01-31-2010, 01:57 AM (This post was last modified: 01-31-2010, 01:58 AM by Arun_S.)
Igorr's blog posting after First PAKFA Flight.
I have underlined some parts to highlight attention. He also mentions/reasserts the un-usual LERX commonality it shares with LCA (something that I too mentioned in earlier post)
Quote:[/url][url="http://igorrgroup.blogspot.com/2010/01/pak-fa-first-flight.html"]PAK FA first flight[/url]
[url="http://1.bp.blogspot.com/_mDvQ8xYRdSI/S2QDM-CrWRI/AAAAAAAAA4A/pCbKacQ3d1s/s1600-h/pak-fa+28.08.2009.jpg"][/url]The new 5[sup]th[/sup] generation fighter prototype T-50-1 ('izdelie 701'), developed within the framework of the Indo-Russian PAKFA/FGFA program, has made its [url="http://www.youtube.com/watch?v=S67zfmEqGxQ&feature=player_embedded"]first flight[/url] at Jan. 29 in Komsomolsk-on-Amur. It was 47 min on the air. Despite the wrap of secrecy, the look of the fighter appeared very close to that, previously [url="http://igorrgroup.blogspot.com/2009/10/outlines-of-pak-fa.html"]described[/url] in the most reliable Russian publications. So, everybody can now compare what was said about the PAK FA specs before, and what exists actually.
Now it is clear, that in its airframe design the fighter is closer related to American F-23 prototype, than F-22 or JSF, but with bigger internal payload bay. However, it has unrepeatable impress of Sukhoi design house, clearly looking as a thoroughbred Su-linage. [color="#2e8b57"]According to the most reliable estimations, T-50 has 10 internal and 2 additional external hardpoints[/color] on the wings (the 'mystery' triangle thickening under the wings). With this great payload capability and much space for the fuel T-50 can became a true military 'workhorse' of the future battlefield! <a name="more">
From relatively unexpected moments [color="#2e8b57"]the controlled LCA-like LERX must be noted[/color][color="#2e8b57"]. It demonstrates the designers' assertiveness (if not hardball) in field of the super-maneuverability.[/color] With currently installed 14.5 t thrust 'izdelie 117' and futuristic 17,2 t thrust Al-41F engine the plane can take off from a 300-400 m horizontal airfield or even a highway. Also, the multiplicity of controlled aerodynamic surfaces, which make precision landing easier, is an indication about intention to use the plane in the future as a carrier-based platform . However, the capability of the aircraft to land on Vikramaditya-size carrier (40 kt) is not yet clear.
The nozzles was designed round, as expected, which provoked speculations about problem in IR and radar stealthness from rear hemisphere. However, the program chief has explained early, that IR and radar observability reduction was achieved not worse than on American 5[sup]th[/sup] gen. fighters, but in different way. The 1[sup]st[/sup] prototype has no TVSs but it's certainly formulated as a part of the program and already developed by 'Klimov'.
The triangle form of the wings is optimized for supersonic maneurability, and[color="#2e8b57"] indirectly confirms the supercruise capability [/color]of the aircraft. On other hand the cross-section of the nose-cone is not so flattened, as was predicted according to flattened AESA form.
As Putin's deputy has officially declared, the prototype already has an installed data link which allows it the battlefield communication. According to him the new 5[sup]th[/sup] gen. avionics, the 'electronic pilot', allow to pilot concentrate its efforts on the battle instead of the piloting. However, Russian PM Putin itself [url="http://premier.gov.ru/events/news/9193/"]said[/url] after the fly, that the designers 'have much to work' on the fighter's weapon and engine. The program is described by the cabinet as the 'first priority military program', and its 100% financing will continue despite the world financial turmoil.
A somewhere disappointing is the old fashion look of the cockpit, but this can relatively easy be improved till entering serial production. The information about the tender for a frame-less cockpit is already [url="http://zakupki.gov.ru/Notification.aspx?PurchaseId=403793"]published[/url].
The production is planned to be started till 2013. Then, according to the PM's publicly announced decision, the first batch of fighters has to come to the practice center in 2013, and in 2015 the fighters have to be on service.
