JF-17 Thunder Multirole Fighter [Thread 2]

[a1b2c145]

hello all
i love JF-17

Both men and JF-17 are cool

 

[gambit]

Yes I read that too.. Thanks for mentioning it.Here it is

An old article dated December 2005.

JANE'S DEFENCE WEEKLY - DECEMBER 07, 2005
Sino-Pakistani fighter improved

<snipped>

The conventional intake with splitter plates found on the first three aircraft has now been replaced with convex diverterless supersonic inlets (DSIs), similar to those found on Lockheed Martin's F-35 Joint Strike Fighter aircraft.

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 spike prevented supersonic air from entering the inlet and maintained a steady flow of subsonic air for the 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'.

 

[Developereo]

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?

 

[Haanzo]

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?

incorporating angular features equals building a whole new plane requiring extensive testing .....the thunder is not big enough to incorporate an internal weapons bay like the silent eagle ....so youre pretty much left with RAM COATINGS and COMPOSITE MATERIALS FOR THE BODY -which reduces number of rivets and stuff so you can cut on extra -AVOIDABLE RCS not reduce it altogather by this metod

 

[gambit]

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?

The question you asked is very loaded in that answers can be very misleading.

For starter...When a military 'spec' out a radar system, the request will be something in the line of: "I want the radar to be able to detect a target of 5m2 at 500km." For example.

Let us say that YOUR aircraft just happened to fall within the enemy's radar capability as he outlined above. At 500km distance, YOUR aircraft will have a frontal RCS of 5m2.

Say you incorporate some RCS reduction measures such as intalling radar absorbers (RAM) and some minor body shaping that will not adversely affect the design's original aerodynamics. But in testing, assuming that your radar is as capable as your enemy's, you found out that at 500km, the modified design has a reduction down to only 4.5m2. Or 5m2 at 450km. Is that an acceptable performance gain? In other words, your modified design will give you a 50km gain before the aircraft will become 5m2 again. Is that acceptable in terms of investments?

Here is what the US did with the Super Hornet...

Flying the F/A-18F Super Hornet

While the F/A-18E/F is not a true stealth fighter like the F-22, it will have a forward sector RCS arguably an order of magnitude smaller than seventies designed fighters. Since every deciBel of RCS reduction counts until you get into the range of weapon payload RCS, the F/A-18E/F represents the reasonable limit of what is worth doing on a fighter carrying external stores.

The F-18E/F might as well be a new design from the original Hornet. The E/F has 100sq/ft of larger wing surface, higher empty weight, larger engine inlets and yet it is an order of magnitude smaller in RCS than the 'legacy' Hornet. That is like moving that 5m2 from 500km to say...250km, meaning that the design will have a 5m2 frontal RCS at 250km instead of the original 500km. You are now much closer to the enemy before he can definitively identify you, it also mean that at 500km, you are effectively 'invisible' to his radar. As you move in closer, say to 400km, you become an anomaly, something ambiguous and is generally dismissed. As you approaches the 300km mark, your enemy become suspicious but still has a high degree of uncertainty. And at 250km, you will be 5m2 to his radar and fully identified. He used to have 500km of distance to formulate a response to threats, now he has only 250km of distance, much less response time. That is how radar detection works and how RCS reduction methods should be assessed, regardless of whether you are designing a completely new aircraft or modifying an existing airframe.

For the B-2, F-22 and F-35, by the time any of them is identified, it will be weapons release time for the pilot. Too late for the defenders.

Radar absorbers (RAM), angled faceting and curved surfaces are not the answers. The solution is in judicious applications of any or even ALL of them at the appropriate places in a design, existing or new. The JF-17 has a single vertical stabilator. The joint where it and the fuselage meet is called a 'corner reflector' and might as well be an electronic beacon. The single stab is why the F-16 cannot be any smaller in terms of RCS, else the F-16's curves can be further improved to reduce its overall RCS. That is not to say the F-16 cannot be improved but that the improvements do not return the expected gains for the investments. That is why the F-16 basic design is being targeted for improvements in avionics instead of RCS reduction.

