PAK-FA and FGFA Thread

jamwal · Post by **jamwal** » 12 Nov 2010 12:07

I haven't seen this picture before in this thread, so posting it

Singha · Post by **Singha** » 12 Nov 2010 12:56

pakfa has the meatiest wheels and legs I have ever seen on a fighter. it could land on gravel runways baring foreign object damage risk to its low slung air intakes.

abhik · Post by **abhik** » 12 Nov 2010 13:29

X-posted,
Youtube Video:-F-35 JSF infrared sensor tracks rocket launch

Northrop Grumman video showing how its distributed-aperture sensor (DAS) for the F-35 Joint Strike Fighter tracked SpaceX's Falcon 9 launch vehicle flight during a test flight of the sensor system on the company's BAC One-Eleven testbed. DAS rpoivies a 360-deg view round the F-35 for missile warning, traget tracking and navigation, The video has been magnified 10 times. DAS detects and tracks the rocket at horizon-break without the aid of external cues, then continuously tracks the rocket through first-stage burnout, second-stage ignition, across boundaries between DAS sensors, and through the rocket's second-stage burnout at a distance of more than 800 miles. The video also shows the DAS detecting and tracking the rocket's first-stage re-entry.

Long way to go for PAK-FA/FGFA

Gaur · Post by **Gaur** » 12 Nov 2010 14:26

^^
Really? How is that any different from OLS of old Su-27s and Mig-29s? The only difference is that F-35 has multiple (6?) IRSTs placed at different places.
I am not ridiculing DAS. May be its IRSTs are excellent. However, as far as this video goes, it is nothing spectacular. Tracking a huge IR emmiter dual stage rocket (even from 1500kms away)....that is something that even the old OLS-27 may have done.

nrshah · Post by **nrshah** » 12 Nov 2010 18:34

Gaur wrote: I am not ridiculing DAS. May be its IRSTs are excellent. However, as far as this video goes, it is nothing spectacular. Tracking a huge IR emmiter dual stage rocket (even from 1500kms away)....that is something that even the old OLS-27 may have done.

Perhaps, Austin might be able to throw more light....

Austin · Post by **Austin** » 13 Nov 2010 11:18

nrshah , The DAS certainly is a very useful sensor in that it combines 6 fixed TI on JSF that provides 360 * coverage bubble for the pilot and can provide visual situational awareness ( must be one amazing packing density and taking care of cooling requirements of TI sensor ) they would probably combine that kind of situational awareness with EOTS to provide strike capability with unprecedented SA and early warning both in ground strike and WVR combat.

I do not think the DAS can aid in BVR combat as it would lack the Laser Ranging capability to guide a missile at long ranges but could be useful in WVR combat , JSF is a strike aircraft so these sensors are designed to aid in strike mission and SA for pilot.

The PAK-FA on the other hand uses AESA Radar to provide 360 * coverage does the same task as DAS but with RF rather then IIR , the advantage of Active RF is that they would also provide firecontrol solution for IR/RF missile within the bubble and provide 360* sensor coverage. The pilot in PAK-FA would be able to fire missile at the target even medium/short range with RF/IIR ( LOBL/LOAL ) types if the patch radar gets a lock at the target all without changing direction of PAK-FA in combat.

The disadvantage is the RF patch radar will alert the enemy via RWR and make the PAK-FA a very visible target in RF band , but it is possible to smartly use the 360* RF coverage using LPI AESA patch sensors ( X/L band ) and smart use of RF energy minimizing exposure time , just like B-2 does with its radar.

