faithfulguy
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Brace yourself for Indian attacks. How many have called you a Muslim or Pakistani?
India's Light stealth aircraft.
- Thread starter MULUBJA
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Brace yourself for Indian attacks. How many have called you a Muslim or Pakistani?
MULUBJA
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You guys are just...
Well, I am lost for words.
You can start copying prperation or stealing the design.
MULUBJA
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Something on design from designer.
>>>>> Let me tell you all that we have completed the CFD analysis of LSA using a 5% airfoil designed by me. and we did it for LSA with 50* sweepback and also for 57* wing of Mig-21. The data supports Mig-21 wing for LSA. This is based on the fact that LERX add lot of lift to a highly swept wing but the L/D ratio suffers as the drag rises accordingly. Using a 72Kn EJ-230 engine, I am able to overcome this handicap and convert it into advantage. Higher alpha for 9G load out means that a large amount of thrust will also contribute to centripetal force which in turn will reduce the requirement for over all lift. This in turn will reduce the corner velocity which will result in much higher turn rates as the load factor is dependent on the cosine of bank angle.
On alternate engine
>>>HTFE-25 was test run in mid Dec 2015 in the presence of DM. This engine has growth potential to hit 40KN dry. The equivalent Ukrainian engine has an afterburner version delivering 41KN thrust. Keeping those figures in mind, I have suggested upgrade of HTFE to 35KN thrust with French help and 56KN wet thrust. the engine of choice for LSA is EJ230 with 72 KN dry and 103KN wet thrust. In twin engine configuration HTFE-35 will be excellent for LSA.
HTFE-25 with a weight of just 350kgs and length of 1.73m and fan diameter of 590mm is probably the smallest engine in this thrust class and seems far superior to even Honeywell F124/125 engine.
>>>>> Let me tell you all that we have completed the CFD analysis of LSA using a 5% airfoil designed by me. and we did it for LSA with 50* sweepback and also for 57* wing of Mig-21. The data supports Mig-21 wing for LSA. This is based on the fact that LERX add lot of lift to a highly swept wing but the L/D ratio suffers as the drag rises accordingly. Using a 72Kn EJ-230 engine, I am able to overcome this handicap and convert it into advantage. Higher alpha for 9G load out means that a large amount of thrust will also contribute to centripetal force which in turn will reduce the requirement for over all lift. This in turn will reduce the corner velocity which will result in much higher turn rates as the load factor is dependent on the cosine of bank angle.
On alternate engine
>>>HTFE-25 was test run in mid Dec 2015 in the presence of DM. This engine has growth potential to hit 40KN dry. The equivalent Ukrainian engine has an afterburner version delivering 41KN thrust. Keeping those figures in mind, I have suggested upgrade of HTFE to 35KN thrust with French help and 56KN wet thrust. the engine of choice for LSA is EJ230 with 72 KN dry and 103KN wet thrust. In twin engine configuration HTFE-35 will be excellent for LSA.
HTFE-25 with a weight of just 350kgs and length of 1.73m and fan diameter of 590mm is probably the smallest engine in this thrust class and seems far superior to even Honeywell F124/125 engine.
If that copy flies earlier and actually works as advertised; that will only make them look smart.
Point being, pragmatic and effective projects that deliver are what India needs; not mismanaged pies in the sky.
MULUBJA
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On war scenario from designer
>>>>>LSA
Passive radars, jammers, LPI radars & IRST take away most of the advantages of stealth. Stealth fighters no longer have Situational Awareness advantage as smaller fighters will be detected later, irrespective of any expensive radar or Low Observation measures applied to larger fighters. Reliance on passive sensors and visual detection will remain the most potent means to gain advantage in any future battle. For BVR combat, stealth fighters are based around idea of radar-based BVR combat which requires active emissions. This in turn surrenders Situational Awareness advantage to the opponent by allowing opponent to identify and engage it from BVR completely passively by giving opponent starting advantage in OODA loop. Radar can be jammed and suffer from high complexity, high cost & low reliability which translate into per-missile Pk ≤0,08 between capable opponents. BVR is only effective against far less capable and less numerous opponents as 10-15 seconds time is required for electronic acquisition for cooperative targeting and that will bring opponent closer by nearly 7-9 Nm depending upon speed and thus exposing complex aircraft to higher risk of being detected.
WVR combat requires large force size & low cost aircraft which provide high sortie rate which will retain the advantage of situational awareness, better cockpit visibility and sensor coverage with high manoeuvrability, faster transients thru very short turn- around time to provide increased high sortie rate. For WVR combat we need an aircraft which has low wing loading, quick acceleration and climb, low drag, high thrust-to-weight ratio, good combat persistence, low drag for high fuel fraction. Aircraft which uses best weapons for reliable kills to achieve high Pk carries adequate ammo & spends minimum time-on-target with minimum vulnerability to countermeasures (simple targeting process) are the need of the modern day air combat. IR jammers make IR missiles more vulnerable to countermeasures so reliance on WVRAAMs with FPA & IIR abilities and return of gun-only dogfights will remain important.
contd.............
strengths,
I fully agree with you and I appreciate the smartness of Chinese.
>>>>>LSA
Passive radars, jammers, LPI radars & IRST take away most of the advantages of stealth. Stealth fighters no longer have Situational Awareness advantage as smaller fighters will be detected later, irrespective of any expensive radar or Low Observation measures applied to larger fighters. Reliance on passive sensors and visual detection will remain the most potent means to gain advantage in any future battle. For BVR combat, stealth fighters are based around idea of radar-based BVR combat which requires active emissions. This in turn surrenders Situational Awareness advantage to the opponent by allowing opponent to identify and engage it from BVR completely passively by giving opponent starting advantage in OODA loop. Radar can be jammed and suffer from high complexity, high cost & low reliability which translate into per-missile Pk ≤0,08 between capable opponents. BVR is only effective against far less capable and less numerous opponents as 10-15 seconds time is required for electronic acquisition for cooperative targeting and that will bring opponent closer by nearly 7-9 Nm depending upon speed and thus exposing complex aircraft to higher risk of being detected.
WVR combat requires large force size & low cost aircraft which provide high sortie rate which will retain the advantage of situational awareness, better cockpit visibility and sensor coverage with high manoeuvrability, faster transients thru very short turn- around time to provide increased high sortie rate. For WVR combat we need an aircraft which has low wing loading, quick acceleration and climb, low drag, high thrust-to-weight ratio, good combat persistence, low drag for high fuel fraction. Aircraft which uses best weapons for reliable kills to achieve high Pk carries adequate ammo & spends minimum time-on-target with minimum vulnerability to countermeasures (simple targeting process) are the need of the modern day air combat. IR jammers make IR missiles more vulnerable to countermeasures so reliance on WVRAAMs with FPA & IIR abilities and return of gun-only dogfights will remain important.
contd.............
strengths,
I fully agree with you and I appreciate the smartness of Chinese.
Congratulations on rediscovering the results of the Mig-21 Analog which the Russians tested back in the mid 60s. Basically "reinventing" the wheel.
The future lies in the MCA. Light fighters and stealth DO NOT HAVE COST EFFECTIVE RESULTS
MULUBJA
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On warefare with 4th generation and fifth generation aircraft.
EFFECT OF LSA ON AIR WARFARE - At the tactical level LSA will have a large impact in Beyond Visual Range and Within Visual Range air combat. Most recent analyses of relative air combat capabilities assume that BVR combat will arise much more frequently than WVR combat. The basis of this assumption is that opposing air combat capabilities are easily detected and tracked by ISR systems, permitting fighter aircraft to choose the time, place and type of engagements to an advantage. This assumption collapses if the opposing fighter has significant VLO capability, as the LSA will have. The result is that attacking LSA will have to be engaged at much closer ranges than existing non-stealthy threats, as they enter predictable geometries, when attacking high value targets such as AWACS/AEW&C platforms, tankers, or defended surface assets. Another important qualification is that the extreme agility of the LSA will significantly degrade the kill probability of all Air to Air Missiles, (AAM) especially though the AIM-120 AMRAAM, which will be challenged to sustain the necessary manoeuvres to defeat the LSA. Like the F-22A Raptor, the LSA will provide a significant capability for the kinematic defeat of inbound missile shots.
