What's new

JF-17 Thunder Multirole Fighter [Thread 6]

Status
Not open for further replies.
it has an onboard oxygen generator, french, integrared as a ECS component.

I am still to come across any confirmation of that. Can you help?

I do not think we have an on board oxygen generator. There have been talks about the lack of it since the JF-17 started rolling out of PAC and then there never was an updated that this issue have been addressed. This is something new and big for me at least.

may be you can help with some confirmation.
 
I have never design a wing. Alongside sensor, I was also an avionics specialist, specifically in processes and sub-systems integration engineering, meaning I do what it takes to make many things work together and whatever does not play well with other, I send it back to the owner. But that does not mean I do not have to know how things should be at least at the design level.

Regarding enlarging the JF-17's wings. It is not as simple as enlarging the surface area.

Let us take the wing itself for now.

The wing produces three main items: lift, drag, and pitching moment. To maximize lift, drag and pitching moment must be minimized. In designing a wing, especially before the age of computer simulations, a design may unintentionally have high drag or high pitch down moment but the designer would not know that until wind tunnel testing or even later -- flight models. Hopefully not manned models, but such tragedies have happened before.

Most important thing to remember: No aircraft is ever without a specific purpose, including the designs that are supposedly 'multi-role'.

The words 'multi-role' is highly misleading when it comes to aircraft designs. The words 'multi-role' indicate the end user's intentions. The C-5 can drop bombs if the desire is there. Not as efficient as the WW II era B-25, of course, but the C-5 certainly can be used to drop bombs. So what the aircraft designer must do is to solicit as accurately as possible the overall purpose of the aircraft from the customer and come up with a wing best suit for that purpose. Humans and bombs are cargo. For the wing designer, how the end user intends to deliver either humans or cargo is none of his concern. All he needs to know is that his wing must lift a type of aircraft. From that, he begins his work.

How many wings does the C-130 and the 767 have ? Believe it or not, each aircraft have only ONE wing. Yes, the C-130, C-5, 747, and the 767 each have only one wing. The C-130 and the C-5 are 'high wing' designs. The Boeings are 'low wing' designs. Being 'high wing' or 'low wing' have its own advantages and disadvantages. The wing may be structurally separable into sections, but aerodynamically speaking, either 'high wing' or 'low wing' are unitary, even if there may be some fuselage blending effect.

For the C-130 and C-5, non-human cargo are priority so ease of loading them leads the aircraft designer towards the 'high wing' design. For Boeing, the priority is human cargo. The 'low wing' will experience ground effects sooner, which make for better take-off performance. The 'low wing' design will also have much less downwash on the tail section, making the tail section more effective in producing stable flights and maneuvers, which translate to a much smoother flight experience. There are plenty more information on the differences and preferences between the two types. Suffice for now that the vertical location of the wing assembly, above or below the fuselage, already set the tone for the wing designer.

How many wings does the F-104 Starfighter have ? Two. Yes, the F-104 Starfighter have two wings. So does the WW II era F-4 Wildcat. In this design, the wings are aerodynamically and physical distinct structures from each other. They are separated by the fuselage. These two aircrafts have the 'mid wing' design. The F-16 is a 'mid wing' design with high fuselage blending.

How many wings does the biplane have ? Two. Yes, the biplane have two wings, or more precisely two aerodynamically and structurally distinct wings. In the case of the Antonov An-2, one wing is fuselage high and one wing is fuselage low. In the case of the WW I era Sopwith Camel and many other biplane designs of the same era, the low wing is fuselage low and the top wing is called a 'parasol wing'. A 'parasol wing' design is when the fuselage is attached to the underside of the wing thru struts.

Parasol wing - Wikipedia, the free encyclopedia

Some designers may take issues with the argument that the Sopwith Camel have a parasol wing but that is for a different debate.

So what does this have to do with the JF-17 ?

The point is that from the beginning, the wing designer, not the aircraft designer, already have a set of constraints. The JF-17 is a fighter, intended foremost to have high maneuverability before cargo capability. High wing designs have high lateral stability, which is good for high volume, heavy weight, and bulky cargo carrying capability. So the C-130, C-141, and C-5 took this approach.

Other factors that create many other sets of constraints are:

1- Horizontal to the fuselage, as in where is/are the wing(s) on or relative to the length of the fuselage.

2- Wing span, whether the aircraft will have a mono-wing like the cargo carriers or two wings like the fighters.

3- Sweep angle.

