PAK-FA, T-50: News #2

magnumcromagnon wrote:

CaptainPakistan wrote:

magnumcromagnon wrote:I'm going to be upfront and honest, I'm very ignorant on the concept of "plasma stealth" technology, and I would love to be enlightened by significantly more informed individuals on this forum on this matter/subject. As of now I only have a rudimentary understanding of the concept, and apparently the Russian federation has developed the technology since 1999, and from what I've heard apparently the RCS signature is reduced by a factor of 100, am I correct? If that case is true is it theoretically possible to install plasma technology on non-stealth aircraft and make them comparable by stealth aircraft standards? Thanks to whoever enlightens me in advance!

Plasma stealth does not exist on any Russian aircraft. It was a theory which they tried to research but which wasnt practical. The west tried the same in 1970, nearly 30 years earlier.

Again I reiterate, I'll wait for an answer on plasma stealth from an "informed individual". If I wanted expertise on how to join the Taliban, or how to bend over and grab ankles in case of a reaper drone strike, then I would of sought advice from you directly CaptainPakistan.

CaptainPakistan wrote:

magnumcromagnon wrote:

CaptainPakistan wrote:

magnumcromagnon wrote:I'm going to be upfront and honest, I'm very ignorant on the concept of "plasma stealth" technology, and I would love to be enlightened by significantly more informed individuals on this forum on this matter/subject. As of now I only have a rudimentary understanding of the concept, and apparently the Russian federation has developed the technology since 1999, and from what I've heard apparently the RCS signature is reduced by a factor of 100, am I correct? If that case is true is it theoretically possible to install plasma technology on non-stealth aircraft and make them comparable by stealth aircraft standards? Thanks to whoever enlightens me in advance!

Plasma stealth does not exist on any Russian aircraft. It was a theory which they tried to research but which wasnt practical. The west tried the same in 1970, nearly 30 years earlier.

Again I reiterate, I'll wait for an answer on plasma stealth from an "informed individual". If I wanted expertise on how to join the Taliban, or how to bend over and grab ankles in case of a reaper drone strike, then I would of sought advice from you directly CaptainPakistan.

So you have resorted to racism because you can not handle the harsh truth? That says a lot about your character. Grow up please. Thanks.

Viktor wrote:Nice.   

Former Soviet PVO centre to conduct RCS tests on T-50 and PAK-DA

The invention relates to the field of aviation. Multi-purpose aircraft comprises a fuselage (1) wing (2), console tselnopovorotnogo vertical tail (3) console tselnopovorotnogo horizontal tail (4), canopy (5) horizontal edge engine inlets (6), fine-meshed nets, shielding devices fence and exhaust air (7), side sloping edge engine inlets , [8] device (9) reduce the effective scattering surface (EPR) power plant and leaf (10) rod compartment in-flight refueling. Optical sensors are rotatable idle for the back side, coated with a radar absorbing coating in the direction of irradiating radar. Antenna compartments closed shielding diaphragms. Antenna plane inclined from the vertical plane. As antennas used airframe. Antenna-feeder system is made on the basis malootrazhayuschih antennas radar wavelengths. The invention is aimed at reducing the quantity of radar visibility. 5 yl.

The invention relates to the field of aviation, in particular tactical aircraft to detect and defeat air, surface and ground targets.
Known multi-purpose aircraft (AV Fomin "Su-27. History fighter", Moscow, "RA Intervestnik", 1999, str.208-251) containing the airframe, power plant, obschesamoletnoe equipment, display system and controls, complex weapons, active and passive countermeasures, surveillance and targeting equipment (radar sighting system, optronic sighting system), system monitoring and recording parameters, the communication system between aircraft and control centers, flight navigation system, countermeasures system, a control system means of destruction and passive countermeasures, providing navigation, piloting in manual and automatic control, embedded control systems, navigation and mezhsamoletnuyu exchange tactical information in the group, guidance from the command control centers, radar overview of airspace and land surface, airspace location, detection and support ground and air targets, target designation means of destruction, setting active radar jammers, the use of uncorrected weapons and aircraft weapons (TSA) with passive heat, passive and active radar homing by land, air and sea targets, use of passive physical resistance .
As disadvantages of the prior art should be noted the high value of the effective surface of the cross section (RCS), the defining characteristic of the aircraft radar detection means enemy. For a known value of the aircraft EPR is about 10-15 m 2 (here is the average value for the selected angle).