DAS/EOTS on JSF is a good sensor for its mission profile which is strike and RF patch sensor/IRST is good for PAK-FA mission which is Air Superiority , they both have their plus and minus and are uniquely designed for their role.

abhik · Post by **abhik** » 13 Nov 2010 13:08

^^^
Two points/questions
AFAIK the JSF too has side and rear facing radars, in addition to the DAS complementing each other.
Also I thought missile guidance required at least an X band or lower and S and L band were only good enough for scanning and tracking due to lack of precision (?)

svinayak · Post by **svinayak** » 13 Nov 2010 13:20

Gaur wrote:^^
Really? How is that any different from OLS of old Su-27s and Mig-29s? The only difference is that F-35 has multiple (6?) IRSTs placed at different places.
I am not ridiculing DAS. May be its IRSTs are excellent. However, as far as this video goes, it is nothing spectacular. Tracking a huge IR emmiter dual stage rocket (even from 1500kms away)....that is something that even the old OLS-27 may have done.

How can I find some resources for IR seeker. I want to do some Knowledge update myself. What are the good sites Thanks in advance

Gaur · Post by **Gaur** » 13 Nov 2010 15:08

^^
Sorry, I don't know of any particular sight as such. I just google. Search for infrared search and track, optical location system. flir, pirate irst, OLS-35 etc.

For particular websites and books, maybe some other knowledgeable members can help you out.

Austin · Post by **Austin** » 13 Nov 2010 17:31

abhik wrote:^^^
Two points/questions
AFAIK the JSF too has side and rear facing radars, in addition to the DAS complementing each other.
Also I thought missile guidance required at least an X band or lower and S and L band were only good enough for scanning and tracking due to lack of precision (?)

I have never come across JSF having side/rear radar , L band can guide the missile to the target should not be a problem as all WVR/BVR missile have their own guidance and L band sensors can guide it till kill box where missile guidance take over , infact I won't be surprised at short ranges 10-30 km L band will be as good as X band radar

nrshah · Post by **nrshah** » 13 Nov 2010 19:25

Austin,

Thanks for the information....

We have been taking of use of L band radar in pak fa to detect VLO targets (read F22/35) on wing edges... Considering the location, the aperture will be very low. With limited TxRx module, will it be able to fulfill the purpose intended?

Also, if you can guide on capabilities of Russian OLS/IRST/TI with respect to the ones used in EOTS/DAS which i believe is more to do with using multiple IRST at various location and fusion of their data. I was thinking if we can develop network of such IRST/OLS on say AMCA/Tejas MK2?

Singha · Post by **Singha** » 13 Nov 2010 19:28

could the two L-band radars on wing edges be "joined" electronically at back end to form a "virtual antenna" of larger aperture?

Kanson · Post by **Kanson** » 13 Nov 2010 19:59

Simple way to put it is F-35 can do the job in emission-free fashion whereas PAK-FA can do the job by announcing its presence with emissions from those radars it has. It can fulfill its primary role as Raptor-killer only by announcing its presence.

DAS & Stealth is a deadly combination. DAS/IR sensors compliments Stealth to such an extent that both techs are natural partners. Though aerodynamic performance, range of F-35 are yet to be established as satisfactory, as a complete weapon system, i guess it will be a top notch fighter atleast for sometime even in the presence of PAK-FA. It may turn out as the best attack fighter we have not seen before. Though its performance cannot be comparable to PAK-FA, it can very well set an ambush for it. With F-22, it presents a formidable challenge.

In tune with Russian philosophy of approach to warfare, PAK-FA is designed to their taste. In a one to one fight again F-22, if PAK-FA meets every expectation set, it may have a chance to win the fight.

Austin · Post by **Austin** » 13 Nov 2010 20:27

I think the problem with passive sensors like OLS , DAS , IIR is that its ability to operate in all weather conditions in bad weather the performance of IR/IIR/TV sensors will degrade significantly , plus as we have seen in Kosovo war the IR sensors were fooled with smart decoys using IR enhancers and stuff.

RF on the other hand can afford all weather capability but will emit and make its presence felt , this can be some what reduced using LPI capability.

In the end it just boils down to trade off , it is possible that future JSF will have radar patches plus DAS and similarly PAK-FA/FGFA will have RF + Passive 360* sensors.

PAK-FA will turn to be a better air superiority fighter by design much like JSF will be a better striker by design.

