DRDO and PSU's

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I had seen a documentary of northrop where they said they achieved stealth with not just edge alignment but also with CURVED SURFACES such that radar waves doesn't bounce back instead scatter away. I think the documentary was abt tacit blue technology demonstrater which was equivalent to have blue which was further developed into f117.
The tacit blue achieved stealth with curved surface unlike f117. The learnings were basis for b2 spirit and later yf23. The chin of yf23. They had also said indirectly yf23 was more stealthier than yf22.

Edge alignment doesn't make a aircraft stealth.
It's just one of the components of stealth, a component used to reduce radar return.

A fighter jet without no edge alignment but designed to scatter radar waves away, in whatever direction except sender direction
with no funneling into certain directions can be be stealthy enough to be called a stealth jet but with edge alignment it could become more stealthy.
a design with single continous wing with an constant angle designed to scatter radar waves away become even more stealthy as it scatters them away and form narrow lobes on side of the aircraft, basically flying wing designs.
Flying wings without vertical tails and constant wing maintaining constant angle, basically have perfect edge alignment.

Stealth by shape:-
include shaping to scatter radar waves away from the sender's direction, edge alignment where possible to further improve stealth, trying to reduce round surfaces at junctions, trying to reduce 90° angles as much as you can.
Best shapes are flying wing, but also most aerodynamically challenging to fly and maneuver.
So a balance is needed between stealth and aerodynamics, based on the requirements.

Stealth by material:-
RAM, RAS.
Good ram is one that can reduces rcs by 15-20 dbsm, can handle high speed, can handle high heat, is long lasting.
Now all these "high" and "long lasting" is relative.
As "good" is also relative.
RAS are basically composites material with RAM like ability to significantly absorb radar waves.
Are much Superior, Stealth is baked into skin of stealth jet, much more capable of handling high speed, heat, longer lasting.
Less hassle to regularly paint the ram.
lockheed calls it's RAS as fibremat, used in f35.
F35 has both ras skin and further coating of ram.


Now how stealthy a jet is depends on combined effect of all these.

And f117's design of having so many angles and edges instead of round surface was due to limit of computers at that time to design a stealth jet.
Better computer+software=can now design a stealth jets with round surfaces too.