Aerodynamics thread

[Equation]

Flight path has nothing to do with thrust vectoring. Thrust vectoring causes change in thrust components. These components are orthogonal. Those components that do not act on the aircraft's center-of-gravity hence produces a moment. Therefore, those components do not change the aircraft's flight direction, nor do they enhances lift.

Hey Engineer, just out of curiosity, does a thrust components cause by thrust vectoring can inhibit flight by disturbing the aircraft's center-of-gravity therefore causing it to be dist-able?

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

Side components of thrust resulting from thrust vectoring produces a moment and not a force, hence has nothing to do with the resultant. In other words, thrust vectoring does not increase lift.


Thrust vectoring up takes place when an aircraft needs a pitch up moment, as would occur during a turn. Your quote from the paper says that vectoring-up decreases lift coefficient, because the converse increases lift coefficient. In other words, the tests showed thrust vectoring on that F-18 kills lift during a turn. This is summarized elegantly in the conclusion section:

Dynamic interference effects caused by vectoring remain.
The lift coefficient was affected by approximately 0.1 with vectoring (Fig. 23). This value varied
slightly at the higher angles of attack. Vectoring-down caused an increase in lift coefficient (C'L), and
vectoring-up the converse, such as a blown flap might produce on a wing. 1° At higher angles of attack,
above the maximum CL,vectoring-down caused a larger increase in the absolute value of lift coefficientincrement from unvectored data than vectoring-up, approximately 0.10 to 0.06, respectively, at a = 55 °


So tell me when do you get the above the maximum CL? is it at a positive angle or at a negative angle, a = 55 ° is it a Negative angle pitch in down or actually a positive angle?

a = 55 ° is a positive pitch up at above the maximum CL

the source says


Deflecting the vanes, or vectoring, resulted in
the an equivalent jet plume angle (average angle for the two plumes). Vectoring-up resulted in an
equivalent effective plume turning angle of - 17 °. For vectoring-down the effective plume turning angle
was 14 °.

what does it mean that? it means it increases pitch up rate or in few words increases in turn rate will reduce the lift but not the pitch rate, the picth rate increases as such vector resultant, in few words the jet is turning faster and quicker and having a better turn rate



Vectoring was intended primarily as a moment-producing effector, so vectoring the
plume up would cause a noseup pitching moment.But the exhaust plume vectored up would
decrease the lift coefficient in the adverse direction while increasing the pitching moment
coefficient in the proverse direction. This behavior is analogous to a blown flap.

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so this equals

Today’s most maneuverable fighters use thrust vectoring, which can make a jet turn faster and more tightly

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So in few words the jet gets more lift vectoring down, or higher pitch rate vectoring up, both ways are benefitial to the jet

 

[MiG-29]

Flight path has nothing to do with thrust vectoring. Thrust vectoring causes change in thrust components. These components are orthogonal. Those components that do not act on the aircraft's center-of-gravity hence produces a moment. Therefore, those components do not change the aircraft's flight direction, nor do they enhances lift.

.

so now pitch up is a propeller type thrust vectoring uhmmm you get the torque as a helicopter propeller wow what a lie

Thrust
Thrust is produced by an aircraft’s propulsion system or engine. The direction of the thrust dictates the direction in
which the aircraft will move. For example, the engines on an airliner point backwards, which means that generally
speaking, the airplane’s thrust vector will point forwards.

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[Engineer]

Re: J-20 The New Generation Fighter Thread IV

Dynamic interference effects caused by vectoring remain. The lift coefficient was affected by approximately 0.1 with vectoring (Fig. 23). This value varied slightly at the higher angles of attack. Vectoring-down caused an increase in lift coefficient (C'L), and vectoring-up the converse, such as a blown flap might produce on a wing. 1° At higher angles of attack, above the maximum CL,vectoring-down caused a larger increase in the absolute value of lift coefficientincrement from unvectored data than vectoring-up, approximately 0.10 to 0.06, respectively, at a = 55 °


So tell me when do you get the above the maximum CL? is it at a positive angle or at a negative angle, a = 55 ° is it a Negative angle pitch in down or actually a positive angle?

a = 55 ° is a positive pitch up at above the maximum CL

the source says

Deflecting the vanes, or vectoring, resulted in the an equivalent jet plume angle (average angle for the two plumes). Vectoring-up resulted in an equivalent effective plume turning angle of - 17 °. For vectoring-down the effective plume turning angle was 14 °.

what does it mean that? it means it increases pitch up rate or in few words increases in turn rate will reduce the lift but not the pitch rate, the picth rate increases as such vector resultant, in few words the jet is turning faster and quicker and having a better turn rate

Nope. Pitch rate increasing turn rate exists only in your imagination, and the article said nothing of the sort. In fact, the source was very explicit in saying the increase of pitch up simultaneously decreases the lift, pointing out that increase of moment coefficient coincides with "0.1 decrease in lift coefficient".

Results from the 30- by 60-ft wind-tunnel aerodynamic interaction test showed that vectoring thrust acted like a blown flap by favorably affecting moment coefficients and unfavorably affecting force coefficients. This results in a favorable increase of up to 0.12 in pitching moment coefficient, and an approximately 0.1 decrease in lift coefficient. The results, using a low NPR of 1.3 and subcriticial exhaust, were correlated with plume deflection and not vane deflection to alleivate the low NPR effects.