Austin · Post by **Austin** » 13 Nov 2010 20:35

nrshah wrote: Also, if you can guide on capabilities of Russian OLS/IRST/TI with respect to the ones used in EOTS/DAS which i believe is more to do with using multiple IRST at various location and fusion of their data. I was thinking if we can develop network of such IRST/OLS on say AMCA/Tejas MK2?

The OLS have in built laser that does the ranging job , passive sensors like IIR/TI cannot do the ranging job and depends on Laser Range Finder to do its job and then these information in combination is useful to guide missile.

DAS as far as I have read has TI which gives it 360* capability good for SI and EW but not good to guide missile , so I do not really know how DAS can be useful to fire missile.

SaiK · Post by **SaiK** » 13 Nov 2010 22:20

Is it the same range of OLS in Mig35 or what is the plan for pakfa?

http://www.youtube.com/watch?v=oO2D6tl8NjE
That diagram at time 2:10 imho, is not correct, perhaps a FGFA redesign aspect for India.

it could land on gravel runways baring foreign object damage risk to its low slung air intakes.

http://www.youtube.com/watch?v=-_whAc7kzd8
Could the design at 0:10 and 0:25 be added/modified to raise the inlets from the ground, and get the required inlet from top of the wings. What would be the vortex problem and lift related issues with this type of design? I am thinking this is an interesting design since the inlet is distributed to both above and below the wings. Any gurus to explain this design?

Gaur · Post by **Gaur** » 13 Nov 2010 22:49

^^
OLS-UE is proposed for MIg-35. That is already outmatched by OLS-35 of Su-35. PAK-FA will use OLS-50.

The PAK-FA shown in the first video is just a 3d model by an amateur artist. One can model anyway one wants to. So, do not believe it to be FGFA.

For the second video, that is a 3D render by a professional CG artist Aleksander Dultsev which was done long before PAK-FA's first flight. There were some more renderings too. The artist had described them as speculative fan art for PAK-FA.

Rahul M · Post by **Rahul M** » 13 Nov 2010 22:53

I thought it was OLS-50 for PAKFA ?

Avarachan · Post by **Avarachan** » 13 Nov 2010 23:19

It's OLS-50.

Avarachan · Post by **Avarachan** » 13 Nov 2010 23:24

And, yeah, I've heard that the F-35's DAS can be used to fire air-to-air missiles. That's why the F-35 marketing guys are saying that "maneuverability doesn't matter" any more. As with most of the marketing claims for the F-35, one should be skeptical. The JSF program is in serious trouble. Read Bill Sweetman for further info.

Gaur · Post by **Gaur** » 13 Nov 2010 23:48

Rahul M wrote:I thought it was OLS-50 for PAKFA ?

Yes, it is OLS-50. I'll edit my post.

BTW, can anyone point me towards any information regarding OLS-30? Any little tidbit will be appreciated as I can hardly find anything by googling.
Thanks.

Gaur · Post by **Gaur** » 14 Nov 2010 00:08

Avarachan wrote:And, yeah, I've heard that the F-35's DAS can be used to fire air-to-air missiles. That's why the F-35 marketing guys are saying that "maneuverability doesn't matter" any more. As with most of the marketing claims for the F-35, one should be skeptical. The JSF program is in serious trouble. Read Bill Sweetman for further info.

AFAIK, DAS's primary role is situational awareness. The only way it comes close to being an offensive system is by assisting the EOTS. EOTS has its own 3rd generation FLIR and can provide high resolution ground imagery, targeting, laser designation and range finding...in short, it's like an integrated litening/sniper XL pod. So how DAS will assist EOTS is a mystery to me as EOTS seems like a self sufficient system. Perhaps DAS will assist by providing the pilot with better thermal imagery of ground targets (the likely answer) or perhaps it may assist as a laser designator (which I highly doubt).
In any case, DAS has no role in guiding AAMs.

