J-20 5th Gen Fighter Thread IV (Closed to posting)

[Air Force Brat]

Is not that exactly, if you remove the canards on J-20, you will still have flow separation by virtue of high AoA, the fore body will still generate vortices and the wing it self will have flow separation, the problem is the flow stops flowing parallel to the flight path thus it creates turbulence and you can see that on a Mirage III or F-106, here is where LEVCONs and even canards and LERX help by re-attaching the flow to the wing.
Where the vortices burst can generate buffeting but having two dorsal fins add stability by symmetric vortex burst, F-18 was prone to have structural failure due to buffeting however LEVCONs are a step ahead of LERX by adding control to the vortex and increasing lift and as such moving the vortex burst farther back.

Drag and structural strength play another part in ventral fins, you can see it on the SR-71 that basically flies straight at low AoA but uses ventral fins to reduce drag or structural strength on ERJ-145 AWACS and A-50 AWACS (Indian and Chinese versions ) both added ventral fins without increasing vertical tail area on their original designs.


Wing rock or any roll instability also is dealt with flattening the nose radome as in X-31 or S-37 Berkut.
J-20 uses chines which will help for lateral stability

Mig, we have an aerodynamics thread, I simply answered another forum members question about the J-20, and why the ventral fins will stay. There are many ways to deal with roll-off, the J-20 designers choose to use ventral fins. brat

 

[Skywatcher]

You can get around a lot of whatever RCS penalties imposed by the ventral fins and canards by building them out of radar transparent materials (like the stuff used for radomes). I would strongly caution against building the fuselage out of radar transparent materials, though.

 

[siegecrossbow]

I will strongly suggest against any aerodynamics/stealth discussions on this thread. The other moderators already made this clear! Please adhere to the forum rules, or suffer the consequences!

 

[MiG-29]

This is the funniest thread i have ever seen on a J-20, a thread where basically aerodynamics and stealth is forbidden?
so then what can be talk about it?

The thread is not even technical, is basically very low in technical aspects, we do not even discuss math or equations

Sorry this thread has become really funny i can respect all your points but this thread is becoming absurd, is becoming really funny well enjoy it, if it is to see pictures i will just google it with all due respect you are destroying the main point of the thread.

If it is true aerodynamics and stealth should not create long discussions forbidding them is also absurd since it is basically J-20 is an aircraft

Please Moderators be also more including do not make this thread a boring chapter in sino defence or simple make it a picture album and no more

 

[Blitzo]

There were aerodynamics and stealth related threads before.

Problem with butting into the main J-20 thread with those posts, is that opposing party's forceful opinions can last multiple pages and devolve into veiled insults with technical discussion that is only tangentially related to the main topic at hand.

And think if you're a newcomer to the forum, do you want to see and read pictures of J-20, its developments and news, or an endless mass of back and forth sparring between two or three members?

 

[MiG-29]

There were aerodynamics and stealth related threads before.

Problem with butting into the main J-20 thread with those posts, is that opposing party's forceful opinions can last multiple pages and devolve into veiled insults with technical discussion that is only tangentially related to the main topic at hand.

And think if you're a newcomer to the forum, do you want to see and read pictures of J-20, its developments and news, or an endless mass of back and forth sparring between two or three members?

I completely agree with you, the discussions should be kept to a few post 3 or 4 and no more but forbidding them is also absurd, we should just keep the discussion to a few posts and move on

 

[kwaigonegin]

There were aerodynamics and stealth related threads before.

Problem with butting into the main J-20 thread with those posts, is that opposing party's forceful opinions can last multiple pages and devolve into veiled insults with technical discussion that is only tangentially related to the main topic at hand.

And think if you're a newcomer to the forum, do you want to see and read pictures of J-20, its developments and news, or an endless mass of back and forth sparring between two or three members?

you're wise beyond your years my friend. I for one am glad the mods here are on top of their game and keep us all in relative check otherwise SDF can easily spiral down into the gutter like a lot of defence forums. This is a high quality site.

 

[Engineer]

There were aerodynamics and stealth related threads before.

Problem with butting into the main J-20 thread with those posts, is that opposing party's forceful opinions can last multiple pages and devolve into veiled insults with technical discussion that is only tangentially related to the main topic at hand.

And think if you're a newcomer to the forum, do you want to see and read pictures of J-20, its developments and news, or an endless mass of back and forth sparring between two or three members?

The problem isn't the discussion of underlying physics, but the employment of fallacies. A thread won't go off-topic unless someone drags in a totally unrelated point to prolong an argument.

 

[airsuperiority]

The problem isn't the discussion of underlying physics, but the employment of fallacies. A thread won't go off-topic unless someone drags in a totally unrelated point to prolong an argument.

Both you and Blitz said it very well. Good discussions are awesome, but when people argue senselessly with fallacies and rhetorics, it degrades the dialogue that otherwise could have been respectful and awesome. Regardless, I do agree we should take the in-depth discussions to a dedicated forum, although I hope you guys will continue to keep up with the excellent discussions!!

 

[siegecrossbow]

NOT GOING TO TO SAY THIS AGAIN! As of now, aerodynamics/stealth discussions contribute to too much off topic ramblings that culminate in personal attacks and the like. We don't allow political discussions here for a similar reason.