JF-17/FC-1 Fighter Aircraft thread
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szbd
Junior Member
Re: New JF-17/FC-1 thread
LERX is "Leading Edge Root Extension". It's in the shape similar with a narrow triangle starts from the root of a wing, extends to under the cockpit. From the above picture, you can see a LERX starts from the white belt (that is the moon in Pakistan national flag) to the mouth of inlet.
LERX is "Leading Edge Root Extension". It's in the shape similar with a narrow triangle starts from the root of a wing, extends to under the cockpit. From the above picture, you can see a LERX starts from the white belt (that is the moon in Pakistan national flag) to the mouth of inlet.
Indianfighter
Junior Member
Re: New JF-17/FC-1 thread
The photos of JF-17 are very good. The inlets seen from the front look different from other fighter aircrafts. I think that this aircraft will be an important player in South-Asian skies for many decades to come.
The photos of JF-17 are very good. The inlets seen from the front look different from other fighter aircrafts. I think that this aircraft will be an important player in South-Asian skies for many decades to come.
Re: New JF-17/FC-1 thread
Dear Sirs:
I don't know about you, but what really surprised me in the new pics was the presence of a series of fine holes on the DSI inlet structure (on a detachable panel -which includes the DSI-bump) and on the inlet cowling itself.
I for one didn't expect this. I was aware that traditional supersonic inlets have such holes, especially on the splitter plate. The function of course was to remove the turbulent boundary layer, and assure laminar inlet flow.
Apparently the DSI needs this function too. Hmm... very interesting.
Best Regards,
Dusky Lim
Dear Sirs:
I don't know about you, but what really surprised me in the new pics was the presence of a series of fine holes on the DSI inlet structure (on a detachable panel -which includes the DSI-bump) and on the inlet cowling itself.
I for one didn't expect this. I was aware that traditional supersonic inlets have such holes, especially on the splitter plate. The function of course was to remove the turbulent boundary layer, and assure laminar inlet flow.
Apparently the DSI needs this function too. Hmm... very interesting.
Best Regards,
Dusky Lim
Re: New JF-17/FC-1 thread
That's not turbulence management. The most modern FBW systems in the world are in airliners and it does not stop them from facing turbulence.
There are configurations that can give a smooth ride even against turbulent conditions, and you don't need an FBW for that. A low aspect wing llike a delta or fully swept variable wing does this very well.
Deltas do not increase wing area per se, especially if you are reducing wing span in order to get the sweep and triangular shape. What you are trying to explain is to increase wing area by increasing the wing root. But you can also do this with sweep wing and you only move the wing tip past and behind the line of the wing root. For example, the Su-27 and the MiG-29. Does not matter if its a sweep (wing point past the end of the wing root), delta (wing tip point perpendicular to the end of the wing root), trapezoidal or diamond (wing tip point ahead of the end of the wing root).
And you don't reduce drag by increasing wing area. You increase drag with increasing wing area, because every square inch of additional surface you put into the wing and plane adds drag. That is a fundamental principle.
Deltas reduce drag by wing sweep, by design does not really increase wing area vs. other alternatives. Check the F-22 and F-23 layouts.
Here is another example. The F-14. It changes its wing from a straight wing to what is practically a delta when fully swept. But does the total wing area change? No. It stays the same. As a matter of fact, when the wings are unswept it gets maximum lift performance at low speeds.
In the case of the double delta, reducing the sweep on the outer edge helps in low speed, but so is the increase of wing span and wing aspect. This was done on the Su-15 and the J-7E.
The shorter fulcrum movement means the torque applied on the lever is closer to the fulcrum center, and this requires a greater force than if the torque is applied farther from the center. This is a simple understanding of the lever principle. The more authority is required, the greater the angle of attack on the control surfaces and the greater drag insues. it also means you are spending more of your elevon's angle of attack to induce this much torque, and for a plane to induce a high AoA maneuver, you would have used up your allocation and won't have sufficient authority for high AoA as opposed to a canarded or tailed configuration. Of course you can improve the pitch torque on the other end, by adding variable camber in the front of the wings help as well as vortice generation on the LERX, but the same may also applied on tailed and canarded aircraft (canards generate vortices), so the latter two will do high AoA even better.