SaiK · Post by **SaiK** » 14 Nov 2010 03:19

Gaur · Post by **Gaur** » 14 Nov 2010 04:10

^^
Yes, the above are also from the same set released by Aleksander Dultsev. IIRC, they were all posted even here a few years before PAK-FA's first flight. If you are interested in his PAK-FA concept art,
then you may visit his website:
http://www.duler.ru/design.html

SaiK · Post by **SaiK** » 14 Nov 2010 06:33

My interest was to find if anyone would be discussing the air intakes per these pics.

Kanson · Post by **Kanson** » 14 Nov 2010 08:49

Gaur wrote:
Avarachan wrote:And, yeah, I've heard that the F-35's DAS can be used to fire air-to-air missiles. That's why the F-35 marketing guys are saying that "maneuverability doesn't matter" any more. As with most of the marketing claims for the F-35, one should be skeptical. The JSF program is in serious trouble. Read Bill Sweetman for further info.
AFAIK, DAS's primary role is situational awareness. The only way it comes close to being an offensive system is by assisting the EOTS. EOTS has its own 3rd generation FLIR and can provide high resolution ground imagery, targeting, laser designation and range finding...in short, it's like an integrated litening/sniper XL pod. So how DAS will assist EOTS is a mystery to me as EOTS seems like a self sufficient system. Perhaps DAS will assist by providing the pilot with better thermal imagery of ground targets (the likely answer) or perhaps it may assist as a laser designator (which I highly doubt).
In any case, DAS has no role in guiding AAMs.

Link says it has fire control.

http://www.es.northropgrumman.com/solut ... targeting/

The DAS surrounds the aircraft with a protective sphere of situational awareness. It warns the pilot of incoming aircraft and missile threats as well as providing day/night vision, fire control capability and precision tracking of wingmen/friendly aircraft for tactical maneuvering.

Kanson · Post by **Kanson** » 14 Nov 2010 08:51

SaiK wrote:My interest was to find if anyone would be discussing the air intakes per these pics.

Inlet may help to enhance the max speed and super cruise capabilities; super cruise may be sustained for longer time. High AoA is doubtful, as it appears engine will stall before wing stalls.

Gurneesh · Post by **Gurneesh** » 14 Nov 2010 09:09

Plus inlets on the top would do wonders in terms of reducing the RCS as well as freeing up some more space for internal weapon storage.

Anyway from a purely aesthetic point, the first pic (back + side view) is just too good. One would struggle to find a plane that looks prettier.

nachiket · Post by **nachiket** » 14 Nov 2010 09:11

High AoA flight would be impossible with those inlets. They may look good but that's about it. Not practical at all.

Gurneesh · Post by **Gurneesh** » 14 Nov 2010 09:21

^^ that is right, this could only work as a stealth bomber.

Sumeet · Post by **Sumeet** » 14 Nov 2010 12:05

Kanson wrote:
http://www.es.northropgrumman.com/solut ... targeting/

The DAS surrounds the aircraft with a protective sphere of situational awareness. It warns the pilot of incoming aircraft and missile threats as well as providing day/night vision, fire control capability and precision tracking of wingmen/friendly aircraft for tactical maneuvering.

Yes one of DAS's feature is acting as a high precision IRST sensor. This accurate tracking of target produces information that can be transmitted to AAM like AIM-9X operating in LOAL mode. In this way it can exhibit fire control capability.

JSF possesses EOSS -- Electro Optical Sensor System that comprises of EOTS [Electro Optical Targetting system] developed by LM based on Sniper program and DAS developed by NG. DAS can also work in conjunction with EOTS to let JSF implement silent offensive attacks.

So both Gaur and Avarachan are right.

Gaur · Post by **Gaur** » 14 Nov 2010 13:41

Kanson wrote:
Gaur wrote: AFAIK, DAS's primary role is situational awareness. The only way it comes close to being an offensive system is by assisting the EOTS. EOTS has its own 3rd generation FLIR and can provide high resolution ground imagery, targeting, laser designation and range finding...in short, it's like an integrated litening/sniper XL pod. So how DAS will assist EOTS is a mystery to me as EOTS seems like a self sufficient system. Perhaps DAS will assist by providing the pilot with better thermal imagery of ground targets (the likely answer) or perhaps it may assist as a laser designator (which I highly doubt).
In any case, DAS has no role in guiding AAMs.
Link says it has fire control.

http://www.es.northropgrumman.com/solut ... targeting/
The DAS surrounds the aircraft with a protective sphere of situational awareness. It warns the pilot of incoming aircraft and missile threats as well as providing day/night vision, fire control capability and precision tracking of wingmen/friendly aircraft for tactical maneuvering.

