Aerodynamics thread

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

1Come on eng, that vid is bogus and you know it, a Flanker with OVT, has a higher turn RATE, than a Flanker without OVT, and the Eagle driver is illustrating their one kill on a Raptor, and the unfortunate IAFs inability to fight their aircraft, but they did learn and were a lot tougher on the second go around, which is why Red Flag works.

The said Flanker wasn't turning as fast as the F-15 opponent, so the pilot engaged TVC. Instead of actually making the aircraft turns faster, the pilot lost as a result of using that TVC. The same thing happened with F-22. Thrust vectoring does the exact same thing as a tail plane does during a turn, which is to pitch the aircraft's nose up to larger AoA. The difference is that a tailplane can become ineffective at certain flight conditions, whereas thrust vectoring works regardless of those conditions. So, TVC doesn't actually make the aircraft turns faster. All TVC does is make sure pitch-authority is there to commence a turn.

2 You're little automation actually proves that OVT does work as your two little aircraft near the edge of the page, the OVT aircraft has a perfect lead on the non-OVT bird and is positioned perfectly for a gun shot or missle shot, nice work ace! Brat

No. The animation shows the aircraft with TVC has large AoA changes, but the arc trajectory made by the aircraft during the turn is the same. The author's own words on his

Please, Log in or Register to view URLs content!

are as follow:

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.

 

[ahadicow]

Re: J-20 The New Generation Fighter Thread IV

Otherwise i will not get involved in an argument where people want to discredit me simply because just for the sake of discredit me.

you just discredited yourself, by spending several pages worth of augrement to dispute a simple and elementry physical truth.

All the terminology do not hide a simple lack of understanding of fundamental mechnics.

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

you just discredited yourself, by spending several pages worth of augrement to dispute a simple and elementry physical truth.

All the terminology do not hide a simple lack of understanding of fundamental mechnics.

Easy to answer to your reply, i did not make the formula

Vertical: L - W + T sin(c) = Fv You can say whatever you want but trigonometry and Vector algebra are not against me.
in fact this proves the NASA webpage

Please, Log in or Register to view URLs content!

However you will claim i was wrong just by pride, not by mathematical explanation

 

[MiG-29]

Re: J-20 The New Generation Fighter Thread IV

1Come on eng, that vid is bogus and you know it, a Flanker with OVT, has a higher turn RATE, than a Flanker without OVT, and the Eagle driver is illustrating their one kill on a Raptor, and the unfortunate IAFs inability to fight their aircraft, but they did learn and were a lot tougher on the second go around, which is why Red Flag works.
2 You're little automation actually proves that OVT does work as your two little aircraft near the edge of the page, the OVT aircraft has a perfect lead on the non-OVT bird and is positioned perfectly for a gun shot or missle shot, nice work ace! Brat

It is not that he accepts it or not.

Thrust vectoring increases Turn rate regardless if he accepts the fact or not
See a Document by NATO

Fig. 3.- Increased Sustained Turn Rate with TVNs

source

Please, Log in or Register to view URLs content!

The thrust vectoring also contributes to an increase of the maximum roll rate (Figure 6). This is due to the fact that
thrust vectoring, even if pitch only, allows a substantial relaxation of the constraints over the aerodynamic control
surfaces, which can then be used to control the roll rate, while the pitch attitude is controlled by thrust vectoring


source

Please, Log in or Register to view URLs content!

Only the F-22 features vectored thrust, giving it twice the
maneuverability of an F-35
The F-22 can turn at twice the rate of an F-35

source

Please, Log in or Register to view URLs content!

 

[hardware]

2 days ago, report that Changsha firm successfully developed a large oven design to cure composite material, the oven is 8 meter long ,
weight 10 ton ,able to chandle large pieces of composite material. such as wing for large passengare aircraft or main fuselage for fighter aircraft.
我国超大型等温碳碳复合材料热工装备研发成功，将应用于国家某重大专项关键部件制造！

出自:

Please, Log in or Register to view URLs content!

作者: sunmingchi 2013-2-17 复制链接

据长沙晚报2月17日报道（记者 张怀中 实习生 于翔林）一台用于中国航天航空某关键部件制造的特种装备——超大型等温碳碳复合材料热工装备，于昨日离开长沙，前往天津支援中国航天航空事业的发展。这一高新技术装备，由湖南顶立科技有限公司研发制造，它打破了西方国家的技术垄断和对我国的禁运，也标志着“长沙制造”已跻身国内成套高端热工装备制造的第一方阵。

顶立科技是中南大学几位教授、博士创办的企业，主要从事高端热工装备及新材料的研发和制造。去年6月，经国家有关单位一年多的考察，将为国家某重大专项关键部件制造的热工装备的任务，交给了长沙企业顶立科技。

昨日记者在顶立科技生产车间看到，长达8米、重约105吨的大型设备，已装车准备发运。顶立科技董事长戴煜博士告诉记者，光这一台设备就价值1600万元，它将充当起某关键部件制造的“产房”，孵化出国家急需要的产品。

.

 

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

you just discredited yourself, by spending several pages worth of augrement to dispute a simple and elementry physical truth.

