I suspect however the twin or more engine mantra with the Russian air force will continue so even a light LFI or LFS will likely have two engines.
It is interesting they are talking about a stealthy 5th gen CAS aircraft to replace the Su-25... is it possible they might go for a cross between an F-35 and Su-25 to get a cheap light but stealthy aircraft with the potential for an internal Air to air payload for stealthy use and a huge external payload for anti armour use that is not so stealthy?
i wonder if that LFS will have share such role too. Heard that day of dedicated CAS like A-10 and Su-25 is over.
hmm thinking that Russian diesel boat will be built like Alfa or Yasen
Blended sail to house rescue capsule and hydrodynamics.. Fuel cell AIP, shrouded propeller and spherical sonar as Yasen.
Her armaments would be 6x 650mm tubes slanted as Yasen. Her sonar suite is spherical as Irtiysh Amfora...
Internally however she is similar as German U-212 submarine
My projection of pressure hull arrangement :
Rather ugly but i think it is representative.. Her "waisted" section house the fuel cell generator and engines. outside the hull lies the Liquid Oxygen tank and bottom of it house Metal Hydrate hidrogen storage tank. The huge ball ahead is the spherical array while small "tube" protruding from the mid section is the rescue capsule's pressure hull.
Trends i heard however Russian will use fuel cell with diesel fuel reformer as source of hydrogen. That's fine but in my view it'll impose penalty as that kind of fuel cell will produce carbon dioxide. disposal of Carbon dioxide is possible with use of Cosworth mechanism BUT This will impose power penalty to the AIP to dispose CO2 using Cosworth system.