Aerodynamics thread

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

SO arrogent, perfectly befitting a person engaged in imaginary physics.



where did you get this at all.

Good advice my buddy, go attend junior high school physics class.

Some V/STOL fighters can improve their instantaneous turn performance through a technique known as "VIFFing" (vectoring in forward flight), in which thrust vectoring can be used to assist the wings


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Abstract : The objective of this thesis is to determine the optimal controls and trajectories which minimize the time to turn for a high performance aircraft with thrust vectoring capability. All determinations are subject to practical physical constraints. The determined controls and trajectories are then compared against other methods of turning in minimum time to conclude the effects and advantages of thrust vectoring. The results indicate that the use of vectored thrust can substantially reduce turning times and increase in-flight maneuverability. The greater the velocity at which the turn is initiated, the more the range of thrust vectoring capability is used and the greater the reduction in turning time. Originator-supplied keywords include: Optimization; Thrust vectoring; Vectored thrust; Minimum time turns; Steepest-ascent method; and Optimal controls

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[Engineer]

Re: J-20 The New Generation Fighter Thread IV

hahah pure fantasies and pride i will show you where you have no idea of how an aircraft turns

Maneuverability
Thrust vectoring can greatly improve the maneuverability of an aircraft such as turning, useful in combat to out maneuver non thrust vector controlled enemy aircraft. later let us go to the math

For turning with vectored thrust, the equation from figure 8 is:
n*W = L + T*sin(a + fT) (11)
Where the load factor n = (T*sin(a + fT) / W) / (L/D) (12)
(Raymer, 2006)
By maximizing the load factor, the turning rate is maximized, so by differentiating equation 12 with respect to thrust angle, and maximizing this equation provides the thrust angle for maximum turn rate, which turns out to be 90º. In other words, when the thrust angle is perpendicular to flight direction, maximum turn rate is achieved

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but let me imagine your reaction No no no wrong hahahahah, moment is not a vector, no vectors have no direction and magnitude, pitch is a sewsaw hahahaha Typical reation No no no, thrust vectoring does not improve turn rate, its the canards of the Eurofighter ITP is just a brochure no no no theya re not engineers like me, ITP is not owned 50% by Rolls Royce no no wrong, irrelevant wrong


hahaha no i do not know what is cross product of vectors but torque is no a vector no no no wrong

LMAO! In your desperation to float your fantasy, you conveniently left out the fact that Raymer's equations are derived for the

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with VOTL ability. F-22 has no such ability. Neither does Eurofighter, MiG-29OVT, Su-30MKI, or Su-35.

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The equations work for the Harrier because the aircraft have nozzle all around the aircraft to provide lift at center-of-gravity. For any other aircraft with nozzle positioned on the tail end, side component of thrust vector produces pitching moment. No lift can be created as a result because the aircraft is free to rotate. That is just simple Laws of Physics. So far, you go around in circle and remain unable to disprove this.

What you have done above is what you have done before, engaging in

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, where you simply extract a few keywords or a single statement from an article, and ignore the rest of the content. Keep on denying reality, but it won't go away:

At these speeds, TVC-equipped aircraft (lower one in animation) actually turns at same rate as non-TVC aircraft; however, TVC increases angle between aircraft and air flow around it (Angle of Attack, abbreviated AoA), resulting in increase in drag for no decrease in diameter of turn (that is, maneuverability), resulting in increased energy loss during maneuvers, leaving aircraft more and more vulnerable to missiles and gunfire as fight drags on. In short, aircraft does not fly in direction its nose is pointing at.

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LMAO!