A radar cross section of only -20 dBSM would deny early Beyond Visual Range (BVR) missile shots using the AIM-120C/D AMRAAM to all current and planned fighters. Doing any better, like -30 dBSM or -40 dBSM, simply increases the level of difficulty in prosecuting long range missile attacks. The consequence of this is that missile combat will be compressed into shorter distances and shorter timelines, putting a premium on the stealth, supersonic persistence and close combat agility of fighters. A larger portion of engagements will be at visual range, and most BVR engagements will end up taking place inside 25 nautical miles. In Beyond Visual Range combat, the combination of supersonic cruise and competitive VLO performance will allow the LSA to emulate the tactics developed for the F-22A Raptor. The LSA can thus be expected to produce greater lopsided air combat exchange rates to those achieved by the F-22A Raptor when flown against legacy fighters. Even if the LSA was only to attain half of the effectiveness of the F-22A Raptor, it will still yield BVR exchange rates of the order of 50:1 against legacy fighters. The arrival of the LSA therefore irrevocably enforces the end of the operational usefulness of the 4th generation of fighter aircraft in the traditional fighter roles of air superiority, air defence and tactical strike in contested airspace. These aircraft will retain operational utility only in permissive environments, where neither the LSA is deployed nor is able to be deployed. No less interesting is the impact at a tactical level when the LSA is flown against the F-22A Raptor. Fights between the F-22A and the LSA will be close, high, fast and lethal. The F-22A will neither get ‘first look’ nor “first shot” with the APG-77, the Advanced Infra Red Search and Track (AIRST) sensor having been deleted to save money, but the LSA will get “first look” & ‘first Shot’ using its advanced infrared sensor. Then, the engagement becomes a supersonic equivalent of the Battle of Britain or air combat over North Korea. The outcome will be difficult to predict as it will depend a lot on the combat skills of the pilots and the capabilities of the missiles for end-game kills. There is no guarantee that the F-22 will prevail every time. The tactical impact of a low cost LSA is therefore a loss of the overwhelming advantage provided until now by the F-22A Raptor. Flown against the LSA, a decisive outcome can only be guaranteed by numerical superiority of the F-22A force in theatre.
The arrival of the LSA therefore also irrevocably enforces the end of the operational usefulness of the F-35 Joint Strike Fighter, defined around a 1990s technology threat spectrum, in the traditional fighter roles of air superiority, air defence and tactical strike in contested airspace. The F-35 will retain operational utility only in permissive environments, where LSA is not deployed. The operational impact of indecisive combat loss exchange rates between a low cost LSA and the F-22A Raptor, and very high F-35 Joint Strike Fighter loss rates against a low cost LSA will have major implications at an operational level, and consequently, at a strategic and political level. Once the LSA is deployed within a theatre of operations, especially if it is supported robustly by counter-VLO capable ISR systems, the adversary will no longer have the capability to rapidly impose air superiority, or possibly even achieve air superiority. This will not only deny the adversary access to an opponent's defended airspace, it also presents the prospect of adversary being unable to reliably defend in-theatre basing and lines of resupply. Should this occur, in-theatre basing and surface assets become exposed to air attack by aircraft armed with a wide range of accurate and highly lethal Precision Guided Munitions, with the potential for very high loss of life and equipment deployed in theatre.
The deployment of a low cost LSA into such an environment very significantly increases risks to adversary forces, as the aircraft can credibly challenge the F-22A Raptor in air combat. While the intended survivable strike/ISR aircraft may, eventually, provide a credible capability to penetrate advanced anti-access capabilities, and thus attack opposing airfields, it will need to be defended against the LSA, and airfields deploying this aircraft will also need to be defended against LSA tasked with counter-air strike missions. The adversary will be denied access to any operational theatre into which credible numbers of the LSA are deployed. In turn, the adversary will be deterred from the use of conventional forces in such a scenario. The consequence of this, in turn, is that significant pressure will be placed to threaten the use of, or operationally use, tactical nuclear weapons. The only practical low risk option available is to deploy over this decade large numbers of advanced fighter aircraft which are competitive against the LSA in air combat. The proposed “sixth generation fighter” is not a viable contender in this time frame. The F-35 is not competitive and cannot be made to be competitive due to basic design limitations in aerodynamic and VLO shaping performance. The only aircraft which can survive in airspace contested by the LSA is the F-22 Raptor, and given the time frame of interest, it is the only design which can be adapted to defeat the LSA. The Ghost is by Western standards a low risk design, following the philosophy of “evolutionary” design, rather than the “Big Bang” approach currently favoured in the West, of trying to start from scratch with most or every key portion of the design.
LSA will be another marvel of frugal engineering skills of us Indians and will be remembered along with Magalyaan mission as a low cost wonder of exceptionally high technical skills. It is derived from two well proven aircraft types which have been extensively used in India. LSA aircraft project is designed to address the need of high performance, affordable, low cost, light fighter which has capabilities of fifth generation fighters and can become an effective replacement for F-4, F-5, F-16, Mig-21, Mig-23/27, Mig-29 and Mirage series of fighters world over. There is a requirment of over 3000 such aircraft today and the aircraft in production are prohibitively costly to be acquired by any country in large numbers.
On engine option , wing loading , various ratios, MTOW etc from designer.
>>>>>>My choice was always EJ230 but now I get another choice which is Indian in the form of HTFE-35 with 35KN dry and 56KN wet thrust. two of them will give me 70KN dry and 112KN wet. Doesn't this thrust level exceed that on EJ-230 with the added safety of twin engine and an Indian engine on top of that? If you had been reading my posts, I had stated it many times that a single engine aircraft shud have more of dry thrust while a twin engine shud have more of wet thrust. I will be fine even will HTFE-33 engine for twin engine version.
I had also told you that LSA is based on HF-24 and Mig-21. If I go for a lower sweepback wing, I can go for a wingloading of upto 550Kgs/sqm which gives it a payload of 7.5tons but if I go for the higher sweep version, the max wingloading will drop down to just about 480 kgs/sqm which will reduce the payload to 6 tons. The MTOW of a fighter can be calculated by the formula, dry Thrust x 2.5 = MTOW. So the 70KN dry thrust with two HTFE-35 engines gives me the ability to lift off with an MTOW of nearly 18 tons. The TWR for higher sweep LSA with EJ-230 will be 0.8 for Dry thrust for loaded weight and 1.27 with wet thrust at A2A combat load. While this changes to 0.78 and 1.38 for twin engine version. F-22 figures for similar weights are 0.8 and 1.21.
EJ-230 is likely to weigh about 1050kgs while the HTFE-35 with afterburner will weigh about 550kgs giving it a TWR of over 10:1. Two of them will be nearly same weight as EJ-230. But the safety they offer will be much more beneficial than anything else. Compare HTFE-25 with Honeywell F125 and you will know that it is more advanced in design with wide chord fan blades and BLISK and also nearly 100 kgs lighter. F125 weighs 615 kgs with afterburner and 520 kgs without. HTFE-25 is presently 350 kgs and add another 100kgs for afterburner + another 75 kgs for stronger materials for increase in thrust to 35 KN, we can easily get it at around 525/550 kgs.
Performance against ATO A Missile and SAM Like S400, Endurance etc.
LSA is not same as LCA. They both belong to light category and that is where the similarity ends. LSA is designed as an long range escort fighter with capability to perform SEAD/DEAD deep inside enemy territory. Advent of missile systems like S-400/500 means that SEAD/DEAD will need to be performed much deeper in enemy territory compared to what it has been till recently.
The stealth load out of LSA for SEAD/DEAD comprises 2xBVRAAM+2xWVRAAM+8xSDB and its stealth load out for escort fighter comprises 3xBVRAAM+4xWVRAAM. These configurations are without wingtip missiles. If we add wingtip missiles the load out increases further by 2xASRAAM.
Rafale has an endurance of 3hrs, SU-30MKI has it for 3 hrs 45 mins. LSA will also have 3 hrs 45mins endurance.
