Kaveri has a lower BPR compared to F-404IN. The best I have read for Kaveri is 0.2-0.24. Normally I read a BPR of 0.16 for kaveri. For F-404 its around 0.36.
F-22 engine ie. the F-119 is not a variable cycle engine. In fact that is one of the main reasons the F-22 got selected instead of YF-23 which had the YF-120 engine by GE and that was a Variable cycle turbofan. Variable cycle engines begin to grow more complex and costly too that is why some of the earliest variable cycle engines were used on exotic mission airplanes like Valkyrie and SR-71. But complexity is often not liked by air forces.
P&W F-119 is the base for the F-135 for JSF F-35 and in future the F-119 is hoped to be turned into a Variable cycle or Adaptive cycle engine (I think multiflow type).
All serious fighter engines today have at least .36 bypass ratio and more modern ones have around 0.59 (AL-31), around 0.57 (F-135). https://engineering.purdue.edu/~propulsi/propulsion/jets/tfans.html
The bypass ratio is important for all types of engines. Only that the exact ratio required is different each time depending upon how far it is operating from its main operating requirements. For example the AL-31/41 series of engines are designed to primarily push the Sukhoi-27/30 family upto Mach 2+. That would be their natural sweet spot. But below those speeds they would be flying for 90% of the times (like all other fighters) esp. while in loaded take off or post stall maneuvering the Sukhoi will require a lot of raw power and that is when the bypass will be very helpful. In future you are going to see higher BPR military engines because that is the maximum time the engines get used and air forces want to cut costs too. And these higher BPRs will be by augmented multiflow variable cycles only.
F-22 engine ie. the F-119 is not a variable cycle engine. In fact that is one of the main reasons the F-22 got selected instead of YF-23 which had the YF-120 engine by GE and that was a Variable cycle turbofan. Variable cycle engines begin to grow more complex and costly too that is why some of the earliest variable cycle engines were used on exotic mission airplanes like Valkyrie and SR-71. But complexity is often not liked by air forces.
P&W F-119 is the base for the F-135 for JSF F-35 and in future the F-119 is hoped to be turned into a Variable cycle or Adaptive cycle engine (I think multiflow type).
All serious fighter engines today have at least .36 bypass ratio and more modern ones have around 0.59 (AL-31), around 0.57 (F-135). https://engineering.purdue.edu/~propulsi/propulsion/jets/tfans.html
The bypass ratio is important for all types of engines. Only that the exact ratio required is different each time depending upon how far it is operating from its main operating requirements. For example the AL-31/41 series of engines are designed to primarily push the Sukhoi-27/30 family upto Mach 2+. That would be their natural sweet spot. But below those speeds they would be flying for 90% of the times (like all other fighters) esp. while in loaded take off or post stall maneuvering the Sukhoi will require a lot of raw power and that is when the bypass will be very helpful. In future you are going to see higher BPR military engines because that is the maximum time the engines get used and air forces want to cut costs too. And these higher BPRs will be by augmented multiflow variable cycles only.