Technical result, The aim of the invention is to reduce the magnitude of radar visibility of the aircraft to an average of about 0.1-1 m 2 .
The invention is illustrated by drawings, where Figure 1 shows a plane integral aerodynamic layout - top view in Figure 2 - aircraft integral aerodynamic layout - bottom view in Figure 3 - aircraft integral aerodynamic layout - front view in Figure 4 - the cross section A-A of Figure 2.; Figure 5 - section B-B Figure 2.
Refer to submittal drawings numerals indicate:
1 - fuselage,
2 - wing,
3 - Console tselnopovorotnogo horizontal tail (CSSC)
4 - console tselnopovorotnogo vertical tail (TSPVO)
5 - canopy,
6 - horizontal edges engine inlets,
7 - fine mesh covering the emissions of air
8 - side sloping edge engine inlets,
9 - A device which reduces the ESR powerplant
10 - bay doors boom refueling.
Complex aircraft equipment includes: obschesamoletnoe equipment; indication system and controls, complex weapons, active and passive physical resistance, surveillance and targeting equipment (radar sighting system, optronic sighting system), system monitoring and recording parameters, the communication system between aircraft and control stations; flight and navigation system, the system of countermeasures; management system means defeat and passive countermeasures, providing navigation, piloting in manual and automatic control modes; embedded control systems; mezhsamoletnuyu navigation and tactical information exchange group guidance from command posts control radar overview of airspace and the underlying surface, the detection and tracking of air and ground targets, setting active radar jammers, uncorrectable weapons, as well as aircraft weapons with passive heat, passive and active radar homing by air, ground and sea targets, means of passive resistance.
EPR EPR aircraft consists of following its constituent parts: the airframe, powerplant, and optical antenna systems on-board equipment; false and nominated in flight equipment.
The magnitude of the EPR airframe and power plant is determined by three factors:
- Shape and the molded mounting as airframe, including air intake and air duct;
- Airframe design, technological and operational joint casings, shutters, hatches and joints between moving and stationary parts of the airframe;
- Use of radar absorbing and shielding materials and coatings.

The molded shape and layout scheme glider helped reduce the amount of energy reflected EM waves in certain angles due to redistribution highs chart backscattering minimum number of areas and the least dangerous sector.

Constructive activities
Cleaning inside the airframe TSA has reduced overall EPR by eliminating the reflection of electromagnetic waves from radar irradiating TSA and their launchers.

Perform inlet duct S-shaped in conjunction with radio coatings (PPP) provides a reduction in the axial direction of the EPR. In other sectors, the forward hemisphere (PPP) - by shielding inlet guide vanes (IGV) engine from the elements which basically is a reflection of electromagnetic (EM) waves irradiating the radar, which is a substantial share (60%) in the EPR system Glider - engine PPP. Drawing on the walls of the PFR inlet duct (EOI) allows you to reduce the amount of electromagnetic signals reflected from the BHA and multipath on the channel walls, thus the overall level of EPR OT PPP reduced.

The device 9 in the intake passage of the engine to reduce the ESR in the forward hemisphere can be mounted in the mold before any channel BHA, but preferably set in a "straight" channels. The device acts as a screen 9, partially overlapping in the axial direction of the BHA from getting EM waves. Apart from the screening device 9 shared channel before the EOI BHA a series of separate cavities formed cylindrical (or concentric or non-concentric) or flat surfaces with the flat surfaces can be parallel or intersecting. Each cavity has a smaller cross sectional area than the channel in that zone VZ. Such segmentation with simultaneous coating of the walls of segments reduces the amount PFR EM signals reflected from the BHA and wall cavities at the multipath device 9, thereby the overall level VZ PPP EPR decreases.
Bringing sweep angles of the front and rear edges of the bearing surfaces, inlets, manholes flaps to two or three directions other than the axial, allows the reduction of global maxima chart backscattering (DOR) to these areas. Such DOR causes a decrease in the overall level of ESR in PPPs.

Ramps fuselage 1 in cross section, the inclination of the vertical aerodynamic surfaces (vertical tail unit 4, the lateral edges 8 OT) to one direction in the cross section reduces the lateral hemisphere EPR (BTS) through multiple reflections of electromagnetic waves falling on the inclined surface of the glider in direction different from the direction of the irradiating radar.

Screening devices and exhaust air intake design elements, as well as a fine mesh to reduce or eliminate the component EPR "irregularities" glider (type hole slit sinus) due to the fact that the linear mesh size covering heterogeneity is less than ¼ length EM wave irradiating plane. In such a situation serves as a fine screen to screen the EM wave, which reduces component indicated irregularities in the EPR.
Closure compartment boom refueling flap 10 excludes component niches and bars in general EPR aircraft.
Application tselnopovortnogo vertical tail 4 to reduce the total area AT and hence reduce the level of the reflected signal IN, which in turn reduces the magnitude of the EPR in the BTS.