4- Cross section or airfoil, as in NACA standards.

5- Dihedral angle.

6- Root chord.

7- Tip chord.

8- Mean aerodynamic chord.

9- Aspect ratio.

10- Taper ratio.

11- Twist angle or washout and this affects lift distribution.

12- Flaps.

13- Ailerons.

14- Incidence angle.

For the JF-17, the 'high wing' design is eliminated and the 'mid wing' design chosen out of the need for maneuverability. Or to put it another way, the greater the need for maneuverability, the greater the need for a higher leading edge sweep angle, which prefers using the fuselage for greater structural strength to withstand the higher stresses created by aerobatics. The 'mid wing' design is also more conducive to the blended fuselage-wing structure.

Some wing designs have non-constant sweep angle: The Space Shuttle. This is not the same as variable sweep angle like on the F-14 and F-111. For the Space Shuttle, the wings' leading edges have two fixed sweep angles starting from the forward fuselage section towards the rear and they are fixed. The front sweep angle is 81 and turns to 45 going aft. Altering one sweep angle without considering the other and the result may be decreased stability performance during reentry or a higher glide landing speed. NASA probably archived those other combinations for future reference.

There is no 'best' wing, only the best combination of all of the above 14 factors once a wing type (high, mid, or low) is finally selected for a particular aircraft design. Even if a wing have no sweep angle, like that on a pure glider, a zero value for sweep angle is still a valid factor. Indiscriminate enlargement of the wing's surface area WITHOUT considering those fourteen factors above WILL produce unexpected and probably reduced performance at some flight regime, such as air density at different altitudes, or increased drag in a turn which will be deadly for the pilot, or possibly with enlarged wing surface area airflow may be too much for the aileron which results in lower roll performance, or there is an increase in pitching moment that cannot be compensated. For the wing designer, his job is to fine tune all those factors to make the aircraft as close to customer demand as possible, and that mean each final combination is a set of constraints unique to that aircraft to give it stability and controllability.

If the wing designer come to me with a proposal for a larger wing on an existing aircraft, my job as a process and sub-system integration specialist, a babysitter of sorts, is to make sure everybody's children can play nice with each other. I would set a meeting with the flight controls engineer, specifically the fligh control laws engineer if the aircraft is a fly-by-wire type FLCS, and ask him if the proposed larger wing can be accepted by the flight controls laws. He may say that the mean aerodynamic chord (MAC) is different, which create a higher roll rate that his roll rate gyro cannot monitor, which affects the pitch-roll integrator that enables smooth turns. Besides the flight controls engineering team, the structural integrity engineering team may say the larger wing area create more stress on the fuselage connection, which in order to support the larger wing they would have to install larger and more expensive support structures which increases overall weight.

Does this mean the JF-17 cannot have larger wings ? The JF-17 CAN have larger wings. The question is more financial than it is technical. Of course, the finance involved may be great enough that might as well Pakistan follow the F-18 path and create a larger JF-17.

Bottom line is this: AFTER the wing type is selected: high, mid, or low, those 14 factors direct the design of the wing in order to accomplish a mission. Changing any one of them demands precise and patient examination on the effects on the rest, which ultimately will change aircraft performance in some ways.
its a great read, I will have to read again to understand fully.
but I am sold.
I really appreciate the time you took to explain .@free soul explained exactly what you did in a much better way.
 
I am still to come across any confirmation of that. Can you help?

I do not think we have an on board oxygen generator. There have been talks about the lack of it since the JF-17 started rolling out of PAC and then there never was an updated that this issue have been addressed. This is something new and big for me at least.

may be you can help with some confirmation.

As per PAC it does not have an OBOGS but a French oxygen regulation system with 3 hours supply. Most likely from GOX or LOX:

Pakistan Aeronautical Complex Kamra - JF-17 Thunder Aircraft
 
JF-17 canopy forming at PAC
Canopy Forming.jpg
:
 
it has an onboard oxygen generator, french, integrared as a ECS component.
I am still to come across any confirmation of that. Can you help?

I do not think we have an on board oxygen generator. There have been talks about the lack of it since the JF-17 started rolling out of PAC and then there never was an updated that this issue have been addressed. This is something new and big for me at least.

may be you can help with some confirmation.
That's why I raised this, If we had someone would have bragged about it in all these years.
 
