Actually Kwai, I'm holdin my breath for something special ahead of those nozzles???? Pitot tube is a relatively external accesory, so I'm suspecting something a little more spectacular, we shall see shortly??? I HOPE! Brat
J-20 5th Gen Fighter Thread IV (Closed to posting)
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Actually Kwai, I'm holdin my breath for something special ahead of those nozzles???? Pitot tube is a relatively external accesory, so I'm suspecting something a little more spectacular, we shall see shortly??? I HOPE! Brat
Remember, the J-20's combat readiness is constantly shifting as systems become mature for it; for example, consider the T:W on a J-20 with an 117 engine set compared to the AL-31 or WS-15s with ~180 KN of thrust. If you assume the J-20 w eighs 30,000 KG, with projected WS-15s you'd get 1.22 T/W while you'd get a 1 T/W with 117 engines.
The J-20's WVR performance could be comparable to the F-15C now, but with TVC added it would probably be superior to the F-22, and between the J-20 and F-15 derivatives (F-15J) it would have stealth.
Compare to the F-35, which is comparable to late model bomb-truck F-16s in WVR.
The more worrying problem is that, lacking EODAS, how the J-20 would perform against the PAK-FA as a WVR fighter. The lower wing loading on the PAK-FA is likely to give the PAK-FA an advantage as a WVR fighter, and the LEVCONs partially cancel out any advantages from the canards.
The J-20's WVR performance could be comparable to the F-15C now, but with TVC added it would probably be superior to the F-22, and between the J-20 and F-15 derivatives (F-15J) it would have stealth.
Compare to the F-35, which is comparable to late model bomb-truck F-16s in WVR.
The more worrying problem is that, lacking EODAS, how the J-20 would perform against the PAK-FA as a WVR fighter. The lower wing loading on the PAK-FA is likely to give the PAK-FA an advantage as a WVR fighter, and the LEVCONs partially cancel out any advantages from the canards.
IF it lacks EODAS. All indications seem to point it will field some sort of 360 degree passive detection system. Whether it will be as comprehensive and capable is another matter.
And LEVCONS cancelling out advantages of canards? I'm really not sure their aerodynamic "benefits" work in this additive way
Engineer
Major
F-22 has better performance despite F-15 having better thrust-to-weight ratio. So, you cannot claim two aircraft to have similar performance just because of the similar thrust-to-weight ratios.
Another thing is that maneuverability doesn't get increased by simply adding TVC. It doesn't work that way at all else aircraft having TVC wouldn't need to have wing. Maneuverability is correlated with complexity in aerodynamics, and the aerodynamics employed on J-20 is far more complex than what was employed on the F-15.
I fail to see your logic, as EODAS has nothing to do with maneuverability.
In the old days, when only the wing is used to generate lift, wing loading was a good way to compare performance of aircraft. Now days, aircraft heavily employ vortex induced lift through the use of LERX and canard. Wing loading doesn't tell you anything about vortex induced lift, so is an outdated method for gauging an aircraft's performance.
As for LEVCON, think of it as an oversized leading-edge flap with an added ability to manipulate vortices. It doesn't provide the same capabilities as canard, such as full pitch authority in high AoA.
I don't see any portholes for EODAS on the J-20 airframe; we saw some holes on the aircraft but these seem to be for maintenance purposes; aside from rumors I don't understand why the J-20 would have EODAS.
EODAS matters in WVR because it can partially cancel out the need for maneuverability in combination with LOAL. It is still an unproven technology and there are still advantages from having higher maneuverability (decreases NEZ of enemy BVR missies, for instance), but it's an advantage.
TVC matters because it does add maneuverability; it enables true post-stall maneuverability, as I've said, and this could be enough.
LEVCONs add maneuverability and I'm guessing high-AOA performance, but do not do it as well as canards do. It is stealthier than canards when it comes to side stealth, however, and probably stealthier when in use than the canards.
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As far as TWR goes, that is one aspect of an aircraft's performance and it can help compensate for other weaknesses. For example, the wing-loading on the J-20 will likely be more comparable to the late-model Flankers than the wing-loading on the Gripen or the F-22. This can be canceled out in part by having a better thrust-to-weight ratio. LERXes can enhance high AOA performance, but between a LERXed-aircraft with low wing-loading and a LERXed-aircraft with high wing-loading, the former will be more maneuverable and show better range and performance.
