alt Hacker News> (context: I used to be involved in the design of military radar systems for the Dutch navy) […] Most "stealth" aircraft are actually fairly visible from other directions.
Is that different than ships, which in recent years/decades have tended to look a certain way (a 'finite' number of fixed angles):
* https://en.wikipedia.org/wiki/Knud_Rasmussen-class_patrol_ve...
* https://en.wikipedia.org/wiki/Absalon-class_frigate
Do ships have to have a low return (?) at more angles?
Replies
As I recall, the faceted look of the early stealth aircraft was said to be a practical matter. It reduced the complexity of modeling the reflections during the design process. So with additional computational complexity, they could go back to smooth surfaces in later designs.
I imagine there are similar issues with ship design. Since these things are wavelength specific, you probably have a bigger computational problem for a bigger vessel. You can't just solve for the design on a miniature and scale it up to build it.
Ships like that are typically optimized to look small from "low" angles, ie from the perspective of other surface combatants and sea skimming anti ship missiles. The large flat surfaces are not so much used to reduce RCS by themselves, but mostly to reduce instances of "corner reflectors" like hatches and exposed cranes the like, which can have a RCS many times larger than their physical size due to their shape.
See also the "Reduction" section on Wikipedia in the article about Radar Cross Section: (https://en.wikipedia.org/wiki/Radar_cross_section#Purpose_sh...).