Commercial airliners are not high sweep wings. If you want an aerofoil characteristic, you would need a high aspect, high wingspan design, like commercial airliners or straight winged aircraft. Or a flying wing. Check the gliders. You only need to see the example of nature with birds like the albatross and seagulls. Deltas like low aspect wings are simply not lift efficient for low speeds.
Fighters are generally low aspect or square because they are targeting lift and drag efficiency at higher speeds. In addition low aspect reduce flight stability so they can roll and turn faster. The advantage of delta is never about increasing wing area---you only need to read books on the genesis of such fighters like the Mirage III and the Delta Dagger---but to improve on speed especially to attain supersonic flight for the least thrust involved. Sweep does this. By increasing the wing root, you also strengthen the aircraft wings and structure, The larger wing root and wing also means you can house more fuel within.
Sorry for going off topic.
We were seriously discussing the same thing on the JF-17 thread in the CDF. The bumps apparently work like golf ball bumps intended to smooth out the boundary layer and reduce turbulence and drag.
The new pics are very sharp and show the plane in quite detail. The workmanship placed on these two planes are superior even to what we have seen on the mass production J-10s, so obviously CAC placed a lot of effort to make that impression. It is up to the future if we can see this level of quality sustained in the mass production run.
That's not turbulence management. The most modern FBW systems in the world are in airliners and it does not stop them from facing turbulence.
There are configurations that can give a smooth ride even against turbulent conditions, and you don't need an FBW for that. A low aspect wing llike a delta or fully swept variable wing does this very well.
Deltas do not increase wing area per se, especially if you are reducing wing span in order to get the sweep and triangular shape. What you are trying to explain is to increase wing area by increasing the wing root. But you can also do this with sweep wing and you only move the wing tip past and behind the line of the wing root. For example, the Su-27 and the MiG-29. Does not matter if its a sweep (wing point past the end of the wing root), delta (wing tip point perpendicular to the end of the wing root), trapezoidal or diamond (wing tip point ahead of the end of the wing root).
And you don't reduce drag by increasing wing area. You increase drag with increasing wing area, because every square inch of additional surface you put into the wing and plane adds drag. That is a fundamental principle.
Deltas reduce drag by wing sweep, by design does not really increase wing area vs. other alternatives. Check the F-22 and F-23 layouts.
Here is another example. The F-14. It changes its wing from a straight wing to what is practically a delta when fully swept. But does the total wing area change? No. It stays the same. As a matter of fact, when the wings are unswept it gets maximum lift performance at low speeds.
In the case of the double delta, reducing the sweep on the outer edge helps in low speed, but so is the increase of wing span and wing aspect. This was done on the Su-15 and the J-7E.
The shorter fulcrum movement means the torque applied on the lever is closer to the fulcrum center, and this requires a greater force than if the torque is applied farther from the center. This is a simple understanding of the lever principle. The more authority is required, the greater the angle of attack on the control surfaces and the greater drag insues. it also means you are spending more of your elevon's angle of attack to induce this much torque, and for a plane to induce a high AoA maneuver, you would have used up your allocation and won't have sufficient authority for high AoA as opposed to a canarded or tailed configuration. Of course you can improve the pitch torque on the other end, by adding variable camber in the front of the wings help as well as vortice generation on the LERX, but the same may also applied on tailed and canarded aircraft (canards generate vortices), so the latter two will do high AoA even better.
Commercial airliners are not high sweep wings. If you want an aerofoil characteristic, you would need a high aspect, high wingspan design, like commercial airliners or straight winged aircraft. Or a flying wing. Check the gliders. You only need to see the example of nature with birds like the albatross and seagulls. Deltas like low aspect wings are simply not lift efficient for low speeds.
Fighters are generally low aspect or square because they are targeting lift and drag efficiency at higher speeds. In addition low aspect reduce flight stability so they can roll and turn faster. The advantage of delta is never about increasing wing area---you only need to read books on the genesis of such fighters like the Mirage III and the Delta Dagger---but to improve on speed especially to attain supersonic flight for the least thrust involved. Sweep does this. By increasing the wing root, you also strengthen the aircraft wings and structure, The larger wing root and wing also means you can house more fuel within.
