LCA Tejas vs JF-17 Thunder

[ersakthivel]

The F-16 was the first production fighter aircraft intentionally designed to be slightly aerodynamically unstable, also known as "relaxed static stability" (RSS), to improve maneuverability. Most aircraft are designed with positive static stability, which induces aircraft to return to straight and level flight attitude if the pilot releases the controls. This reduces maneuverability as the aircraft must overcome its inherent stability in order to maneuver. Aircraft with negative stability are designed to deviate from controlled flight and thus be more maneuverable. At supersonic speeds the F-16 gains stability (eventually positive) due to changes in aerodynamic forces.


To counter the tendency to depart from controlled flight—and avoid the need for constant trim inputs by the pilot, the F-16 has a quadruplex (four-channel) fly-by-wire (FBW) flight control system (FLCS). The flight control computer (FLCC) accepts pilot input from the stick and rudder controls, and manipulates the control surfaces in such a way as to produce the desired result without inducing control loss. The FLCC conducts thousands of measurements per second on the aircraft's flight attitude to automatically counter deviations from the pilot-set flight path; leading to a common aphorism among pilots: "You don't fly an F-16; it flies you."

The FLCC further incorporates limiters that govern movement in the three main axes based on current attitude, airspeed and angle of attack (AOA), and prevent control surfaces from inducing instability such as slips or skids, or a high AOA inducing a stall. The limiters also prevent maneuvers that would exert more than a 9 g load.

Although each axis of movement is limited by the FLCC, flight testing revealed that "assaulting" multiple limiters at high AOA and low speed can result in an AOA far exceeding the 25° limit; colloquially referred to as "departing". This causes a deep stall; a near-freefall at 50° to 60° AOA, either upright or inverted. While at a very high AOA, the aircraft's attitude is stable but control surfaces are ineffective and the aircraft's pitch limiter locks the stabilators at an extreme pitch-up or pitch-down attempting to recover; the pitch-limiting can be overridden so the pilot can "rock" the nose via pitch control to recover.

Unlike the YF-17, which had hydromechanical controls serving as a backup to the FBW, Grumman took the innovative step of eliminating mechanical linkages between the stick and rudder pedals and the aerodynamic control surfaces. The F-16 is entirely reliant on its electrical systems to relay flight commands, instead of traditional mechanically-linked controls, leading to the early moniker of "the electric jet". The quadruplex design permits "graceful degradation" in flight control response in that the loss of one channel renders the FLCS a "triplex" system.

The FLCC began as an analog system on the A/B variants, but has been supplanted by a digital computer system beginning with the F-16C/D Block .

So this is what the fly by wire system is all about and it is not there in jf-17.Why are you talking about J-10?

http://weapons.technology.youngester.com/2011/12/top-modern-fighter-planes-2011.html

The F-15's superior maneuverability and acceleration are achieved through high engine thrust-to-weight ratio and low wing loading. Low wing-loading (the ratio of aircraft weight to its wing area) is a vital factor in maneuverability and, combined with the high thrust-to-weight ratio, enables the aircraft to turn tightly without losing airspeed.

The advantages of an intentionally unstable design over that of a stable arrangement include greater agility – particularly at subsonic speeds - reduced drag, and an overall increase in lift (also enhancing STOL performance).

So low wing loading and high TWR are potent as a combination in a FBW controlled relaxed static stability fighter ,regardless of whether the plane is twin engined or single engined.

Fact is from 2001 the prototypes that flew were of fully relaxed stability unstable configuration for tejas.Not so for the JF-17.FBW in one axis is not relaxed static stability.Relaxed stability means plane always attempting to depart from level flight,meaning more maneuverability, It cannot be built into next block or as an add on later.

The airframe must be developed right from the begining for this purpose.We are not discussing J-10 in this thread i suppose.
SO i wont discuss further about rafale vs typhoon as you seem to be fixated on the idea that it is a political deal and not technical.

 

[farhan_9909]

JFT.

Some sources state that the system has been upgraded to provide fly-by-wire flight control in the roll and yaw axis also, the serial production aircraft having a digital quadruplex (quad-redundant) FBW system in the pitch axis and duplex (dual-redundant) FBW system in the roll and yaw axis

s it that hard to understand?