As I said, my understanding is that it assists EOTS. That is its "fire control" capability.
Though technically, it has both a FLIR and a laser rangefinder. So, it "can" act as a independent unit for LGB guidance. However, since EOTS exists for the sole purpose of that, IMHO DAS role will be to provide a supporting role at best.

Sumeet wrote: Yes one of DAS's feature is acting as a high precision IRST sensor. This accurate tracking of target produces information that can be transmitted to AAM like AIM-9X operating in LOAL mode. In this way it can exhibit fire control capability.

JSF possesses EOSS -- Electro Optical Sensor System that comprises of EOTS [Electro Optical Targetting system] developed by LM based on Sniper program and DAS developed by NG. DAS can also work in conjunction with EOTS to let JSF implement silent offensive attacks.

You mean that DAS can accurately act as an independent sensor for a short range missile? Or does it overlap with the IR missile's sensor to provide better tracking of aerial targets? Unfortunately, I have not come across any these roles of DAS. Even your later statement says that DAS works in "conjunction" with EOTS....which can only mean support for ground targeting.

So, how does short range AAM guidance come into picture? If you have come across a reference to the above, could you provide a link here for our benefit?

Thanks.

abhik · Post by **abhik** » 14 Nov 2010 15:58

Austin wrote: I have never come across JSF having side/rear radar , L band can guide the missile to the target should not be a problem as all WVR/BVR missile have their own guidance and L band sensors can guide it till kill box where missile guidance take over , infact I won't be surprised at short ranges 10-30 km L band will be as good as X band radar

This is a promo video of the JSF, pay attention from 1:50min on wards, it shows all the sensors and their locations on the plane.http://www.youtube.com/watch?v=y44lftPGWvM

SaiK · Post by **SaiK** » 14 Nov 2010 17:36

kanson, thanks for the explanations. how about say additional TVC nozzles or the existing improved 360*TVC as a counterbalance for loss of control during AoA maneuvers?

didn't x31 used paddles for vectoring? any use here to improve AoA?

Gaur · Post by **Gaur** » 14 Nov 2010 18:16

abhik wrote:
Austin wrote: I have never come across JSF having side/rear radar , L band can guide the missile to the target should not be a problem as all WVR/BVR missile have their own guidance and L band sensors can guide it till kill box where missile guidance take over , infact I won't be surprised at short ranges 10-30 km L band will be as good as X band radar
This is a promo video of the JSF, pay attention from 1:50min on wards, it shows all the sensors and their locations on the plane.http://www.youtube.com/watch?v=y44lftPGWvM

You are talking about L-band antennas? They are for satellite linking and are developed by Ball Aerospace.

Gaur · Post by **Gaur** » 14 Nov 2010 18:31

SaiK wrote:kanson, thanks for the explanations. how about say additional TVC nozzles or the existing improved 360*TVC as a counterbalance for loss of control during AoA maneuvers?

didn't x31 used paddles for vectoring? any use here to improve AoA?

I am not qualified to evaluate these particular 3d renders. But in general, if any intake is incapable of handling high AOA, use of TVC will only cause the engines to flame out. This is because inlet If the airflow inside the inlet is too sparse or/and too turbulent, TVC will not solve that problem. Before being able to utilize TVC, one will have to consider the limit of both aerodynamics and inlet.

If the wings stall at low AOA, vortex generates may need to be added. If the aerodynamics are too flawed, even that may not help and major redesigning has to be done.