 

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

Some V/STOL fighters can improve their instantaneous turn performance through a technique known as "VIFFing" (vectoring in forward flight), in which thrust vectoring can be used to assist the wings


Source

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Abstract : The objective of this thesis is to determine the optimal controls and trajectories which minimize the time to turn for a high performance aircraft with thrust vectoring capability. All determinations are subject to practical physical constraints. The determined controls and trajectories are then compared against other methods of turning in minimum time to conclude the effects and advantages of thrust vectoring. The results indicate that the use of vectored thrust can substantially reduce turning times and increase in-flight maneuverability. The greater the velocity at which the turn is initiated, the more the range of thrust vectoring capability is used and the greater the reduction in turning time. Originator-supplied keywords include: Optimization; Thrust vectoring; Vectored thrust; Minimum time turns; Steepest-ascent method; and Optimal controls

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As your own sources have stated, these are V/STOL aircraft that can vertically take off and land. They have more than one nozzles located fore and aft of the center-of-gravity, unlike aircraft with TVN positioned only at the tail of the aircraft. From your own source:

There are currently two distinct variations in V/STOL design. The first of these to be considered is the thrust-vector type, typified by the British Harrier. This design has four jet exhaust nozzles that can be pivoted to direct the exhaust directly astern, or downward, or even slightly forward. Two nozzles are located behind and two forward of the CG, so that the aircraft can be supported in a hover by the four downward columns of jet exhaust, much like the legs of a four-poster bed. The Harrier has only a single engine, but fighters of this type with multiple engines could follow. While it is at very slow speeds the fighter's attitude is controlled by small reaction jets of engine bleed air located in the nose and/or tail and on the wing tips.

An aircraft with TVC such as the F-18 HARV does not have four columns of jet exhaust projected downward. Additionally, your source described a second type of V/STOL aircraft:

The second type of V/STOL fighter is the lift-fan design, such as the Russian Yak-36 Forger. This type incorporates one or more (two in the Forger) lift jets that exhaust only downward; these are used in conjunction with the main engine(s). The primary engine of the Forger has two pivoting exhausts located in the rear, much like the Harrier, to vector the thrust downward or aft. The lift jets support the front of the aircraft and the main engine supports the rear during a hover.

The keyword here is hover, which cannot be done by aircraft such as the F-18 HARV. Neither can F-22, MiG-29OVT, Su-30MKI and Su-35 achieve such a feat. The only modern day aircraft matches that described arrangement is the F-35, which utilizes thrust vectoring to hover but not for combat maneuvers.

 

[Air Force Brat]

Re: J-20 The New Generation Fighter Thread IV

I have no prejudice against thrust vectoring, just as I have no prejudice against an aileron, an elevator or a rudder. All I have been saying is that thrust vectoring does not produce lift that turns an aircraft. Certain someone has problem accepting that, as the fact I have presented contradict his imagination of how thrust vectoring should work. So far, that statement of mine has stood up to scrutiny and yet to be dis-proven.

Fair enough Eng, and I agree TVC does not produce lift, it certainly does NOT increase thrust, and using it for aircraft manuevering COSTs Fuel, and it is very maintenance intensive since it lives in a very harsh environment, all I'm asking you to do is not to go to the least common denominator and involve yourself in that argument. I know you are well grounded and studied in this subject, and I hope I have been respectfull, thats the one thing I most admire about the Chinese culture is Respect, I like you, I consider you a friend, and our little "discussions" make me think and help me understand, thats why I reopened this discussion in this thread, we don't have to make excuses. I also like Mig, although I have much less hair than I did when I started some of these discussions with him, one thing I admire about you is that you are able to "deal" with someone disagreeing with you, without taking it personally. I would love to see us keep this discussion above board, there are lots of posters who would probably like to ask questions as I did, and all this negative stuff scares them off, I look at you as a "professor" and a more than serious student of the science of aerodynamics, at the same time someone who can relate it back to someone such as myself who is more "practical" in schooling as opposed to your "formal" education. thanks, Brat

 

[ahadicow]

