Source/proof and all aerospace companies are saying that DSI worked under the Mach-2, you know nothing about basic of aerodynamics aircraft engineering and you consider yourself proclaimed expert on aerodynamics/aircraft engineering what the fcuk
@undertakerwwefan 
and tell me which jet with DSI can reach Mach-2+ speed with DSI
@undertakerwwefan 
and don't tell me J-20 was achieved with current WS-10B/AL-31FN J-20 can't super cruise lets forget MACH-2+ speed
@undertakerwwefan 
and there 2 type of engines low by pass ratio turbofan which using most of the 5th gen jets like F-119/Al-31/WS-10/AL-41F which acting like early turbo jets to go beyond Mach-2+, and high by pass ratio turbo fan which best for cruising at subsonic and Can't reach Mach-2( F-35 engine is high by pass ratio turbo fan F-135), that why high by pass ratio turbo fan using all airlines of the world for economic cruising/fuel efficiency
@undertakerwwefan
Because the priorities for military aircraft (engines) are different. While it is true that the high bypass turbofans have better fuel economy (in cruise) and are less noisy, the low bypass engines offer significant advantages when we take into account their intended use in combat aircraft, such as:
- The response of the low bypass turbofans to throttle adjustments is faster compared to the high bypass turbofans; the inertia is less and less air mass is involved (for increasing the velocity)- This is important during combat, when thrust requirements change rapidly.
- They have less frontal area, reducing the drag produced. For aircraft expected to fly at supersonic speeds, however briefly, this is important.
- Better thrust to weight ratio- 6:1 in Trent 1000 Vs 9:1 F119 (used in F-22 Raptor)- Even if the actual thrust produced by the low bypass turbofans is lesser, they produce more thrust per kg of engine, which means that the engine can be more compact in size.
- The low bypass turbofans are more efficient at higher speeds compared to the high bypass turbofans.
- The lesser size of the low-bypass turbofans mean that the aircraft can be made stealthier by 'burying' the engines in the fuselage, which is all but impossible in case of high bypass turbofans
its aerodynamic tech known known to all aerospace companies of west @undertakerwwefan