Argentina's Jet Fighter Replacement Options Narrow

Nov. 30, 2014 - 10:46AM |
By JOSÉ HIGUERA and USMAN ANSARI





BUENOS AIRES AND ISLAMABAD
— The UK’s moves to block the sale of Gripen fighters to Argentina has triggered a round of angry accusations in Buenos Aires, while laying bare Argentina’s dilemmas in replenishing its fighter fleet after years of neglect.
Argentina's Jet Fighter Replacement Options Narrow

Nov. 30, 2014 - 10:46AM |
By JOSÉ HIGUERA and USMAN ANSARI


It also raised the prospect of Argentina purchasing fighters from Russia or China, experts said.

While Gripens are made by Saab of Sweden, about 30 percent of the aircraft contains parts supplied by the UK, Argentina’s longtime foe.

On Oct. 31, Argentina’s defense minister announced an interest in purchasing 24 Gripens. According to a senior military source in Buenos Aires, the proposal to sell 24 Gripen fighters, at a cost of US $2.9 billioncame as an initiative of the Brazil’s Ministry of Defense and was briefly discussed and accepted by its Argentine counterpart. In October, Brazil signed a deal to purchase 36 Gripens.

The same source pointed out that Saab, the original builder and owner of the design of the Gripen, “never made any attempt to offer the aircraft directly, neither new nor second-hand, possibly because the firm’s officials knew that the UK would block any sale to Argentina.”

In recent years Saab has provided Argentina with other weapon systems, including its RBS-70 man portable air defense system (MANPADS) and AT4 anti-tank rockets, which do not include British components.

After Britain balked at the transfer of Gripens to Argentina, local commentators pointed out that the failure of previous attempts to acquire surplus Mirage F-1s from Spain and refurbished Kfirs from Israel was also the result of diplomatic interference by London.

But, according to Emilio Meneses, a defense analyst based at Santiago, the reasons Buenos Aires failed to take earlier measures to replace its old Mirages, which were procured both new and second-hand in the 1970s and ’80s, “are more related to local politics and fiscal finances than to any kind of foreign intervention.”

Defense budgets have been systematically reduced in Argentina since the mid-1980s. The military dictatorship, after being defeated in its attempt to take the Falkland Islands by force, was forced to restore democracy and to give back power to an elected civilian government.

“In that scenario, where cutting budgets was seen by the public as a sort of fair punishment over the armed forces, the political authorities found it easy to underfund the military,” Meneses said.

The underfunding of the armed forces reached an all time low in 2003, when President Nestor Kirchner came in office. Kirchner’s policies were continued by his wife, Cristina Fernandez, who was elected president in 2007.

The senior military source in Buenos Aires said Spain started to offer its surplus Mirage F-1s in 2008, but Fernandez rejected the request of funding to procure those jet fighters. The aircraft were offered again late in 2012, when the serviceability of the remaining older Mirages in the Argentine inventory had reached a critical level.

But the Argentine government failed to grant the funding to procure the Mirage F1s in time. The Spanish capacity to provide airworthiness certification for the fighter jets, as required by the very strict Argentine regulations, ended.

The option to get such certification from France was very expensive, as the French government and industry were more interested in persuading Argentina to take surplus Mirage 2000s instead.

As a result, the Spanish Mirage F-1s were discarded and negotiations to procure a number of refurbished Israel Aerospace Industries Kfir fighter jets started. The negotiations suffered from a lack of support from Argentina’s higher levels of government, and the Air Force also had some misgivings about the aging Israeli machines. As result of both, the negotiations stalled.

As for what may happen now, the local military source pointed out that France has had a long-standing interest to sell some of its used Mirage 2000s, which are modern enough and by being single-engine fulfills one of the basic requirements of the Argentine Air Force.

The source also underlined that the Air Force prefers Western aircraft, but would be willing to consider a Russian option if the West doesn’t provide a solution.

A Russian solution would be financially convenient for cash-strapped Argentina, as President Vladimir Putin, who made an official visit to Buenos Aires last September, offered to accept beef, wheat and other food goods as payment for military equipment.

The China Option
Yet some analysts believe there is another path.

Analysts such as author and former air commodore Kaiser Tufail said China’s FC-1/JF-17 is well-suited to Argentina’s operational requirements when considering acquisition and operating costs, as well as an increasing range of advanced weaponry.

“I believe that, given Argentina’s serious financial troubles, the FC-1/JF-17 would be just the right choice,” he said. “Despite the aircraft being short-legged, it is cheap and can be bought in large numbers.”