Sorry for going off topic.
We were seriously discussing the same thing on the JF-17 thread in the CDF. The bumps apparently work like golf ball bumps intended to smooth out the boundary layer and reduce turbulence and drag.
The new pics are very sharp and show the plane in quite detail. The workmanship placed on these two planes are superior even to what we have seen on the mass production J-10s, so obviously CAC placed a lot of effort to make that impression. It is up to the future if we can see this level of quality sustained in the mass production run.
Last edited:
Re: New JF-17/FC-1 thread
I just saw this posted in AFM by google.
ANE'S DEFENCE WEEKLY - APRIL 04, 2007
________________________________________
Air Chief Marshal Tanvir Mahmood Ahmed: Pakistan's Chief of Air Staff
Farhan Bokhari JDW Correspondent
Islamabad
'We want an avionics package of our own choice on the J-10'
The Pakistan Air Force (PAF) is undergoing a transition, positioning itself to acquire some of the latest versions of the US-built F-16 multirole fighter aircraft while increasing its reliance on China as a key supplier of hardware through the induction of the JF-17 'Thunder' fighter and future plans to acquire the J-10 fighter aircraft. Pakistan's reliance on China reflects something of a fail-safe philosophy following Islamabad's experience of sanctions imposed on the country in the 1990s.
Against this background, PAF Chief of Air Staff Air Chief Marshal Tanvir Mahmood Ahmed aims to maintain his fighter fleet at a strength of 400 aircraft, including the induction of new aircraft from China and the US.
"We might end up buying another high-tech aircraft from the Chinese; the J-10 is something we're looking at along with the JF-17, which will in fact form the backbone of the Pakistan Air Force in the future," said ACM Ahmed. The PAF has received its first two JF-17s and these flew at the country's Resolution Day ceremony on 23 March in Islamabad. The service expects to receive a total of eight or nine JF-17s by the end of this year, although formal induction into the PAF will begin in just under two years. ACM Ahmed said the PAF had increased its initial target of buying 150 JF-17s to acquiring up to 250 aircraft. The future development of the JF-17 will allow Pakistan to induct its own choice of avionics and weapons already in stock.
"The shape of the JF-17 you see today is slightly different from the first prototype. We have added aerodynamic variations to make it more versatile and more manoeuvrable. We now hope that this particular shape will reflect the final configuration and we'll add the other capabilities of the aircraft," said ACM Ahmed. The JF-17 programme has not been without controversy, mainly surrounding the status of the aircraft's Russian-built RD-93 engine. A number of reports during the past three years claimed that Russia had not approved the re-export of the RD-93 engines from China to a third country - in this case Pakistan. The arrival of the two JF-17s equipped with the RD-93 engines has, however, confirmed what Western analysts are beginning to understand: that the Russians may have given verbal agreement to the re-export without issuing formal licences. According to Western defence analysts, the transaction may have been conducted in this manner as Russia is reluctant to annoy India, with which it has had a long-term partnership in defence sales. India, the analysts argue, has quietly lobbied to block the engine sale as a way of disrupting supplies to Pakistan.
"Frankly, the engine issue is between the Russians and the Chinese. We haven't contracted with the Russians on this so the deal is between Russia and China and we have no issues related to this," said ACM Ahmed, adding that "there have been efforts to impede progress by creating some road blocks in this particular path, but I don't think they will work". For the moment, the ACM is content with plans to buy a mix of new F-16 Block 50/52 C/Ds (an initial 18 and an option for an additional 18) and some 26 older F-16A/B models, under an agreement with Washington that gives Pakistan the status of a non-NATO US ally. This effectively means that Pakistan can be supplied with excess defence equipment where there is no cost involved for the platform but Islamabad is required to pay for upgrades.
The acquisition of the F-16A/B models has recently been the subject of some controversy. While the US Air Force is willing to release 12 of its older F-16s, the US Navy has refused to release up to 14 aircraft designated for Pakistan. ACM Ahmed said this could change the number of used F-16s that Pakistan plans to purchase, but the plan to buy a mix of new and used F-16s remained on track. "I am quite hopeful that the US Air Force will be able to release the 12 aircraft but we are not sure of the US Navy - we are working with them but we are not sure if they will release those aircraft for us," he said. "If they don't, the US Air Force will probably look at other aircraft in their inventory. They have a large number of A/Bs which could be made available."