EFFECT OF LSA ON AIR WARFARE - At the tactical level LSA will have a large impact in Beyond Visual Range and Within Visual Range air combat. Most recent analyses of relative air combat capabilities assume that BVR combat will arise much more frequently than WVR combat. The basis of this assumption is that opposing air combat capabilities are easily detected and tracked by ISR systems, permitting fighter aircraft to choose the time, place and type of engagements to an advantage. This assumption collapses if the opposing fighter has significant VLO capability, as the LSA will have. The result is that attacking LSA will have to be engaged at much closer ranges than existing non-stealthy threats, as they enter predictable geometries, when attacking high value targets such as AWACS/AEW&C platforms, tankers, or defended surface assets. Another important qualification is that the extreme agility of the LSA will significantly degrade the kill probability of all Air to Air Missiles, (AAM) especially though the AIM-120 AMRAAM, which will be challenged to sustain the necessary manoeuvres to defeat the LSA. Like the F-22A Raptor, the LSA will provide a significant capability for the kinematic defeat of inbound missile shots.
A radar cross section of only -20 dBSM would deny early Beyond Visual Range (BVR) missile shots using the AIM-120C/D AMRAAM to all current and planned fighters. Doing any better, like -30 dBSM or -40 dBSM, simply increases the level of difficulty in prosecuting long range missile attacks. The consequence of this is that missile combat will be compressed into shorter distances and shorter timelines, putting a premium on the stealth, supersonic persistence and close combat agility of fighters. A larger portion of engagements will be at visual range, and most BVR engagements will end up taking place inside 25 nautical miles. In Beyond Visual Range combat, the combination of supersonic cruise and competitive VLO performance will allow the LSA to emulate the tactics developed for the F-22A Raptor. The LSA can thus be expected to produce greater lopsided air combat exchange rates to those achieved by the F-22A Raptor when flown against legacy fighters. Even if the LSA was only to attain half of the effectiveness of the F-22A Raptor, it will still yield BVR exchange rates of the order of 50:1 against legacy fighters. The arrival of the LSA therefore irrevocably enforces the end of the operational usefulness of the 4th generation of fighter aircraft in the traditional fighter roles of air superiority, air defence and tactical strike in contested airspace. These aircraft will retain operational utility only in permissive environments, where neither the LSA is deployed nor is able to be deployed. No less interesting is the impact at a tactical level when the LSA is flown against the F-22A Raptor. Fights between the F-22A and the LSA will be close, high, fast and lethal. The F-22A will neither get ‘first look’ nor “first shot” with the APG-77, the Advanced Infra Red Search and Track (AIRST) sensor having been deleted to save money, but the LSA will get “first look” & ‘first Shot’ using its advanced infrared sensor. Then, the engagement becomes a supersonic equivalent of the Battle of Britain or air combat over North Korea. The outcome will be difficult to predict as it will depend a lot on the combat skills of the pilots and the capabilities of the missiles for end-game kills. There is no guarantee that the F-22 will prevail every time. The tactical impact of a low cost LSA is therefore a loss of the overwhelming advantage provided until now by the F-22A Raptor. Flown against the LSA, a decisive outcome can only be guaranteed by numerical superiority of the F-22A force in theatre.
The arrival of the LSA therefore also irrevocably enforces the end of the operational usefulness of the F-35 Joint Strike Fighter, defined around a 1990s technology threat spectrum, in the traditional fighter roles of air superiority, air defence and tactical strike in contested airspace. The F-35 will retain operational utility only in permissive environments, where LSA is not deployed. The operational impact of indecisive combat loss exchange rates between a low cost LSA and the F-22A Raptor, and very high F-35 Joint Strike Fighter loss rates against a low cost LSA will have major implications at an operational level, and consequently, at a strategic and political level. Once the LSA is deployed within a theatre of operations, especially if it is supported robustly by counter-VLO capable ISR systems, the adversary will no longer have the capability to rapidly impose air superiority, or possibly even achieve air superiority. This will not only deny the adversary access to an opponent's defended airspace, it also presents the prospect of adversary being unable to reliably defend in-theatre basing and lines of resupply. Should this occur, in-theatre basing and surface assets become exposed to air attack by aircraft armed with a wide range of accurate and highly lethal Precision Guided Munitions, with the potential for very high loss of life and equipment deployed in theatre.
The deployment of a low cost LSA into such an environment very significantly increases risks to adversary forces, as the aircraft can credibly challenge the F-22A Raptor in air combat. While the intended survivable strike/ISR aircraft may, eventually, provide a credible capability to penetrate advanced anti-access capabilities, and thus attack opposing airfields, it will need to be defended against the LSA, and airfields deploying this aircraft will also need to be defended against LSA tasked with counter-air strike missions. The adversary will be denied access to any operational theatre into which credible numbers of the LSA are deployed. In turn, the adversary will be deterred from the use of conventional forces in such a scenario. The consequence of this, in turn, is that significant pressure will be placed to threaten the use of, or operationally use, tactical nuclear weapons. The only practical low risk option available is to deploy over this decade large numbers of advanced fighter aircraft which are competitive against the LSA in air combat. The proposed “sixth generation fighter” is not a viable contender in this time frame. The F-35 is not competitive and cannot be made to be competitive due to basic design limitations in aerodynamic and VLO shaping performance. The only aircraft which can survive in airspace contested by the LSA is the F-22 Raptor, and given the time frame of interest, it is the only design which can be adapted to defeat the LSA. The Ghost is by Western standards a low risk design, following the philosophy of “evolutionary” design, rather than the “Big Bang” approach currently favoured in the West, of trying to start from scratch with most or every key portion of the design.
LSA will be another marvel of frugal engineering skills of us Indians and will be remembered along with Magalyaan mission as a low cost wonder of exceptionally high technical skills. It is derived from two well proven aircraft types which have been extensively used in India. LSA aircraft project is designed to address the need of high performance, affordable, low cost, light fighter which has capabilities of fifth generation fighters and can become an effective replacement for F-4, F-5, F-16, Mig-21, Mig-23/27, Mig-29 and Mirage series of fighters world over. There is a requirment of over 3000 such aircraft today and the aircraft in production are prohibitively costly to be acquired by any country in large numbers.
On engine option , wing loading , various ratios, MTOW etc from designer.
>>>>>>My choice was always EJ230 but now I get another choice which is Indian in the form of HTFE-35 with 35KN dry and 56KN wet thrust. two of them will give me 70KN dry and 112KN wet. Doesn't this thrust level exceed that on EJ-230 with the added safety of twin engine and an Indian engine on top of that? If you had been reading my posts, I had stated it many times that a single engine aircraft shud have more of dry thrust while a twin engine shud have more of wet thrust. I will be fine even will HTFE-33 engine for twin engine version.
I had also told you that LSA is based on HF-24 and Mig-21. If I go for a lower sweepback wing, I can go for a wingloading of upto 550Kgs/sqm which gives it a payload of 7.5tons but if I go for the higher sweep version, the max wingloading will drop down to just about 480 kgs/sqm which will reduce the payload to 6 tons. The MTOW of a fighter can be calculated by the formula, dry Thrust x 2.5 = MTOW. So the 70KN dry thrust with two HTFE-35 engines gives me the ability to lift off with an MTOW of nearly 18 tons. The TWR for higher sweep LSA with EJ-230 will be 0.8 for Dry thrust for loaded weight and 1.27 with wet thrust at A2A combat load. While this changes to 0.78 and 1.38 for twin engine version. F-22 figures for similar weights are 0.8 and 1.21.
EJ-230 is likely to weigh about 1050kgs while the HTFE-35 with afterburner will weigh about 550kgs giving it a TWR of over 10:1. Two of them will be nearly same weight as EJ-230. But the safety they offer will be much more beneficial than anything else. Compare HTFE-25 with Honeywell F125 and you will know that it is more advanced in design with wide chord fan blades and BLISK and also nearly 100 kgs lighter. F125 weighs 615 kgs with afterburner and 520 kgs without. HTFE-25 is presently 350 kgs and add another 100kgs for afterburner + another 75 kgs for stronger materials for increase in thrust to 35 KN, we can easily get it at around 525/550 kgs.
Performance against ATO A Missile and SAM Like S400, Endurance etc.