The former Sukhoi's chief (now working with 'MiG' in UAC directorate) and the 'father' of PAK FA program Mikhail Pogosyan said after the flight, that the United Air-building Corporation (UAC) will follow to work with the Indian counterparts on this program and he is sure, that this product will catch the world market too.
I personally estimate the fighter (in single and two-sitter configuration) jointly produced in Russia and India can be [color="#2e8b57"]exported to Russian and Indian friendly countries around the world.[/color] The list of the countries who can afford T-50, includes in the first place those, who already use Soviet/Russian fighters in AF and want generation upgrade. It could be Belorussia, Kazakhstan, Venezuela, Algeria, Malaysia, Libya and in some circumstances ââ¬â Iran. The second line, if economically improved, the follow states could become T-50's customers too: Myanmar, Indonesia, Syria, Serbia and even Ukraine (if more realistic president will be elected). However, I think, China has zero chance to be allowed for T-50 import for obvious reasons.
Other problem is the unfair competition, sometimes accompanied by huge kickbacks. The natural competitors of Indo-Russian T-50 on the world market is JSF and the 4+ gen eurojets. If aggressive marketing of those planes succeeds, the prospects of PAKFA/FGFA program may be worse for simple reason of fund devastation. I'm not sure, how this fact is reflected in political consciousness in two countries. Methinks both countries must concentrate maximum efforts on their most advanced fighter program instead supporting third part foreign competitors by massive purchases. Posted by Igor Djadan at [url="http://igorrgroup.blogspot.com/2010/01/pak-fa-first-flight.html"]12:02 PM[/url]
[quote name='Arun_S' date='31 January 2010 - 01:44 AM' timestamp='1264881961' post='103806']
Two L-band AESA radar on the wing slats is less-use / useless because it will have no beam firming capability in elevation (vertical) plane. Such limited capabelity is of little use in a flighter while at the same time transmitting a Rf beams with no elevation control is inviting trouble in LO radar.[/quote]
Arun , one of the idea proposed is to use L band T/R module on wings and Tail
02-01-2010, 10:40 AM (This post was last modified: 02-01-2010, 10:51 AM by Arun_S.)
[quote name='Austin' date='31 January 2010 - 08:43 PM' timestamp='1264950324' post='103825']
Arun , one of the idea proposed is to use L band T/R module on wings and Tail
Check this link for more details [url="http://www.ausairpower.net/APA-2009-06.html"]Assessing the Tikhomirov NIIP L-Band Active Electronically Steered Array[/url]
I think the same can be applied for PAK-FA depending what gold plated version of PAK-FA one is building
[/quote]
The article talking of largely using AESA modules for direction finding (spatial location). I t does not claim using L band AESA for radar (detection and ranging).
Antenna gain is a function of physical planar area of antenna array. Thus when mounted on leading edge of the wing, one will get excellent antenna gain and beam steering in azimutal plane, but because the number of L band antenna elements that can be put into (say 1 foot thick) leading edge wing surface is limited to about 8 (at serious risk to inter element isolation) the gain is seriosuly limited, and the resulting beam is very thick in elevation. Overall the gain of the antenna is due to elements in horizontal wing. Radar's range is a function of peak EIRP that radar can generate and such antenna due to limited antenna gain will have poor range, as well as poor pointing accuracy in elevation, but reasonably good on azimuth. One can realize good 2-D radar performance from such radar, but not 3-D radar performance.
Putting the AESA element on tail fin similarly has problem in azimuthal plane. However by synthesizing antenna elements in leading edge of both fins one can get reasonably good gain in azimuth and elevation. However because the tail is separated a distance that is many times the L band wavelength, there will be lots of fringing in azimuth beam formation (beam splitting due to Fresnel effect). Hence reasonable 2-D radar but not so great 3D radar performace. Teh problem with tail is it has small field of view and blind to the bogies below the wing plane.
Now instead of leading edge if they us the flat tail surface to construct the AESA radar that will work great; note that it will be looking in space that is not served by main nose radome antenna. And yes that flat surface can still be made stealthy for the time duration the radar is not transmitting or receiving.. Similarly AESA can be mounted conformal on main wing surface looking above and below.