EODAS matters in WVR because it can partially cancel out the need for maneuverability in combination with LOAL. It is still an unproven technology and there are still advantages from having higher maneuverability (decreases NEZ of enemy BVR missies, for instance), but it's an advantage.
TVC matters because it does add maneuverability; it enables true post-stall maneuverability, as I've said, and this could be enough.
LEVCONs add maneuverability and I'm guessing high-AOA performance, but do not do it as well as canards do. It is stealthier than canards when it comes to side stealth, however, and probably stealthier when in use than the canards.
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As far as TWR goes, that is one aspect of an aircraft's performance and it can help compensate for other weaknesses. For example, the wing-loading on the J-20 will likely be more comparable to the late-model Flankers than the wing-loading on the Gripen or the F-22. This can be canceled out in part by having a better thrust-to-weight ratio. LERXes can enhance high AOA performance, but between a LERXed-aircraft with low wing-loading and a LERXed-aircraft with high wing-loading, the former will be more maneuverable and show better range and performance.
Engineer
Major
So you admitted there are portholes, then at the same time denied seeing any porthole. This seems like a self-contradicting statement to me.
While EODAS is an advantage, it can hardly serve as a partial replacement for maneuverability the way you claimed. At the end of the day, for an aircraft to get behind an opponent's 6 o'clock requires maneuverability. To outrun an opponent or a missile also requires maneuverability.
This is a misconception. While TVC enables post-stall maneuverability, it does not equate to added maneuverability in the sense of letting an aircraft get to an opponent's 6 o'clock easier. To understand this, think of thrust vectoring as something that allows the aircraft's nose to point to different directions, while maneuverability as something that gives the ability to an aircraft to fly in circles. To fly in circles, the aircraft needs a force that pulls the plane toward the center of the turn. Doing so requires lift, which is an aerodynamic property. TVC doesn't provide extra lift, so it doesn't add to turning performance.
I do not see how your logic works on this one.
No. Maneuverability is related to the amount of lift generated, not wing loading. Consider two aircraft having the same weight, the aircraft that can generate more lift will have better maneuverability irrespective of whether the wing loading is higher. Let's look at a real world example. F-15 has and . F-22 has and . It is quite obvious that F-22 has better maneuverability despite having higher wing loading.
Obviously, having high thrust-to-weight ratio is good. There is no denying that. However, this doesn't mean two aircraft having similar thrust-to-weight ratio means similar performance. Going off tangent on why high thrust-to-weight ratio is good doesn't make your generalization a valid one.
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The diamond shaped windows on the side of the nose are certainly possible contenders, no?
If you look at F-35, it is very difficult to spot its DAS apertures. Considering the paint scheme of J-20 and how difficult it is to spot any weapon bay or landing gear bay join or even any seal between fuselage pieces, the fact that EODAS holes are difficult to spot is not surprising
Blitzo:
Yeah, I'd agree that the windows on the side of the nose are contenders, but they don't seem to be evident all around the body like the 360-degree EODAS system of the F-35.
With regards to Engineer:
You have a condescending or didactic air that makes people dislike arguing with you. If you're going to call me out for flaming, your attitude is getting to me and I am going to call you out for it.
I'm not equivocating, but I said portholes for EODAS. We saw portholes on the aft of the aircraft, but people decided that those were maintenance portholes or vents for the engine as on the F-22.
TVC provides additional maneuverability by allowing a fast change in the direction of thrust, which is probably more useful for instantaneous turn-rates than sustained turn rates as it entails at least a temporary reduction in the rear 0-degree thrust vector.
As far as not affecting turning performance, let's do a thought experiment. An F-22 or Su-35BM is locked to a point in space and all rearward thrust is negated by an equivalent to Laplace's Demon exerting a countervailing pushing force. We assume that magically the airplane can sustain the complete push against its thrust force without falling apart. With the forward thrust vector completely removed, the upward or downward thrust vector while TVC is active and forces the F-22 to do somersaults. That's considered a turn. You can tilt the plane on its side and do the same thing. That's still a turn, even with a turn radius of 0 feet.
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Traveling waves that hit the canard eventually reach the rear of the canard and rescatter, creating unwanted emissions. With planform alignment, these waves can be mostly absorbed by the wing or other aspect of the aircraft and reduce the return emissions to the original source. But this is not superior to having a single wing, with a LEVCON attached in front, providing a single continuous structure.
I do admit that the canards are superior for vortex control and for the fact that the LEVCONS under some conditions can block engine air flow, but canards are inferior for stealth.