LSA is not same as LCA. They both belong to light category and that is where the similarity ends. LSA is designed as an long range escort fighter with capability to perform SEAD/DEAD deep inside enemy territory. Advent of missile systems like S-400/500 means that SEAD/DEAD will need to be performed much deeper in enemy territory compared to what it has been till recently.
The stealth load out of LSA for SEAD/DEAD comprises 2xBVRAAM+2xWVRAAM+8xSDB and its stealth load out for escort fighter comprises 3xBVRAAM+4xWVRAAM. These configurations are without wingtip missiles. If we add wingtip missiles the load out increases further by 2xASRAAM.
Rafale has an endurance of 3hrs, SU-30MKI has it for 3 hrs 45 mins. LSA will also have 3 hrs 45mins endurance.
Aasimkhan
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First LCA and now LSA, HA HA , one blunder leading to another bigger blunder, Indians never learn
MULUBJA
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Heighest speed of LSA Mach 2.25+
We are exploring the possibilty to send our engineers to learn from you guys. It will improve thereafter. Meanwhile this shall be our pace of developing the weapon.
On weqpon bay:
....LSA is very different as Picard's design is non stealthy and mine is stealthy with internal weapon bays. My design has unique weapon bays design which has not been thought of by people who create such designs. Russians and Chinese have used F-22 and F-35 as their base aircraft. I created which is completely different from F-22 & F-35.
We are exploring the possibilty to send our engineers to learn from you guys. It will improve thereafter. Meanwhile this shall be our pace of developing the weapon.
On weqpon bay:
....LSA is very different as Picard's design is non stealthy and mine is stealthy with internal weapon bays. My design has unique weapon bays design which has not been thought of by people who create such designs. Russians and Chinese have used F-22 and F-35 as their base aircraft. I created which is completely different from F-22 & F-35.
ssethii
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They are learning but as technology advances the the costs for R&D are getting higher and higher. Learning is good as long as it's not at the cost of national security.
holysaturn
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What do you mean by that? Based on what are you saying this? A lot of the space occupied in fighters are multimission avionics which have no relevance during a specific single mission Eg: CAP mission, interception, Air superiority missions do not require a Nav/Attack system, Terrain Hugging mode, these systems are not only bulky but their integration and maintenance cost high in terms of complexity and availability. The F-35 was ruined primarily by the requirement of the lift fan.
So if you design an aircraft for specific requirements(if you can keep requirement creep at bay) in place like in this case Escort/SEAD/DEAD it is possible to design a compact package. Multimission aircraft are not that effective not only because of higher cost,complexity,size but pilots are not as multi-mission capable, even with all the man machine interface pilots still have to be trained extensively for specific missions(Air combat,CAS,Anti shipping,Strike,EW), omnirole training of pilots is still a fantasy.
Aircraft Designer Ed Heinemann described it as a cycle where equipment less relevant to combat are eliminated like the jet fuel starter, nose wheel steering, onboard ladders the weight not only decrease as a direct result but also because of indirect reasons as the landing gear now can be lighter, the airframe can be made less stronger, it also had an effect on complexity and cost. This was the basis of the A-4 skyhawk where the requirement was met by a compact light platform which was not thought possible.
Yes it may an analog to the Mig-21 concept of the 60s so what? technology changes but the nature of combat doesnt, if this concept can create a mig-21 analog to f-4 analogs like F-22/Pak-Fa/J-20 then why not? the challenges which were in the 1960's havent disappeared. BTW I suggest you read the LSA design first, your quoted design has no similarities with it.
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MULUBJA
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More on design:
LSA is probably the only aircraft in the world which has dimensions based on Golden/Divine Ratio of Phi=1.618.
The tail span multiplied by phi gives the wing span, wingspan x phi = aircraft length, fuselage thickness x phi = fuselage width. nose width x phi = intake width and 10 x phi x LERX area = wing area. even the aileron area x phi = flap area.
It depends on what you want your aircraft to do. Low aspect ratio and high sweepback are good for interceptors while 45-50* sweep is good for Omni/multirole aircraft and lower than 45* sweep is good for bombers.
I created LSA with the aim to use all the equipment and infrastructure created for Mig-21s like drop tanks, weapons and ground support equipment. Only weapon system that I will need to buy for LSA will be K-77M BVRAAM. The program development cost is just INR1700crores which is less than the money spent on creating Tata Nano car. Each LSA will cost about USD25M only however if we decide to put Rafale systems in it like SPECTRA, the cost will go up and it may cost as much as USD40M. The biggest advantage of LSA is that it does not involve R&D for any onboard system and uses off-the-shelf technology which can be upgraded at a later stage.
The most immediate benefit of this deal will accrue to LCA MK1A. We must use the system architecture of Rafale for LSA also. The biggest cost of the deal as published in newspapers is on account of Weapon integration and Associated equipment amounting to over Euro 3.5b. This cost is onetime cost and this cost content in each aircraft will reduce by increasing the order size thru Make-in-India which will bring down the unit fly away price from 1600 crores to below 600 crores for a fleet size of 200 Rafale. Creating platforms like LSA which will use the same tech will bring the cost further down for Rafale as well as LSA. The major part of the cost of integrating India specific weapons is due to rewriting codes of SPECTRA active cancelation system for each weapon and configuration. That needs 360x360x360=47 million variations for each new weapon system and its load out with other weapons as the RCS will change with every new weapon which will need to be cancelled by SPECTRA system. Even the Fly-by-Wire flight control system codes will need to be rewritten to ensure full control of the aircraft. LSA is designed to have Power-by-Wire control system with internal weapon bays. LSA can be very easily adapted to Rafale systems including SPECTRA and will become completely invisible to all types of radars due to its small size and active cancellation. 90% of stealth is about small size, shaping, internal weapons bay and balance 10% is about reflectivity, Radar absorbent materials/paints/structures and cancellation of resonance waves in V/UHF frequency range using active cancellation tech.
Flight test of an aircraft has basically four stages:–
- Proving the hardware-This involves proving the design & sub systems of the aircraft as a war fighting platform. For LSA it will mean proving the weapon bay doors operations and its ability to safely deploy weapons from the internal bays including FCS laws and safe weapons separation from wing pylons.
- Proving the Software-This involves proving the software associated with sensors and weapons.
- Weapon Trials-This is to prove the ability of the platform to use the weapons it is designed to fire.
- Data generation for Safe Operations-This phase starts from first flight and continues till all the data needed for entry into service has been compiled for normal & emergency operations of the aircraft with varied weapon loads, configurations and emergencies etc.
The last few paragraphs are from the details I had sent to top boss about LSA.
Jai ParshuRam. Desh sarva pratham, Deshvasi Dvitiyam, Antin swarth sadaiva.
Light vs. heavy fighters
Fighter aircraft may be fielded anywhere in a continuum ranging on one end from light, relatively simple with only essential features, and lower cost, to on the other end heavier, more complex with added features, and more expensive. The light or lower cost fighter concept is to be on the generally lower half of this range in order to project highly effective force per unit of budget via an efficient design with only essential features. Light fighters generally features a smaller and generally less expensive airframe deliberately designed to be effective based on a high TWR, high maneuverability, high reliability, and moderate per unit cost. Larger fighters provide the opportunity for more technology, such as longer range radars, and for heavier weapon load outs that can make use of longer radar range in addressing a larger number of opponents per friendly fighter. Though stealth is not inherently limited to larger fighters, so far in its history its higher cost has led to it being deployed on larger and more expensive fighters.
In the past some very light fighter designs were sometimes the result of the desire to use a particular engine or non-strategic materials that demand the airframe be as small and light as possible in order to reach acceptable performance with limited available power. That class of ultra-light fighters has often been dismissed by military planners as being too limited in capability, but a few of these very light fighters have been effective. A prominent example is the Japanese ZERO, the lightest major fighter of WWII, which was deliberately designed to be as light as possible to get competitive performance using the limited horsepower engines available in Japan just before WWII. The Zero scored high kill ratios early in WWII, though the Allies later achieved air dominance over it with improved aircraft and tactics.
