Rear S-Ducted Exhausts on Future Aircraft?

[X-39]

Hi, i am relatively new, and I've been lurking around for quite some time but finally this is my first post

It is widely known that stealth aircraft use serpentine intakes with the purpose of reducing IR signature, scatter radar waves and also preventing engine faces from creating additional reflections. But i wonder whether we might see the emergence of more intricate designs in future aircraft to further improve Low observability, like shown below, where we can clearly see the ADVENT and SR-72 concepts feature not only curved inlets, but the exhaust ducts are also shaped to prevent direct line of sight from the rear :

Also i found this image suggesting the B-2 Spirit may in fact use such system, but its just a rumour as far as i know, whereas the F-22 and YF-23 engine blades are fully visible:

Do you think we could see this some day in the future on aircraft like PCA and B-21, or the costs and complexity of shielding an aircraft's rear will outweight the benefits of this application?

 

[antigravite]

Hi

This may not answer your question but it can help understanding what is possible, what is not, and what's coming up.

A while back at the Paris Airshow, I saw in a French booth a manufacturer exhibiting a 6-axis 3D printing machine. This very peculiar printer was sintering metals in a neutral atmosphere. The beauty of this thing is that you could start your design with a sintered aluminium powder and end up at the other end of the same design, with a standard stainless steel alloy. Now what. If you apply this to any S-turn shaped inlets / exhaust, you can design anything with stealth related ferromagnetic properties at the begining and heat dissipation at the end. Your part can be tailored to graded functional properties. 6 axis means that the 3S printer was composed of a 3 axis table on which the 3D part would be grown, as well as a standard 3-axis arm having powder injectors combined with a laser.

A.

 

[Manuducati]

GD-McAir A-12 already had this kind of exhaust if I'm not mistaken.

 

[flateric]

But i wonder whether we might see the emergence of more intricate designs in future aircraft to further improve Low observability, like shown below, where we can clearly see the ADVENT and SR-72 concepts feature not only curved inlets, but the exhaust ducts are also shaped to prevent direct line of sight from the rear :

Also i found this image suggesting the B-2 Spirit may in fact use such system, but its just a rumour as far as i know, whereas the F-22 and YF-23 engine blades are fully visible:

It's not 'suggesting' that B-2 has S-shaped exhausts, she _has_ it for 30+ years. This is [sanitized] drawing from B-2A TO.