Re: J-20 The New Generation Fighter Thread IV

Fair enough Eng, and I agree TVC does not produce lift, it certainly does NOT increase thrust, and using it for aircraft manuevering COSTs Fuel, and it is very maintenance intensive since it lives in a very harsh environment, all I'm asking you to do is not to go to the least common denominator and involve yourself in that argument. I know you are well grounded and studied in this subject, and I hope I have been respectfull, thats the one thing I most admire about the Chinese culture is Respect, I like you, I consider you a friend, and our little "discussions" make me think and help me understand, thats why I reopened this discussion in this thread, we don't have to make excuses. I also like Mig, although I have much less hair than I did when I started some of these discussions with him, one thing I admire about you is that you are able to "deal" with someone disagreeing with you, without taking it personally. I would love to see us keep this discussion above board, there are lots of posters who would probably like to ask questions as I did, and all this negative stuff scares them off, I look at you as a "professor" and a more than serious student of the science of aerodynamics, at the same time someone who can relate it back to someone such as myself who is more "practical" in schooling as opposed to your "formal" education. thanks, Brat

The probelm here is that you and Mig put country before the plane, and put plane before the science. F-22 does not become a better or worse plane when painted with different country's flag, science certainly does not twist itself when it was ultilized on different jet fighters. So fact and truth come first. Your opinion of which plane does better in combat come after that and your feeling for your country come after that. This is called "objectivity" and it is the basic principle for any pupil of science.

Mig does have a problem of respect in the way he try to suggest the other people he discuss with are less intelligent or educated than himself. If you don't, that's good for you. But still, a disscusion that is conducive to the revealing of truth cannot rely on the principles of interpersonal relationships. In other words, I may like you, I may dislike you, I may have a respect for you, I may not, it doesn't change one thing about how I preceive the turthfulness of your words.

So, if you have a thesis, state it. If you have an argument, state it. This thread is not about which jet fighter perform better in aero combat or which country is better and don't act like your feeling has been hurt because people do not want to twist the fact they know to support a thesis that allow you a better feeling about the jet fighter of your country.

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

As your own sources have stated, these are V/STOL aircraft that can vertically take off and land. They have more than one nozzles located fore and aft of the center-of-gravity, unlike aircraft with TVN positioned only at the tail of the aircraft. From your own source:

An aircraft with TVC such as the F-18 HARV does not have four columns of jet exhaust projected downward. Additionally, your source described a second type of V/STOL aircraft:

The keyword here is hover, which cannot be done by aircraft such as the F-18 HARV. Neither can F-22, MiG-29OVT, Su-30MKI and Su-35 achieve such a feat. The only modern day aircraft matches that described arrangement is the F-35, which utilizes thrust vectoring to hover but not for combat maneuvers.

Look you just try to lie to your self

To date, there have been 5
aircraft testing thrust vectoring technology --the F-15 STOL/MTD (Short Takeoff and
Landing/Maneuvering Technology Demonstrator), the X-31 (Enhanced Fighter
Maneuverability demonstrator), the F-18 HARV (High Alpha Research Vehicle), the YF-
22 (Advanced Tactical Fighter), and the F-16 MATV (Multi-Axis Thrust Vectoring).
The F-15 and YF-22 programs used pitch-only vectoring and were limited in scope with
respect to exploring the capabilities of thrust vectoring.The results of the operational test were equally impressed. The MATV pilot
could take advantage of the F-16s maximum turn capability improving the ability to killand survive.


To improve the ability to kill based upon the maximun turn means basicly improved turn rate

what this means this, that as in the case of Eurofighter, the thrust vectoring does increase turn rate

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Eurofighter says

Daniel Ikaza, ITP project manager - nozzles, says Dasa's study shows that a Eurofighter flying at 30,000ft (9,150m) and a speed of M1.8 requires a 4° upward flaperon deflection to maintain level flight. A 5° upward nozzle deflection instead would enable the aircraft to fly "clean" and reduce the required engine thrust by 3%.