The more modern view of light fighters is as a more capable weapon intended to well satisfy the main criteria of air to air combat effectiveness. These criteria in order of importance are the ability to benefit from the element of surprise, to have numerical superiority in the air, to have superior maneuverability, and weapon systems effectiveness. Light fighters have tended to statistically enjoy the element of surprise more often than not due to smaller visual and radar signatures, which is a critical advantage since historically about 80% of air to air kills do occur by surprise. The comparative lower cost and higher reliability of light fighters due to their intentional simplicity also allows them to out-number the enemy in the air under combat conditions on a per budget basis. Their light weight also enhances maneuverability. It is only in the generally least important (in relative terms) category of weapons systems effectiveness that the more limited weight carrying capacity of a light fighter may work against its capability. However, modern single engine light fighters such as the F-16 and the Gripen-E generally carry the same type of cannon and air to air missile weaponry as heavier twin engine fighters, simply not as much ammunition or as many missiles. As they are in general approximately as capable and sometimes more capable in air to air combat on a per plane basis as heavier twin engine fighters for many mission types, while being significantly lower in cost, they represent the opportunity to in many cases be more effective on a per budget basis.
A prominent example is the American Gen 3 F-5 light fighter, which has proven in combat and in extensive aggressor and trial usage to be quite competitive with the larger and more expensive fighters of its era, and surprisingly competitive with later Gen 4 fighters that are an order of magnitude more expensive. With its small size it very effectively utilizes the key elements of surprise, lost cost and high reliability, and maneuverability. Though with its limited radar it does not have a strong BVR capability, it can hold its own in the WVR mode even today, over 50 years after its original introduction.
Though it has been proven that well designed light fighters can generally compete with and sometimes excel heavier fighters on a per plane basis, they do not always have to do so in order to be effective weapons, so long as their cost is significantly less. For a given budget, lower cost light fighters allow greater numbers, bringing into the play the issue of quantity vs. quality. Larger numbers of fighters that are not too severely inferior can often defeat a smaller force of superior aircraft. Formally, this is a result of Lanchester’s Laws, a mathematical formulation of attrition rates in combat. With modern weapons that engage multiple targets over a distance, the rate of attrition depends on the number of firing platforms in a non-linear way. Lanchester determined that the power of such a force is proportional not to the number of units it has, but to the square of the number of units. This is known as Lanchester's Square Law. Fundamentally it requires an N-squared-fold advantage in quality on one side to compensate for an N-fold advantage in quantity on the other side. This non-linear relationship favors the low cost and light fighter.
The high practical and budgetary effectiveness of modern light fighters for many missions is why the U.S. Air Force adopted both the F-15 & F-16 in a "hi/lo" strategy of both an outstanding but expensive heavy fighter and a lower cost but still excellent light fighter. This mixture allows using the ideal weapon for the mission at hand, such as heavier fighters with longer range radar and larger weapon load outs for the most demanding Beyond Visual Range missions, and lighter and lower cost fighters for bulk combat against large numbers of enemy fighters.
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Advantages of Light Fighters
"The F-22 costs 10 times as much as an early model F-16 fighter and, due to its huge maintenance load, can fly only half as many sorties per day. Thus, for equal investment, the F-22 delivers only one-twentieth as many airplanes over enemy territory as the F-16."- Pierre Sprey
The single strongest design feature in favor of the light fighter in air-to-air combat is the element of surprise, since about 80% of kills do occur by surprise, thus dominating all other factors. A small fighter like the F-5 with a planform area of about 300 square feet or the F-16 at about 400 square feet, compared to about 1050 square feet for the F-15, has a major advantage in visual combat. The small fighter is typically invisible to opposing pilots beyond about 4 miles, whereas a larger fighter such as the F-15 is visible to about 12 miles, and much farther if the engines smoke. This is a non-linear advantage to the light fighter in terms of detection area (similar altitude) and even more so in sky volume (if altitudes are different). Additionally, smaller targets take longer to visually acquire even if they are visible. This is particularly so if the Pilots of Heavy fighters have only been practicing air combat with heavies only and do not have DACT experience with small Light Fighters. These two factors together give the light fighter pilot much better statistical odds of seeing the heavy fighter first and setting up a decisive first shot. Once the small fighter sees and turns towards the opponent its very small frontal area reduces maximum visual detection range to about 2.0 to 2.5 miles. This allows the light fighter to set up a high reliability short range heat-seeking missile shot by ambush while still invisible to the target (heat-seeking missile range being about 6 to 20 miles depending on the particular missile).
Unless complete air superiority allows AWACs aircraft to dominate the battlespace, radar cannot be counted upon to give the large fighter a winning advantage, as modern light fighters have radar range nearly as far as heavy fighters. This is further offset by the fact that larger fighters with typical radar cross sectional area of about 10 m² are detectable by radar at about 50% farther range than the 2m² to 3m² x-section of the light fighter. For example, the F-15 actually presents about 20m² radar cross sectional area, and has been typically defeated by opposing F-16 forces not only in close dogfighting combat, but also in extensive Beyond Visual Range (BVR) trials. Also, airborne fighter radars are limited in coverage zone (front only) and are far from perfect in detecting enemy aircraft. Despite extensive use of radar in the Vietnam War by the United States, only 18% of North Vietnamese fighters were first detected by radar of any kind, and only 3% by air-to-air radar on board a fighter aircraft. The other 82% were visually acquired, which explains why visual signature favoring the light fighter has remained a significant advantage.
Not even taking into account the sometimes superior combat capability of lighter aircraft based on surprise and maneurverability, the pure numbers issue of lower cost and higher reliability also tends to favor light fighters. It is a basic outcome of Lanchester’s Laws that a larger number of less-sophisticated units will almost always be successful over a smaller number of more advanced ones; the damage dealt is based on the square of the number of units firing, while the quality of those units has only a linear effect on the outcome. This argues that air forces should use larger numbers of cheaper aircraft instead of smaller number of expensive aircraft, and this is a major argument for the light, as in inexpensive, fighter.
Lighter designs also have the advantage of covering more area. Assuming an aircraft can patrol an area roughly defined by its radar coverage (or visible range in the case of pre-radar designs), and given that in the radar equation range varies with the fourth power of energy, a larger number of less-powerful radars will provide more coverage than a smaller number of more powerful radars. This same basic outcome also means that response to on-call ground attack missions will be more rapid, as, on average, an aircraft will be closer to the action if there are more aircraft in the air. Additionally, the complex systems in larger aircraft tend to be less reliable, so it has been argued that a larger number of less capable aircraft with nevertheless produce a greater overall combat capability.
Disadvantages of Light Fighters
Two additional considerations have a strong bearing on the smaller-is-better argument. One is that the total load carried by an aircraft is often defined more by its total power than its extra power; this implies that smaller aircraft will have less payload and/or fuel and thus be less effective than a larger design when these considerations are important. This is, of course, offset by the fact that a heavier aircraft requires more energy to keep aloft, and thus burns more fuel. Generally, however, the advantage is on the side of larger designs. It is precisely this consideration that led to the WWII concept of the heavy fighter, normally twin-engined designs that were specifically intended to carry more fuel for longer range while carrying heavier weapons.
However, this assumed advantage does not always hold up when lighter fighters are intentionally designed for longer range. The equations for range of both propeller and jet aircraft show in general how minimizing drag and maximizing engine efficiency and fuel fraction allow smaller aircraft to match or beat the range of larger aircraft. This was demonstrated in practice during WWII by the light ZERO with range of 2010 miles, and the lightweight P-51 with range of 1650 miles, compared to the heavy twin engine P-38 with range of 1300 miles and the German Me 210 with range of 1400 miles. In the age of modern jet fighters, the lightweight F-16A not only had longer range than the heavy F-15A, but longer range than any other fighter in the USAF inventory.
Another more minor concern in performance terms is that designs with more power generally go faster. For subsonic designs, maximum speed is strongly defined by total power. This is due to the effects of wave drag, which becomes extremely powerful as the aircraft enters the transonic regime, and its effect rises so rapidly that the normally lower drag of a smaller aircraft is rapidly offset by even minor increases in speed. Overcoming this drag requires power, so designs with more powerful engines almost always have higher top speed. For supersonic designs this equation no longer holds, at least not as directly, but limitations on engine performance, especially due to intake design considerations, again favour larger designs with more powerful engines. This is not always the case; the F-104, considered a light fighter by some definitions, was capable of a highly credible Mach 2.0. But light fighters are generally slower; the F-5 was capable of M1.4, the T-50 about M1.5, and the F-16 about M2.0.
