JF-17 Thunder Multirole Fighter [Thread 6]

[Sine Nomine]

@Oscar Sir Jf-17 has not full FBW i read somewhere,what disadvantages it does have and will future blocks will carry full FBW,i will be thankful if my ignorance is removed.

 

[SQ8]

@Oscar Sir Jf-17 has not full FBW i read somewhere,what disadvantages it does have and will future blocks will carry full FBW,i will be thankful if my ignorance is removed.

It is not FBW, go through the JF-17 info pool completely to get updated. Full FBW can be offered but as such the current setup does the job just fine and full FBW is an upgrade and expense that is not needed.

 

[alimobin memon]

It is not FBW, go through the JF-17 info pool completely to get updated. Full FBW can be offered but as such the current setup does the job just fine and full FBW is an upgrade and expense that is not needed.

Can you tell the difference b/w full and limited FBW ? just for knowledge

 

[ACE OF THE AIR]

It is not FBW, go through the JF-17 info pool completely to get updated. Full FBW can be offered but as such the current setup does the job just fine and full FBW is an upgrade and expense that is not needed.

I remember reading in one of the JF-17 threads that this aircraft was supposed to be fully FBW but when France refused PAF had to rely on conventional methods. This does not imply that it can not be fully fly by wire or fully conventional.

Can you tell the difference b/w full and limited FBW ? just for knowledge

A fully FBW aircraft is unstable in flight characteristics and it is flown by computers and wires replace the controlling mechanism where as limited fly by wire aircraft has to have limited instability so that a pilot may be able to control its flight manually in the case of computer malfunction.

 

[Sine Nomine]

It is not FBW, go through the JF-17 info pool completely to get updated. Full FBW can be offered but as such the current setup does the job just fine and full FBW is an upgrade and expense that is not needed.

what are advantages of Full over current setup and vice verse.

 

[Danish saleem]

15-201.
A team visiting from Belarus
via #Asif Iqbal from SDFView attachment 210302

Year 2015, Block II, First Aircraft.
15-01

 

[The SC]

View attachment 212031

Awesome, I have never seen this pic before.

 

[Beast]

I remember reading in one of the JF-17 threads that this aircraft was supposed to be fully FBW but when France refused PAF had to rely on conventional methods. This does not imply that it can not be fully fly by wire or fully conventional.

when did JF-17 become France / pakistan joint project? Did you take wrong medicine this morning? JF-17 development all the while is in China chengdu.

China develop the J-10 with full FBW so what makes Chinese unable to do it for JF-17? It's all about cost for JF-17 that they decide not to use full FBW.

The Mig-29 has no digital FBW but still has outstanding agility.

 

[ACE OF THE AIR]

when did JF-17 become France / pakistan joint project? Did you take wrong medicine this morning? JF-17 development all the while is in China chengdu.

China develop the J-10 with full FBW so what makes Chinese unable to do it for JF-17? It's all about cost for JF-17 that they decide not to use full FBW.

The Mig-29 has no digital FBW but still has outstanding agility.

France was to give the Avionics.

In October 1995, Pakistan was reportedly to select a Western company by the end of the year to provide and integrate the FC-1's avionics, which was expected to go into production by 1999. The avionics were said to include radar, Inertial navigation system, Head-up display, and Multi-function displays. Competing bids came from Thomson-CSFwith a variant of the Radar Doppler Multitarget (RDY), SAGEM with a similar avionics package to those used in the ROSE upgrade project, and Marconi Electronic Systems with its Blue Hawk radar. FIAR's (now SELEX Galileo) Grifo S7 radar was expected to be selected due to the company's ties with the PAF.

Because of sanctions placed on Pakistan after the country's 1998 nuclear weapons tests, design work progressed very slowly over the next 18 months, preventing delivery of the Western avionics to the PAF. In early 2001, the PAF decided to decouple the airframe from the avionics, enabling design work on the aircraft to continue. As the airframe was developed, any new avionics requirements by the PAF could be more easily integrated into the airframe.

CAC/PAC JF-17 Thunder - Wikipedia, the free encyclopedia

 

[JamD]

Can you tell the difference b/w full and limited FBW ? just for knowledge

From what I know JF-17 has FBW in pitch only. That is how it is 'limited'. I don't think "limited instability" means anything. All things are either stable, unstable or marginally stable.

Also almost all FBW systems have backup hydraulic/manual systems.

what are advantages of Full over current setup and vice verse.

As I said earlier the JF-17 has FBW in pitch. This allows the computer to augment stability in pitch. So maneuvers that involve the elevator must have excellent response.

In the lateral modes (roll and yaw) the JF-17 is old school. This means it relies on ventral fins and rudders and manually operated ailerons for stability and control. So it won't be as good as, let's say an F-16, at aileron rolls etc. This is not to say the aircraft isn't physically capable of doing as well as any other aircraft. Just that it'll be harder for the pilot to make the aircraft behave in lateral modes as easily as he or she would have in a full FBW.

It all comes down to the cost. I'm sure they realized that it cost way too much to get too little benefit from going full FBW.

I had also heard rumors that the JF-17 that crashed (the only one) crashed due to the elevator doing something funny. Allah behtar jaanay actually kya hoa tha.

 

[alimobin memon]

Well its an standard system. I remember a chinese claim of fly by flight more better yet cheap to be installed in jf17 which was full system.

 

[Beast]

France was to give the Avionics.