All the terminology do not hide a simple lack of understanding of fundamental mechnics.

Exactly! Spamming terminologies is just an attempt to hide the fact that he was proven wrong. All he did was committing a fallacy called

Please, Log in or Register to view URLs content!

.

Easy to answer to your reply, i did not make the formula

Vertical: L - W + T sin(c) = Fv You can say whatever you want but trigonometry and Vector algebra are not against me.
in fact this proves the NASA webpage

However you will claim i was wrong just by pride, not by mathematical explanation

Please, Log in or Register to view URLs content!

already says you are wrong in pointing out thrust vectoring as a moment-producing effector. The position of the engine nozzle does not lie at the aircraft's center-of-gravity, so any side component in thrust will result in moment. Moment is not a force, so thrust vectoring has nothing to do with vertical forces.

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]

Re: J-20 The New Generation Fighter Thread IV

It is not that he accepts it or not.

Thrust vectoring increases Turn rate regardless if he accepts the fact or not
See a Document by NATO

Fig. 3.- Increased Sustained Turn Rate with TVNs

source

Please, Log in or Register to view URLs content!

The thrust vectoring also contributes to an increase of the maximum roll rate (Figure 6). This is due to the fact that thrust vectoring, even if pitch only, allows a substantial relaxation of the constraints over the aerodynamic control surfaces, which can then be used to control the roll rate, while the pitch attitude is controlled by thrust vectoring

source

Please, Log in or Register to view URLs content!

Firstly, increase roll rate has nothing to do with turned rate. Quoting a paragraph describing roll rate does not prove there is an increased to lift and turn rate. Secondly, said document was not authored by NATO, but by the company which designs TVN for the Eurofighter hoping to net a customer in a conference held by NATO. In short, the document is not a scientific paper but a sell brochure. No one believed in the claims made by the paper, since there is no customer for said TVN.

Whether you accept it or not, TVC does not increase lift to increase turn rate. For one,

Please, Log in or Register to view URLs content!

. Although not a discussion of that particular exercise, the

Please, Log in or Register to view URLs content!

contained an explanation for the outcome, stating:

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.

Then we have

Please, Log in or Register to view URLs content!

, showing no increase in lift during pitch up maneuver with thrust vectoring:

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.

Only the F-22 features vectored thrust, giving it twice the maneuverability of an F-35 The F-22 can turn at twice the rate of an F-35

source

Please, Log in or Register to view URLs content!

A comparison like that only says F-22 is a better aircraft with better aerodynamics, and does not say anything about effectiveness of thrust vectoring. It is about as meaningful as saying Su-27 can out maneuver a MiG-15, which is not meaningful at all.

 

[ahadicow]

Re: J-20 The New Generation Fighter Thread IV

Easy to answer to your reply, i did not make the formula

Vertical: L - W + T sin(c) = Fv You can say whatever you want but trigonometry and Vector algebra are not against me.
in fact this proves the NASA webpage

so you still pretend jet fighter is a point, and all forces are exerted to this point. that is what i call a simple lack of understanding. let's see, if i put a piece of wood on a table, and you manage to use a finger holding one end of the wood to lift it off the table, then i'll give it to you that trust vectoring can generate lift. how about it? a little experiment, a little empirical data to shcok our world of theorical physics, that would be interesting.

you have murdered so many concepts in this thread.

first is thurst vector and force vector. thurst vector is exerting a vector force on the tail of the plane to produce a torque, a pitch-changing force. the movement of plane's center of gravity is decided by its own force vector, that is the force that directly resulted on the plane's center of gravity. you can't expect to put force anywhere on a object like jet plane and generate same result, so please stop confusing the force vector at tail of the plane with force vector at the center of gravity.

you also fail to distinguish maximum roll rate and maximum sustainable rate of turning. when we say "turn rate" we mean how fast the direction of travel the center of gravity of the plane is changing. maximum roll rate are how fast the nozzle is changing its direction. you can point your nozzle all you want, but that doesn't mean your plane would follow. if you have any clue to the theory of dogfighting, it is the max sustainable turn rate that matters in a dogfight because that allow you to just outturn a tailing bandit. But if you just roll your plane sharply, without changing your direction of travel too much, you're just setting up a easy target for the plane beind you.

i think what i wrote is written in futility, you're already in a deep state of believing that is beyond my reach.

 

[Engineer]

Re: J-20 The New Generation Fighter Thread IV

so you still pretend jet fighter is a point, and all forces are exerted to this point. that is what i call a simple lack of understanding. let's see, if i put a piece of wood on a table, and you manage to use a finger holding one end of the wood to lift it off the table, then i'll give it to you that trust vectoring can generate lift. how about it? a little experiment, a little empirical data to shcok our world of theorical physics, that would be interesting.

In his case, it is not a simple lack of understanding but an intentional distortion of the truth. In any case, one can write equations all he wants, but when those equations cannot be applied to a real systems, then those equations are irrelevant.

 

[jobjed]

Re: J-20 The New Generation Fighter Thread IV

If you aim the thrust of an aircraft in the direction shown in the image, it will head into a nosedive. How that helps your "TVC produces lift" argument escapes me.