In sum, NOTHING airborne is invisible to radar and the US never claim the F-22 or F-35 is so 'invisible'. No such claims yet anyway. But the correct issue is distance of that detection and from what I have seen of the JF-17's design so far, it is an unlikely candidate for any RCS reduction measures that would be considered a good Return-On-Investment (ROI). There is nothing to bar either China or Pakistan to pursue that avenue, but if billions are spent on only a few percentage points gain in effective detection distance, it would be considered a waste in any radar engineer's eye when the Super Hornet is pretty much the unofficial standard in RCS reduction measures on an existing design.

Clear as mud?

 

[zraver]

In sum, NOTHING airborne is invisible to radar and the US never claim the F-22 or F-35 is so 'invisible'. No such claims yet anyway.

An exchange pilot did say he had an F-22 in visual range in gun mode (very close) and his fighters radar would not lock up. Even if that is only true of certain situations, its still damn useful. An E/F-18 Growler got an F-22 kill so close range its AESA radar can lock up even if older non-AESA F-16 and F-15 radars can't. But the point remains that technology can make things invisible to some radars some of the time. F-22's mixing it up with Mig-29's or SU-27/J-11's might only have to worry about IR missiles and collisions while the J-11/Mig 29 pilot has to worry about IR, radar guided missiles, guns and collisions.

 

[MZUBAIR]

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?

My Dear JF-17 is just made on the concept of 4th generation fighter. It cannot be compared with 5th generation fighter features. Airframe of 5th generation fighters is quite different.

U can compare JF-17 with following 4th generation air crafts.

France
Dassault Mirage 2000


Republic of China
AIDC ****-1 Ching-kuo

Soviet Union
Mikoyan MiG-29 'Fulcrum'
Mikoyan MiG-31 'Foxhound'
Sukhoi Su-27 'Flanker'
Sukhoi Su-33 'Flanker D'

United Kingdom
Panavia Tornado ADV

United States
Grumman F-14 Tomcat
McDonnell Douglas / Boeing F-15
General Dynamics / Lockheed Martin F-16 Block A/B (may be C/D)
McDonnell Douglas F/A-18 Hornet

_____________________________________________-

But yes, with improvements it can be compares with 4.5th geneeratio fighters. Like new engine, western Avonics, AESA Radar and external coating to obserb radar signals (RAM) can add stelthy feature.

 

[gambit]

An exchange pilot did say he had an F-22 in visual range in gun mode (very close) and his fighters radar would not lock up. Even if that is only true of certain situations, its still damn useful. An E/F-18 Growler got an F-22 kill so close range its AESA radar can lock up even if older non-AESA F-16 and F-15 radars can't. But the point remains that technology can make things invisible to some radars some of the time. F-22's mixing it up with Mig-29's or SU-27/J-11's might only have to worry about IR missiles and collisions while the J-11/Mig 29 pilot has to worry about IR, radar guided missiles, guns and collisions.

I would opine that his radar did find the F-22. But radar detection is also a statistical process, meaning there has to be a certain number of VALID echoes over time in order for the radar computer to establish a target profile. The F-22's body is formed in such a way that during maneuvers, it is supposed to create difficulties for the opposing radar to establish such a profile. Any moment of hesitancy increases the odds of a lost. This is why the Russians and the Chinese are so hard at work propagandizing their junks to gullible buyers.

===

On a different note...

Flying the F/A-18F Super Hornet

2.2 The Virtual Speedbrake

The next handling demonstration involved involved the speedbrake and some high alpha low speed handling, an area in which many fighters experience problems in maintaining direction and avoiding a departure into uncontrolled flight.

The first demonstration involved the virtual speedbrake effectiveness and handling in this configuration. The F/A-18A-D, like the F-15 series, employs an upper fuselage hydraulically deployed speedbrake. The Super Hornet has no such device, yet achieves the same effect through what can only be described as digital magic. The speedbrake function is produced by a balanced deployment of opposing flight control surfaces, generating drag without loss of flight control authority or change in aircraft pitch attitude.

