Variable pitch fans for turbomachinery engines

A turbomachinery engine comprising:

• a fan assembly including a plurality of variable pitch fan blades, a first VPF parameter, and a second VPF parameter, wherein:
• the first VPF parameter is defined by a fan blade radius ratio (RR) divided by a fan pressure ratio (FPR) at a static sea-level takeoff operating condition;
• the second VPF parameter is defined by a bearing spanwise force (F_Span) at a redline operating condition measured in pounds force divided by a fan area (F_Area) measured in square inches;
• and
• the first VPF parameter is within a range of 0.1 to 0.25 and the second VPF parameter is within a range of 2-30 lbf/in2;
• a core engine including one or more compressor sections and one or more turbine sections;
• and
• a gearbox including an input and an output, wherein the input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, wherein the output is coupled to the fan assembly and has a second rotational speed which is less than the first rotational speed.

A turbomachinery engine comprising:

• a fan assembly including a plurality of variable pitch fan blades, a first VPF parameter, and a second VPF parameter, wherein:
• the first VPF parameter is defined by a fan blade radius ratio (RR) divided by a fan pressure ratio (FPR) at a static sea-level takeoff operating condition;
• the second VPF parameter is defined by a bearing spanwise force (F_Span) at a redline operating condition measured in pounds force divided by a fan area (F_Area) measured in square inches;
• and
• the first VPF parameter is within a range of 0.10 to 0.40 and the second VPF parameter is within a range of 5.25-30.0 lbf/in2;
• a core engine including one or more compressor sections and one or more turbine sections;
• and
• a gearbox including an input and an output, wherein the input is coupled to the one or more turbine sections of the core engine and comprises a first rotational speed, wherein the output is coupled to the fan assembly and has a second rotational speed which is less than the first rotational speed.