Sukhoi PAK FA

Payeng

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It seems the F-22's speed is either governed or simply hidden. AFAIK, greater than Mach 2 speed is actually a self imposed restriction. F-15s had major restrictions as well.

It is more draggy than F-15 and will require greater power to move as fast. But I think less draggy if weapons stores are added on the teen.

There is no doubt the F-22 can manage Mach 1.6 for 40 minutes using supercruise, according to requirements. I think they mentioned something about a 200-400Km supercruise range with a combination of subsonic speeds for 1000Km.

Comparatively I think Mig-31 can do Mach 2.35 for a 700Km range.
For a Mig-31, I think to break the sound barrier she will need to go for after burners and after burners are not known to be used for prolonged duration it is also not fuel efficient, after burners are for short shots usually for added power and thrust at the cost of fuel inefficiency.

The reason I am asking this question is that afaik non variable geometry inlet arrangement jet fighter generally have a maximum speed of M 1.8 while fighters crossing that mark implement modified inlet arrangement to tackle shock waves required to cross 1.8-2.0 mark. All known M1.8+ jet fighters have variable geometry inlets as like F-15, Mig-31/25,Su-27/30,Mig-29 and Mirage 2000( with its movable cone) while fixed geometry inlet fighters like Rafale, Su-34 and other comparable even including the DSI designed F-35 fighter jets are not known to exceed M 1.8-2.0. Note the difference between Mirage 2000 and Rafale where the later one is later produced and can do super cruise but have a lower top speed, and also su-27/30 and su-34 while both share an almost similar design but the later do not include a variable geometry inlet arrangement and top speed drops to M1.8 mark. I also wonder if the J-20 could cross the M 1.8 mark with her fixed geometry DSI inlet design.

F-22 is know to have a fixed geometry inlet design.
 
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Payeng

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^^ updated post to make it more readable.
 

Payeng

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Some times it is said that F-22 is an exception with her high power engine but I am not ready to buy it with out any explanation and F-35 have a even powerful engine (although it have a single engine) Air frame does matter but modern airframe should usually tackle M2.0+ usually while for conventional winged aircraft is limited to transonic speed (Boieng 747, C-130) that is below M 1.0, Jet fighter configuration is expected to do more then that, and yes new generation air frame is usually capable to do super cruise considering required engine thrust but not necessarily achieve M 2.0 without any inlet air control. For crossing M 1.8-2.0 mark some modification in inlet is required for the engine to breath.
 

Payeng

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While it is believed that F-16 had reached a top speed of M 2.0 with a modified intake optimised for the purpose the usual top speed for fixed geometry intake for production jet is around Mach 1.7 to 1.8, for higher speed it will require a modified intake design-a setup not optimised for sub sonic and transonic speed. So a variable geometry inlet design is introduced as a fill gap measure for optimun performance both at sub-transonic speed and supersonic speed in access to Mach 1.8.

It seems that DSI setup helps in optimum performance both in sub-transonic speed and super sonic speed comparatively with traditional setup but do not help in plus Mach 1.8 speed an assumed benchmark for Fixed geometry intake design.

Here are some interesting data regarding DSI intake research.

In this paper the computed flow and performance characteristics at low angle-of-attack
(AOA) of an integrated Diverterless Supersonic Inlet (DSI) are presented near its design
mass flow rate. The subsonic characteristics are evaluated at M∞=0.8 while the supersonic
characteristics are evaluated at M∞=1.7, which is near the design Mach number for the
intake.
In addition to the external flow features, the internal intake duct flow behavior is also
evaluated. The results of this study indicate effective boundary layer diversion due to the
"bump" compression surface in both subsonic and supersonic regimes. At M∞=1.7, the
shockwave structure (oblique / normal shockwave) on the "bump" compression surface and
intake inlet is satisfactory at intake design mass flow ratio. The intake duct flow behavior at
subsonic and supersonic conditions is generally consistent with "Y" shaped intake duct of
the present configuration. The secondary flow structure inside the duct has been effectively
captured by present computations. The computed intake total pressure recovery at M∞=1.7
exhibits higher-then-conventional behavior at low mass flow ratios, which is attributed to
inlet design feature.
Overall computed subsonic and supersonic total pressure recovery
characteristics are satisfactory under the evaluated conditions and are also in agreement
with wind tunnel test data.
http://pdf.aiaa.org/preview/2010/CDReadyMASM10_1812/PV2010_481.pdf
 

Payeng

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Again PAK-FA is claimed to have 3 X band radars at front and 2 L band radars ( probably at wings),wonder where are the second and third X band radars are located , one must be in that nose randome cone.
 

p2prada

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Interesting about the inlets. But we cannot say for sure unless they release more info about the inlet design.