For the future, the PAF is positioning itself to buy up to two squadrons of Chinese J-10 fighters as it seeks to diversify its inventory of top-of-the-range aircraft. ACM Ahmed said negotiations for the purchase have begun, with the PAF outlining its preference for avionics and weapon systems. "We want an avionics package of our own choice on the J-10. The kind of weaponry and various other pods and electronic warfare suites [the aircraft will carry] is another area [under discussion]," he said.
Additionally, the PAF has been in negotiations with Beijing for the future purchase of Chinese-built airborne early warning (AEW) aircraft. While declining to specify which specific Chinese AEW is under consideration, ACM Ahmed noted: "We have tested and evaluated [the AEW aircraft] and [found it to be] fairly good, but there are areas where we definitely want improvement, both in the platform and radar."
I just saw this posted in AFM by google.
ANE'S DEFENCE WEEKLY - APRIL 04, 2007
________________________________________
Air Chief Marshal Tanvir Mahmood Ahmed: Pakistan's Chief of Air Staff
Farhan Bokhari JDW Correspondent
Islamabad
'We want an avionics package of our own choice on the J-10'
The Pakistan Air Force (PAF) is undergoing a transition, positioning itself to acquire some of the latest versions of the US-built F-16 multirole fighter aircraft while increasing its reliance on China as a key supplier of hardware through the induction of the JF-17 'Thunder' fighter and future plans to acquire the J-10 fighter aircraft. Pakistan's reliance on China reflects something of a fail-safe philosophy following Islamabad's experience of sanctions imposed on the country in the 1990s.
Against this background, PAF Chief of Air Staff Air Chief Marshal Tanvir Mahmood Ahmed aims to maintain his fighter fleet at a strength of 400 aircraft, including the induction of new aircraft from China and the US.
"We might end up buying another high-tech aircraft from the Chinese; the J-10 is something we're looking at along with the JF-17, which will in fact form the backbone of the Pakistan Air Force in the future," said ACM Ahmed. The PAF has received its first two JF-17s and these flew at the country's Resolution Day ceremony on 23 March in Islamabad. The service expects to receive a total of eight or nine JF-17s by the end of this year, although formal induction into the PAF will begin in just under two years. ACM Ahmed said the PAF had increased its initial target of buying 150 JF-17s to acquiring up to 250 aircraft. The future development of the JF-17 will allow Pakistan to induct its own choice of avionics and weapons already in stock.
"The shape of the JF-17 you see today is slightly different from the first prototype. We have added aerodynamic variations to make it more versatile and more manoeuvrable. We now hope that this particular shape will reflect the final configuration and we'll add the other capabilities of the aircraft," said ACM Ahmed. The JF-17 programme has not been without controversy, mainly surrounding the status of the aircraft's Russian-built RD-93 engine. A number of reports during the past three years claimed that Russia had not approved the re-export of the RD-93 engines from China to a third country - in this case Pakistan. The arrival of the two JF-17s equipped with the RD-93 engines has, however, confirmed what Western analysts are beginning to understand: that the Russians may have given verbal agreement to the re-export without issuing formal licences. According to Western defence analysts, the transaction may have been conducted in this manner as Russia is reluctant to annoy India, with which it has had a long-term partnership in defence sales. India, the analysts argue, has quietly lobbied to block the engine sale as a way of disrupting supplies to Pakistan.
"Frankly, the engine issue is between the Russians and the Chinese. We haven't contracted with the Russians on this so the deal is between Russia and China and we have no issues related to this," said ACM Ahmed, adding that "there have been efforts to impede progress by creating some road blocks in this particular path, but I don't think they will work". For the moment, the ACM is content with plans to buy a mix of new F-16 Block 50/52 C/Ds (an initial 18 and an option for an additional 18) and some 26 older F-16A/B models, under an agreement with Washington that gives Pakistan the status of a non-NATO US ally. This effectively means that Pakistan can be supplied with excess defence equipment where there is no cost involved for the platform but Islamabad is required to pay for upgrades.
