JF-17 Thunder Multirole Fighter [Thread 7]

[Signalian]

advantages: Kids going crazy over the stunts performed by a jangi jahaz . Yaaaay

disadvantages : These gimmicks wont stop a bvr to tear it apart

can it lead to developing a STOVL aircraft?

 

[CriticalThought]

Mig 29 OVT uses thrust vectoring nozzles that could turn 15 degrees in any direction using RD 33 engines.

Can thrust vectoring be tried on a single engined JF 17 using RD 93 engine, what could be advantages or dis advantages

It's been tried on an experimental version of F-16.

In theory I want to see OVT on Thunder but I have been lazy and having done any computations.

The real equation of TVC involves a balance between weight, thrust and lift. TVC adds a lot of weight to the engine. If it isn't countered through aerodynamics and thrust, it becomes a liability.

Then, all those maneuvers you see based on TVC, requires a part of thrust to be diverted. This means the aircraft us falling like a stone, a deadly situation to have if enemy is on your tail. It gives you advantage of you are at enemy's six and want to adjust your nose.

It would be welcome if it comes as an upgrade to RD-93 IF the thrust to weight makes sense.

can it lead to developing a STOVL aircraft?

STOVL would require downward airflow at both front and aft. So no, TVC alone wouldn't be enough.

 

[Basel]

Mig 29 OVT uses thrust vectoring nozzles that could turn 15 degrees in any direction using RD 33 engines.

Can thrust vectoring be tried on a single engined JF 17 using RD 93 engine, what could be advantages or dis advantages

US have successfully tested TVC on single engine planes so it's possible.

 

[CriticalThought]

US have successfully tested TVC on single engine planes so it's possible.

Being possible doesn't necessarily make it sensible.

 

[Basel]

Being possible doesn't necessarily make it sensible.

It will be good for JFT because it may reduce take off and landing speed, improve AoA etc.

 

[CriticalThought]

It will be good for JFT because it may reduce take off and landing speed, improve AoA etc.

How?

 

[Basel]

How?

TVC allow better handling at low speed at low level so it also help in landing and takeoff too.

@gambit you opinion will be appreciated.

How?

http://www.icas.org/ICAS_ARCHIVE/ICAS2000/PAPERS/RESERVED/ICA0534.PDF

 

[Jungibaaz]

Mig 29 OVT uses thrust vectoring nozzles that could turn 15 degrees in any direction using RD 33 engines.

Can thrust vectoring be tried on a single engined JF 17 using RD 93 engine, what could be advantages or dis advantages

It improves maneuverability, allows an aircraft to tilt along its axis as its moving in any given direction. So higher AoA can be reached but the G limitation is still there no matter what, you can't overcome the limit due to structural limitations of an aircraft and human limitations. Vectored thrust in all cases except maybe the F-22 isn't as useful as advertised IMO. The supermaneuverability especially is overrated, with post-stall or near stall, if used in actual combat it would see the aircraft bleed a lot of energy with increased drag and the much touted cobra maneuver and its earlier variants are mostly airshow tricks, actually doing anything like that would leave an aircraft with no energy at all and the aircraft would need valuable time to recover and it's a sitting duck in the meantime.

There are other uses of vectored thrust but they're less obvious, one is that it can be used in place of using more control surfaces for stealth, it could possibly be used for more optimal flight by adjusting which way the thrust is directed, it might help in extending range and helpful at higher speeds (supersonic maneuverability) and higher altitudes, might also help with STOL capability:

A specific application of thrust vectoring is already being used to provide aircraft with Short Ta e-Off and Landing (STOL) characteristics. An improvement in thrust vectoring technology has the potential of improving (shortening) the take-off requirements of conventional aircraft. The greatest potential benefit of thrust vectoring resides in the development of future generations of attack and fighter aircraft, with increased emphasis being placed on stealth characteristics. Such aircraft have increased requirements for low weight, reduced optical signatures and high maneuverability at low to moderate speeds in order to ensure their survival. Thrust vectoring may be substituted for stability and aerodynamic control surfaces for reasons of low observability, with additional benefits derived through a decrease in mechanical complexities and structure, cost and savings in weight.

http://www.google.sr/patents/WO1996020867A1?hl=nl&cl=en

The maneuverability aspect is less important and even if there are some advantages, those were dreamt up in an era where we didn't have the combination of JHMCS and other HDMs along with HOBS missiles like the Aim-9x. Having thrust vectoring can give an aircraft some advantages, but in WVR combat, those advantages erode pretty quickly with the factors listed above.

