Thrust Vectoring for stealth fighters does it matter for China`s new J-20 and J-31?

Originally Posted by jobjed

This is really pointless. Do you know why? Because you agree with what Engineer and I have been talking about in the last dozen posts or so. What we have been saying is: TVC does NOT increase thrust any more than other modern jet engines. The website that mig-29 posted however said that TVC DOES increase thrust. Now it doesn't increase thrust per se, it just makes the exit area optimal for producing the most thrust/speed. But that isn't a trait unique to TVC's, every modern jet engine possess that capability as demonstrated by the videoS that WE posted. No one denied that TVC can change the direction of thrust, in fact, that might be the only unique feature it brings to an aircraft. However, mig-29 is saying that not only does TVC change the direction, it also has the unique capability of increasing thrust, which I just said is not unique to TVC. So basically, you and I have being arguing for no reason since we both agree that TVC does not increase thrust.

I do not know what do you understand by increasing thrust, but increasing thrust is increasing thrust.

they are clear

This is due to the combination of
two effects: increase of nozzle internal thrust; and reduction
of nozzle external drag.


TVC nozzles modify the shape, true any axisimmetric nozzle changes the shape of nozzle thus they increase thrust, however the ITP nozzles modify the nozzle into a shape that non TVC nozzles can not achieve therefore it actually increases the thrust further and reduces the external drag but remember this, ITP`s nozzles uses a shape regular and conventional nozzles without TVC nozzles can not achieve.

By changing the direction of thrust it changes the thrust yield thus increasing the thrust yield of EJ-200 beyond what it yields without TVC nozzles

Originally Posted by NikeX

I know this may come as a shock to you but you will notice the changing shape of the variable convergent -divergent nozzle as the thrust is vectored. How else could the direction of the thrust be directed except by changing the shape of the exhaust stream using the nozzle?





And of course there is the patent which will set you on the path of right thinking

Patent US4994660 - Axisymmetric vectoring exhaust nozzle - Google
www.google.com/patents/US4994660A thrust vectoring axisymmetric convergent divergent variable exhaust nozzle is ... General Electric Company, Vectoring exhaust nozzle seal and flap retaining ...

that shape in the case of Eurofighter`s is not achieveable by non TVC nozzle, therefore engines like F100 without TVC nozzles can not increase the thrust and redirect the thrust in the same way, however i do not know if the americans achieved the same effect because not all TVC nozzles and technologies are the same.

Originally Posted by NikeX

To state things clearly my position is that TVS enhances maneuverability when integrated into the flight control system. The aircraft can operate in areas beyond post stall. This thrust debate is not my discussion

it does increase turn rate is something already know not only increases post stall however the Eurofighters have a HMS while F-22 has not, the Raptor is very limited to some angular approaches to hit the target, while the HMS fitted Eurofighter only need look at the target, it is not lack of agility of F-22, it was the targeting system of Eurofighter is superior


see



If you want to shoot down an F-22 in a Eurofigher Typhoon (pictured directly above), here's how:

Step 1: Find the F-22 on infrared. The Raptor is very hard to spot on radar, but it's big, and it's hot. A Typhoon can pick up a Raptor from about 50 kilometers away with infrared sensors.

Step 2: Get close and stay close. F-22s excel at long-range combat, so bring the fight to them.

Step 3: Force an aggressive, turning dogfight. In its slickest configuration (without external fuel tanks), the Typhoon (which is smaller, lighter and more powerful) can outmaneuver, outaccelerate and outclimb the F-22. The Raptor does have those fancy thrust vectoring engines, but using the thrust vectoring takes a lot of energy, meaning that the Raptor can make rapid direction changes but becomes vulnerable immediately afterwards as it "sinks" and has to recover.

Step 4: Use your helmet-mounted sight to engage. Technical problems prevented the Raptor from being designed with an integrated helmet sight, which lets Typhoon pilots simply look at a target to lock onto it.

http://dvice.com/archives/2012/08/f-22-raptors-pr.php

however thrust vectoring only increases turn and roll rate up to a limit, so a ver agile fighter like Eurofighter indeed can give it a fight to F-22 in close combat

Originally Posted by MiG-29

I do not know what do you understand by increasing thrust, but increasing thrust is increasing thrust.

they are clear

This is due to the combination of
two effects: increase of nozzle internal thrust; and reduction
of nozzle external drag.


TVC nozzles modify the shape, true any axisimmetric nozzle changes the shape of nozzle thus they increase thrust, however the ITP nozzles modify the nozzle into a shape that non TVC nozzles can not achieve therefore it actually increases the thrust further and reduces the external drag but remember this, ITP`s nozzles uses a shape regular and conventional nozzles without TVC nozzles can not achieve.