Under the same conditions, but in a sustained turn, where the pitch element of the control surface deflection was 6° up, this could be reduced to 2° combined with a 4° nozzle-up component. In this configuration lift coefficient would be increased by 14%, translating into a 9% improvement in turn rate. Take-off distance could be cut by at least 25%.

The figures include an adjustment for the extra weight

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Next generation rocket propulsion systems are shifting towards higher levels of performance by incorporating advanced thrust vectoring capabilities for increased missile turning rates and maneuverability

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Obviously a missile has its nozzles at one of its ends so you can not say it is a harrier

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

The probelm here is that you and Mig put country before the plane, and put plane before the science. F-22 does not become a better or worse plane when painted with different country's flag, science certainly does not twist itself when it was ultilized on different jet fighters. So fact and truth come first. Your opinion of which plane does better in combat come after that and your feeling for your country come after that. This is called "objectivity" and it is the basic principle for any pupil of science.

Mig does have a problem of respect in the way he try to suggest the other people he discuss with are less intelligent or educated than himself. If you don't, that's good for you. But still, a disscusion that is conducive to the revealing of truth cannot rely on the principles of interpersonal relationships. In other words, I may like you, I may dislike you, I may have a respect for you, I may not, it doesn't change one thing about how I preceive the turthfulness of your words.

So, if you have a thesis, state it. If you have an argument, state it. This thread is not about which jet fighter perform better in aero combat or which country is better and don't act like your feeling has been hurt because people do not want to twist the fact they know to support a thesis that allow you a better feeling about the jet fighter of your country.

Look i have never said you are less smart or i love F-22, never i meant that if you felt offended sorry, i never meant for you to feel insulted.

However i will be truely honest, vectorial algebra or basicly linear algebra states that momement, torque and basicly all objects have direction and magnitude when they move.

If you understand that you will understand what i said, i said lift and thrust are vectors, as such have direction.

Pitch has a direction is up or down and a magnitude is called pitch rate.
Torque has a direction and a magnitude, and it is the product of vectors, the center of gravity is a a vector projection of the gravity pulling down vector

Torque has a direction simply becuase if you open a door it opens into one direction simply like that and opens with a pitch rate or speed, you can slam the door or open it slowly.

Pitch or torque is the cross product of two vectors on a jet, gravity vector from center of gravity and thrust projection based upon the vertical force it generates.

When a jet turns with thrust vectoring the thrust is having a projection based upon two angles.

It is a fact thrust vectoring increases turn rate, lift is a up direction vector, pitching up also is a up direction vector.

The end result is Fighters increase turn rayes because the projection of thrust upon the axis of the jet increases the picht rate on a nose up direction, gravity as a vector is pulling down against lift, but thrust creates two projections one vertical for that you use sine and one horizontal for that you use cosine.
The center of gravity is also a vector, if you have studied the cross product of two vectors you will see the center of gravity is a horizontal projection of the gravity pulling down.



If you cheked well the formulas i posted, which by the way are not mine, i gave you the resources, you will understand what i said.

I have no hard feelings to you in fact i do not care if you beleive me or not, i know perfectly thrust vectoring has a vertical element and has a horizontal element, i know it increases turn rate in fighters like F-18, F-22, F-16 or Eurofighter as well as Harriers.

 

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

Look you just try to lie to your self

To date, there have been 5 aircraft testing thrust vectoring technology --the F-15 STOL/MTD (Short Takeoff and Landing/Maneuvering Technology Demonstrator), the X-31 (Enhanced Fighter Maneuverability demonstrator), the F-18 HARV (High Alpha Research Vehicle), the YF-22 (Advanced Tactical Fighter), and the F-16 MATV (Multi-Axis Thrust Vectoring). The F-15 and YF-22 programs used pitch-only vectoring and were limited in scope with respect to exploring the capabilities of thrust vectoring.The results of the operational test were equally impressed. The MATV pilot could take advantage of the F-16s maximum turn capability improving the ability to killand survive.