Dave demonstrated the speedbrake function, and I was asked to observe over the shoulder and in the mirrors the raised ailerons, lowered trailing flaps, raised spoilers and splayed out rudders. Deceleration is smooth and there is no observable pitch change.

At Mach 0.63 Dave invited me to fly another 360 aileron roll, to observe that the aircraft retains considerable control authority despite the fact that the rudders are splayed out, and the ailerons, spoilers and flaps are generating balanced opposing pitching moments. I applied roughly 1/2 stick input and the aircraft very cleanly rolled through 360 degrees at about 90 degrees/sec roll rate. I commented on the lower roll rate and Dave observed that we were significantly slower, he then proceeded to demonstrate the roll again with a full stick input, producing around 180 degrees/sec with a slight overshoot on recovery. The aircraft feels very stable throughout the manoeuvre and there is no observable change in control forces or control input response by the FCS.

This make the 'Cobra maneuver' by the Russian Sucky series worthless.

The F-18E/F achieved the same effect, which is to radically reduce forward momentum, without resorting to extreme pitch angle. Imagine the rear stabs creating a roll in one direction but the wings' control surfaces creating a roll in the opposite direction. All surface deflections are delicately balanced to achieve the desired rate of forward momentum reduction without pitch attitude changes and loss of flight control. With the Sucky pilot doing his extreme pitch up to slow down, his field of view radically changes and with such an extreme attitude come increased odds of losing flight control. The pilot of the new F-18 would have no such field of view loss and would remain in control of his ship.

 

[hj786]

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.

I think you got the wrong idea Gambit, JF-17 uses the DSI design precisely because it is not complex. A fixed design, with no moving parts, that gives high intake efficiency at sub-sonic/supersonic flight up to ~Mach 2 (according to an article in Lockheed Martin's Code One magazine). Some bits of info on the JF's inlet design:
The JF-17 Thunder: A hefty punch at an affordable price.

The most notable of these has been the convex DSI (Divertless Supersonic Inlets) intakes. These have helped reduce the overall weight of the airframe, and after an internal redesign, freed up space for more stores, most notably fuel for slightly increased range.

Pakistan Military Consortium :: www.PakDef.info

n order to improve the aircraft's performance, study on diverterless supersonic intake has been in progress since 1999. Bump intake design on JF- 17 took almost two years with a number of intake models subjected to high and low speed wind tunnel tests. Analysis show that at high speeds, the bump works with forward-swept inlet cowls to give high performance, high total pressure recovery, low integrated distortion, and, good engine/intake matching. It redirects unwanted boundary layer airflow away from the inlets, essentially doing the job of heavier, more com*plex, and more costly approaches being used

------------------------------------------------------------------

An old article dated December 2005. It is very much appreciable if you can provide credible source to back your claim of current configuration or atleast the changes have been made in the PT-06 instead of putting smileys.

Sources for FBW in pitch axis and conventional stability augmentation system in roll/yaw axis:
Pakistan Military Consortium :: www.PakDef.info
According to Wg Cdr Abid Ali Khan and Sqn Ldr Ahsan Rafiqui:

This has resulted in better matching of the aerodynamic focus with the Center of Gravity (CG) and better harmonization of the air-to-air and air-to-ground CG vari*ations by taking advantage of the pitch digital fly-by-wire Flight Control Systems (FCS). This has improved not only the controllability but has also enhanced the performance through reduction of the supersonic drag.
...
This multi-role, third generation air*craft is designed to be highly maneuverable with fly-by wire flight controls in pitch axis and stability augmentation system in the "Role and Yaw" axis.