Now if the AESA antenna array is not just along the wing's leading edge but also extend out back into the wing surface (top and bottom) that will give good performance, and cover broad solid angle (minimizing blind spots)
Some info on Russian Development on RCS reduction ( via keypubs/coolien099 )
Quote:Andrey Lagarjkov, Director General of the United Institute of High Temperatures of the Russian Academy of Sciences (and an Associate Member of the Academy), talks about Russian stealth technology in the following interview with the Russia/CIS Observer.
Until recently, all Russian developments in the field of stealth technologies were strictly classified. There weren't any reports made concerning research institutes dealing with these issues. The veil was raised somewhat last year when it was announced for the first time that the United Institute of High Temperatures of the Russian Academy of Sciences was carrying out research in the domain of reduced aircraft visibility. The information was rather sketchy. It was reported that the institute is specialized in creating materials with new properties, in particular with ferromagnetics and so-called artificial magnetics. It was pointed out that technologies developed by the institute were used in designing and manufacturing the Sukhoi Su-27M and Su-37 (Su-47). Director General Lagarjkov, who hasn't spoken about such matters in public before, told Sergey Sokut about work of his institute in greater detail.
How does Russia's way of making aircraft stealthy differ from the American technology?
- The Americans have two approaches. The first, and earliest one, was used for the F-117 and B-2. The low radar cross-section (RCS) was achieved through the shape of the aircraft and the use of radar-absorbing materials to cover the airframe. In this application, the principle of minimal level of visibility was a cornerstone - and other characteristics had to be sacrificed. For example, both aircraft are subsonic. Later the Americans tried another approach: modern radar absorbing materials are applied to F-16 and F-18, as well as to 5th generation F-22 and JSF combat aircraft, which have a traditional shape. The low level of visibility is achieved through different techniques, which Mikhail Pogosyan, director of Sukhoi, and I are going to reveal in the near future. We and the Americans are close to each other in this type of technology. Russia possesses the technology for upgrading in-service aircraft with modern stealth characteristics, and moreover, this technology is demanded by foreign operators of Russian aircraft. We, together with Sukhoi, have achieved world-class results in this area, which are confirmed by tests of real aircraft. We also can optimize the shape of the aircraft to lower the level of visibility, but I still wouldn't like to speak about the use of our techniques for 5th generation aircraft.
When would it be possible to speak about achieved results?
- Some discussion is possible today. The exact results of radar cross-section reduction will never be disclosed, neither here in Russia nor abroad. But sometime ago it was announced that the RCS of a MiG-21 fighter after its treatment by our institute is approximately 0.25 sq m. This corresponds to the characteristics of a cruise missile.
How far is it possible to go in reducing visibility of the 4th generation aircraft, and what additional improvements can be achieved in the next generation?
- My MiG-21 example demonstrates that the RCS of upgraded/modernized aircraft can be reduced 12-15 times. If we speak about new designed models, I wouldn't want to discuss the numbers publically.
In the press, information has been published about exotic technologies for providing low visibility, for example, plasma. How effective is it?
- We use plasma in solving the problems of RCS of an aircraft's nosecone. In general, plasma technologies are very useful at flight altitudes of more than 25 km. At low altitudes it is impossible to use them, because there is not enough power on board.
What is the share of stealth technologies in the total aircraft cost?
- If stringent, but reasonable requirements for visibility are implemented in the project from the very beginning, it won't be too large. I'd like to point out here that at my institue, we have carried out advanced work in fundamental research. I also want to stress here that we had to do this without governmental support - funding our research from out-of-budget sources during the last 10-15 years.
It is known that you cooperate closely with Sukhoi. What about the institute's work with other design bureaus?
- Recently, we have started cooperating intensively with the others as well.
If we compare achievements of different countries in the reduction of aircraft visibility, who would the leaders be? Obviously, the Americans would hit the top, wouldn't they?
- The Americans are no. 1 because of the application of stealth to a large volume of real products. But considering the understanding of the whole problem in general - and the potential - I don't think the Americans are better than we are. We are able to achieve, and already have achieved, the same - and even in some areas, we have had somewhat better results. Another plus for the Americans is their broader application of stealth. In particular, they are entering the world market with the stealthy aircraft. Similar developments are being made in Europe, but the level of these countries is not so high. The French are tackling this problem as well. They have very good research equipment - anechoic chambers, for example. Their Rafale fighter is advertised as an aircraft with a low radar cross-section.
I doubt that they will leave the prime real-estimate volume between the engines, unused. That is where one would install rack full of internal weapons.