The acquisition of the F-16A/B models has recently been the subject of some controversy. While the US Air Force is willing to release 12 of its older F-16s, the US Navy has refused to release up to 14 aircraft designated for Pakistan. ACM Ahmed said this could change the number of used F-16s that Pakistan plans to purchase, but the plan to buy a mix of new and used F-16s remained on track. "I am quite hopeful that the US Air Force will be able to release the 12 aircraft but we are not sure of the US Navy - we are working with them but we are not sure if they will release those aircraft for us," he said. "If they don't, the US Air Force will probably look at other aircraft in their inventory. They have a large number of A/Bs which could be made available."
For the future, the PAF is positioning itself to buy up to two squadrons of Chinese J-10 fighters as it seeks to diversify its inventory of top-of-the-range aircraft. ACM Ahmed said negotiations for the purchase have begun, with the PAF outlining its preference for avionics and weapon systems. "We want an avionics package of our own choice on the J-10. The kind of weaponry and various other pods and electronic warfare suites [the aircraft will carry] is another area [under discussion]," he said.
Additionally, the PAF has been in negotiations with Beijing for the future purchase of Chinese-built airborne early warning (AEW) aircraft. While declining to specify which specific Chinese AEW is under consideration, ACM Ahmed noted: "We have tested and evaluated [the AEW aircraft] and [found it to be] fairly good, but there are areas where we definitely want improvement, both in the platform and radar."
Indianfighter
Junior Member
Re: New JF-17/FC-1 thread
crobato by your excellent classification above, the Indian delta's wingtip is not 'perpendicular' to the fuselage but has a 5 degree angle. So this makes the wingtip past the end of the wingroot.
The F-14's wings are shoulder-mounted. Shoulders do not count in the addition of wing area (at least to what I gathered). The wings are affixed inside the shoulder slots, inside which are joints to sweep the wings back and forth.
The swept-wing does leave a wide gap between itself and the fuselage (from top-view it appears to be filled by the tail). But considering that it is assisted by the shoulders to extend outward of the fuselage, well a gap remains. This gap is cemented by a delta.......the next step after the swept wing.
The CG of all aicraft is quite in the centre and not close to the elevons. So I don't think AoA is wasted in short fulcrum moment. This would apply to tailed aircraft like JF-17 also.
Analysis of JF-17 : Tailed delta. Delta does not have much sweep, so the designers had maneuverability at lower speeds in mind. Wing-area is also good so induced-drag will be less, also lift will be assisted. LERXs will assist in lift generation and at low AoA; expect JF-17 to be quite maneuverable.
The resemblance to F-16 is unmistakable. Tailed delta, the shape of the tail are very similar. LERXs can give JF-17 an edge at higher AoA. The major difference is the intakes.
crobato by your excellent classification above, the Indian delta's wingtip is not 'perpendicular' to the fuselage but has a 5 degree angle. So this makes the wingtip past the end of the wingroot.
The F-14's wings are shoulder-mounted. Shoulders do not count in the addition of wing area (at least to what I gathered). The wings are affixed inside the shoulder slots, inside which are joints to sweep the wings back and forth.
The swept-wing does leave a wide gap between itself and the fuselage (from top-view it appears to be filled by the tail). But considering that it is assisted by the shoulders to extend outward of the fuselage, well a gap remains. This gap is cemented by a delta.......the next step after the swept wing.
The CG of all aicraft is quite in the centre and not close to the elevons. So I don't think AoA is wasted in short fulcrum moment. This would apply to tailed aircraft like JF-17 also.
Analysis of JF-17 : Tailed delta. Delta does not have much sweep, so the designers had maneuverability at lower speeds in mind. Wing-area is also good so induced-drag will be less, also lift will be assisted. LERXs will assist in lift generation and at low AoA; expect JF-17 to be quite maneuverable.
The resemblance to F-16 is unmistakable. Tailed delta, the shape of the tail are very similar. LERXs can give JF-17 an edge at higher AoA. The major difference is the intakes.
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Re: New JF-17/FC-1 thread
In the F-14, the shoulder area is considered a lifting area, especially its flat underneath. In fact, the whole body is considered a lifting area.