Pakistan Aeronautical Complex....
According to Aircraft Manufacturing Factory, Pakistan Aeronautical Complex:

New Designed Flight Control System
* JF-17 has composite flight control system comprising conventional controls with stability augmentation in roll and yaw axis and fly by wire in pitch axis.
* Simple autopilot
* Control system of lift increasing device, leading edge slats / flap and trailing edge flaps will be an automatic control system referring to air speed and angle of attack for improving aircraft maneuvering

Pakistan Military Consortium :: www.PakDef.info
According to Usman Shabbir (interviewer) and Chief Project Director, JF-17 Project, PAF (interviewee):

Q. Currently, the JF-17 prototypes are equipped with a mix of hydraulic and FBW system. Will the production models retain this unique system or will they be equipped with a complete FBW system?

A. The flight controls of JF-17 aircraft are commanded through six computers and operated by two hydraulic systems. The six &#8216;flight control computers&#8217; have a lot of redundancy within themselves, therefore, the aircraft would keep flying normally, even if couple of computers fail. This redundancy is a common feature of almost all the fly-by-wire control systems in the world. However, a unique feature of JF-17 aircraft is that it can fly like a conventional aircraft even when all its flight control computers fail. This arrangement is an added safety feature, which provides an additional advantage to the aircraft without any adverse effects. Therefore, it would be retained in the serial production aircraft as well.

Sources for Fly-By-Wire in all axis:
The JF-17 Thunder: A hefty punch at an affordable price.
According to Usman Ansari, a journalist (made Chief Analyst of Warships - International Fleet Review in 2006, the 'Pakistan Correspondent' for Defense News in October 2008, has also written for Classic Military Vehicle, Military Machines International, Combat Aircraft, Land Rover World, Air Forces Monthly, and 4x4):

Other internal changes include a full fly-by-wire set of controls, and more high tech avionics.

Chinese Military Aviation
According to Hui Tong (a respected source on Chinese discussion boards, translates Chinese language articles):

The 04 prototype was expected to fly by the end of 2005 with full suite of avionics but this was delayed until April 2006 due to several structural modifications. They include new diverterless supersonic inlets (DSI/Bump) similar to those of American F-35 to reduce weight and achieve better performance. A large rectangular-shaped fairing is installed on top of the vertial tailfin which may house ECM equipment. A new FBW system (quadruplex digital FBW in pitch axis, duplex analog FBW in roll axis). A UV band MAWS has been installed at the root of the vertical tailfin to provide rear hemisphere coverage. Two enlarged F/A-18 style LEX are thought to offer higher AOA as well. The first flight of 04 prototype took place on April 28, 2006, and 06 prototype on September 10, 2006.

Finally, an interview with the PAF's then Chief of Air Staff, ACM Tanvir Mehmood Ahmad, interviewer: Geo TV anchor Kamran Khan (skip to 4 minutes in). A quick translation:

Khan> Which aircraft can it (JF-17) be compatible (comparable?) with, is there a role model for this jet?
ACM Ahmad> Our role models are high-tech aircraft such as the F-16 Block 50 model which we have a contract for, and in Europe the Typhoon and Gripen type jets, this (JF-17) will be a high tech aircraft as well, the main difference being weapons capacity, these (F-16 and Gripen?) jets have 9 stations and currently (JF-17) has 7, but we are working to increase that to 9 also. But advanced weapons which can be fitted to other aircraft will be fitted to it (JF-17), ... avionics are modern enough to be comparable to those of new generation jets, flight control it (JF-17) also has fly-by-wire just as other jets have it....

Current AESA platforms
AN/APG Family.
SABR.
RBE-2.
CAPTOR-E.
SELEX Vixen 500.
SELEX Vixen 1000.
Phazotron NIIR Zhuk-AE.
Elta EL/M-2032 & 2052.
A Chinese variant which still not matured enough.
From the above only few are available in the market for Pakistan and you can see that only Vixen 1000 is technically and strategically viable for PAF.

I agree Vixen 1000 is a likely choice, but it's still speculation and you know it. You don't know how mature a Chinese AESA would be, they already surprised the PAF with their radar and avionics suite which was finally chosen for JF-17. A PAF official has stated they did not lower their requirements (http://www.strategycenter.net/research/pubID.48/pub_detail.asp), the Chinese radar beat the Italian one fair and square. In the near future, the SELEX Vixen will not be the only European AESA on the market.