It is right where the aircraft's CG is, and that space is must suited for conformal volume expansion. The only issue is if that expanded cross section will kill the design on account of pressure drag coefficeint (area rule) for high supersonic cruise.
As for Russian RCS technology, selective application of absorbing material is appropriate. the problem with all RF absorbing material is trade-off between RF bandwidth and the thickness of the material required.
Composites greatly help allowing to put RF absorbing material inside the skin.
L-Band and lower is a challenge for RF absorbing material, X band and above is far easier.
L-band stealth is better handed by structural shape and interface design.
[quote name='Arun_S' date='03 February 2010 - 12:09 AM' timestamp='1265135481' post='103858']
I doubt that they will leave the prime real-estimate volume between the engines, unused. That is where one would install rack full of internal weapons.
It is right where the aircraft's CG is, and that space is must suited for conformal volume expansion. The only issue is if that expanded cross section will kill the design on account of pressure drag coefficeint (area rule) for high supersonic cruise.
[/quote]
Indeed most of the internal weapons will be carried between the engines , how does one minimise the pressure drag co-efficient in this case ?
They have mentioned ability to carry some internal weapons side ways ( 2 small AAM ) near the wings but thats highly doubtful L-band
Quote:stealth is better handed by structural shape and interface design.
What is your opinion on the structural shape of PAK-FA , are they capable of all aspect stealth which takes care of most band i.e. L,S,X and VHF ?
02-03-2010, 11:03 AM (This post was last modified: 02-03-2010, 11:04 AM by Arun_S.)
[quote name='Austin' date='03 February 2010 - 06:05 AM' timestamp='1265156828' post='103867']
Indeed most of the internal weapons will be carried between the engines , how does one minimise the pressure drag co-efficient in this case ?[/quote]
Supersonic drag (aka pressure wave drag) is generally minimized by ensuring that the cross section area along the length for the whole aircraft be key constant (the reason why supersonic aircraft fuselage is coke bottle shaped, narrow in the mid section because the wings take up cross section area. It is my suspicion that they have not bulged the space between the engines because the whole aircraft may have lot of cross section area in that vital section. Of course if the fighter mission is to log external weapon it means it will not fly supersonic while that payload is lugged, but after discharging the external payload, it will fly supersonic without too much excessive pressure drag penalty.
Minimizing pressure drag is a multi variate optimization problem, and teh designer will trade off various features to balance all priorities. No straight answer to how to minimize it, without compromising some other performance consideration.
Quote:They have mentioned ability to carry some internal weapons side ways ( 2 small AAM ) near the wings but thats highly doubtful L-band
What is your opinion on the structural shape of PAK-FA , are they capable of all aspect stealth which takes care of most band i.e. L,S,X and VHF ?
Looking at the pcitures and line drawing ti is difficult to point out RF LO weakness for these radar bands, because the design looks very stealthy from all aspects, except dead behind the engine. But that narrow axis is weak for all stealth aircraft's except B-2.
VHF radar stealth will IMHO be the poorest. No different from F22 and F35.
very high res pics , clicky to Enjoy <img src='http://www.india-forum.com/forums/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />
02-04-2010, 08:40 AM (This post was last modified: 02-04-2010, 09:27 AM by Arun_S.)
[quote name='Austin' date='04 February 2010 - 08:31 AM' timestamp='1265251989' post='103892']
very high res pics , clicky to Enjoy <img src='http://www.india-forum.com/forums/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />
[quote name='Arun_S' date='04 February 2010 - 08:44 AM' timestamp='1265252770' post='103893']
So PAK-FA is perhaps the first supersonic optimized aircraft that is also well designed for subsonic and low speed high AoA handling.
The Levcon and engine thusrt vectoring allow the plane to be very controllable even when the AoA is high.
[/quote]
Indeed that seems to be the case , it is also an indication that they will develop a carrier variant of PAK-FA as reported earlier , IN could see joint Indo-Russian 5th gen fighter post 2020.
Well after it gets over its obsession for JSF <img src='http://www.india-forum.com/forums/public/style_emoticons/<#EMO_DIR#>/wink.gif' class='bbc_emoticon' alt='' />
02-05-2010, 01:13 AM (This post was last modified: 02-05-2010, 01:21 AM by Arun_S.)
