成飞那架从照片上看很明显有split rudder。B-2是不需隐身是用split rudder，需要隐身时不用split rudder，因为使用split rudder降低隐身性。我们不清楚成飞那架是任何时候都使用split rudder，还是像B-2那样只有不需要隐身时才用split rudder.
至于B-21则是完全不用split rudder。因此至少在这方面，B-21的隐身技术超过B-2及成飞那架。成飞那架在这方面，至多只到B-2的水平，也就是五代机的水平。
Reference: https://hushkit.net/2023/11/16/why-the-new-b-21-raider-stealth-bomber-look-the-way-it-does/
Excerpt 1:
The B-2 users split drag rudders for directional control when not in stealth mode, while relying on differential thrust and the remaining control surfaces when LO is vital.
Excerpt 2:
The B-21 geometry is consistent with advances in both predictive tools and confidence gained from related LO platforms. The elimination of the split rudders and potential exploitation of proverse yaw is an example.