The top speeds of modern light fighters are more a matter of deliberate design trade-offs to make the fighter more combat effective than aerodynamic limits in the concept. Modern engines and aerodynamics generally allow for lighter fighters to have top speeds that match similar technology heavy fighters, as it is a simple matter of thrust to drag ratio. In fact, the single engine configuration typical of light fighters has lower wave drag. But, the question is whether very high top speeds should even be attempted when full combat effectiveness considerations and trade-offs are taken into account. It is well known in the literature that, unlike the importance of top speed in WWII to close with or escape enemy fighters, there are strong limits to the benefit of very high (>M2) top speeds in jet fighters. The aerodynamic requirements to operate at such speeds add considerable complexity, weight, and cost to the aircraft (thus limiting numbers) by requiring more exotic materials, more expensive engines, and complex structures such as variable engine inlets and bellmouths. Even in aircraft that have these features, such as the claimed Mach 2.5 top speed of the F-15, they are in practice unusable. The F-15 top speed when carrying a weapons load is under Mach 1.8. Taking the weapons off (even the cannon must come out to reduce weight) to allow Mach 2.5 requires an aerial refueling at altitude, and more than 5 minutes at that speed will destroy the engines. As an example of a poor trade-off for higher top speed, smaller and more streamlined canopies also limit the key parameter of visibility out of the cockpit to maximize surprise. But, after paying all these penalties attempting get greater than Mach 2 speeds, it is found they have zero utility in combat. Combat speeds have never been known to exceed Mach 1.8 and seldom 1.2, for two reasons. First, it requires extensive use of the afterburner, which typically increases fuel consumption by about a factor of three or even four, and rapidly reduces operational radius or even runs the fighter out of fuel. Second, speeds even above Mach 1 so widen the turn radius in maneuvering combat that the fighter is thrown too wide to get a tracking solution on an opponent, such that typical fighting speeds are in the range of 0.5M to 1.0M. This reality is why even subsonic fighters like the F-86 and MiG-17 can often defeat supersonic fighters if the supersonic fighter does not use its superior speed to flee the combat (the only supersonic F-8 losses in Vietnam were to the subsonic MiG-17). Speed has reached the limit of its practical combat value, such that optimum fighter design requires understanding the penalties the endless search for higher speed imposes, and sometimes deliberately choosing not to accept those penalties.
In contrast to the very limited value of high top speeds, acceleration to regain energy rapidly in an energy bleeding subsonic dogfight is highly valuable, and the lightweight fighter with high thrust to weight ratio excels in that practical performance parameter. Also, unlike the highest of top speeds, high cruise speed in order to maximize surprise instead of being surprised by being overtaken from the rear, is even more valuable. The tail-less delta configuration like the light Gripen with a typical cruise speed of about 0.9M to 1.1M (super-cruise) as compared to the typical 0.7-0.9M for standard configurations, maximizes this advantage.
A more subtle argument, but much more powerful in real world purchasing policy, is the overall cost of operating an aircraft. While it might seem that a less expensive aircraft will allow more to be purchased and operated, this ignores the fact that the majority of an aircraft's lifetime costs are related to pilot training. For instance, F-18 purchased in the early 1980s had a total unit cost of $35 million per aircraft, and have been in service since 1982 – 34 years as of 2016[update] - for a yearly cost of just over $1 million. In comparison, training a pilot in the US currently costs about $6 million. Given these sorts of numbers, the cost benefit of the light fighter may be minimal or nonexistent. Consider a two aircraft, the Hawk 200 at ~$25 million compared to the current F-18E at ~$61 million. Assuming the Hawk has a quality (in Lanchester's terms) of 0.5 and pilots have an active duty "tour" of 5 years, over the 30 year lifetime of the aircraft:
When one adds the additional considerations of logistics, and especially the increased number of bases needed to support larger number of aircraft, the disparity increases. In the opposite case where the total fleet numbers are fixed by external factors, like the size of an aircraft carrier's decks, the advantage of the more expensive aircraft may become overwhelming. It is primarily this consideration that leads to the generally unfavourable opinion of less expensive designs in western air forces, and was also the primary reason that the original Lightweight Fighter, a day fighter as original conceived, was dramatically changed to a multi-mission aircraft during its development.
However, the above analysis for total cost only takes into account basic pilot training, and not the fact that far more cost occurs from long term operational training where there is a widely different operating cost of light/lightweight fighters as compared to heavy fighters. For example, as of 2013, total heavy F15C operating cost is reported at $41,900 per hour, and light F-16C cost at $22,500 per hour. The much lower operating cost of light fighters is usually regarded as a significant strength in allowing adequate training to maintain expert pilot proficiency. More accurate equations than the above that do take long term operational training costs into account are available in the literature. Additionally, this example assumes a lower combat effectiveness for lightweight fighters, thus requiring more fighters, whereas some lightweight fighters are actually superior plane for plane to heavier fighters. A key example of lower cost combined with higher effectiveness is the F-16 vs. the F-15, as shown by the U.S. Air Force's own trial results as well as combat results.
Modern era of Air Combat
The advent of the air superiority fighters such as the F-15, meant that high value assets (HVAs) like tankers, AEW&C, command platforms, bombers and attack aircraft would need to be protected by air superiority fighters, sometimes flying far afield and ahead of them, engaging distant enemy air units, rather than by direct escorts staying in sight nearby. The development of the multirole fighters such as F-18, Rafale, Typhoon, also decreased the need for escorts, as the aircraft on air strike mission became capable of effective self-defense. However the need to protect HVAs will remain a cause of concern and costly multirole fighters will be a waste of assets if required to be used to protect these HVAs. These HVAs will remain a necessity if the full potential of these costly heavy multirole fighters is to be exploited optimally. The small numbers of such costly assets and their limited sortie generation rate further complicates the equation and tilts it decisively in the favor of Light Fighters specifically designed for the particular roles of Interceptor/Air Superiority fighter/ Escort/ Penetration fighter roles with secondary Strike/CAS/Interdiction roles.
Just to clarify a few terms here, a penetration fighter is used for a long-range Fighter aircraft designed to penetrate enemy air defenses and attack defensive interceptors/point defense fighters. The concept is similar to the escort fighter, but differs primarily in that the aircraft would not operate in close concert with bombers. This is also at times referred to as, “Fighter Sweeps”. Their aim is to lure and force enemy fighters to get airborne and engage them in air combat. This was, in effect, the same role played by the P-51 during WW2, whose presence above Germany allowed USAAF bombers to fly at will over the country.
Air interdiction (AI), also known as deep air support (DAS), is the use of preventative aircraft attacks against enemy targets, that are not an immediate threat, in order to delay, disrupt, or hinder later enemy engagement of friendly forces. It is a core capability of virtually all military air forces, and has been conducted in conflicts since WW1. A distinction is often made between tactical and strategic air interdiction, depending on the objectives of the operation. Typical objectives in tactical interdiction are meant to affect events rapidly and locally, for example through direct destruction of forces or supplies en-route to the active battle area. While strategic objectives are often broader and more long-term, with less direct attacks on enemy fighting capabilities, instead focusing on infrastructure, logistics and other supportive assets.
The term deep air support, relates to CAS and denotes the difference between their respective objectives. Close air support, as the name suggests, is directed towards targets close to friendly ground units, as closely coordinated air-strikes, in direct support of active engagement with the enemy. Deep air support or air interdiction is carried out further from the active fighting, based more on strategic planning and less directly coordinated with ground units. Despite being more strategic than close air support, air interdiction should not be confused with strategic bombing, which is unrelated to ground operations.
The latest air combat tactics have moved away from pure stealth to a mix of stealth for air superiority & Interdiction to non-stealth for destruction of enemy assets using “Arsenal Aircraft” for large scale combat. This has happened due to the validity of Lanchester’s laws for modern combat including stealth. In the posts so far I have stated that stealth is costly and needs heavy fighters but if we look at nature and learn from it, we realise that small size, agility, camouflage and strong punching power defines a “Predator”. These attributes of nature’s laws will remain valid as long as we have human on Earth. The latest example of F-15 & F-16 is supposed to act as “Arsenal Aircraft” capable of carrying nearly 18 missiles to combat in non-stealthy mode. Where does LSA stand with respect to such aircraft?