The use of conductive sealants allows electrical conductivity between the individual structural and technological elements of the airframe, which in turn eliminates the EPR component in the plane "irregularities" (such as gap junction) due to the fact that in the absence of electrical inhomogeneities no scattering of surface electromagnetic waves .

Use of EPA can significantly reduce the global maxima ESR due to the fact that the principle of SAR is a partial absorption of energy falling on the material of the EM wave, thus ensuring reduction in the level of the reflected radar signal.
Implementation provides a metallized glass lamp EM impermeability so that the glazing is essentially impermeable represents a sloping wall, which reflects the incident electromagnetic wave irradiator away from the radar.

The main component of interventions to reduce on-board equipment in the EPR are the following:
1. Using a frequency-selective structures in radomes, allowing radiation to pass in the operating frequency range of the antenna and its own be impervious to radiation other frequency bands (irradiating RLS). Thus, on the falling radomes irradiating electromagnetic wave from the radar pereotrazhayutsya (due to shape the fairings formed by surfaces inclined to the vertical plane) toward the direction of irradiation.
2. Rotate the optical part of the optical sensors in the idle state with the application of PSC on the back side. Thus, in working (passive) sensors state (state minimum ESR) sensor faces the direction of irradiating radar side coated with EPA providing partial absorption of the incident electromagnetic waves, thereby decrease the EPR.
3. Application screening diaphragms in antenna compartments to eliminate the effect of the wandering wave when the incident wave after multiple reflections in a closed compartment amplified and radiated into outer space. Set the aperture shield around the antenna post so that bordered on the periphery of the post. On the wall of the diaphragm facing the irradiator radar attached PFR. Upon irradiation protective diaphragm does not penetrate the EM wave antenna compartment, while absorbing some of the incident wave energy and to lower the ESR.
4. Deviation from the vertical plane of the antenna, and hence the deviation from the normal horizontal plane antennas provide change in the direction of the reflected electromagnetic waves to the irradiating direction of the radar, thereby reducing ESR antennas.
5. Reducing the total number of antennas and the use of airframe design as antennas (eg, vertical tail as an antenna connection). Reducing the total number of antennas reduces the overall ESR, because each antenna brings certain component in the EPR. Using an existing airframe (IN) as an antenna allows not to use a separate antenna, which naturally reduces the ESR compared with one single antenna.
6. Application of antenna-feeder system based antennas in malootrazhayuschih radar wavelengths. Malootrazhayuschie properties antennas provided by the fact that they are made for flush-mounted external contour of the airplane and do not contribute to the EPR component aircraft due to a direct reflection of electromagnetic waves.

Comprehensive implementation of the activities listed together for maximum effect to reduce the visibility with minimal negative impact on the aerodynamic, weighted technological, operational and other characteristics of the aircraft.

Multifunctional plane containing airframe propulsion, avionics equipment, characterized in that the airborne weapons placed within the airframe, the air intake channel is formed S-shaped, and on the inlet duct wall applied coverings, the channel with the air intake device is installed, the separating channel the inlet before the inlet guide vane into a series of separate cavities formed by cylindrical or flat surfaces and edges of inlet form a parallelogram, the angles of sweepback edges of the front and rear bearing surfaces, the air intake covers flaps given to two or three directions, the sides of the fuselage cross-sectional tselnopovorotnoe vertical tail are inclined from the vertical plane in one direction, the unit air inlet and outlet are made with shielded, cut off fuel rods refueling aircraft in flight flap closed, in addition, the space between the individual structural and technological elements glider filled conductive sealants, glazed skylight holds metallized, radomes are made of the frequency-selective structures, optical sensors are rotatably idle for the back side coated with a radar-absorbing coating in a direction of irradiating the radar, the antenna sections are closed screening apertures; antenna plane inclined from the vertical plane, in this case, at least partly used as the antenna airframe and antenna-feeder system is performed based on malootrazhayuschih antennas in radar wavelengths.

Details of the Sukhoi Design Bureau's work on the stealthy aspects of the T-50 PAK FA fighter aircraft emerged in late December 2013, when the company's patents were published.

According to the patent paperwork, taken together, all of the stealthy measures offer significant improvements over legacy fighter designs. The papers claim that the radar cross-section (RCS) of an Su-27 was in the order of 10-15 m 2 , with the intention being to reduce the size of the RCS in the T-50 to an "average figure of 0.1-1 m 2 ".