In October 1995, Pakistan was reportedly to select a Western company by the end of the year to provide and integrate the FC-1's avionics, which was expected to go into production by 1999. The avionics were said to include radar, Inertial navigation system, Head-up display, and Multi-function displays. Competing bids came from Thomson-CSFwith a variant of the Radar Doppler Multitarget (RDY), SAGEM with a similar avionics package to those used in the ROSE upgrade project, and Marconi Electronic Systems with its Blue Hawk radar. FIAR's (now SELEX Galileo) Grifo S7 radar was expected to be selected due to the company's ties with the PAF.

Because of sanctions placed on Pakistan after the country's 1998 nuclear weapons tests, design work progressed very slowly over the next 18 months, preventing delivery of the Western avionics to the PAF. In early 2001, the PAF decided to decouple the airframe from the avionics, enabling design work on the aircraft to continue. As the airframe was developed, any new avionics requirements by the PAF could be more easily integrated into the airframe.

CAC/PAC JF-17 Thunder - Wikipedia, the free encyclopedia

Avionics has nothing to do with digital FBW. Are you sure we are in the same note? Hello?

FBW need to be done at plane design development phase. Software input and source codes. What does avionics do with FBW?

 

[Mughal-Prince]

I had also heard rumors that the JF-17 that crashed (the only one) crashed due to the elevator doing something funny. Allah behtar jaanay actually kya hoa tha.

The only JFT which dropped out of the sky because of a device installed over it to take some readings for building simulator and while flying at high speeds at altitudes the drag of that device force to disintegrate the part where it's attached, that was the reason which I read here at the forum.
Later I have never heard that JFT fleet has been grounded so that makes me think that "elevator doing something funny" is hard to believe because it may lead the whole fleet grounded for further test and check for any hardware and software anomaly.

 

[gambit]

Can you tell the difference b/w full and limited FBW ? just for knowledge

The 'fly-by-wire' flight control system continues to confuse people. But it is understandable...

When the F-16 was under design, the philosophy was to create an exceptionally maneuverable fighter, one that would stress the human pilot more than the aircraft itself could be designed. When we finally admitted that the best the human pilot could withstand is 9g, that became the benchmark for maneuverability. The F-16 was designed with certain g-limit but it was based on the human limit. If General Dynamics wanted to, they could have designed the F-16 to withstand 20g, but what would be the point in that when the human pilot can handle only 9g ? So they designed the F-16 to be 10-ish g-limited. I was on the F-16 for five yrs. I know what 9g felt like on my body and to my vision.

Anyway...How to make such a maneuverable fighter ?

Traditional aircraft designs have always been about stability. The problem is that the higher the airspeed, the greater that stability to the point where the aircraft could not maneuver at all. It may sound somewhat odd but a certain degree of instability is needed to make maneuvers possible. What GD did was designed the F-16 to be unstable, not 'stable with some degrees of instability'. Do not confuse aerodynamics with stability. They are two separate things. Related -- but distinct. It soon became clear that the more unstable the design, the less the human pilot will be able to keep the aircraft under control.

Now there are three distinct items...

- Aerodynamics
- Stability
- Controllability

Item one -- easily done.

Items two and three -- serious problems.

General Dynamics resorted to using computers to replace the flight control system from cockpit to hydraulic actuators. Basically, there are only three truly mechanical components in the FLCS: stick, rudder, hydraulic actuators Everything in between are electrical wires. Some people might nitpick and consider the gyros and accelerometers as also mechanical components but that would be missing the larger point.

The system is a closed loop. At a high level explanation, when the pilot initiate a command thru the stick, the computer respond by moving the hydraulic actuator, which changes the aircraft's attitude such as pitch up/down or wings roll left/right. As the aicraft changes its attitude, the gyros and accelerometers senses the changes and feed that back to the computer, who then compares the result against the pilot's command. The entire loop works fast enough that stability and controllability are achieved and maintained throughout the maneuver, whether it is pitch up/down or wings roll left/right.

So to answer your question: There is no such thing as limited or full FBW FLCS.

What I explained above is either you have a FBW in an FLCS axis or a traditional mechanical FLCS in that axis.

I maybe wrong, but I think you misunderstood the design philosophy of the JF-17. The JF-17 was designed to have pitch instability but roll and yaw are primarily stable, so the pitch axis have FBW-FLCS but roll and yaw are traditional mechanical FLCS. Some people called this as 'limited' but it is incorrect. Does this mean the JF-17 design philosophy is the same as the F-16 ? No. The F-16 have all three axes as unstable.

Some people might say that if an aircraft have FBW-FLCS, that mean the design is unstable. That is incorrect. Airbus and Boeing moved to full FBW-FLCS in all three axes in their highly stable airliners. Weight is a penalty in flight. Airbus and Boeing literally saved thousands of kilos in weight by using FBW-FLCS. The FBW-FLCS actually made maneuvers even more stable and controlled in these large body aircrafts. Take-offs and landings in high and/or cross wind situations are safer because the computers can respond faster to attitude changes, large and small, created by the wind.

Hope that helped.

 

[Beast]

The only JFT which dropped out of the sky because of a device installed over it to take some readings for building simulator and while flying at high speeds at altitudes the drag of that device force to disintegrate the part where it's attached, that was the reason which I read here at the forum.
Later I have never heard that JFT fleet has been grounded so that makes me think that "elevator doing something funny" is hard to believe because it may lead the whole fleet grounded for further test and check for any hardware and software anomaly.

It so sad there are so many imposter trying to bad mouth JF-17, talking rot of elevator problem without FBW that causes crashed and even more ridiculous comment that we need France assist for FBW in this project.