How designer created LSA
HOW I CREATED LSA
My aim was to create a combination of Mig-21 and Mig-27 which relies on low cost stealth like shaping, small size, composites and Radar absorbent paint to achieve a degree of stealth which will allow it to move within WVRAAM firing range. I am one of those few pilots who have done DACTs with Ajeet (Folland Gnat). That small bird used to send chill down our spine as we always detected it when it was aligning itself in our rear quarter for gun shot. Ajeet, due to its small size also was difficult to detect on radar even though it did not have any kind of stealth shaping.
I wanted an interceptor with good range and endurance which cud act as escort and penetrative fighter with ability to perform as an air superiority fighter at mid-high altitudes. This meant that Mig-21 planform became the first choice. A stealth aircraft is not required to fly and fight at low levels to avoid radar. Its stealth does that job for it, so mid & high altitude performance became paramount. Over a period of time, Mig-21 added lot of weight which resulted in poor performance due to increased span & wing loading while nothing was done to improve the Oswald span efficiency factor and span efficiency which resulted in much higher induced drag. I also studied HF-24 Marut design during this time and to my surprise I found that combining HF-24 & Mig-21, we have a home grown Light Stealth Aircraft.
"The F-22 costs 10 times as much as an early model F-16 fighter and, due to its huge maintenance load, can fly only half as many sorties per day. Thus, for equal investment, the F-22 delivers only one-twentieth as many airplanes over enemy territory as the F-16."- Pierre Sprey
The single strongest design feature in favor of the light fighter in air-to-air combat is the element of surprise, since about 80% of kills do occur by surprise, thus dominating all other factors. A small fighter like the F-5 with a planform area of about 300 square feet or the F-16 at about 400 square feet, compared to about 1050 square feet for the F-15, has a major advantage in visual combat. The small fighter is typically invisible to opposing pilots beyond about 4 miles, whereas a larger fighter such as the F-15 is visible to about 12 miles, and much farther if the engines smoke. This is a non-linear advantage to the light fighter in terms of detection area (similar altitude) and even more so in sky volume (if altitudes are different). Additionally, smaller targets take longer to visually acquire even if they are visible. This is particularly so if the Pilots of Heavy fighters have only been practicing air combat with heavies only and do not have DACT experience with small Light Fighters. These two factors together give the light fighter pilot much better statistical odds of seeing the heavy fighter first and setting up a decisive first shot. Once the small fighter sees and turns towards the opponent its very small frontal area reduces maximum visual detection range to about 2.0 to 2.5 miles. This allows the light fighter to set up a high reliability short range heat-seeking missile shot by ambush while still invisible to the target (heat-seeking missile range being about 6 to 20 miles depending on the particular missile).
Unless complete air superiority allows AWACs aircraft to dominate the battlespace, radar cannot be counted upon to give the large fighter a winning advantage, as modern light fighters have radar range nearly as far as heavy fighters. This is further offset by the fact that larger fighters with typical radar cross sectional area of about 10 m² are detectable by radar at about 50% farther range than the 2m² to 3m² x-section of the light fighter. For example, the F-15 actually presents about 20m² radar cross sectional area, and has been typically defeated by opposing F-16 forces not only in close dogfighting combat, but also in extensive Beyond Visual Range (BVR) trials. Also, airborne fighter radars are limited in coverage zone (front only) and are far from perfect in detecting enemy aircraft. Despite extensive use of radar in the Vietnam War by the United States, only 18% of North Vietnamese fighters were first detected by radar of any kind, and only 3% by air-to-air radar on board a fighter aircraft. The other 82% were visually acquired, which explains why visual signature favoring the light fighter has remained a significant advantage.
Not even taking into account the sometimes superior combat capability of lighter aircraft based on surprise and maneurverability, the pure numbers issue of lower cost and higher reliability also tends to favor light fighters. It is a basic outcome of Lanchester’s Laws that a larger number of less-sophisticated units will almost always be successful over a smaller number of more advanced ones; the damage dealt is based on the square of the number of units firing, while the quality of those units has only a linear effect on the outcome. This argues that air forces should use larger numbers of cheaper aircraft instead of smaller number of expensive aircraft, and this is a major argument for the light, as in inexpensive, fighter.
Lighter designs also have the advantage of covering more area. Assuming an aircraft can patrol an area roughly defined by its radar coverage (or visible range in the case of pre-radar designs), and given that in the radar equation range varies with the fourth power of energy, a larger number of less-powerful radars will provide more coverage than a smaller number of more powerful radars. This same basic outcome also means that response to on-call ground attack missions will be more rapid, as, on average, an aircraft will be closer to the action if there are more aircraft in the air. Additionally, the complex systems in larger aircraft tend to be less reliable, so it has been argued that a larger number of less capable aircraft with nevertheless produce a greater overall combat capability.
Disadvantages of Light Fighters
Two additional considerations have a strong bearing on the smaller-is-better argument. One is that the total load carried by an aircraft is often defined more by its total power than its extra power; this implies that smaller aircraft will have less payload and/or fuel and thus be less effective than a larger design when these considerations are important. This is, of course, offset by the fact that a heavier aircraft requires more energy to keep aloft, and thus burns more fuel. Generally, however, the advantage is on the side of larger designs. It is precisely this consideration that led to the WWII concept of the heavy fighter, normally twin-engined designs that were specifically intended to carry more fuel for longer range while carrying heavier weapons.
However, this assumed advantage does not always hold up when lighter fighters are intentionally designed for longer range. The equations for range of both propeller and jet aircraft show in general how minimizing drag and maximizing engine efficiency and fuel fraction allow smaller aircraft to match or beat the range of larger aircraft. This was demonstrated in practice during WWII by the light ZERO with range of 2010 miles, and the lightweight P-51 with range of 1650 miles, compared to the heavy twin engine P-38 with range of 1300 miles and the German Me 210 with range of 1400 miles. In the age of modern jet fighters, the lightweight F-16A not only had longer range than the heavy F-15A, but longer range than any other fighter in the USAF inventory.
Another more minor concern in performance terms is that designs with more power generally go faster. For subsonic designs, maximum speed is strongly defined by total power. This is due to the effects of wave drag, which becomes extremely powerful as the aircraft enters the transonic regime, and its effect rises so rapidly that the normally lower drag of a smaller aircraft is rapidly offset by even minor increases in speed. Overcoming this drag requires power, so designs with more powerful engines almost always have higher top speed. For supersonic designs this equation no longer holds, at least not as directly, but limitations on engine performance, especially due to intake design considerations, again favour larger designs with more powerful engines. This is not always the case; the F-104, considered a light fighter by some definitions, was capable of a highly credible Mach 2.0. But light fighters are generally slower; the F-5 was capable of M1.4, the T-50 about M1.5, and the F-16 about M2.0.
The top speeds of modern light fighters are more a matter of deliberate design trade-offs to make the fighter more combat effective than aerodynamic limits in the concept. Modern engines and aerodynamics generally allow for lighter fighters to have top speeds that match similar technology heavy fighters, as it is a simple matter of thrust to drag ratio. In fact, the single engine configuration typical of light fighters has lower wave drag. But, the question is whether very high top speeds should even be attempted when full combat effectiveness considerations and trade-offs are taken into account. It is well known in the literature that, unlike the importance of top speed in WWII to close with or escape enemy fighters, there are strong limits to the benefit of very high (>M2) top speeds in jet fighters. The aerodynamic requirements to operate at such speeds add considerable complexity, weight, and cost to the aircraft (thus limiting numbers) by requiring more exotic materials, more expensive engines, and complex structures such as variable engine inlets and bellmouths. Even in aircraft that have these features, such as the claimed Mach 2.5 top speed of the F-15, they are in practice unusable. The F-15 top speed when carrying a weapons load is under Mach 1.8. Taking the weapons off (even the cannon must come out to reduce weight) to allow Mach 2.5 requires an aerial refueling at altitude, and more than 5 minutes at that speed will destroy the engines. As an example of a poor trade-off for higher top speed, smaller and more streamlined canopies also limit the key parameter of visibility out of the cockpit to maximize surprise. But, after paying all these penalties attempting get greater than Mach 2 speeds, it is found they have zero utility in combat. Combat speeds have never been known to exceed Mach 1.8 and seldom 1.2, for two reasons. First, it requires extensive use of the afterburner, which typically increases fuel consumption by about a factor of three or even four, and rapidly reduces operational radius or even runs the fighter out of fuel. Second, speeds even above Mach 1 so widen the turn radius in maneuvering combat that the fighter is thrown too wide to get a tracking solution on an opponent, such that typical fighting speeds are in the range of 0.5M to 1.0M. This reality is why even subsonic fighters like the F-86 and MiG-17 can often defeat supersonic fighters if the supersonic fighter does not use its superior speed to flee the combat (the only supersonic F-8 losses in Vietnam were to the subsonic MiG-17). Speed has reached the limit of its practical combat value, such that optimum fighter design requires understanding the penalties the endless search for higher speed imposes, and sometimes deliberately choosing not to accept those penalties.