As for the JF-17, thrust vectoring has been done on single engine aircraft before, the X-31 is an exceptional example, it was also tried on F-16 MATV and VISTA, but never saw its way to production, that should tell you its effectiveness and need. Of course with a single engine, roll control is lost, it works better with two engines deferentially, pitch is probably the most useful for thrust vectoring. Even the F-35 doesn't have it, I'm sure if it ws useful and cost-effective it would have been considered more.

So long story short, it's not needed, it's not going to be cost effective, the maneuverability advantaged is hyped and nullified greatly by HOBS + effective HMDs and multiple engagements. What advantages it does have aren't terribly useful for PAF in its only theatre of engagement.

 

[CriticalThought]

TVC allow better handling at low speed at low level so it also help in landing and takeoff too.

@gambit you opinion will be appreciated.



http://www.icas.org/ICAS_ARCHIVE/ICAS2000/PAPERS/RESERVED/ICA0534.PDF

You missed my question. I was asking how will it help towards any of these aims in JF-17? All these benefits have, in practice, been realized only for twin engine aircraft, because TVC is achieved by diverting some of the thrust. It might provide benefits for landing. But check out the rotation phase of JF-17 at the Paris airshow:

It lasts approx. from 1:13 - 1:15. For a two second benefit, you wouldn't be installing a new TVC engine.

All of the above is contingent on TVC providing enough thrust in the air for it to be meaningful. If the recovery time after TVC is found to be too long, then it would make no technical sense at all.

I have wanted the upgraded RD-33 version for JF-17, but always with the tacit assumption that OVT will need to be evaluated by designers. The new version has many other advantages for which it should be considered, such as being smokeless and FADEC. But OVT will need very careful evaluation.

 

[Basel]

You missed my question. I was asking how will it help towards any of these aims in JF-17? All these benefits have, in practice, been realized only for twin engine aircraft, because TVC is achieved by diverting some of the thrust. It might provide benefits for landing. But check out the rotation phase of JF-17 at the Paris airshow:

It lasts approx. from 1:13 - 1:15. For a two second benefit, you wouldn't be installing a new TVC engine.

All of the above is contingent on TVC providing enough thrust in the air for it to be meaningful. If the recovery time after TVC is found to be too long, then it would make no technical sense at all.

I have wanted the upgraded RD-33 version for JF-17, but always with the tacit assumption that OVT will need to be evaluated by designers. The new version has many other advantages for which it should be considered, such as being smokeless and FADEC. But OVT will need very careful evaluation.

Have you read the document in link I posted?? If you have then you would have not asking these questions.

http://www.boeing.com/history/products/x-31-vector-research-aircraft.page

 

[Dazzler]

Preliminary work on blk3 design has begun at AMF and CAC simultaneously.

 

[Jinn Baba]

Preliminary work on blk3 design has begun at AMF and CAC simultaneously.

Block 3 or 4? Isn't block 3 already finalised?

 

[CriticalThought]

Have you read the document in link I posted?? If you have then you would have not asking these questions.

http://www.boeing.com/history/products/x-31-vector-research-aircraft.page

No, you haven't understood my post at all. Show me which production single engine aircraft uses TVC? JF-17 is a real aircraft, not an experimental design. I don't want to digress into X31 on a JF-17 thread, but I only want to point out that X31 is experimental and we cannot directly take the findings as ground truth. Also, in the area of combat maneuvers, the article is validating what I stated eariler: post-stall maneuvers give it an advantage if at enemy's six.

Preliminary work on blk3 design has begun at AMF and CAC simultaneously.

Awesome news. Is this a recent development, or an earlier one that is being announced now?

 

[untitled]

No, you haven't understood my post at all. Show me which production single engine aircraft uses TVC? ....

Harrier family?

 

[CriticalThought]

Harrier family?

You might as well say F-35 What I mean is, no single engine fighter jet uses TVC for post-stall maneuvering in the real world, V/STOL notwithstanding.