In common with other low observable aircraft designs, this reduction is achieved throught the use of radar-absorbing and radar-shielding materials and coatings, panel shaping (especially around the air intakes) and in the design of the junctions between moving elements, such as flaps and hatches.

In particular, the patent spells out the benefits of internal weapons carriage, s-shaped engine air ducts, (which were considered but are actually not implemented in the production PAK FA), and the use of radar blockers. It adds that the inlet guide vanes of the engines' compressors generate "a significant portion [up to 60%] of the radar cross-section of the airframe-powerplant system in the forward hemisphere" and that this is reduced by using radar-blocking devices and radar-absorbing coatings in the walls of the air ducts.

The shape of the airframe reduces the number of directions that radar signals are reflected in with the angles of sweep of the wings and the tail plane's leading and trailing edges, the edges of the air intakes and hatch covers being reduced and deflected from the aircraft's axis. Viewing the aircraft from the flank, the fuselage sides, lateral edges of the air intakes and vertical empennage are all deflected at the same angle.

Some openings and slots on the airframe's surface - such as the boundary-layer bleeds on the sides of the air intakes and the openings on the upper fuselage immediately aft of the cockpit - are covered with a thick grid, featuring a mesh of less than one quarter of the wavelength of a search radar, which reduces the reflections from these uneven surfaces. Gaps between the airframe elements are filled with conducting sealants, while the glazing of the cockpit canopy is metallised.

The surfaces of the PAK FA's own five radar arrays are also angled off from the vertical plane, helping to 'deflect' enemy radar signals. The covers of the radar arrays are selective, letting through their own signals, but blocking other frequencies. Additionally, the array compartments are edged with radar-absorbing 'curtains' to reduce possible leaks of these amplified signals.

Antennas are recessed from the surface of the skin to reduce protuberances (the vertical empennage serves as a communications antenna), while the turret of the aircraft's nose-mounted infrared search-and-track (IRST) sight is rotated backwards into a cruise position, exposing its rear hemisphere, which is covered with a radar-absorbing coating.

The release of this list of patents follows the July 2013 release of documentation covering the configuration of the fighter's integrated avionics suite.

There are currently five T-50 prototypes - the latest, T-50-5, first flew on 27 October 2013 - supporting the development programme and they are believed to have undertaken over 300 sorties to date.

In the 'Schedule of Activity for the Russian Ministry of Defence for 2013 to 2020' published in mid-2013, the PAK FA's Initial Operational Capability and the launch of full-scale series production is scheduled for 31 December 2016. The Russian National Armament Programme stipulates that 60 production PAK FA fighters will be delivered between 2016 and 2020.

The assembly of aircraft T-50-6-1 is nearing completion and three further aircraft (T-50-6-2, T-50-7 and T-50- are in build. One of the T-50-6 aircraft is intended for static trials and the other one is intended for flight testing.

magnumcromagnon wrote:Out of curiosity has there been any developments in creating stealth air-to-air, air-to-ground, and or cruise missiles? Personally I think Russia already has the advantage with extreme long range BVR air-to-air missiles, the gap will only widen with stealth equivalents of its missile arsenal.

TR1 wrote:

magnumcromagnon wrote:Out of curiosity has there been any developments in creating stealth air-to-air, air-to-ground, and or cruise missiles? Personally I think Russia already has the advantage with extreme long range BVR air-to-air missiles, the gap will only widen with stealth equivalents of its missile arsenal.

Sure, many air-to-ground munitions have taken lowered RCS signature into account- from the small European cruise missiles to the big Kh-101.

Not so much with Air-Air missiles though, they are pretty small as is and you would just face severe kinematic penalties.

You can always treat them with RAM, and I think that was done on a Su-27 in the 90s as part of RCS reduction testing, not so much for the missile itself being stealth, but a loaded platform.
Nobody uses that in line units though.

eridan wrote:why does that talk of roughly 0.5 m2 rcs persist? first it was that article which claimed an indian official from their MoD said FGFA will have RCS of 0.5 m2, now this patent story about 0.1 to 1 m2 RCS.

While of course we can't know what's really true and what's not, tactical usefulness of 0.5 m2 plane is miniscule, even 0.1 m2 plane would be, in this day and age, pretty diminished. somehow i get a feeling one wouldn't even bother with internal weapon bays and other stealth features if the best one could achieve is 0.1 or even 0.5 m2.

Viktor wrote:
5. Just example - look at that 5m tall vertical tail of the F-22 under about 40-50 angle and image F-22 RCS when ground based radar illuminate it from the side. It will have 100% radar return   of that 10m2 huuuge tail surface