JF-17 Thunder Multirole Fighter [Thread 4]

[pshamim]

Only because J10 is high end for PAF, doesn't make it high end for PLAAF or PLAN. The same high / low mix of a heavy twin engine and medium single engine fighter is used in several forces all over the world. Also having the same engine for J10 and J15, makes it even easier and more cost-effevective to operate them, compared to a J15 / JF17 combo and not to mention that the cost for J10 and Chinese forces aren't that high either, so cost is not a real argument here.

My point was more in regard to the design and structural differences between JF 17 and J10 and if there would be any advantage that would make JF 17 more favourable to be a carrier fighter?

You may call me crazy for dragging the Thunder in to PLA Navy carrier. Briefly,one of the simmering issue at present is how far J-10 can be improved and upgraded. J-10 is reaching a point where further upgrades may not be possible even though it is a great aircraft. JF-17 is not only inexpensive but has a lot of room to grow. A lot of talks and rumors are circulating, not necessarily that they are all true but they point to ideas that may or could be incorporated. I may state a few of them:

1. The single tall vertical tail may make way for twin tail to make it more stealthy. Also as Chinese have not designed and produced a twin tail yet, there seems to be a desire by the Chinese to introduce their own designed twin tail and introdece it for FC-1/JF-17
2. Twin tail will also reduce the weight
3.Change the circular rcs to diamond shaped cross section to improve stealthiness.
5. Keep the iconic DSI but make modify it due to changes in the nose
6. Increase the rounded edges on the wing. This will not only enable Thunder to perform better at low speed and at low altitude flying
This will also increase the wing tank capacity and increase range
7.Change the spine design and raise the cockpit for a better flight vision
8.Increase the take off weight.

Rest later. My eyes are hurting now.

Thank you so much for the respect shown by many on this forum and others. I am grateful. It is a bonus for old peorson like me to enjoy it at a time when respect for elders by youngsters is wanning in the new world.

P.S. MuradK not his true name, and i joined PAF on the same day but left at different times. He stayed with PAF and I went on to work in Defence industry in UK and USA in 1970s.

 

[Edevelop]

Lately we are seeing lots of arguments about having twin engine fighter jets like J-11 and J-20.

I have a quick question in my mind. If small size jets like Eurofighter and Rafale can have twin engines, then why can't we do the same to JF-17 in blocks 3 and advanced?

... If these plans go ahead, they will be great for the Navy in the future...

 

[Donatello]

Lately we are seeing lots of arguments about having twin engine fighter jets like J-11 and J-20.

I have a quick question in my mind. If small size jets like Eurofighter and Rafale can have twin engines, then why can't we do the same to JF-17 in blocks 3 and advanced?

... If these plans go ahead, they will be great for the Navy in the future...

Eurofighter is small? You got to be kidding me. I went to the RAF museum and they had a full size replica. It was pretty huge.

If the Swedes saw this.......they'd want to commit suicide.

 

[Darth Vader]

lol em in love with 4 badass planes 1 f 35, f 22 , f 16 , jf 17 soon em gone fly 1 of them lets wait and watch when norway gets hand on other 3

 

[Thorough Pro]

Can any body be kind enough (and please consider I am an Idiot) to point any thing insulting towards anybody from my side. AlsoIs JFT block II coming out this year?

Chil out Farooqi, we all (Pakistanis) come here because we love Pakistan and take keen interest in its defence related matters. We discuss isues and express our opinions, but we do not try to force our ideas down others throats. Our free memebrship, access to host of valuable informatin and opportunity to express our opinions is a privelage not a right. Don't get on peoples nerves, be respectful and enjoy.

 

[Liquidmetal]

I think so you just answered yourself, Respect is a two way street, you can't take it on gun point or by insulting someone. Knowledge and IQ is not based on someone's age and besides winning the "i am elder than you" game on internet is simply lame. Maybe it's not your questions but the way you interact with other forum members which created a cumulative effect?

Oh keeping with the trend, i am 36 years old father of two just making a judgement because you asked for it, flame on

I apologise for getting into this debate, I know I should keep my nose out of this but I did want to point out to our respectful colleagues that Mr Farooqi is merely debating the issues and benefit of this jet and he has now politely requested to be informed what has offended people; esp in the last 2 weeks.

May I suggest that let bygones be bygones and can we move on to appreciating our country's achievement which for a so called 'failed' state is simply astounding.

For a people who are perceived to be living under rocks (by the idiots in other countries), this 1st attempt by a poor country is something I am, personally, very proud of.

Can we celebrate these things as well as genuinely criticise failures, stupidity and corruption. So that we can collectively improve our great country.

