SamuraiBlue
Captain
oh, and yes those "black birds" had 400lbs of radar absorbent paint! and yes it does work, they did indeed fly deep into China.
No matter how much radar absorbent paint you put on, a look down radar will spot a plane from above due to the large wing surface that is visible to the radar.
Radar cross section is measured by the amount of radar energy bouncing back to the source.
From the frontside, the surface space is relatively small compared to the large wing surface you can see from above.