>Yes, the theory behind stealth was a Russian discovery, but the aircraft designers never put it into practice. They have had great designers and mathematicians, but the political structure didn’t reward risk takers.
Air force never was main priority in Soviet army. It’s not surprising that Ufimtsev’s theoretical work was not used for practical works in USSR.
>At this point, the new fighter is more like an F-18E, with reduced radar cross section, rather than true stealth.
Why its RCS should be matched with 4th-generation F-18E???
PAKFA has a lot of stealth features: small inclined tail, big usage of composites, internal weapons bays, S-shaped inlet channels.
F-18 still uses classical 4th generation airframe design with external pylons for weapons.
“Air force never was main priority in Soviet army. It’s not surprising that Ufimtsev’s theoretical work was not used for practical works in USSR.”
Air power never was main priority of the Soviet military. Why? Because the Russians know that air power cannot hold ground, only masses of troops can do that - which is why they had enormous armies and proportionatly few planes. Troop casualties were considered insignifigant; they were prepared to lose tens of thousands of troops in any conflict with the west (cf the taking of Germany in WWII).
One other reason air power was not a major consideration was the Russians planned on taking out western fighter bases with tactical nukes. Leaving only their long range bombers and fighters flying. Using nukes was and is always the Russian first response to direct conflict with the west.