Similarly, analyst Haris Khan of the Pakistan Military Consortium think tank said Argentina’s occasionally difficult relations with Western nations and inability to modernize its airpower since 1982 means the FC-1/JF-17 should be all the more attractive.

“Argentina’s Air Force needs urgent replacements and FC-1/JF-17 very much fits the bill. It is more or less embargo free since it has almost zero parts involved from Western nations/NATO member states,” he said.

Chinese officials reportedly offered the FC-1 to Argentina last year at the Paris Air Show, and even offered an option of local assembly, but the Argentineans were apparently more tempted by offers of surplus Mirage F-1s from France and Spain respectively, and also an Israeli offer of Kfir Block 60s, before these options fell out of favor.

Argentina has a growing defense relationship with China that has seen it start to co-produce the Changhe Z-11, the CZ-11 Pampero, which is based on the Eurocopter A350 Ecureuil (Squirrel).

The CZ-11 program is part of Argentina’s bid to build up its aviation industry, therefore the offer of local production of the FC-1/JF-17 could still be tempting.

“I’m not sure what the base line of the local production capacity is, but this might be one of the avenues to have Argentina buy this aircraft. China has been very impressive with the line of weapons it has tabled in the past few years and it might just be able to fulfill all of Argentina’s requirements,” Khan said.

However, notwithstanding the FC-1/JF-17’s merits vis-a-vis Argentina’s operational requirements and its low operating costs, and despite China being Argentina’s second largest trading partner, plus its support for Argentina’s claim over the Falkland Islands, analysts acknowledge politics may yet impede a deal, especially considering the strength of an alternative Russian offer.

Brian Cloughley, former Australian defense attache to Islamabad, believes the Russians may win.

“The FC-1/JF-17 is an excellent system, and Argentina could do worse than equip its Air Force accordingly, but the devil is in the detail, and given Russia’s concentration on expanding its trade and general economic cooperation with South American nations, it is likely that Moscow could offer a very good deal involving provision of Flankers.”

Nevertheless, Tufail does not think that purchasing Russian aircraft, such as members of the Flanker family, would be of much practical benefit to Argentina.

“Russian fighters would most certainly be unaffordable in large numbers and would merely be showpieces,” he said. “Also going in favor of the FC-1/JF-17 is the demonstrated operational status with an important air force like the [Pakistani Air Force].

“A BVR weapons fit would be an irresistible icing on the package,” he added, referencing the SD-10A beyond-visual-range air-to-air missile currently arming Pakistani JF-17s.

Given the efforts the British have put into denying Argentina advanced aircraft, Cloughley, who started his military career in the British Army, said Britain’s diplomatic efforts to deny Argentina the chance to modernize its airpower may have backfired by pushing it into the arms of China and Russia.

He said the British may now be more worried at the threat to their military supremacy.

“It is little wonder the British are worried, because, given the savage defense cuts of all governments that have reduced the armed forces to near impotence, the Argentineans could probably take over the Falklands if they had some more modern equipment,” he said. “In practical terms, the numbers of Argentinean aircraft would not matter a great deal, because the British couldn’t get there to defend the islands, anyway.” ■

Email: jhiguera@defensenews.com; uansari@defensenews.com.
 
jhWNl9N.jpg



Today at IDEAS 2014, Pakistan's, Air Chief Marshal Tahir Rafique Butt NI(M) has said Nigeria and South Africa are taking interest in Pakistani JF-17 Thunder fighter aircraft, while Pakistan's training aircraft Mushaq is being used by Saudi Arab, Amman, Qatar, and Pakistan is now exploring Iraq.
 
not suggesting any changes to an already exiting and finalized design.. just thinking if it was done right at the start. but as mentioned by other members, the bigger wings might not always work out well as in the case of F2 (super falcon)

F-2 type enlargement with AL-31FN TVC engine and better avionics will enhance PAF's capabilities.
 
jhWNl9N.jpg



Today at IDEAS 2014, Pakistan's, Air Chief Marshal Tahir Rafique Butt NI(M) has said Nigeria and South Africa are taking interest in Pakistani JF-17 Thunder fighter aircraft, while Pakistan's training aircraft Mushaq is being used by Saudi Arab, Amman, Qatar, and Pakistan is now exploring Iraq.

South Africa? A correction on this statement is due!
 
Last edited:
5 new block 2 - can't wait, 55 Thunders- that is 3 squadrons.
 
Status
Not open for further replies.
Back
Top Bottom