JF-17 Thunder Multirole Fighter [Thread 2]

[mean_bird]

well, i mean the long range missiles, 2000KM for instance. coz you have to assault every single airport within the enemy territory, not only the front line ones. in this case, a GPS system (or others) is needed. moreover, it is the ACs that you want to destory not the airport, so an long range surveillant system is a must too.

Why would you need to launch a long range cruise missile from an aircraft?

Currently, only the ballistic missiles have that range (2000 + km) and the babur cruise missile (Ground launched) has 700/750km range.

 

[Guest]

Why would you need to launch a long range cruise missile from an aircraft?

Currently, only the ballistic missiles have that range (2000 + km) and the babur cruise missile (Ground launched) has 700/750km range.

1)
suppose you wanna to attack a southen airport of india, what other options do you have?

2)
wiki infos
US:
Hyunmoo IIIC - 1500km
AGM-86B 2,400+ km
BGM-109 Tomahawk 2,500km

Russia:
Kh-55 2,500 km
Kh-55SM 3,000 km

China:
DH-10 >4,000km

 

[Arsalan]

How hard would it be to add some of the stealth features of 5gen aircraft to the JF-17?

I mean is it that hard to incorporate the angular features and radar absorbing paint into the JF-17 design?

Sir, Gambit have really come up with a composite answer but i guess the case with JF17 will be bit different from the examples he have quoted!

the JF 17 will be more of a low price solution to counter the increasing quantitative edge of IAF and also provide good technology to deal wiht normal combat role, if not, the high end role. alos it will provide with an aircraft that will fit in varity of role anging from ground support, to naval warfare and eventually the A2A combat!
further the future of the plane is also dependent on export order it wins. ifPAF manage to win some orders the money will be utilized to explore new front for the plane!
sating all this let us come to the %th generation feature! for a JF17, it will be a NO!. the plane is not meant to rise upto the fifth generation!. as far as some of the technologies for RCS are concerned, the RCS of JF17 is on the lower side. it wins from most of its conterparts in this field and as you have asked about what features it may borroe from Fifth generation then yes, it is use of composite materials to further reduce RCS. composite are not the only thing requird to reduce the RCS of a plane but is surely an important one. JF17 is also planned to be using more composite materilas in the next blocks as it wil also reguce its weight!

i guess you get some help from this post!

regards!

I just went through the last post by Muzbair and was happy to learn that he had made more or less the same points! Thankyou

 

[greatsequence]

I dont understand. Chief is comparing jf-17 with f-16 block 50 and typhoon. If so then upgrading f-16 and buying j-10 does not make any sense or is he just fooling the public. Can someone please clarify.

 

[gambit]

Although not related to what you guys are discussing still as a military professional how would you compare an AMRAAM with the Russian R-77?
You already named the russian sukhoi series as sucky series.

In terms of features, both the American AMRAAM and the Russian R-77 are equal. However, equal features does not mean equal capabilities.

Let us take the fact that both missiles employed monopulse radar as an example...

[3.0] Modern Radar Technology (1)

send multiple pulses with angular offsets at the same time.

In practice, a monopulse system will have four feed horns to track a target along both axes.

In a monopulse system, the four distinct echoes of a target is summed and differenced in separate operations. But that does NOT mean there are four distinct antennas, only that a single antenna assembly contains four distinct transmitters, to put it simply. The radar computer will then perform the necessary calculations upon those four echoes and create a target profile and that the entire antenna assembly should keep the target inside that dark area created by the four transmitters that overlapped each other.

Here is what the Vympel supposedly is capable of doing...

Vympel R-77 - Wikipedia, the free encyclopedia

If the seeker is jammed, it switches automatically to a passive mode and homes on the source of jamming.

The same claim is made for the American AMRAAM.

To seduce a monopulse system require an active ECM system and for most aircrafts that would require an ECM pod or a dedicated ECM platform like the American EF-111. One method to seduce a monopulse system is to process the four transmit signals, isolate at least one of them, and create ONE false signal that will, electronically speaking, enlarge that dark area beyond a certain threshold. That will force the antenna to continuously try to reacquire the target based upon ambiguous sums and differences of those four signals.