DSIs can be variable too. Seems the J-20s intakes are variable.

Anyway a F-16 Block 30 reached Mach 2 with DSI.

PAKFA will have one X band array in the nose, one on both sides of the canopy(or nose) and the third at the tail.
 

Payeng

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DSI on F-16 was tried on experimental basis aka technology demonstrator, it is not the production version of F-16 Block 30, I think even a Mach 2.4 is possible with a fixed geometry design but at the expense of sub sonic performance. Though I have not checked for credible source regarding performance of F-16, I mean not sure if Block 30 product can achieve Mach 2 or not, but still not pass Mach 2 as a benchmark. Regarding Variable geometry DSI is a subject not discussed yet. Although new technologies can have out of the box concept applied but for the namesake DSI IS a fixed geometry inlet design.
 

Twinblade

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Again PAK-FA is claimed to have 3 X band radars at front and 2 L band radars ( probably at wings),wonder where are the second and third X band radars are located , one must be in that nose randome cone.
Interesting about the inlets. But we cannot say for sure unless they release more info about the inlet design.

DSIs can be variable too. Seems the J-20s intakes are variable.

Anyway a F-16 Block 30 reached Mach 2 with DSI.

PAKFA will have one X band array in the nose, one on both sides of the canopy(or nose) and the third at the tail.

Sorry to prick a pin in the bubble guys, but those L-Band aesa arrays are not radars. A lot of confusion sprung from take-off.ru's report on MAKS 2011 where it mentioned NIIP aesa radar for Pak-Fa and the L-band aesa array in the same line. Just two paragraphs down the article was the description of the arrays,

Other novelties from GRPZ at MAKS 2011 were the4283E AESA two-band digital IFF interroga-tor and 4280MSE multifunction integratedIFF responder.
PAK T-50 5G Russian Plane (Pg 28)

GRPZ (Ryazan State Instrument-making Enterprise), is the manufacturer of those L-band arrays as well as NIIP Aesa's radar processor, the N-036EVS computer system. Those L-band arrays are not radars, but IFF transponders and receivers. They might have a secondary role (data links, jammers) but an array that thin cannot have an effective scan volume beyond a few degrees in the vertical plane (not to mention the power output that can be expected out of them).

Regarding the tail radar, it has almost become a Sukhoi urban legend. First speculated on Berkut (in the longer tail spine), resurfaced on Su-27M (seen below flying with a dielectric cone on the spine in 1999), Su-34 and Su-35.


The tail radar did not feature on Su-30 Mki or Su-35. The large tail of Su-34 which could have housed a radar turned out to be equipped with APU, large amount of electronics and flare dispensers (considering its role as a ground attack platform). No tail radar has been displayed for Pak-fa, neither the aircraft has flown with a dielectric cone on the tail and considering only two prototypes are left befor VVS receives them in 2013, in my opinion, it is unlikely that it will feature any. However the IAF has insisted for a "360 degree aesa", which could imply a conformal array or something very similar to AN/ALR-94 suite like f-22 raptor.
 
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Defcon 1

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I have one question. Is PAK FA being designed as a strike plane or an air-superiority fighter like the MKI & Mig-29?????

I am asking this question as I feel that india has only air superiority fighters currently.
 

p2prada

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I have one question. Is PAK FA being designed as a strike plane or an air-superiority fighter like the MKI & Mig-29?????

I am asking this question as I feel that india has only air superiority fighters currently.
Air superiority of course. IAF requirements have always been air superiority with secondary strike capability for all new aircraft. Rafale changes that a bit, but it is still more or less the same.

LCA and AMCA are air superiority as well.

Strike will be handled by UCAVs in the future. Rustom H and AURA can manage it.
 

Defcon 1

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Air superiority of course. IAF requirements have always been air superiority with secondary strike capability for all new aircraft. Rafale changes that a bit, but it is still more or less the same.

LCA and AMCA are air superiority as well.

Strike will be handled by UCAVs in the future. Rustom H and AURA can manage it.
Exactly this is what I feared. Isn't air superiority a defensive strategy????

I mean an aggressive force would always want to conduct strikes. Why are we being so defensive???
 

p2prada

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Exactly this is what I feared. Isn't air superiority a defensive strategy????

I mean an aggressive force would always want to conduct strikes. Why are we being so defensive???
Air superiority fighters are meant for an offensive force. You can't conduct strikes if you don't control the air.