By ITP's own statement, the mechanism that enables the so called "increased thrust" is the variable convergent-divergent section. The feature is not a result of exercising thrust vectoring. From the very paper which you have quoted;

The use of an independently controlled divergent section allows A9 to be optimised for any engine running condition at any flight point

Likewise, the reduction of nozzle drag is not due to thrust vectoring, but as a result of the same "independently controlled divergent section". The WS-10 separates the exterior and interior of the nozzle out of the same consideration:

Originally Posted by MiG-29

By changing the direction of thrust it changes the thrust yield thus increasing the thrust yield of EJ-200 beyond what it yields without TVC nozzles

Changing the direction of thrust does not increase thrust.

I think quite simply, Mig-29 is either ignoring or does not understand the context of his claims. A variable convergent-divergent section increases thrust relative to other TVC designs that predate it, as it minimizes the amount of thrust lost by deflection from the nozzle surface. That does not mean a variable convergent divergent nozzle adds extra thrust to what's being produced by the turbofan. It simply mitigates the loss of thrust as the exhaust is being expelled from the nozzle.

Originally Posted by Quickie

No such thing as changing the direction of thrust would somehow increase the thrust. The fact of the matter, changing the direction of the thrust will always result in a reduction of the thrust, and of course, this comes with the gain of a pitching/moment force. No such thing as a free lunch in Physics.

Thinking that just because something can do both A(e.g. thrust-vectoring) and B(e.g. adjusting nozzle diameter to optimize thrust) means A causes B is a failure in logic. Thinking that changing the direction of thrust would somehow increase thrust is a failure in physics. Having either logic or physics knowledge would prevent someone making ridiculously idiotic statements like TVC can increase thrust, and this is why only people who fail in both logic and physics but specializes in mumbo-jumbo, like Mr. Mig29, would make claims like that.

Originally Posted by dingyibvs

Thinking that just because something can do both A(e.g. thrust-vectoring) and B(e.g. adjusting nozzle diameter to optimize thrust) means A causes B is a failure in logic. Thinking that changing the direction of thrust would somehow increase thrust is a failure in physics. Having either logic or physics knowledge would prevent someone making ridiculously idiotic statements like TVC can increase thrust, and this is why only people who fail in both logic and physics but specializes in mumbo-jumbo, like Mr. Mig29, would make claims like that.

Exactly. The claim is no less retard than saying a rubber tire provides thrust for an aircraft. It is called fallacy of division.

Originally Posted by dingyibvs

Thinking that just because something can do both A(e.g. thrust-vectoring) and B(e.g. adjusting nozzle diameter to optimize thrust) means A causes B is a failure in logic. Thinking that changing the direction of thrust would somehow increase thrust is a failure in physics. Having either logic or physics knowledge would prevent someone making ridiculously idiotic statements like TVC can increase thrust, and this is why only people who fail in both logic and physics but specializes in mumbo-jumbo, like Mr. Mig29, would make claims like that.

for further complaings complaign to:

Industria de Turbo Propulsores S.A. (ITP)
Parque Tecnológico, edificio 300
48170 Zamudio, Spain
daniel.ikaza@itp.es
presented at
NATO R&T ORGANIZATION Symposium




If you want to contact Daniel in Spanish do not hesitate i can write for you a letter in Spanish,


For example, for a supersonic cruise case (Mach 1.2, altitude
36,000 ft, engine at Max Dry condition) of EJ200 engine on
Eurofighter, the use of independent A9 control could lead to
an improvement of up to 7% in installed net thrust relative to
the current performance. This is due to the combination of
two effects: increase of nozzle internal thrust; and reduction
of nozzle external drag.


Additionally, pure A9 control movements are performed by
moving top and bottom actuators in parallel while the other
two stay static, hence “hinging” the outer ring open or close.
The divergent section opens or closes relative to the nominal
position, acquiring an “oval” shape. Hence this movement is
sometimes referred to as “ovalization”. Of course, A9
movements can be combined with A8 movements and/or
vectoring movements.


http://ftp.rta.nato.int/public//PubF...051-PSF-11.pdf
watch “ovalization”


do not hesitate in ITP`s mexico plant they need designers probably they need your knowledge

On rereading my post, I think it's more complete to explain this way.

No such thing as changing the direction of thrust would somehow increase the thrust. The fact of the matter, changing the direction of the thrust will always result in a reduction of the thrust in the original thrust direction, and of course, this comes with the gain of a pitching/moment force.

Deleted double post.

Mig29, you literally just replied to an an accusation of logical fallacy with the same exact logical fallacy. I suppose you didn't click on Engineer's link? I never thought explaining anything to you is anything more useful than playing music to an ox, I just hoped that others would see through your ludicrous claims, but I'm feeling generous today so I'll explain:

Fallacy of division - Wikipedia, the free encyclopedia

A fallacy of division occurs when one reasons logically that something true of a thing must also be true of all or some of its parts.
An example:
A Boeing 747 can fly unaided across the ocean.
A Boeing 747 has jet engines.
Therefore, one of its jet engines can fly unaided across the ocean.
The converse of this fallacy is called fallacy of composition, which arises when one fallaciously attributes a property of some part of a thing to the thing as a whole. Both fallacies were addressed by Aristotle in Sophistical Refutations.

