J-20 Mighty Dragon and F-22 Raptor have the best planform alignment
Definitions and Terminologies:
Stealth technology - Wikipedia, the free encyclopedia
"Planform alignment is also often used in stealth designs.
Planform alignment involves using a small number of surface orientations in the shape of the structure. For example, on the F-22A Raptor, the leading edges of the wing and the tail surfaces are set at the same angle. Careful inspection shows that many small structures, such as the air intake bypass doors and the air refueling aperture, also use the same angles.
The effect of planform alignment is to return a radar signal in a very specific direction away from the radar emitter rather than returning a diffuse signal detectable at many angles."
F-22 Stealth
"Jul 7, 2011
The leading and trailing edges of the wing and tail have identical sweep angles (a design technique called planform alignment)."
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Let's examine the planform alignment for the Chinese J-20 Mighty Dragon, U.S. F-22 Raptor, and Russian Pak Fa/T-50. The comparison will focus on the main wings and the winglets (e.g. canards for J-20 and tailplanes for the F-22 and T-50).
The J-20 Mighty Dragon edge alignment for its main wings and canards has only five different sweep angles (e.g. red, green, orange, yellow, and blue).
The F-22 matches the J-20 in edge-alignment design for its main wings and rear horizontal tailplanes. The F-22 also has a total of only five different sweep angles (e.g. red, green, orange, yellow, and blue).
The Pak Fa/T-50 has the worst edge-alignment design for its main wings and rear horizontal tailplanes. The Pak Fa/T-50 has a massive total of 11 different sweep angles (e.g. addition of pink, light blue, purple, dark red, black, and white).
In conclusion, the Pak Fa/T-50 cannot match the stealthiness of the planform alignment design of the main wings and winglets for the J-20 and F-22. With an extra six different sweep angles, the Pak Fa/T-50 is clearly more detectable by radar in many more directions.
[Note 1: There is a small correction to this post. This picture of the Pak Fa led me to conclude that the Pak Fa has a total of 11 different sweep angles. If you look at other more vertical pictures of the Pak Fa, it is clear the Pak Fa has nine different sweep angles. The conclusion of this post doesn't change. The Pak Fa's nine different sweep angles are still almost twice as many as the J-20's and F-22's five sweep angles.]
[Note 2: I want to credit "Phaid" (post on 10/3/2010 8:03:28 AM) with noticing the inferior planform alignment of the Pak Fa/T-50. Though he did not perform the detailed analysis that I just did, I want to credit him with the earlier insight.]