The first finished model of 2017. HobbyBoss kit in 1:72ish scale (closer to 1:60 I guess) and Begemot decals. Several changes had to be made in order to bring the kit, built to represent the first two prototypes, to the rebuilt 5th flying prototype.
Full article and gallery here: https://vvsmodelling.com/2017/08/01/sukhoi-su-57-t-50-5r-pak-fa/