The problem is that chaff is not jamming but should be recognized as seduction. Jamming is active in the sense that there are powered transmitters that attempts to overwhelm a certain amount of bandwidth. Chaff is not active in the sense that the strips are not self-powered emitters, they 'emit' only when there are signals impacting them. So if there is sufficient chaff to saturate the missile's electronic field-of-view (FoV), for either the American's or the Russian's, then the missile will be homing in on chaff. But then again, once the strips become emitters because of signals impacting them, some have argued that at that point chaff should be considered as active jamming for as long as there are transmissions.

Monopulse systems are highly accurate in terms of target profiling but can be equally highly vulnerable to seduction IF the ECM platform is aware that it is going up against a monopulse radar.

Moving on...

There are three distinct modes of passive seekings:

1- Antiradiation homing. This is usually against surface radars such as shipborne or missile launchers. Very wideband. Surface radars signals should not be considered to be in same class as wideband noise jamming signals. Surface radars signals have characteristics that clearly distinguish them from noise, such as multiple pulse repetition freqs (prf), freq agility, amplitude agility, and the list goes on...

2- Home on Jam (HoJ). This is what concerns air-air combat. These jamming signals are usually directional, meaning they can be tracked to come from a certain direction. Their signals are noise designed to saturate a certain bandwidth. Responses to chaff reflections falls under HoJ.

3- Radiometric. This mode seeks out innate thermal radiation from a body, contrast that against background radiation, and home in on that contrast. This is the simplest of designs but is also limited to two dimensional targets, like a tank or even a human body contrasting against the trees in the background, although the tank will give the greatest contrast. With millimeter-wave, or millimetric radars, small mammals like rodents have been contrasted by the radar.

Item two (HoJ) is what will distinguish the American AMRAAM and the Russian R-77 in terms of lethality.

Wideband noise is brute force and intends to saturate, but it also is an excellent source of angular direction of those signals and angular calculations are the bread and butter of any monopulse system. Remember, the monopulse radar computer will seek to zero out any angular discrepancies.

Chaff is not two but three dimensional because the target is moving and dispensing chaff at the same time, creating not only a saturated field-of-view but also in depth of that saturation.

So what happens is that the missile initially detect a target with its own radar, the target dispensed chaff, then the missile homes in on the chaff bloom. At this point, there is the 'jammer-to-signal' ratio the missile must recognize. The 'signal' here is the skin return that the missile classified as 'the target'. As this ratio increases in favor of noise, the seeker switches to passive tracking of the noise. We do not know the precise tolerances for both missiles on how each will process this ratio. If the missile switches to passive seek mode too soon after the J-S ratio have just been detected it may ignore valid skin returns from the target.

As the missile travels through the chaff bloom's electronic noise cloud, the J-S ratio should decrease in favor of that skin return PROVIDED that the target remains within the missile's radar field-of-view (FoV). Aircrafts that dispensed chaff do not remain static and docile. They will violently maneuver and will seek to turn the table on their attackers. We do not know the precise mechanical tolerances for both missiles as far as the sweep angles of their radar antennas. The wider the better but we simply do not know. If the missile switches to passive seek mode when the J-S ratio is too small, it may be susceptible to multiple directions noise jamming. The balance is delicate.

The problem for the R-77 is that the American 'stealth' aircraft series are designed to be problematic for centimetric and millimetric wave radars, which is usally the X-band, whose high freq are vital for any moving target, even police speed radars uses the X-band. Aircrafts with larger antennas have had problems acquiring target locks on the F-22, let alone a missile's far smaller radar antenna.

There are simply too many unknowns as far as technical data goes for both the American AMRAAM and the Russian R-77. Any Russian or Chinese who declare that categorically the R-77 is superior is merely desperate.

Clear as mud?

 

[gambit]

If the launch aircraft has an AESA and if there is a secured data link between the launch aircraft and the missile, %90 of the problems associated with a monopulse system is eliminated.

