J-20... The New Generation Fighter III

Bltizo said:

Never accused DoD of misreporting J-20.
Though I wonder why they call J-10 and J-11 by F-10 and F-11. By that logic J-20 should = F-20

Click to expand...

Engineer said:

To summarize, Dr. Song started out with a wing that has low drag at supersonic speed but performs poorly at subsonic speed/high AoA, and augmented the heck out of it with lift. The first obvious feature is LEX, then comes canards, and finally lift from body. In the end, through the interaction between LEX and canards, he was able to get even more lift by reducing* the wing's aspect-ratio, even though the conventional wisdom is that the larger aspect-ratio the better. The presence of LEX enables the canards to be placed far from the wings yet provide similar lift enhancement as close-couple canards. Canard configuration is also chosen because in the absence of TVC, canards provide total pitch authority at maximum AoA whereas elevators cannot.

*Obviously, the J-20 is an unconvential design, and cannot only be analyzed with classical aerodynamic theories.

Click to expand...

siegecrossbow said:

.....If China was willing to trade maneuverability for weight then the obvious choice would be implementing larger vertical stabilizors instead of risking all moving ones.

Click to expand...

Quickie said:

Looks like those people are not able to see pass the more conventional aerodynamics design they're so used to, to come to understand the more unconventional methods of achieving aircraft design requirement as proposed in Dr Song's paper.

My opinion is that the use of canards in the J-20 design, or any other jetfighter, already points to a maneuverablity requirement. The thing is, if the intended design is that of a striker jetfighter, the use of the canards would already be out of the question. There has never been a dedicated canard striker/bomber jetfighter and the J-20 designer would certainly not make an exception as if designing a stealth figher is not already complicated enough.

Click to expand...

siegecrossbow said:

Two more flights today. THis makes it... I don't know... These flights are significant, however, since the J-20 and the JF-17 performed aerobatic maneuvers for Xi Jinping! Here are the pictures.

Click to expand...

Engineer said:

The presence of LEX enables the canards to be placed far from the wings yet provide similar lift enhancement as close-couple canards. Canard configuration is also chosen because in the absence of TVC, canards provide total pitch authority at maximum AoA whereas elevators cannot.

*Obviously, the J-20 is an unconvential design, and cannot only be analyzed with classical aerodynamic theories.

Click to expand...