In another article on the F/A-18 MATV, it is explicitly stated that pitch-up moment occurs with decrease in lift coefficient:

Vectoring was intended primarily as a moment-producing effector, so vectoring the plume up would cause a noseup pitching moment. But the exhaust plume vectored up would decrease the lift coefficient in the adverse direction while increasing the pitching moment coefficient in the proverse direction.

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Vectoring was intended primarily as a moment-producing effector, so vectoring the plume up would cause a noseup pitching moment.But the exhaust plume vectored up would decrease the lift coefficient in the adverse direction while increasing the pitching moment coefficient in the proverse direction. This behavior is analogous to a blown flap.

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so this equals

Today’s most maneuverable fighters use thrust vectoring, which can make a jet turn faster and more tightly

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So in few words the jet gets more lift vectoring down, or higher pitch rate vectoring up, both ways are benefitial to the jet

In a few words, TVC killed lift on that F/A-18 MATV when the aircraft pitches up for a turn. The key phrase being "pitch-up moment occurs with decrease in lift-coefficient." That should be the same thing that occurs with tailplane during a turn, which produces negative lift to push the tail down to keep the nose up. So at the end of the day, the change in lift is simply a result of location of center-of-gravity.

 

[Engineer]

so now pitch up is a propeller type thrust vectoring uhmmm you get the torque as a helicopter propeller wow what a lie

Thrust
Thrust is produced by an aircraft’s propulsion system or engine. The direction of the thrust dictates the direction in which the aircraft will move. For example, the engines on an airliner point backwards, which means that generally speaking, the airplane’s thrust vector will point forwards.

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ROFL! Given that you were the one who posted a helicopter diagram to explain a jet aircraft, it looks to me you have just admitted to lying:

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The kinematics of a helicopter has nothing to do with the kinematics of a jet fighter. The force of a rotor acts on the center-of-gravity of the helicopter. Thrust vectoring on a jet causes change in thrust components that are orthogonal to each other. Components that do not act on the aircraft's center-of-gravity produces a moment, as explained by the following diagram.

Moment has nothing to do with lift, thus does not cause change to the flight path. Go back and retake physics.

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

Nope. .

yup

Vectoring was intended primarily as a moment-producing effector, so vectoring the
plume up would cause a noseup pitching moment.But the exhaust plume vectored up would
decrease the lift coefficient in the adverse direction while increasing the pitching momentcoefficient in the proverse direction. This behavior is analogous to a blown flap

Because

The gases coming out of the vector nozzle help push the airplane's nose up or down. This vectoring increases the roll rate of the plane by 50 percent, making it much more maneuverable than other fighters

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Let me repeat you once more



The gases coming out of the vector nozzle help push the airplane's nose up or down. This vectoring increases the roll rate of the plane by 50 percent, making it much more maneuverable than other fighters=But the exhaust plume vectored up would
decrease the lift coefficient in the adverse direction while increasing the pitching momentcoefficient in the proverse direction=Today’s most maneuverable fighters use thrust vectoring, which can make a jet turn faster and more tightly

 

[MiG-29]

ROFL! you were the one who posted a helicopter diagram to explain a jet aircraft.

vectors are vectors

 

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

yup

Vectoring was intended primarily as a moment-producing effector, so vectoring the plume up would cause a noseup pitching moment.But the exhaust plume vectored up would decrease the lift coefficient in the adverse direction while increasing the pitching momentcoefficient in the proverse direction. This behavior is analogous to a blown flap

Nope. Pitching moment is not lift. Furthermore, the paper said that pitch-up moment causes decrease in lift coefficient. Pitch-up occurs when the aircraft is in a turn, so this means thrust vectoring doesn't add lift to increase turn rate. From

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:

Vectoring was intended primarily as a moment-producing effector, so vectoring the plume up would cause a noseup pitching moment. But the exhaust plume vectored up would decrease the lift coefficient in the adverse direction while increasing the pitching moment coefficient in the proverse direction.

 

[Engineer]

vectors are vectors

Helicopter is not a jet fighter. Repeating "vectors" over and over isn't going to make a jet fighter behaves like a helicopter. Thrust vectoring produces moment and doesn't add to lift, as your own sources have shown. Physics are physics.

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

Nope. Pitching moment is not lift. Furthermore, the paper said that pitch-up moment causes decrease in lift coefficient. Pitch-up occurs when the aircraft is in a turn, so this means thrust vectoring doesn't add lift to increase turn rate.

look your fantasy and lack of knowledge does not pass a physics test let us see what is momentum

Momentum is a vector quantity. As discussed in an earlier unit, a vector quantity is a quantity that is fully described by both magnitude and direction

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so now

Let me repeat you once more



The gases coming out of the vector nozzle help push the airplane's nose up or down. This vectoring increases the roll rate of the plane by 50 percent, making it much more maneuverable than other fighters=Vectoring was intended primarily as a moment-producing effector, so vectoring the
plume up would cause a noseup pitching moment.But the exhaust plume vectored up would
decrease the lift coefficient in the adverse direction while increasing the pitching moment
coefficient in the proverse direction. This behavior is analogous to a blown flap=Today’s most maneuverable fighters use thrust vectoring, which can make a jet turn faster and more tightly .