Low specific thrust engines tend to have a high bypass ratio, but this is also a function of the temperature of the turbine system.
42.
However, ultra-high bypass ratio turbofans have a very low design fan pressure ratio ( e . g . 1.2, on the bypass section ).
43.
The bypass ratio was intentionally designed to be very low, to avoid the inlet instability issues associated with earlier TF30 engines on the F-111.
44.
Boeing was far behind its competitors when the 737 was launched, as rival aircraft Pratt & Whitney JT8D-1 low-bypass ratio turbofan engine, delivering thrust.
45.
For turbojets the gain is limited to 50 %, while it depends on the bypass ratio in a turbofan and can be as much as 70 %.
46.
If, however, the afterburner is to be hardly used, a low specific thrust ( low fan pressure ratio / high bypass ratio ) cycle will be favored.
47.
The amount of air that bypasses the core engine compared to the amount flowing into the engine determines what is called a turbofan's bypass ratio ( BPR ).
48.
While current engines operate best at a single point in the flight envelope, newer engines could vary their bypass ratios for optimum efficiency at any speed or altitude.
49.
Some high bypass ratio ( e . g . civil ) turbofans now feature a mixer, the advantage being a small thrust gain, which improves specific fuel consumption.
50.
The FJX-2 engine was designed with many experimental systems and manufacturing processes to minimize parts count and lower production costs and having a bypass ratio of 4 : 1.