During Battle of Longewala, it was IAF which controlled the skies hence it was IAF that delivered the strike package on PA.

Currently we have 100 odd modern strike fighters like the Jaguars. Air superiority fighters can also carry and drop bombs once they have control of the air. Aircraft like Rafale can do everything at once.
 

Defcon 1

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Air superiority fighters are meant for an offensive force. You can't conduct strikes if you don't control the air.

During Battle of Longewala, it was IAF which controlled the skies hence it was IAF that delivered the strike package on PA.

Currently we have 100 odd modern strike fighters like the Jaguars. Air superiority fighters can also carry and drop bombs once they have control of the air. Aircraft like Rafale can do everything at once.
Jaguar is a 35 year old plane. What I am suggesting is that shouldn't we focus on 5th gen stike planes which can conduct deep strikes by bypassing the ground air defences. Wouldn't that cut the need the need to control air in the first place. I strongly believe that this is important against the pakis and in line with our cold start strategy.
 

p2prada

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Jaguar is a 35 year old plane. What I am suggesting is that shouldn't we focus on 5th gen stike planes which can conduct deep strikes by bypassing the ground air defences. Wouldn't that cut the need the need to control air in the first place. I strongly believe that this is important against the pakis and in line with our cold start strategy.
Jaguar maybe old by design, but it is a very effective strike fighter. It needs to be upgraded though.

Aircraft like PAKFA, AMCA and AURA can bypass ground defences and strike deep within enemy territory.

However enemy aircraft will have the upperhand all the while and we will depend on luck to ward off attacks. If the enemy attacks us with fighters then we will have nothing to defend against. Without an air superiority aircraft there is no air force.

What we can use are heavy bombers, but we don't have such a need as of today.
 

Payeng

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Anti radar missile for Su-30 MKI the one that will also carry the air launch Brahmos.

I wonder what the big hush about tactical bombers?
 

Payeng

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Exactly this is what I feared. Isn't air superiority a defensive strategy????

I mean an aggressive force would always want to conduct strikes. Why are we being so defensive???
Defcon 1 Air superiority fighters should be able to perform tactical bombing mission considering you got the ammunition compatible with the aircraft, after all most of IAF machines are multirole capable not dedicated air superiority, if you are talking about strategic bomber, India will need to manufacture one to get one, I doubt other nations does offer us weapons for any aggressive purpose but for the defensive purpose.
 

balai_c

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Air superiority of course. IAF requirements have always been air superiority with secondary strike capability for all new aircraft. Rafale changes that a bit, but it is still more or less the same.

LCA and AMCA are air superiority as well.

Strike will be handled by UCAVs in the future. Rustom H and AURA can manage it.
P2p, are you sure that LCA has the potential to perform the role of maintaining air superiority? As far I have read, it is meant for point defense role primarily. It is a cranked delta wing with a payload capacity of approximately 6 tonnes, typically in the domain of Gripen c/d and JF-17. Considering it's wing shape, it has limited low altitude subsonic combat capabilities, not good for a typical "knife fight" for fighter jocks. Awaiting your comments.
 

Defcon 1

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Jaguar maybe old by design, but it is a very effective strike fighter. It needs to be upgraded though.

Aircraft like PAKFA, AMCA and AURA can bypass ground defences and strike deep within enemy territory.

However enemy aircraft will have the upperhand all the while and we will depend on luck to ward off attacks. If the enemy attacks us with fighters then we will have nothing to defend against. Without an air superiority aircraft there is no air force.

What we can use are heavy bombers, but we don't have such a need as of today.
I fully understand the need of maintaining air superiority. But my question is why we are developing only one kind of aircraft?

We have two fifth gen fighter programs. Shouldn't we spread our capabilities??? AMCA for strike role and FGFA, being more advanced can be used for air superiority.

Su-30 MKI is already the most advanced fighter aircraft in whole of asia (Except for the Saudi Typhoons). Shouldn't we take this opportunity and focus on an area where we are behind?

Pakistan's anti-aircraft defences are more advanced than their Indian counterparts. shouldn't we make some efforts to negate it.

I understand when you say that FGFA & AMCA will be able to penetrate ground defences. But there should be some reason that strike aircrafts are still in service with all major airforces of the world.
 

Payeng

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Defcon 1 MCA was suppose to be a deep penetration and strike aircraft , but current trend of multirole capabilities eliminates the need for dedicated fighter jets, why to have only the bomber if you can have the added capabilities of air role.
 

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