JFT is all fbw except in throttle.

mentioned J-10 because both has same FBW system

 

[farhan_9909]

]JF-17 has Type 634 quadruplex digital Fly-By-Wire (FBW) for pitch axis and duplex analog FBW in roll axis. The maximum G and maximum Angle-of-Attack (AOA) values are set at limited values for different levels of flight. During a deep stall, JF-17's computer compares values of pitch, Angle-of-Attack, speed and attitude with default values of normal stall. Based on its instincts it decides to recover automatically.

JF-17 Thunder's Avionics - PAFwallpapers Blog

both JFT,J-10 use type 634 quadruplex digital fbw

JFT is full fbw except in throttle(again only in pitch) the production variant has been upgraded to provide full digital fbw in roll and yaw axis as well

f-16c/d,f-18 all uses the same

 

[farhan_9909]

Fact is from 2001 the prototypes that flew were of fully relaxed stability unstable configuration for tejas.Not so for the JF-17.FBW in one axis is not relaxed static stability.Relaxed stability means plane always attempting to depart from level flight,meaning more maneuverability, It cannot be built into next block or as an add on later.

JFT saw major redesigning from pt-03 to pt04/pt06.

beside this i quoted that from JFT official site.

 

[farhan_9909]

Fact is from 2001 the prototypes that flew were of fully relaxed stability unstable configuration for tejas.Not so for the JF-17.FBW in one axis is not relaxed static stability.Relaxed stability means plane always attempting to depart from level flight,meaning more maneuverability, It cannot be built into next block or as an add on later.

JFT saw major redesigning from pt-03 to pt04/pt06.

beside this i quoted that from JFT official site

Note:Full FBW was planned.extract from 2005..

so this is nt that yesterday we integrated full digital quadruplex FBW..bt since the prototypes stages

 

[Agnostic Muslim]

I will be the first to admit that modern air-combat tactics are not a strength of mine - that said, everything that I have read indicates that most modern air-combat will not be close range 'dog fights' where aircraft maneuverability would offer an advantage, but that most engagements will be through AAM's and almost every modern AAM can outmaneuver the most maneuverable manned fighter jets available.

Aircraft maneuverability is also limited by the physical limitations of the human body (the pilot).

 

[farhan_9909]

So the +point of LCA with FBW is over

you may nt agree.may be i am nt even full correct.
bt these are the following because of them they are better over each other

LCA:
*Better radar than JFT block 1(Notenly block-1)
*1 additional hardpoint for pods

JF-17
*much better payload
*better speed
*maneuveribility beyond the level of LCA mk1
*Already operational Operational
*More in number
*less cost
*Weapon package is very diverse
*a cropped delta design like F-16 might be one of the reason of ultra maneuveribility
*better ceiling
*better range
*DSI(Less rcs)
*RAM coating(courtesy Najam book about JFT)
*Block 2 within few months
*block 3 with major redesigning and ws-13B(121kn engine) to be mass produced even before the entry of LCA mk2(2017-18)
*Already won export order and growing
*twin ventral fins
*Lerx(for better AOA)
*Anti-ship role operational with yj83 and cm-400akg
*Sead role operational with brazil mar-1
*SOM role with C-802AKG
*BVR with sd-10A(in future sd-10B)
*LS-6 operational
*Present engine generate upto 85-86kn thrust
*A much better twr
*1000000 times better Cockpit comparable with any 4th/4.5th gen fighter

and what not

 

[farhan_9909]

JF-17 cockpit explained(courtesy najam sahab)

 

[Patriot]

So the +point of LCA with FBW is over

you may nt agree.may be i am nt even full correct.
bt these are the following because of them they are better over each other

LCA:
*Better radar than JFT block 1(Notenly block-1)
*1 additional hardpoint for pods

JF-17
*much better payload
*better speed
*maneuveribility beyond the level of LCA mk1
*Already operational Operational
*More in number
*less cost
*Weapon package is very diverse
*a cropped delta design like F-16 might be one of the reason of ultra maneuveribility
*better ceiling
*better range
*DSI(Less rcs)
*RAM coating(courtesy Najam book about JFT)
*Block 2 within few months
*block 3 with major redesigning and ws-13B(121kn engine) to be mass produced even before the entry of LCA mk2(2017-18)
*Already won export order and growing
*twin ventral fins
*Lerx(for better AOA)
*Anti-ship role operational with yj83 and cm-400akg
*Sead role operational with brazil mar-1
*SOM role with C-802AKG
*BVR with sd-10A(in future sd-10B)
*LS-6 operational
*Present engine generate upto 85-86kn thrust
*A much better twr
*1000000 times better Cockpit comparable with any 4th/4.5th gen fighter

and what not

Specs are gr8 farhan, Thanks for your effort. can you provide bit more light on stealth part of the JF-17 as how the stealth incorporated in the design of JF-17 & is going to help in achieving the stealth. Thanks in advance.

