TomS said:
It still has to penetrate defenses. Any radar looking from off axis (from the side or even from above or below) will see a nice clear constant-radius curve.
And don't even get started on the IR issues of making no attempt to conceal hot metal or to attenuate exhaust.
This is a bad joke of a design if they are even slightly concerned about signature management.
With all due respect, the bad joke here is the assumption that this is what the final product will look like. Where does that come from?
It seems *decidedly* more likely to me that this is but the first of several prototypes, and intended to test aspects (FCS? Autonomy? Structures? Inlet performance?) for which full LO would be a needless waste of money. Flateric has already mentioned the X-47B as such an example, which was aerodynamically representative but also paid little heed to RCS reduction in detail because its job was merely to demonstrate aerial refueling and carrier ops. Apart from its "antenna farm", the nozzle was actually decidedly improvised too - sure, it was non-axisymmetric but the exhaust deck edges were exposed and *anything* but stealthy:
https://www.ainonline.com/sites/default/files/uploads/2013/06/x-47b.jpg
https://upload.wikimedia.org/wikipedia/commons/f/f6/X-47B_receiving_fuel_from_a_707_tanker_while_operating_in_the_Atlantic_Test_Ranges.jpg
https://www.northropgrumman.com/Photos/pgL_UC-10028_020.jpg
http://cms.ipressroom.com.s3.amazonaws.com/295/files/201607/220750.jpg
Last but definitely not least, the leaked slide which gave us the first public glimpse of Okhotnik showed a configuration (with hindsight probably a full-scale mock-up or RCS test model) that had a perfectly stealthy rear end:
https://www.uasvision.com/wp-content/uploads/2017/08/Hunter-B-project.jpg
As do the silhouettes painted on Su-57 #053. So to believe that the engine nozzle will stay this way flies in the face of both logic and multiple clues.
sferrin said:
Interesting that it also appears to have a radome up front.
The B-2 has two

Another possibility could be a sense-and-avoid radar for peace time operations in civilian airspace (which would be another important technology to test that doesn't require the airframe to be stealthy, in fact).