Its not the CG that I am referring but where in the plane's lever is the torque being applied. With a delta, that torque happens to be closer to the CG, and this means you need a greater effort to push it down to move the nose up. This is because of the elevons being in the main wing. On a tailed plane, the elevators are at the end of the aircraft and sometimes extend further back. The farther you can set the elevator on the back, the less effort you need to push the tail down to move the nose up. Hence greater pitch authority, and with that, greater controllability at high AoA. You can check the F-22 design and see what lengths it tries to put the elevators all the way back. This is one reason why tailless deltas have difficulty achieving sustained high AoA maneuvers, like the stuff Flankers can do. However sustained high AoA maneuvers should be regarded as optional desperation moves, and not something I would chase at. A delta should stick to its forte, which is high speed maneuvers. Keep turns fast and wide, avoid turning slow and tight.
Sounds pretty accurate and close to my own opinions. Note the JF-17 actually has a little more sweep on the wing than the F-16. The LERX is an outward one similar to the Hornet rather than the inward one used on the F-16. The Hornet style of LERX is intended to generate more lift in addition to vortices, while the inward style of LERX, which the Flanker also uses, is mainly intended to generate vortices.
In the F-14, the shoulder area is considered a lifting area, especially its flat underneath. In fact, the whole body is considered a lifting area.
Its not the CG that I am referring but where in the plane's lever is the torque being applied. With a delta, that torque happens to be closer to the CG, and this means you need a greater effort to push it down to move the nose up. This is because of the elevons being in the main wing. On a tailed plane, the elevators are at the end of the aircraft and sometimes extend further back. The farther you can set the elevator on the back, the less effort you need to push the tail down to move the nose up. Hence greater pitch authority, and with that, greater controllability at high AoA. You can check the F-22 design and see what lengths it tries to put the elevators all the way back. This is one reason why tailless deltas have difficulty achieving sustained high AoA maneuvers, like the stuff Flankers can do. However sustained high AoA maneuvers should be regarded as optional desperation moves, and not something I would chase at. A delta should stick to its forte, which is high speed maneuvers. Keep turns fast and wide, avoid turning slow and tight.
Sounds pretty accurate and close to my own opinions. Note the JF-17 actually has a little more sweep on the wing than the F-16. The LERX is an outward one similar to the Hornet rather than the inward one used on the F-16. The Hornet style of LERX is intended to generate more lift in addition to vortices, while the inward style of LERX, which the Flanker also uses, is mainly intended to generate vortices.
Zimbabwe ordered 12
Wanted to know if anybody heard of such a aircraft request before Zimbabwe ordered 12 FC1. Wanted to know if this was true or not? I thought Pakistan was the only customer, thanks
This part of the story I found and posted a link to the rest.
More recently, Robert Mugabe’s government in Zimbabwe ordered 12 FC1 fighter jets from China as well as 100 military vehicles in late 2004, China’s most advanced military aircraft order from an African nation that was worth $200 million.
According to the Commissioner of the U.S.-China Economic and Security Review Commission, this move enraged South Africa, with many political analysts fearing that such transfers could spark an arms race in southern Africa (testimony given before House of Representatives Committee on International Relations, July 28, 2005). Previously, it was widely reported that Chinese small arms were exchanged for eight tons of Zimbabwean elephant ivory in May 20
Full story
Wanted to know if anybody heard of such a aircraft request before Zimbabwe ordered 12 FC1. Wanted to know if this was true or not? I thought Pakistan was the only customer, thanks
This part of the story I found and posted a link to the rest.
More recently, Robert Mugabe’s government in Zimbabwe ordered 12 FC1 fighter jets from China as well as 100 military vehicles in late 2004, China’s most advanced military aircraft order from an African nation that was worth $200 million.
According to the Commissioner of the U.S.-China Economic and Security Review Commission, this move enraged South Africa, with many political analysts fearing that such transfers could spark an arms race in southern Africa (testimony given before House of Representatives Committee on International Relations, July 28, 2005). Previously, it was widely reported that Chinese small arms were exchanged for eight tons of Zimbabwean elephant ivory in May 20
Full story
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