Here's what's wrong with your argument:

The engine can adjust its nozzles to increase thrust.
The engine has TVC.
Therefore, the TVC can increase thrust.

Originally Posted by MiG-29

for further complaings complaign to:

Industria de Turbo Propulsores S.A. (ITP)
Parque Tecnológico, edificio 300
48170 Zamudio, Spain
daniel.ikaza@itp.es
presented at
NATO R&T ORGANIZATION Symposium




If you want to contact Daniel in Spanish do not hesitate i can write for you a letter in Spanish,


For example, for a supersonic cruise case (Mach 1.2, altitude 36,000 ft, engine at Max Dry condition) of EJ200 engine on Eurofighter, the use of independent A9 control could lead to an improvement of up to 7% in installed net thrust relative to
the current performance. This is due to the combination of two effects: increase of nozzle internal thrust; and reduction
of nozzle external drag.

Wrong. The very paragraph you quoted contradicts your own claim, as it states explicitly that the so called "increased thrust" is due to control of the divergent section (A9) of the convergent-divergent nozzle. In fact, even your very own source states that the variable convergent-divergent section already exists on regular nozzle:

The current EJ200 engine is equipped with a variable-geometry Convergent-Divergent (Con-Di) Nozzle, developed by ITP. This nozzle can modify the area to match the engine running point and afterburner setting, but it has no vectoring capability.

Convergent-divergent nozzle is nothing new, as it is widely used on modern fighter engines. Here is a video of a F-100 engine being tested, which shows variable convergent-divergent nozzle is not a result of thrust vectoring:


So far, there is zero evidence from your own source to support your claim that thrust vectoring improves engine performance. However, it is proven that improvement of engine performance is not related to thrust vectoring, but a feature of a variable convergent-divergent section.

Originally Posted by MiG-29

Additionally, pure A9 control movements are performed by moving top and bottom actuators in parallel while the other
two stay static, hence “hinging” the outer ring open or close. The divergent section opens or closes relative to the nominal position, acquiring an “oval” shape. Hence this movement is sometimes referred to as “ovalization”. Of course, A9 movements can be combined with A8 movements and/or vectoring movements.


http://ftp.rta.nato.int/public//PubF...051-PSF-11.pdf

do not hesitate in ITP`s mexico plant they need designers probably they need your knowledge

Wrong. The ability to create an oval shaped exit area does not come automatically from thrust vectoring. It is an additional option, according to your own source:

Many different configurations have been studied at ITP for TVNs, the result being a “baseline” configuration, plus a series of options available for every particular application.

Even though the baseline option supports thrust vectoring, the option has no capability to independently control the divergent (A9) section. This is explained in the following paragraph of your own source, which explicitly states A9 cannot be controlled independently from A8.

It has three degrees of freedom (DOFs), namely: Throat area (A8), Pitch vectoring and Yaw vectoring. Any oblique vectoring is made of a combination of pitch and yaw. Exit area (A9) follows a certain relationship to A8.

The ability to change the exit area into an oval shape is called A9 Control Option, which has nothing to do with thrust vectoring. This is explained in your own source in the following statement:

This option consists basically of the baseline design, except for the fact that the outer ring is split in two halves, forming a “hinged” outer ring.

Furthermore, your own source states:

Additionally, pure A9 control movements are performed by moving top and bottom actuators in parallel while the other two stay static, hence “hinging” the outer ring open or close. The divergent section opens or closes relative to the nominal position, acquiring an “oval” shape. Hence this movement is sometimes referred to as “ovalization”. Of course, A9 movements can be combined with A8 movements and/or vectoring movements.

The phrase "pure A9 control movements" means the A9 is actuated independently of thrust vectoring. Likewise, the sentence "A9 movements can be combined with A8 movements and/or vectoring movements" means A9 movements can be performed without exercising thrust vectoring. Once again, your claim that the feature comes from thrust vectoring is disproven.

So, if you have further disagreement, please direct your retard claims to:

Industria de Turbo Propulsores S.A. (ITP)
Parque Tecnológico, edificio 300
48170 Zamudio, Spain
daniel.ikaza@itp.es
presented at
NATO R&T ORGANIZATION Symposium

Originally Posted by dingyibvs

Mig29, you literally just replied to an an accusation of logical fallacy with the same exact logical fallacy.

Actually, he is knowingly doing this on purpose, thus employing another fallacy called argumentum ad nauseam. Whenever he copies and pastes his previous post, just respond by repeating your previous points.

This thread is closed until I clean it up in a couple of days...Such intelligent people making silly arguments. If I find anyone else that needs a Fall holiday they shall surely receive one!

Any member sending me a PM about this thread shall be banned for an unspecific amount of time.



bd popeye super moderator