 

[farhan_9909]

@Patriot
My knowledge about this is very limited.
so far in PAF JFT has the least RCS(even less than the block 52 f-16)

JFT uses RAM coating in many parts of the airframe(RAM was exclusively developed by PEC and NESCOM for Babur cruise missile)

e.g

The area along the side of fuselage is coated with Radar Absorbing Material (RAM), which decreases the radar signature of the aircraft. JF-17 is one of the fewest aircraft with smaller visual/IR and radar signature.

JF-17 Thunder's Aerodynamic Configuration - PAFwallpapers Blog

Beside this

JF-17 USES DSI which significantly reduces the RCS such as on F-35
apart from this is the small size of JFT

Diverterless supersonic inlet - Wikipedia, the free encyclopedia

with the increase use of composites in block 2(30-35%) and the serial produced block 1(8-15%) the rcs might even decrease

 

[sayareakd]

"Others aim to use the JF-17 to replace their second-and third-generation fighters, says Khalid, adding that the JF-17's capabilities put it between third and fourth generations."

pakistan's JF-17 'Thunder' Aircraft More Primitive Than Any Fourth-Generation Fighter, Admits Its Project Director - AA Me, IN

so it is either 3.25 or 3.5g

Air Commodore Khalid Mahmood, Deputy Chief Project Director for pakistan's JF-17 [FC-1] induction programme, was quoted on this at the recently held Zhuhai Air Show in China.

pakistan's JF-17 'Thunder' Aircraft More Primitive Than Any Fourth-Generation Fighter, Admits Its Project Director - AA Me, IN

 

[LETHALFORCE]

@sayareakd

when I said JF-17 was at best a 3rd generation plane with 30 year old technology
many Indians started arguining that it was 4th gen, now the Director of the program
even says the same.

 

[Sam2012]

Doesn't matter which on is 3rd generation or 4th generation , only head to head battle can determine who is winner . Like Mig-21 vs starfigher . Mig-21 was clearly on top in 1971

 

[Sam2012]

For PAK JF-17 is best for India LCA is best this will never end , but the one on one dog fight will determine who is best

 

[gokussj9]

Doesn't matter which on is 3rd generation or 4th generation , only head to head battle can determine who is winner . Like Mig-21 vs starfigher . Mig-21 was clearly on top in 1971

A JF 17 with Zahil Hamid as pilot is impossible to defeat. Imagine before the enemy's BVR hits JF 17 and Zaid Hamid ejects and grabs the enemy jet with a suicide
bomb on his body, and desperate to get his 72. Can anybody match that Huh?

 

[SpArK]

For PAK JF-17 is best for India LCA is best this will never end , but the one on one dog fight will determine who is best

Its like asking a Maruti 800 to go one on one with BMW. Technically superior ones always have a upper hand.

The dog fight argument doesnt work any more.If so lets compare F-22 with Mig-21.

 

[sayareakd]

Its like asking a Maruti 800 to go one on one with BMW. Technically superior ones always have a upper hand.

The dog fight argument doesnt work any more.If so lets compare F-22 with Mig-21.

PAF pilot can win with any fighter on Goat, remember it is not the machine that matter, it is pilot that matter, even on Goat.

 

[farhan_9909]

one liners should rather contriibute to the thread or just read and leave

 

[gokussj9]

PAF pilot can win with any fighter on Goat, remember it is not the machine that matter, it is pilot that matter, even on Goat.

In a new kind of warfare from Bakistan, all the hard points in JF 17 will be filled with suicide bombers in whose veins gunpowder is running,
and they will be shot over Indian territory marking the beginning of Bhadwa-e-Hind.

 

[farhan_9909]

JF-17 is indeed a third generation fighter as per pakistan/chinese terminology of fighter aircraft generation

even the PAC site official term it as 3rd generation.nothing wrong about this

bt here

3rdgen=4th gen