This confirms my assessment that L band radar on leading edge can only provide azimutal beam steering, and no control in elevation. Obviously with just one patch antenna in the row the beam amgle in vertical plane will be quite wide. In no case narrower than ~ +/- 15 degrees.
This Array CAN BE part of stealthy aircraft.
and this image shows 12 element array (presumably L band, each encased in metal walled enclosure to provide isolation with adjacent element (vital for beam steering), with common services for the AESA elements provided by bigger modules located aft of the array.
[quote name='Austin' date='05 February 2010 - 08:44 AM' timestamp='1265339177' post='103915']
Hi Arun , Can you explain how this L Band AESA array can help in practical combat scenario ?
The Proposed L band AESA array is for Su-30MKI/Su-35 aircraft upgrade along with the X band ~ 1500 T/R AESA module.
For the new fighter they will come up with some better stealthy radar patch , its still a long way off till we see the PAK-FA in production.
[/quote]
Well L band can see though rain and weather phenomenons, unlike higher frequency beams (e.g. X band). Also L band is IMHo more difficult to be stealthy because RF absorbers for that frequency impose too much space/volume and weight, and stealth using reflection suppression, by use of smooth reflecting surface) do not work as well at those low frequencies (compared to X band).
In combat scenarios, L band in leading edge of wing surface (I.e. linear AESA array) can be periodically turned one for use as surveillance radar (getting 2-D scene of the scanned volume). If something is found then 3D scanning radar can be cued to that suspected solid volume (of space) to characterize the target and if necessary missile engagement. L band typically also gives higher range.
and during combat, craft quipped by L band can hide behing weather, that an adversary equipped with X band radar cant detect, while craft equipped with L band radar can clearly see the target.
Similary L bad AESA also serves as useful communication channel with network centric connection with nodes on ground or AWACS located far off in bad weather.
Prospective complex tactical aircraft (PAK FA) is in the sky.These are new machines and devices, composite materials, radar systems and engines created for Russian enterprises.
Su-47 Berkut - combat aircraft with swept back wings. In the 90 years he mistakenly called fifth-generation fighter. Many countries have tried to make a similar, but the problem of destructive load on the wing could be solved only in Russia.
"It was a unique work, but unfortunately he did not go in the series. However, this aircraft was manufactured, such an aircraft with wing-swept composite no one else has," - said Vladimir Vikulin, General Director of the CVTS " Technology.
"Berkut" exists in a single copy, is now flying laboratory for testing new technologies. In Su-47 has no future, but he gave life to another plane - the fifth generation fighter with the code T-50.
"Companies within the Group, producing products and components for the fifth generation fighter aircraft - about 70% belong to the PAK FA aircraft, which made its maiden flight", - says Director General of Civil Rostekhnologii Chemezov.
After the first flight of talking, if not the superiority of the Russian aircraft over the U.S., exactly the parity in the air. Who will flog the first - the main issue in modern air combat. Technology invisible "stealth" means that the plane should emit as little as possible heat and carry a minimum of metal. So close the nozzle and the blades of engines, using composite materials.
"On foreign prototypes - the F-22 Raptor and created the F-35 - Composites are widely used, more than 40%. And we are sure that in our forward-looking fighter use of these materials will be no less a figure", - notes Nikolay Vymornov, Chief technologist NPK "Composite".
At the Scientific-Production Enterprise "Technology" specially for the fifth-generation fighter developed a new carbon fiber material.
"We have created a composite snap-in: it does not snap out of invarovyh metal alloys, which the West is very expensive. Invarovyh of Why? Must be very low coefficient of thermal expansion. A lightweight composite tooling, corresponds to the ratio and quality of the products to them better," - explains Vladimir Vikulin.
In the battle of two equal stealth to win the one who has a better radar system.
"When it comes to that, the sigma of our aircraft and the perceived enemy in the meter, we can effectively deal with such aircraft, even winning some dueling situation", - said Vladimir Zagorodnii, Chief Designer, Head of NIIP named after V. Tikhomirov .
Sigma - a measure of invisibility, the magnitude of the reflection beam from the enemy planes. The smaller the sigma, the more difficult to detect aircraft.