 

[gambit]

I think you got the wrong idea Gambit, JF-17 uses the DSI design precisely because it is not complex. A fixed design, with no moving parts, that gives high intake efficiency at sub-sonic/supersonic flight up to ~Mach 2 (according to an article in Lockheed Martin's Code One magazine).

I was illustrating the history of inlet air control and how it came to be that non-moving inlet air offers the best all around solution. The F-15 has moveable ramps as another method for inlet air control. Higher than Mach 2 and some forms of variable inlet air controls become increasingly necessary.

One extreme example is here...

Mach 20 or Bust | Flight Today | Air & Space Magazine

One research goal is to try different shapes for scramjet engines in the search for greater efficiency, starting with the air inlet. Instead of a simple rectangular slot, shaped like the front of a Dustbuster vacuum cleaner, the inlet for the REST (rectangular-to-elliptical shape transition) engine is three-dimensional and more complex. The opening is still generally rectangular, but it includes faces that slant in toward the combustion chamber. Michael Smart, an associate professor in the HyShot group at the University of Queensland, explains: “The reason these 3-D inlets are more efficient is that the air is compressed by all surfaces of the inlet. A 2-D inlet only compresses the air in one plane: The side walls create drag, but don’t do any compression.”

Without inlet air control at supersonic regions, maximum Mach limited to around Mach 2 with engine longevity considerations. Currently, fixed inlet air control method is preferred.

 

[M.ASIF AMIN]

HELLO ALL
ANY IDEA OR ANY INFORMATION ABOUT H-4 WEAPON
any one person who get picture JF-17 related person's right side patch photo ..one person have PAF H-4 patch ,,, any one who attended IDEAS-2008 please... chech yours picturs of IDEAS 2008 jf17 technitions

 

[IceCold]

I would opine that his radar did find the F-22. But radar detection is also a statistical process, meaning there has to be a certain number of VALID echoes over time in order for the radar computer to establish a target profile. The F-22's body is formed in such a way that during maneuvers, it is supposed to create difficulties for the opposing radar to establish such a profile. Any moment of hesitancy increases the odds of a lost. This is why the Russians and the Chinese are so hard at work propagandizing their junks to gullible buyers.

===

On a different note...

Flying the F/A-18F Super Hornet
This make the 'Cobra maneuver' by the Russian Sucky series worthless.

The F-18E/F achieved the same effect, which is to radically reduce forward momentum, without resorting to extreme pitch angle. Imagine the rear stabs creating a roll in one direction but the wings' control surfaces creating a roll in the opposite direction. All surface deflections are delicately balanced to achieve the desired rate of forward momentum reduction without pitch attitude changes and loss of flight control. With the Sucky pilot doing his extreme pitch up to slow down, his field of view radically changes and with such an extreme attitude come increased odds of losing flight control. The pilot of the new F-18 would have no such field of view loss and would remain in control of his ship.

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.

 

[Guest]

can this bird launch any cruise missiles? coz you don't have to trade your enemy plane by plane in the air, it has to land on somewhere eventually. And this is the most cost-effective way for PA to destory the enemy AC. of course i know a cruise missile project needs xxx billions to complete. but the missile itself is cheap yet potent provided you can share the recon and navigation informations from your allies.

 

[Owais]

can this bird launch any cruise missiles? coz you don't have to trade your enemy plane by plane in the air, it has to land on somewhere eventually. And this is the most cost-effective way for PA to destory the enemy AC. of course i know a cruise missile project needs xxx billions to complete. but the missile itself is cheap yet potent provided you can share the recon and navigation informations from your allies.

ofcourse JF17 can launch CM. Raad ALCM is designed for it.

Ra'ad (Hatf-8) (Pakistan) - Jane's Air-Launched Weapons

JF17 can also carry H2 and H4 guided bombs having range of 60km and 120km respectively

 

[Guest]

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.