In contrast to the very limited value of high top speeds, acceleration to regain energy rapidly in an energy bleeding subsonic dogfight is highly valuable, and the lightweight fighter with high thrust to weight ratio excels in that practical performance parameter. Also, unlike the highest of top speeds, high cruise speed in order to maximize surprise instead of being surprised by being overtaken from the rear, is even more valuable. The tail-less delta configuration like the light Gripen with a typical cruise speed of about 0.9M to 1.1M (super-cruise) as compared to the typical 0.7-0.9M for standard configurations, maximizes this advantage.
A more subtle argument, but much more powerful in real world purchasing policy, is the overall cost of operating an aircraft. While it might seem that a less expensive aircraft will allow more to be purchased and operated, this ignores the fact that the majority of an aircraft's lifetime costs are related to pilot training. For instance, F-18 purchased in the early 1980s had a total unit cost of $35 million per aircraft, and have been in service since 1982 – 34 years as of 2016[update] - for a yearly cost of just over $1 million. In comparison, training a pilot in the US currently costs about $6 million. Given these sorts of numbers, the cost benefit of the light fighter may be minimal or nonexistent. Consider a two aircraft, the Hawk 200 at ~$25 million compared to the current F-18E at ~$61 million. Assuming the Hawk has a quality (in Lanchester's terms) of 0.5 and pilots have an active duty "tour" of 5 years, over the 30 year lifetime of the aircraft:
When one adds the additional considerations of logistics, and especially the increased number of bases needed to support larger number of aircraft, the disparity increases. In the opposite case where the total fleet numbers are fixed by external factors, like the size of an aircraft carrier's decks, the advantage of the more expensive aircraft may become overwhelming. It is primarily this consideration that leads to the generally unfavourable opinion of less expensive designs in western air forces, and was also the primary reason that the original Lightweight Fighter, a day fighter as original conceived, was dramatically changed to a multi-mission aircraft during its development.
However, the above analysis for total cost only takes into account basic pilot training, and not the fact that far more cost occurs from long term operational training where there is a widely different operating cost of light/lightweight fighters as compared to heavy fighters. For example, as of 2013, total heavy F15C operating cost is reported at $41,900 per hour, and light F-16C cost at $22,500 per hour. The much lower operating cost of light fighters is usually regarded as a significant strength in allowing adequate training to maintain expert pilot proficiency. More accurate equations than the above that do take long term operational training costs into account are available in the literature. Additionally, this example assumes a lower combat effectiveness for lightweight fighters, thus requiring more fighters, whereas some lightweight fighters are actually superior plane for plane to heavier fighters. A key example of lower cost combined with higher effectiveness is the F-16 vs. the F-15, as shown by the U.S. Air Force's own trial results as well as combat results.
Modern era of Air Combat
The advent of the air superiority fighters such as the F-15, meant that high value assets (HVAs) like tankers, AEW&C, command platforms, bombers and attack aircraft would need to be protected by air superiority fighters, sometimes flying far afield and ahead of them, engaging distant enemy air units, rather than by direct escorts staying in sight nearby. The development of the multirole fighters such as F-18, Rafale, Typhoon, also decreased the need for escorts, as the aircraft on air strike mission became capable of effective self-defense. However the need to protect HVAs will remain a cause of concern and costly multirole fighters will be a waste of assets if required to be used to protect these HVAs. These HVAs will remain a necessity if the full potential of these costly heavy multirole fighters is to be exploited optimally. The small numbers of such costly assets and their limited sortie generation rate further complicates the equation and tilts it decisively in the favor of Light Fighters specifically designed for the particular roles of Interceptor/Air Superiority fighter/ Escort/ Penetration fighter roles with secondary Strike/CAS/Interdiction roles.
Just to clarify a few terms here, a penetration fighter is used for a long-range Fighter aircraft designed to penetrate enemy air defenses and attack defensive interceptors/point defense fighters. The concept is similar to the escort fighter, but differs primarily in that the aircraft would not operate in close concert with bombers. This is also at times referred to as, “Fighter Sweeps”. Their aim is to lure and force enemy fighters to get airborne and engage them in air combat. This was, in effect, the same role played by the P-51 during WW2, whose presence above Germany allowed USAAF bombers to fly at will over the country.
Air interdiction (AI), also known as deep air support (DAS), is the use of preventative aircraft attacks against enemy targets, that are not an immediate threat, in order to delay, disrupt, or hinder later enemy engagement of friendly forces. It is a core capability of virtually all military air forces, and has been conducted in conflicts since WW1. A distinction is often made between tactical and strategic air interdiction, depending on the objectives of the operation. Typical objectives in tactical interdiction are meant to affect events rapidly and locally, for example through direct destruction of forces or supplies en-route to the active battle area. While strategic objectives are often broader and more long-term, with less direct attacks on enemy fighting capabilities, instead focusing on infrastructure, logistics and other supportive assets.
The term deep air support, relates to CAS and denotes the difference between their respective objectives. Close air support, as the name suggests, is directed towards targets close to friendly ground units, as closely coordinated air-strikes, in direct support of active engagement with the enemy. Deep air support or air interdiction is carried out further from the active fighting, based more on strategic planning and less directly coordinated with ground units. Despite being more strategic than close air support, air interdiction should not be confused with strategic bombing, which is unrelated to ground operations.
The latest air combat tactics have moved away from pure stealth to a mix of stealth for air superiority & Interdiction to non-stealth for destruction of enemy assets using “Arsenal Aircraft” for large scale combat. This has happened due to the validity of Lanchester’s laws for modern combat including stealth. In the posts so far I have stated that stealth is costly and needs heavy fighters but if we look at nature and learn from it, we realise that small size, agility, camouflage and strong punching power defines a “Predator”. These attributes of nature’s laws will remain valid as long as we have human on Earth. The latest example of F-15 & F-16 is supposed to act as “Arsenal Aircraft” capable of carrying nearly 18 missiles to combat in non-stealthy mode. Where does LSA stand with respect to such aircraft?
How designer created LSA
HOW I CREATED LSA
My aim was to create a combination of Mig-21 and Mig-27 which relies on low cost stealth like shaping, small size, composites and Radar absorbent paint to achieve a degree of stealth which will allow it to move within WVRAAM firing range. I am one of those few pilots who have done DACTs with Ajeet (Folland Gnat). That small bird used to send chill down our spine as we always detected it when it was aligning itself in our rear quarter for gun shot. Ajeet, due to its small size also was difficult to detect on radar even though it did not have any kind of stealth shaping.
I wanted an interceptor with good range and endurance which cud act as escort and penetrative fighter with ability to perform as an air superiority fighter at mid-high altitudes. This meant that Mig-21 planform became the first choice. A stealth aircraft is not required to fly and fight at low levels to avoid radar. Its stealth does that job for it, so mid & high altitude performance became paramount. Over a period of time, Mig-21 added lot of weight which resulted in poor performance due to increased span & wing loading while nothing was done to improve the Oswald span efficiency factor and span efficiency which resulted in much higher induced drag. I also studied HF-24 Marut design during this time and to my surprise I found that combining HF-24 & Mig-21, we have a home grown Light Stealth Aircraft.
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