To improve the ability to fill based upon the maximun turn means basicly improved turn rate

Wrong, as that is a

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. Turn capability contributes to kill ability, but there are multiples contributor to kill ability so turn capability cannot be inferred from kill ability. Your own quote stated that the pilot on the F-16 took advantage of the maximum turn capability, which means he was using something that is already existed by design. This was explained in the document:

While the production F-16 is one of the world's most maneuverable fighters, directional stability is lost between 30 and 50 degrees AOA when most of the vertical tail is blocked by the fuselage. (The rudder losses effectiveness at 35 degrees AOA.) Flight control limiters help prevent departure/spins, but restrict commanded AOA to 25.5 degrees--well short of the 32 degrees angle required for maximum lift. With yaw stability provided through thrust vectoring, the 25.5 degree restriction is eliminated maximizing inherent aircraft aerodynamics.

The keywords being inherent aircraft aerodynamics, something that existed with or without thrust vectoring. So, the F-16 was prevented from reaching maximum AOA before. When restriction was lifted, the aircraft obviously should perform better. This would be the case even if there were no thrust vectoring. No extra lift was created by TVN during this process.

Additionally, improved kill ability was due to post-stall maneuvering. Back then, when only a few aircraft has thrust vectoring, only a few pilots have experience flying against an aircraft with thrust vectoring, resulting in no effective means to counter an opponent going post-stall. That has

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.

During defensive maneuvering, thrust vectoring increased the survivability of the F-16 MATV due to the ability to use post-stall maneuvering. Post-stall maneuvering caused the attacking pilot to feel defensive and thereby modify his tactics to guard against the thrust vectoring jet. A graphic depiction of a post-stall maneuver during a one-vs-one high aspect single circle engagement is provided in Figure (6).

Now days, pilots have training against F-22 with known counters to post-stall maneuvers, but I digress. Post-stall maneuverability does not equate to performance.

what this means this, that as in the case of Eurofighter, the thrust vectoring does increase turn rate

Source

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Eurofighter says

Daniel Ikaza, ITP project manager - nozzles, says Dasa's study shows that a Eurofighter flying at 30,000ft (9,150m) and a speed of M1.8 requires a 4° upward flaperon deflection to maintain level flight. A 5° upward nozzle deflection instead would enable the aircraft to fly "clean" and reduce the required engine thrust by 3%.

Under the same conditions, but in a sustained turn, where the pitch element of the control surface deflection was 6° up, this could be reduced to 2° combined with a 4° nozzle-up component. In this configuration lift coefficient would be increased by 14%, translating into a 9% improvement in turn rate. Take-off distance could be cut by at least 25%.

The figures include an adjustment for the extra weight

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We have already went over this particular source. The article from Flightglobal is an extract from that

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which you have posted earlier. We know the document has misrepresentation because it purposely ignored the existence of canard in their "analysis". We also know that no Eurofighter ordered the TVN, which is a sign of lack of faith. Mean while, from

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we see the truth:

At these speeds, TVC-equipped aircraft (lower one in animation) actually turns at same rate as non-TVC aircraft; however, TVC increases angle between aircraft and air flow around it (Angle of Attack, abbreviated AoA), resulting in increase in drag for no decrease in diameter of turn (that is, maneuverability), resulting in increased energy loss during maneuvers, leaving aircraft more and more vulnerable to missiles and gunfire as fight drags on. In short, aircraft does not fly in direction its nose is pointing at.

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

Wrong, :

I aspected this wrong hahahaha let me remind you a bit

Next generation rocket propulsion systems are shifting towards higher levels of performance by incorporating advanced thrust vectoring capabilities for increased missile turning rates and maneuverability.

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hahahaha

let me show you where the AIM-9X has its thrust vectoring system

h
hahahaha

I can imagine your face what! no no no what!


You said harrier only can increase turn rates hahahahaha

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

double post

i