An interesting video about T-50 program was published by Russian 'Roscosmos TV'. The follow text is my translation to English:
Short acceleration –
Ilia Fedorov, the Supervising Director of NPO 'Saturn', deputy general director of the Russian 'United Engine-building Corporation' (UEBC) tells about the difference of t-50's engine:
- "It has different thrust, naturally different tuning control. The number of constructive differences allow better thrust with lower fuel consumption. And the most important – it has totally different system of control".