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My argument has never been that wing-loading is the sole determinant of airframe performance, but rather that wing loading is one aspect of airframe performance and that other aerodynamic features can add to maneuverability despite having a poor wing-loading.
In the case of the F-22, the F-22 is augmented by having TVC nozzles to increase pitch control and increase turn rate, as well as having LERXes to enhance body lift. Comparing the F-22 and the F-15, the lower wing loading is compensated for by aerodynamic bells and whistles.
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And as far as claiming that wing-loading is something completely irrelevant, we can make a determination of this quite easily.
Let's say, we have a J-10 loaded with 100% fuel and 50% fuel. The one with 100% fuel has higher wing loading, as it has the same wing area os the 50% fuel J-10, but also has higher weight. The one with higher fuel quantities will be less maneuverable than J-10 with lower fuel quantities because the lift force is acting on a lighter weight than the one with the full fuel.
All other factors being equal, the aircraft with the higher wing loading is less maneuverable. This can be compensated for by aerodynamic bells and whistles, of course.
Yeah, I'd agree that the windows on the side of the nose are contenders, but they don't seem to be evident all around the body like the 360-degree EODAS system of the F-35.
With regards to Engineer:
You have a condescending or didactic air that makes people dislike arguing with you. If you're going to call me out for flaming, your attitude is getting to me and I am going to call you out for it.
I'm not equivocating, but I said portholes for EODAS. We saw portholes on the aft of the aircraft, but people decided that those were maintenance portholes or vents for the engine as on the F-22.
TVC provides additional maneuverability by allowing a fast change in the direction of thrust, which is probably more useful for instantaneous turn-rates than sustained turn rates as it entails at least a temporary reduction in the rear 0-degree thrust vector.
As far as not affecting turning performance, let's do a thought experiment. An F-22 or Su-35BM is locked to a point in space and all rearward thrust is negated by an equivalent to Laplace's Demon exerting a countervailing pushing force. We assume that magically the airplane can sustain the complete push against its thrust force without falling apart. With the forward thrust vector completely removed, the upward or downward thrust vector while TVC is active and forces the F-22 to do somersaults. That's considered a turn. You can tilt the plane on its side and do the same thing. That's still a turn, even with a turn radius of 0 feet.
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Traveling waves that hit the canard eventually reach the rear of the canard and rescatter, creating unwanted emissions. With planform alignment, these waves can be mostly absorbed by the wing or other aspect of the aircraft and reduce the return emissions to the original source. But this is not superior to having a single wing, with a LEVCON attached in front, providing a single continuous structure.
I do admit that the canards are superior for vortex control and for the fact that the LEVCONS under some conditions can block engine air flow, but canards are inferior for stealth.
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My argument has never been that wing-loading is the sole determinant of airframe performance, but rather that wing loading is one aspect of airframe performance and that other aerodynamic features can add to maneuverability despite having a poor wing-loading.
In the case of the F-22, the F-22 is augmented by having TVC nozzles to increase pitch control and increase turn rate, as well as having LERXes to enhance body lift. Comparing the F-22 and the F-15, the lower wing loading is compensated for by aerodynamic bells and whistles.
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And as far as claiming that wing-loading is something completely irrelevant, we can make a determination of this quite easily.
Let's say, we have a J-10 loaded with 100% fuel and 50% fuel. The one with 100% fuel has higher wing loading, as it has the same wing area os the 50% fuel J-10, but also has higher weight. The one with higher fuel quantities will be less maneuverable than J-10 with lower fuel quantities because the lift force is acting on a lighter weight than the one with the full fuel.
All other factors being equal, the aircraft with the higher wing loading is less maneuverable. This can be compensated for by aerodynamic bells and whistles, of course.
Canards don't impede stealth if they are kept parallel to the wing. The only time when you need canards to manoeuvre is when you're in a dogfight, by which point stealth doesn't matter at all, unless you have camouflage panels that allow you to blend in with the sky. For all practical purposes while not dogfighting, elevons can do the limited manoeuvring required.
MiG-29
Banned Idiot
Canards are not worse for stealth, that is true, but tailplanes are better behind the wing since they are shielded by the wing reducing the RCS from a frontal aspect, J-20 has worse RCS than F-22 simply for that, its canards with dihedral are not shielded from a frontal view by the wing and basicly are very visible from a frontal view, having also diferent angle than the vertical tails and ventral tails increasing RCS into another direction.
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