JF-17 Thunder Multirole Fighter [Thread 4]

[Alfa-Fighter]

F-16 and JFT both are unstable designs thats why they have fBW to stabilize them in flight. You cannot have a fbw in an already stable design because it will become useless since the role of fbw is to convert the negative stability into positive. Without a fbw, both F-16 and JFT have a nose down tendency and will eventually crash.

Its flight control includes a Type 634 quadruplex digital FBW in pitch axis and a duplex analog FBW in roll axis.

Chinese Military Aviation: Fighters II

Analog ???? in age of digital things, it has analog?

 

[Bratva]

Analog ???? in age of digital things, it has analog?

An example, MKI crashed last year due to complete failure of Digital FBW . JF-17 has a analouge FBW so in case of Digital FBW failure, Plane have better chance of survivability

 

[Manticore]

canards are not installed with stability in mind but give extra maneuverability.

here you can see different fighters with canards but not all are unstable
http://www.defence.pk/forums/air-wa...aracteristics-canard-non-canard-fighters.html

Aerodynamic Characteristics

Perfection in airframe performance can give the pilot battle-winning edge, providing that airframe is part of the Eurofighter Typhoon Weapon System.

Eurofighter Typhoon has a foreplane/delta configuration which is, by nature, aerodynamically unstable.

The instability of the aircraft is derived from the position of a theoretical “pressure point” on the longitudinal axis of the aircraft. This is calculated from the contribution to lift from each of the aircraft components (the wings, the canards, fuselage etc). If the pressure point is in front of the centre of gravity on the longitudinal axis, the aircraft is aerodynamically unstable and it is impossible for a human to control it.

With the Eurofighter Typhoon, in subsonic flight the pressure point lies in front of the centre of gravity, therefore making the aircraft aerodynamically unstable, and is why Eurofighter Typhoon has such a complex Flight Control System – computers react quicker than a pilot.

When Eurofighter Typhoon crosses into supersonic flight, the pressure point moves behind the centre of gravity, giving a stable aircraft.

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).

Source: http://www.defence.pk/forums/air-wa...canard-non-canard-fighters.html#ixzz2KzTMOFv6

 

[Alfa-Fighter]

An example, MKI crashed last year due to complete failure of Digital FBW . JF-17 has a analouge FBW so in case of Digital FBW failure, Plane have better chance of survivability

If you not read/know correctly, MKI crashed because pilot switched off the FBW.

Well Digital FBW is for Pitch Axis and and Analogue for Roll Axis, anyone if get not working cant overtake other rolls.

Please get you knowledge updated.

 

[BlueDot_in_Space]

An example, MKI crashed last year due to complete failure of Digital FBW . JF-17 has a analouge FBW so in case of Digital FBW failure, Plane have better chance of survivability

Analouge is for yaw and roll control, and Digital is for pitch control. If Digital fails, JF17 cannot be controlled in pitch. MKI failure was due to inadvertent shut down of FBW by the Pilot. Russian provide a switch in the cockpit to shut down FBW, crazy.

 

[Agnostic_Indian]

Analouge is for yaw and roll control, and Digital is for pitch control. If Digital fails, JF17 cannot be controlled in pitch. MKI failure was due to inadvertent shut down of FBW by the Pilot. Russian provide a switch in the cockpit to shut down FBW, crazy.

Russian philosophy is that a FBW System makes a average pilot a better one but it also makes a very good pilot to average one.

 

[farhan_9909]

Analog ???? in age of digital things, it has analog?

Onwards PT-04 the FBW was upgraded

 

[Agnostic_Indian]

Onwards PT-04 the FBW was upgraded

upgraded to digital one ?

 

[farhan_9909]

upgraded to digital one ?

Sources: Pakdef & Zafar Iqbal's Report (Some Text also taken from this report)
JF-17 has quadruplex, digital, fly-by-wire flight control system and two hydraulic systems for backup

JF-17 Avionics | JF-17 Thunder

yes later done

Fighter aircraft with Quadruplex FBW=JFT,j-10,EFT,F-16,F-18,SU 35

 

[Irfan Baloch]

here you can see different fighters with canards but not all are unstable
http://www.defence.pk/forums/air-wa...aracteristics-canard-non-canard-fighters.html

reverse fatwa?

F-16 and Typhoon are both unstable yet only one has canards

 

[BlueDot_in_Space]

Sources: Pakdef & Zafar Iqbal's Report (Some Text also taken from this report)
JF-17 has quadruplex, digital, fly-by-wire flight control system and two hydraulic systems for backup

This sounds strange as hydraulic system cannot be a backup for FBW as only a computer can make an unstable plane fly. That is why FBW systems use redundancy.

 

[farhan_9909]

This sounds strange as hydraulic system cannot be a backup for FBW as only a computer can make an unstable plane fly. That is why FBW systems use redundancy.

from wiki..with slight bit of more explanation

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.[49]

 

[hatf IX]

BTW i am too a vegitarian or one can say more SHAKAHARI & less MANSAHARI, i didn't mean to insult Vegi-eater but ... you know.
Well I dont think that JF-17 is an Unstable design, may be @ANTIBODY could comment. as far as i know canarad designs like Euror canard, J-10 etc are unstable designs. F-16, F-18, JF-17, F-35, F-22 are examples of stable design. Well i could be wrong though.

My man, F-16 is the very very first example of unstable design and have fly by wire, very first one again

from viki

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.[51] 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

http://en.wikipedia.org/wiki/General_Dynamics_F-16_Fighting_Falcon

 

[Manticore]

Ive highlighted some aspects in my 2 posts on page 635

 

[BlueDot_in_Space]

F-16 and JFT both are unstable designs thats why they have fBW to stabilize them in flight. You cannot have a fbw in an already stable design because it will become useless since the role of fbw is to convert the negative stability into positive. Without a fbw, both F-16 and JFT have a nose down tendency and will eventually crash.

Its flight control includes a Type 634 quadruplex digital FBW in pitch axis and a duplex analog FBW in roll axis.

Chinese Military Aviation: Fighters II

Actually FBW is not used only for augmenting stability in military planes. Boeing (777) and Airbus (320) use FBW.