JF-17 Thunder Multirole Fighter [Thread 4]

[BATMAN]

Picture is from distance.. why not a targeting pod?

 

[Dazzler]

stress testing....

 

[Safriz]

stress testing....

the chick on the left is better looking (sorry coudlnt resist )

 

[SQ8]

For a Layman like myself :

(i) What significance does that have ?

(ii) Is that because of F-16's better T/W ratio ?

(iii) Is that a weakness & its ensuing threat, we're looking into to cover ?

1.Modern Air combat is not done in one plane, It is fought both vertically and horizontally.
2.Yes
3. It is a weakness as such but for now the PAF seems to be tied with funds and is contending with the RD-93.

 

[SQ8]

The superior T:W ratio also comes in handy in all maneuvers, not just climbing ones. Recall that the rate of change of velocity is acceleration, and thrust throughout a accelerative maneuver can improve its sustainability.

Thrust to weight is not a good indicator of energy loss during turning fights. (Thrust : drag) to weight is a better indicator.
So is the JF-17 more draggy as compared to the F-16?.. and hence will that ratio effect it's performance is what matters.

 

[Argus Panoptes]

Thrust to weight is not a good indicator of energy loss during turning fights. (Thrust : drag) to weight is a better indicator.
So is the JF-17 more draggy as compared to the F-16?.. and hence will that ratio effect it's performance is what matters.

Great point Sir. Weight and drag are force vectors of a particular direction, as is thrust. Thrust helps maintain changes in velocity, otherwise known as acceleration. I do not know of any detailed comparison of drag changes between the JF-17 and F-16 during maneuvers, but looking at flights displays it is evident that the F-16 can use its superior thrust to counter weight as well as drag to its advantage. I would suggest that while the JF-17 does come close in instantaneous turn rates, sustained rates would favor the F-16.

Having said that, such comparisons of such parameters are not the end of the discussion. The JF-17 does what it does admirably well, at an unbeatable price point.

 

[SQ8]

Great point Sir. Weight and drag are force vectors of a particular direction, as is thrust. Thrust helps maintain changes in velocity, otherwise known as acceleration. I do not know of any detailed comparison of drag changes between the JF-17 and F-16 during maneuvers, but looking at flights displays it is evident that the F-16 can use its superior thrust to counter weight as well as drag to its advantage. I would suggest that while the JF-17 does come close in instantaneous turn rates, sustained rates would favor the F-16.

Having said that, such comparisons of such parameters are not the end of the discussion. The JF-17 does what it does admirably well, at an unbeatable price point.

Unfortunately, this is the bane and boon of the aircraft.
Because the price has to be kept down; A lot of improvements or additions cannot be made to the airframe as that drives up costs.

The T/W ratio is also a little misnomer, The T/W ratio is usually calculated on the basis of an engines testbed thrust.. i.e thrust on the ground.. where the engine as all the air it needs.
Inside an aircraft, due to the intakes and other parameters.. engines do not actually develop as much thrust as they advertise.

 

[Argus Panoptes]

Unfortunately, this is the bane and boon of the aircraft.
Because the price has to be kept down; A lot of improvements or additions cannot be made to the airframe as that drives up costs.

The T/W ratio is also a little misnomer, The T/W ratio is usually calculated on the basis of an engines testbed thrust.. i.e thrust on the ground.. where the engine as all the air it needs.
Inside an aircraft, due to the intakes and other parameters.. engines do not actually develop as much thrust as they advertise.

All aircraft are particular sets of compromises. The JF-17's compromises are the ones that work out very well for PAF, and that is all that matters.

 

[Kompromat]

 

[Manticore]

delta fighters like mirage have higher drag and they particularly need an engine with greater thrust to take care of this bleeding energy

there is an interview of a chinese pilot I posted in the info pool where it explains the horizontal and vertical acceleration of jf17 and the use of lerx to achieve better AoA and dog fighting abilities particularly at sub sonic speeds

There is a stuck thread in the air warfare section regarding flight characteristics

 

[Capt.Popeye]

the chick on the left is better looking (sorry coudlnt resist )

Ah; so you could'nt resist the "Stress"?
But you're right, she is. And less stressed.

 

[Jango]

(which are still largely sheet metal and not that strong.. a honeycomb structure would have been better..but more expensive)

Well that's interesting...could you specify a bit more that till where the sheet metal runs to...and where the honeycomb starts.

 

[SQ8]

Well that's interesting...could you specify a bit more that till where the sheet metal runs to...and where the honeycomb starts.

That would be unlikely. The sheet metal information I know of because I asked the very same question about the pod to the relevant person.

 

[gambit]

...quad+ dual redundant FCS (blk -15s have single analog fly by wire FCS),...

Folks,

Let us be clear about this...

All fly-by-wire flight control system, henceforth shortened as FBW-FLCS, are quadruplex, regardless of analog or digital.

If an axis (pitch, roll, yaw) is FBW-FLCS, then that axis is quadruplex, analog or digital. If all three axes are FBW-FLCS, then each axis is quadruplex. There is no getting around this architecture if you want a reliable axis.

Quadruplex means four signals/inputs/outputs. A source can be single, like the pitot-static tube on the radome tip, but then those air data inputs will be split into four somewhere in the system. Four pitot and four static. Usually it is a simple manifold.

Another single source is the pilot control stick. The single stick have four positional transducers and each signal will be routed to the flight control computer (FLCC).

Another single source is the rudder pedal assembly with the same architecture of four positional transducers feeding the FLCC.

The intention is to use three signals for voting purposes. If one of the three is out of some arbitrary tolerance, then the standing by 4th is enlisted. If two out of three are out of tolerance at any time, then the system will flag a sort of 'red alert' and pretty much the flight, or scheduled flight, should be aborted.

Each ELECTRICAL signal will be physically routed through different areas of the aircraft. This is to prevent a single area mishap, such as combat, that could destroy the entire system. If such a combat damage result in only two or even one from the four, the system is programmed to have defaulted values but would have severely degraded flight maneuverability and in combat, such degradation might as well trigger an ejection by the pilot.

Now...It is said that the J-17 have pitch FBW-FLCS only while roll and yaw axes are conventional mechanical-hydraulics. That means there are four distinct electrical signals for pitch running through the aircraft. Analog or digital -- same.

It is the hydraulics that is dual redundant: Primary and Utility.

Primary is for flight controls, landing gear, speed brakes, and wheel brakes. Utility is for air refueling probe, electrical generator, and anything of similarly not crucial for flight and flight stability. Either system can power the aircraft by itself but would have degraded performance.

 

[Armstrong]

@gambit : I've no effing idea what you just said !

Can you please explain the gist of your post in a mere 3-4 lines in the King's English !