 

[Tempest II]

I dont understand. Chief is comparing jf-17 with f-16 block 50 and typhoon. If so then upgrading f-16 and buying j-10 does not make any sense or is he just fooling the public. Can someone please clarify.

He did not say "equal" ... ... or did he? One can compare any aircraft to another.

Please consider that PAF is equipping to face IAF with MiG-29s, Su-27 and the MMRCA ... ... logic should tell you that the JF-17 is not as toothless and backward as most posters are assuming.

 

[Tang0]

This is nothing new, not even for the American F-35.

The 1960s technology F-111 actually has a more complex mechanical-pneudraulics system of inlet air control.

Close up RAAF F-111G & C images
01-F-111C-INTAKE

In the 'INTAKE' image above, that trisectional and long piece is called the 'inlet spike'. As speed increases, the Flight Control System (FLCS) calculate pitot-static air pressures and command the spike to 'translate', meaning move aft, and 'blossom', meaning expand, decreasing inlet volume, slowing down supersonic air to the subsonic region, making the engine more efficient. This system was derived from the SR-71 where the P&W J58 engines have full conical spikes while the F-111's TF30s have quarter spikes. The J58's spikes also 'translate' aft and in doing so, decreases inlet volume to slow down supersonic air.

Factsheets : J58 Turbojet Engine


The system is complex in design and execution and I remember well the hours required to perform a 'spike ops check'. Doing it in mid-winter with wind chill below zero was certainly no fun.

This 100lb tester is called the TTU-205...

TTU-205 Comparison Chart | TestVonics, Inc.
used Garret / Kollsman Military TTU 205/E, TTU205/E for sale | Garrett/Kollsman TTU205/E Pressure Temperature Set

And is used to simulate altitude and speed through the pitot probe. There are three pitot probes on the F-111, one on the radome and one each in front of the inlets. For a 'spike ops check', the inlet pitot probe is used.

02-RF-111C--INTAKE

Not visible in the above image are several static ports on the walls of the intake. A mechanical assembly covers them up and is attached to a second TTU-205 to simulate static pressure inside the intake. Many FLCS techs, myself included, have painfully learned to avoid those intake air control fins. Back and head injuries are the usual results from carelessness and darkness. From all those pitot/static pressures, the FLCS then sends commands to the spike's hydraulics to move and expand the assembly. Going back to the first F-111 INTAKE image above, the largest hole visible on the spike is to hold a measurement rod with a scale and pointer. At certain altitude/speed combination the spike should be at a certain degree of 'blossom' and there are several combinations to check.

We learned that while it is possible to control supersonic air, the level of on aircraft complexity and requisite maintenance simply does not make the system very cost efficient. Those who scoffed at American aircrafts that have lower Mach specs than Russian junks have not a clue of what supersonic air does to the engines in terms of performance and longevity, which affect aircraft availability, or 'Code One' status. For now, a fixed but proven air inlet control system is the preferred method. The F-35 and others who took this path are more the wiser.

Finally...

Patches- 523rd TFS

I was a 'Crusader'.

Interesting. I recall reading an article about using a series of wedges that could push in and out of the surface of the engine inlet to help control turbulent flow and optimize efficiency at different levels of thrust. The only problem was that the system required hours of calculations for minutes of flow, and there is no way to "look ahead" in the flow to see what the oncoming air looked like. Course, you could make predictions based on AOA, speed, airframe, and altitude, but that is multiple differential equations to solve and not much time to solve them. Also, you have to consider the flow history, no fun at all.

A more reasonable system here: Mission adaptive inlet - Google Patent Search

Do you know if this has ever been applied in any real airframes? Prototypes maybe?

 

[greatsequence]

He did not say "equal" ... ... or did he? One can compare any aircraft to another.

Please consider that PAF is equipping to face IAF with MiG-29s, Su-27 and the MMRCA ... ... logic should tell you that the JF-17 is not as toothless and backward as most posters are assuming.

He said "19 20 ka farak ho ga" I will be really glad if that is the case laikin hazam nahi ho raha.

 

[Tempest II]

He said "19 20 ka farak ho ga" I will be really glad if that is the case laikin hazam nahi ho raha.

