keep the jet flyable status with various payloads, advanced engine is also proposed by GE and Rolls Royce which uses adaptive variable cycle engine as shown in Fig. 2.6. It is not certain that other aircraft like FCAS will carry the variable cycle engine however, similar technology should be attained to FCAS as one of competitive contender. Concept of the engine is basically controlling the bypass ratio of the jet to maximize its fuel economy; saving power is directly connected to magazine of the DEW.

Not only for its self-defense, also weapon for offensive punch already start its race as shown in Fig. 2.7. Recent race for hypersonic weapon is not irrelevant to this trend because ace in the hole for the 6^th generation fighter would become hypersonic missile or glider to penetrate enemy air-defense. Miniature version of ‘Kinzhal’ missile will be popular and large volume of internal bay should be prepared for that kinds missiles. Although performance of stealth, sensors, or network capabilities are not represented in fancy art or OML shape, to maximize effectiveness of payloads or hardware of the jets, numerous videos already emphasized wide range of stealth, fused-sensors, and network capabilities with UCAVs. Commercial of USAF (http://jaesan-aero.blogspot.com/2018/03/usaf-2030-commercial.html) or replacement of tornado jet fighter by Airbus as shown in Fig 2.8 and 2.9.

Conventional jet fighter will RTB when they use all of their payload however, 6^th generation fighters loiters air-space to control or provide precise ISR information to friendly air-asset. It maximized not only performance of own, also of friendly forces; it represented reality that even major countries could not replace all of their jets using 6^th generation fighters. Co-operating with previous generation jet fighter or UCAV essential.

Certainly Common things in Concepts

l  Large platform for payload/endurance

l  Highly Stealth

l  ISR performance with network capabilities

Fig. 2.6. Concept of variable cycle engine by GE; it is not surprise that YF-120 had proposed similar configuration.

Fig. 2.7. One of ‘Silver Bullet’ type weapon developed for F-35 or 6^th generation fighters; highly stealth or hypersonic weapon will be carried inside of the jets for day-1 strike mission.

Fig. 2.8. Network capabilities with friendly asset is continuously shown in commercial of 6^th generation fighters (Airbus)

Fig. 2.9. Network capabilities with friendly asset is continuously shown in commercial of 6^th generation fighters (USAF 2030)

2.2. Discrimination between Concepts

Table 1 Summary table for common and different things of 6^th generation fighters’ concepts

Previous paragraph described common goals and concepts of the jets however, even in the CGs, there are some differences as shown in Table 1. First of all, we selection of seat # for each concept; most of concepts choose single seat while FCAS and F/A-XX for two seat (even F/A-XX could be unmanned). FCAS emphasized endurance on the enemy air-space and ISR role, and naturally leads to additional crew. Requirement for F/A-XX might be similar if F/A-XX replace EA-18G and F/A-18E/F series. Other jets like F-X or Tempest also emphasize that way however they show no sign of additional crew behind the pilot. We could assume that USAF has enough resources to cover needs of additional crew for the fighter, however, USN or French-German’s should cover various role in limited number of sorties.

As described in the figures and descriptions, all of the 6^th generation fighter jet has large planform of the wing however, in the configuration of the tails, there is some differences. While others deleted HT as pitch control, tail surface of Lockheed still remained. Actually, Northrop’s one seems like big warship than conventional fighters, so it is the most radical approach among 6^th generation fighters. Also, it is the only Northrop that air-inlet is installed upper surface of the jet and deleted TVC; upper inlet and deletion of TVC shows worst performance in conventional maneuver in air combat. Approaches of F/A-XX from Boeing, FCAS and Tempest is between Lockheed and Northrop; LEVCON of FCAS, TVC of Tempest and F/A-XX compromise between conventional maneuverability and warship like concepts.

As a payload of 6^th Generation fighters, DEW is the most controversial thing; degree of maturity of DEW and other RAM style weapons, SACM and MDSM, determine dependence of conventional maneuverability. As the Northrop one more depend on technological maturity of such things, their jet become warship like bigger one. 6^th generation fighters of US and UK definitely showed concept of usage of DEW while French-German one is in uncertainty. UK Tempest, revealed at most recently, showed concept of carriage of UCAV inside of IWB; in US commercial, transports or bombers will be specialized for this duty. Or maybe in USN, unmanned module is installed in F/A-XX to cooperate manned version.

2.3. Advent of Stealth Tankers

Stealth tanker proposal is another issue for USAF and USN; both are planning to develop own stealth tankers. If the tactical aircraft is non-stealth, stealth tanker itself is not pursued. And also, every tanker could not be stealth because of cost. Indeed, we could speculate stealth tanker will be member of team which consists of stealth tanker + 6^th generation fighter + 5^th generation fighter + UCAV + swarm of drones. That kinds of package replace conventional strike package which is armada of air fleet before stealth technology was emerged. As shown in Fig. 2.10 and 11, USN and USAF currently develop stealth tanker while USN proceed further; they already receive competition of three companies, Boeing, General Atomics, and Lockheed.

Advent of stealth tanker and long range/endurance of 6^th generation fighter is not irrelevant. As the threat from J-20 and Pak-Fa become invisible and their military depth of air-defense is deeper, whole components of the strike package is under the threat. Cost of 5^th and 6^th generation fighter is rising; they should cover longer time of campaign with limited number of jets. It means whole strike package require large amount of fuel in one sortie, however, no tactical level jet could carry massive internal fuel for that requirement. MQ-25 of USN and Stealth tanker of USAF will never refuel for their aircraft in the enemy air-space, however, their stealth performance significantly reduces the distance from enemy air-defense system where refuel is managed. So, adaptive-variable cycle engine, large platform, and stealth tanker make synergy for perfect overwhelming of enemy air-space in spatially and temporally.

Fig. 2.10. MQ-25 : USN’s new stealth tanker

Fig. 2.11. One model of USAF’s Stealth tanker is shown.

3. Conclusion and future of further

Author had written short review for 6^th generation fighters with limited information; most of them could be changed as concept is matured. Actually, need for 6^th generation fighter was sluggish until threat of J-20 and Pak-Fa was realized. As they challenged technological superiority of old-western world, current edge of US Aerospace technology, F-22 and F-35 expose their weakness, high cost, short range for long depth, and small-payload.

Revealed 6^th generation fighters commonly emphasize large platform for flexibility/range/payload/enhanced capability of ISR with stealth performance. Another aspect of the concept is co-work with previous generation fighter, UCAV, and stealth tankers. Advertisement of previous generation fighters always emphasized simple-overwhelming of pre-previous ones, and recommend air-forces to replace all of their jets. However, as cost of jet fighter rises sky-rocketing, number of 6^th generation fighter is under the pressure. So the concepts have studied more about co-operation capability with other assets of forces, and try to maximize overall effectiveness of sorties. Unlike 5^th generation fighters, 6^th generation fighter does not pursue winning every aspect of previous generation fighters; the new planned fighter will take the leading role of the fighting group, containing 6^th and 5^th generation fighters, UCAV, and even with stealth tanker.

As they limited their role in aerial warfare, it is hard to imagine the new fighter perform fancy maneuver; DEW and small munitions guard the fighter or other friendly jet like Aegis warships. Fight of aerial fleet having multi-layered weapon and vehicle become more systematic than fight in the past. Even the new weapon emerges like hypersonic MIRV air-to-air missile (https://jaesan-aero.blogspot.com/2017/04/1-high-aoa-aerodynamics-for-combat_21.html), the fleet just need absorb the new weapon as one of their spear. It is interesting to see how evolve these concepts until 2030s.