Of course, I trust that everyone will understand this is just my personal and hopefully it has been received as a polite request. No offense is intended to anyone - friend or foe.

 

[Manticore]

If the Swedes saw this.......they'd want to commit suicide.

we need members to post this comparison on different fora and spread this poster -- husnain , nabil , imran,taimi -- ive seen them on different fora , spread the awareness guys!

gripen info used is not wrong [consciously degraded by me].... however swedes may want to add a ''+'' on some of these values just to prove a point
SAAB JAS-39 "Gripen"
Aerospaceweb.org | Aircraft Museum - JAS 39 Gripen
http://www.defence.pk/forums/jf-17-...hunder-over-jas-39-gripen-25.html#post2938181
jft info based mostly on dubai airshow presentation

 

[Jango]

...
2. Twin tail will also reduce the weight
....

Could anybody explain this?

How is weight reduced by twin tail?

 

[Manticore]

vortex will generate lift , high AoA --

twin tails might give stability [directional control?]...Having two vertical stabilizers allow each of them to be smaller than a single one, would decrease height in hangers-->reduction of the load at the root

The LERX were designed in to keep airflow attached at high alpha .Strakes wereadded to the LERX to stabilise the vortex

I read somewhere that twin tails reduced supersonic drag and saved structural weight -- at subsonic Mach the two fins interfere with each other, which reduces their effectiveness as lifting surfaces--At a supersonic speed, the 2 surfaces begin to work independently --twin tail fins helps the airplane benefit from this vortex and retain yaw control in high AoA--- if one engine fails , 2 vertical tails would be better in controlling the fighter --shedding vortices from the wing root , vortices being shed by the strakes are used to energise airflow over twin fins thus retaining control

my understanding [layman] is high vortex--high aoa but high drag ----> this drag can be reduced by twin tails

Drag reduction, combine the tasks of the elevators and rudder,increase surface area without increasing aspect ratio are other things that ive read regarding Vtails like on f117


the two vertical stabilizers on the F-22 Raptor angled sort of like a V-Tail as opposed to being completely vertical 90 degrees-- i guess due to stealth issue aswell as stability

Early design development

During the early design development of the F-16, General Dynamics had considered both single and twin vertical tails. Wind tunnel tests had showed that vortices produced by the forebody strake generally improved directional stability, but that certain strake shapes actually reduced stability at high angles of attack when twin tails were used. It was concluded that a twin-tail format would result in significantly greater development risks and that a single vertical tail would give satisfactory results provided that it was sufficiently tall.
http://www.f-16.net/f-16_versions_article4.html

There are 2 considerations that have a strong influence on the vertical tail arrangements. Both come into play for rather high angles of attack and occur because of strong vortices which originate near the wing root-fuselage intersection or at a wing leading edge sweep change for some designs. These vortices cause high amplitude buffeting if the tails are too close to them at the most critical angles of attack. The F-14 and F-15 aircraft were strongly affected and had a lot of extra maintenance because of this. The other factor is for certain angles of attack and sideslip one of these vortices impinging on a vertical tail can lead to forces which are in the wrong direction so there needs to be one which is on the upwind side and is completely clear of such wake interactions to guarantee the needed control authority over all angles of attack and sideslip.

"A quick look at the F-22 reveals an adherence to fundamental shaping principles of a stealthy design. The leading and trailing edges of the wing and tail have identical sweep angles (a design technique called planform alignment). The fuselage and canopy have sloping sides. The canopy seam, bay doors, and other surface interfaces are sawtoothed. The vertical tails are canted. The engine face is deeply hidden by a serpentine inlet duct and weapons are carried internally. "

http://www.codeonemagazine.com/archives/1998/articles/apr_98/apra_98.html
The wing planform and airfoil design were chosen to minimize weight while providing the maximum turn capability and supersonic cruise. The single vertical tail, however, presented problems in achieving a totally stealthy design. General Dynamics ran many wind tunnel tests to find a location and shape for twin canted vertical tails on the T configuration. The vortex flow off the forebody and delta wing produced unstable pitching moments when it interacted with twin tails. Without horizontal tails, the aircraft did not have enough pitch authority to counteract these moments. A single vertical tail and no horizontal tails was finally identified as the best overall approach to the design despite the degradation of radar cross section in the side sector. The proposal configuration was designated T-330.
A few months before the proposals for the dem/val phase of the program were to be submitted, the Air Force amended its proposal request. The change significantly increased the importance of stealth in the design. Lockheed, with a stealthy configuration derived from the F-117, made no modifications to its design as a result of the new requirements. Boeing made some slight modifications to the design of their inlet to address the increased stealth requirements.The company was, however, satisfied that its twin-tail design would meet the stealth requirements.