If the engines flame out at high AOA, then the inlet system has to be looked into. Also, it has to be seen if some other airframe design factors are not causing turbulent air to be added in inlet.

abhik · Post by **abhik** » 14 Nov 2010 18:32

what's the reason you guys don't think that the DAS cant guide IR short range missiles?

Gaur · Post by **Gaur** » 14 Nov 2010 18:51

^^
Because LM has never said that it can. People are just basing their speculations upon vague statements. Till now, it has never been claimed by NG that DAS sensors are anything other than typical IRST/OLS systems which are basically FLIR and a laser rangefinders. Though technically speaking, any IRST/OLS may be able to guide missiles but that would not be very efficient. First of all, missile seeker's performance will far outmatch that of IRST/OLS simply because it will be much closer to the target. The performance depriciation will be even more huge if there is rain, fog etc. Secondly, IRST/OLS will view the target from a different perspective view than that of missile head. So, the IRST/OLS has to use its laser rangerfinder and process the accurate co-ordinates of the target and continuesly send it to the IR missile. But the IR AAM does not understand space co-ordinates. So, the information has to be further processed so that the missile seeker is tricked to see ir signature in the proper place. But even the laser rangefinder will not work properly in smoke and fog.
In short, you can guide a missile using IRST/OLS if you want to, but there is simply no need. Why try complicated alternatives when there is a simple way present.

Frankly, I do not understand why people are so disappointed that DAS cannot guide missiles. DAS was mainly developed for situational awareness and hopefully it can do that job well enough. Why does it have to do every other job?

Added Later: As I have said earlier, it is not that it cannot be done. I am simply saying that, IMO, there is no need (also it may prove to be even less efficient). However, LM may believe differently and use DAS to guide IR missiles anyways. But if so, it could only be believed if someone could provide us with proper reference. If that is provided, then I would be happy to be educated. But till then, I do not understand the need to do speculations based on some vague statements.

Kanson · Post by **Kanson** » 14 Nov 2010 20:17

SaiK wrote:kanson, thanks for the explanations. how about say additional TVC nozzles or the existing improved 360*TVC as a counterbalance for loss of control during AoA maneuvers?

didn't x31 used paddles for vectoring? any use here to improve AoA?

No. Here at high AoA, as we infer/assume that the engine stalls before wing, the problem is not with control surfaces during AoA. It is the loss of engine power. Fighter planes are not like gliders which can float even without power. So with loss of power, it is just a dead weight that is expected to fall from sky. When engine fails at high AoA in this situation, control surfaces are still active and can be used to stabilize the aircraft from the spin while attempting to re-light the stalled engine.

But then, this rendering shown has LERX and then wing fence like structure/depression leading to inlet. So we can't simply conclude that it can't do high AoA. How high the AoA it can do, can only be determined in wind tunnel test. In addition new techniques can be used to keep the air flow to the engine. But then we are only talking about the inlets.

Paddles are another way of vectoring thrust. It is similar to jet vanes used in missiles. But then it is of any use only when there is enough thrust from the engine. When engine stalls, what is the use of such devices to attain high AoA?

Gaur · Post by **Gaur** » 14 Nov 2010 22:15

Posting in PAK-FA thread has reminded me of something. 5 months ago, I had modeled a modified PAK-FA/FGFA with dual seats and flat nozzles. However, I have abandoned the jingo project because I am no good at creating complex textures in photoshop. Generally one can find free textures on the net, but I am having no luck.

Is any member skilled in photoshop/gimp etc willing to help? I will only need base camouflage pattern. I can add other layers like IAF roundels, bump, screws, dirt,other symbols etc on my own.

To clarify, by basic pattern I mean something like this. Of course, instead of army camo pattern I would need aircraft skin's patter.

I do not want the current PAK-FA non stealth Russian camo. I want a black stealth camo like that of YF-23. If someone is willing to paint/find one, I would be highly grateful.

Thanks.

PS: Just to clarify, this is a personal jingo project to visualize final version of FGFA in IAF colours. Just like my previous rendering of Tejas, I gain nothing commercially by finishing this.