Vladimir Zagorodnii lovingly examines the brainchild of his team - radar for the new fighter. There, over four thousand small receiving-transmitting elements, such technology is called AFAR - active phased array antenna.
"AFAR - the eyes and ears for the airplane, the more so for the fifth generation. It differs from passive antennas so that each channel antennas are located on the transfer of power amplifiers," - says Oleg Alexeyev, deputy chief designer of NIIP named after V. Tikhomirov.
Passive antenna control rays can not, for scanning and tracking turns himself locator. At the fifth-generation fighter radar motionless, looking for and accompany themselves goal rays. If spotted by the enemy, no aerobatics not help, get out of the zone of such a radar is extremely difficult. And the T-50 will install five radars - one in front and two on each side with a phased array radar and a pair of UHF in the wings. Now at the Research Institute of Instrument Design Tikhomirova just experienced Maintenance Mode 20-30 goals. The potential for AFAR, say developers, yet for decades to come.
"The fact that a price today, I have not seen a Raptor, or in the F-35", - said Vladimir Zagorodnii.
American F-22 until the T-50 was considered invincible. His ideology - to be hardly noticeable for ground radar. Ideology "Sukhov Fighters - Raptor detect earlier and more effectively fight in close combat. To improve the maneuverability of fighter plane equipped with new engines with thrust vector control.
"He has another attraction, and other adjustments, applied a number of fundamentally different design solutions. But the main thing - it is a different regulatory system," - says Ilya Fedorov, managing director of NPO Saturn, Deputy Director General of the Criminal Code "JDC".
The new engine Saturn - the development of the power unit with an index of 117, is the heart of Su-35. The engine of the fifth generation is being improved, resources and traction. Although already in the first flight of the T-50 has demonstrated its power - the rise was almost vertical. And now a fighter ready to go at supersonic speeds without the Fast and the Furious.
"This plane can go out on such a regime in the process of refinement and testing. But it is a question for the plane, but not to the engine. The engine provides all of this," - says Ilya Fedorov.
The plane took off from the airfield in Komsomolsk-on-Amur - the first prototype. His image can still change. But those devices, components and assemblies for the T-50, which have already been tested on the ground, soon to rise in the air on the new prototype.
"Commence negotiations, and in the near future, I hope, will sign an agreement establishing a joint India-Russia aircraft of the fifth generation. And this aircraft will be jointly sold by us abroad", - said Sergei Chemezov.
And perhaps in the future, T-50 and F-22 converge in a training battle, and it becomes clear who now reigns in the air.
[/url]The new 5[sup]th[/sup] generation fighter prototype T-50-1 ('izdelie 701'), developed within the framework of the Indo-Russian PAKFA/FGFA program, has made its [url="http://www.youtube.com/watch?v=S67zfmEqGxQ&feature=player_embedded"]first flight[/url] at Jan. 29 in Komsomolsk-on-Amur. It was 47 min on the air. Despite the wrap of secrecy, the look of the fighter appeared very close to that, previously [url="http://igorrgroup.blogspot.com/2009/10/outlines-of-pak-fa.html"]described[/url] in the most reliable Russian publications. So, everybody can now compare what was said about the PAK FA specs before, and what exists actually.
![[Image: NIIP-L-Band-AESA-DPMP-1S.png]](http://www.ausairpower.net/NIIP-L-Band-AESA-DPMP-1S.png)
![[Image: 50_1-1.jpg]](http://i25.photobucket.com/albums/c52/bharatrakshak/50_1-1.jpg)
![[Image: 50_2.jpg]](http://i25.photobucket.com/albums/c52/bharatrakshak/50_2.jpg)
![[Image: SPL6802_su.jpg]](http://pilot.strizhi.info/wp-content/uploads/2010/02/SPL6802_su.jpg)
![[Image: 992U8980_su.jpg]](http://pilot.strizhi.info/wp-content/uploads/2010/02/992U8980_su.jpg)
![[Image: 0FAW2424_su.jpg]](http://pilot.strizhi.info/wp-content/uploads/2010/02/0FAW2424_su.jpg)
' />![[Image: esu3d4.jpg]](http://i26.tinypic.com/esu3d4.jpg)
![[Image: NIIP-AESA-L-Band-Brochure-2S.jpg]](http://www.ausairpower.net/NIIP-AESA-L-Band-Brochure-2S.jpg)