Can you translate what that means please?

 

[greatsequence]

"19 20 ka farak ho ga" means the difference will be really minute. He also said it has got a very good radar, the avionics will be on par with other aircrafts it has fly by wire like other, All advance weapons which will be on other jets can be carried by jf-17 as well.

 

[Tempest II]

When did he say that?

I guess if JF-17 ends up with the same weapons (AIM-120 and Meteor), and has a good enough radar with jamming capability - maybe he is right that it will not be far DEPENDING ON HOW PAF PLANS TO USE IT.

Avionics I believe so if we consider how many other radars the Chinese looked at while developing the LKJ-7. Unless one considers the Chinese hopeless, I can see a good radar if you appriciate that they looked at the Zhuk M-series and Kopyo radars and some Israeli options. I don't find it hard to believe. If you then consider also the Pakistan input, i.e. Kamra has been making Western radars for years and they had available to them Western offers for JF-17 to "leak" to the Chinese if it made sense. There was information galore for the Chinese to work with.

 

[Manticore]

When did he say that?

check the videos here
http://www.defence.pk/forums/military-aviation/22396-interviews.html

 

[gambit]

Interesting. I recall reading an article about using a series of wedges that could push in and out of the surface of the engine inlet to help control turbulent flow and optimize efficiency at different levels of thrust. The only problem was that the system required hours of calculations for minutes of flow, and there is no way to "look ahead" in the flow to see what the oncoming air looked like. Course, you could make predictions based on AOA, speed, airframe, and altitude, but that is multiple differential equations to solve and not much time to solve them. Also, you have to consider the flow history, no fun at all.

A more reasonable system here: Mission adaptive inlet - Google Patent Search

Do you know if this has ever been applied in any real airframes? Prototypes maybe?

Inlet air control have been an issue, or problem, since the time we were able to go supersonic with jet engines, and at the same time there are plenty of attempts to make air flow controls feasible for deployment. The SR-71's J58 is the perfect example, on both how it is possible to have such controls but also how difficult it can be for flightline maintainers to keep the aircraft flying, and that system was designed back in the 1950s. NASA and JPL no doubt each have their own repositories of paper only ideas to actual wind tunnel models, but personally am not aware of any deployed aircraft that have that complex level of inlet air controls.

For the F-111's inlet air control system, the 'spike', its translation and blossom was calculated purely from simulated altitude and airspeed, pitot-static, through the TTU-205 testers. Same for the F-15's inlet air ramps. Any more complex and the system might overwhelm logistics, training and maintenance. Another way to slow down supersonic air for the engines is to have long intake throats, look at the SR-71's engine nacelles for example. So instead of having a straight we can bend the air flow through several turns, but that would require a radical departure from current fuselage shaping. That is why currently line aircrafts are limited to Mach 2 with fixed inlet air controls, with perhaps brief dashes close to Mach 3.

How Things Work: Supersonic Inlets | Military Aviation | Air & Space Magazine

The simplicity of the JSF design makes for an inlet that requires less maintenance, reduces aircraft weight by 300 pounds, and costs $500,000 less than a traditional fighter inlet.

 

[mean_bird]

I dont understand. Chief is comparing jf-17 with f-16 block 50 and typhoon. If so then upgrading f-16 and buying j-10 does not make any sense or is he just fooling the public. Can someone please clarify.

No he's not trying to fool anyone. But you must realize the interview is for general public, 90% or more of whom probably do not even know what's a block 50 or a typhoon. Even the interviewer hasn't a clue about aviation and is actually asking how 'compatible' the plane is.

Secondly, he is just referring to the technologies involved. Till now PAF didn't have any BVR, or FBW (except the F-16), etc. So it will have all the advanced technologies which western aircrafts have and which PAF previously lacked. Ofcourse, within the technologies there can be more and less capable equipment and only time will tell how the systems on the JF-17 are.

Thirdly, JF-17 does indeed have a lot of good technology like a fully integrated cockpit environment using smart MFDs, BVR, datalink, ECM, etc. You can check out the detailed Avionics of JF-17 here