The upgraded requirements forced engineers at General Dynamics to again reconsider twin tails in a variety of locations, including out on pods on the wing. The trailing edge of the wing and the control surfaces were cut into chevrons aligned with the leading edge, giving the wing a bat-like look. In the end, no acceptable location for the twin tails was found, and the design was submitted with a single centerline tail and a serrated trailing edge. The new final configuration was labeled T-333.

Note the animation here, demonstrating how the leading and trailing edges of wings and elevators are kept at the same angles to reduce radar signature AND the angles of the engine inlets and the splayed tails are lined up, as well.
http://www.f-22raptor.com/st_fa22tricks.php#stealthfeatures



http://www.f-22raptor.com/st_fa22tricks.php#stealthfeatures

http://www.scribd.com/doc/18029452/NASA-SR71-Blackbird-Challenges-and-Lessons-Learned-2009
NASA's Lessons Learned from the SR-71 program. page 36 RCS reduction

F-15 Silent Eagle with canted vertical tails?

It is one of the many issues and choices made during the design of an aircraft.
Having two vertical stabilizers allow each of them to be smaller than a single one. That in turns allows a reduction of the load at the root, hence a slightly lighter structural strength requirement; shorter tails would also reduce the magnitude of the roll coefficient due to rudder deflection.
In the case of a fighter that could be shot at, having twin units provides a certain measure of redundancy.
But perhaps the most important consideration is that, at a very high angle of attack, twin rudders that are mounted on the edge of the fuselage would not be 'blanked' by the wake of the fuselage, and could retain a measure of efficiency when the flow detaches. This is however done at the expense of a 'buzzing', and interaction from the vortex from the wing leading edge interacting with the vertical tails which, at least in the case of the F-18, was found to fatigue the structural components there, requiring frequent inspection and repairs.
Another aspect is that twin fins do not have to be perfectly vertical, and the angle that they would be set at could be a factor in the reduction of the radar cross section. If you check the F22 and the F-35 (for which twin fins could not have anything to do with helping stability in case of the loss of an engine, since it has only one to start with), the angle is destined to allow stealth.

At High angles if attack, sure enough, the VS/Rudders are "hooded" from symmetric flow. This directional sincerity is falling off as the Chines on either side of the forebody start to shed flow rather than direct it. Without these chines, the fuselage would wobble uncontrollably side to side as very high AoA is approached. The Chines do not "energise" the flow to enhance aft controlled Yawing moment, instead, they provide the stability needed to Replace that lost by the "shaded" VS/Rudder.

Source: http://www.defence.pk/forums/air-wa...canard-non-canard-fighters.html#ixzz1wLd9kk2k

again i am a layman and might be completely wrong .. sir pshamim would be able to correct my assumptions -- particularly the last qoute

 

[Jango]

So the twin tails alter the lift-weight ratio rather than the weight of the aircraft itself.

You are a whole library ANTIBODY!!!

 

[Zarvan]

So the twin tails alter the lift-weight ratio rather than the weight of the aircraft itself.

You are a whole library ANTIBODY!!!

When on earth Pakistan will get those 50 Plane which we were supposed to get from China it is now more than a year but still no news of those 50 Planes also no news of any new JF-17 produced in Pakistan

 

[TaimiKhan]

When on earth Pakistan will get those 50 Plane which we were supposed to get from China it is now more than a year but still no news of those 50 Planes also no news of any new JF-17 produced in Pakistan

Those 50 planes are not coming.

End of discussion.


If anyone asked this question again, be prepared for anything.

 

[Jango]

When on earth Pakistan will get those 50 Plane which we were supposed to get from China it is now more than a year but still no news of those 50 Planes also no news of any new JF-17 produced in Pakistan

It was just a shosha by the media. Don't get worked up on it.

 

[Arsalan]

Those 50 planes are not coming.

End of discussion.


If anyone asked this question again, be prepared for anything.

hahahahaaaa

relax dear!!!

@ZARVAN
brother, please do check out some last pages and you will find your answer. i can reply you here but t will be better if you can take out time and search for it your self. you will get complete details and also may find some other interesting things that are new to you!

regards!

 

[ziaulislam]

reason for FC1 to be considered for carrier could be a logistic reason.?
its much more difficult to keep larger birds on a carrier, may be PLAN is ready to keep smaller birds on its deck. I think more FC1s can be placed on a same carrier than J-10.?