Aircraft with boundary layer ingestion device having center position between center position of fuselage and center position of rear end portion of fuselage
An aircraft according to the present technology includes: a fuselage section; and a BLI propulsion section. The fuselage section has a cylindrical shape that is long in an axial direction and short in a width direction and a vertical direction, and includes a rear end portion on a rear side in the axial direction. The BLI propulsion section is a BLI propulsion section that is provided on a rear side of the fuselage section and includes an intake port, a center position of the intake port being offset from a center position of the rear end portion in at least one of the vertical direction or the width direction.
1 . An aircraft, comprising:
a fuselage section that has a cylindrical shape with a first predetermined length in an axial direction and a second predetermined length in a width direction and a vertical direction, and includes a rear end portion on a rear side in the axial direction, wherein the first predetermined length is longer than the second predetermined length, wherein the fuselage section has a shape in which an outer diameter gradually decreases toward the rear end portion on the rear side, wherein a center position of the rear end portion is located above a center position of the fuselage section at a position corresponding to a maximum diameter of the fuselage section in the vertical direction; and
a boundary layer ingestion (BLI) propulsion device that is provided on the rear side of the fuselage section and includes an intake port, wherein a center position of the intake port is located between the center position of the fuselage section and the center position of the rear end portion in the vertical direction, and wherein the center position of the intake port is offset below the center position of the rear end portion in the vertical direction,
wherein the BLI propulsion device includes at least one impeller that is rotatable with an axis directed in the axial direction as a central axis, and
wherein a position of the central axis is offset above the center position of the intake port in the vertical direction.
2 . The aircraft according to claim 1 , wherein a non-overlapping region exists where a region corresponding to the maximum diameter of the fuselage section and a region corresponding to the intake port do not overlap with each other when the maximum diameter of the fuselage section and the intake port are viewed from the axial direction, and
wherein an area of the non-overlapping region occupies less than 60%.
3 . The aircraft according to claim 1 , wherein a value of AR is 1.3 or more, AR being represented by (2a) 2 /Sfan, 2a being a length of the intake port in the width direction, Sfan being an area of the intake port.
4 . The aircraft according to claim 1 , wherein the at least one impeller includes a first impeller and a second impeller aligned in the width direction, and
wherein a rotation direction of the first impeller and a rotation direction of the second impeller are in opposite directions.
5 . The aircraft according to claim 4 , wherein the rotation direction of each of the first impeller and the second impeller is a rotation direction corresponding to inboard-up rotation.
6 . The aircraft according to claim 1 , wherein the at least one impeller has a central axis of rotation located outside the center position of the intake port in the width direction.
7 . The aircraft according to claim 1 , further comprising:
a landing section provided below the fuselage section; and
an angle formed between the axial direction and a tangent connecting a ground contact point of the landing section and the lowest point of the BLI propulsion device when the fuselage section and the landing section are viewed from the width direction, wherein the angle exceeds 10.5°.
8 . The aircraft according to claim 1 , wherein the intake port is disposed behind a position where a width of the fuselage section is 50% of a maximum value of the width of the fuselage section in the axial direction.
9 . The aircraft according to claim 1 , wherein a position of the BLI propulsion device corresponding to the center position of the intake port is not joined to the fuselage section.
10 . The aircraft according to claim 1 , wherein the intake port is disposed behind a position where a cross-sectional area of the fuselage section perpendicular to the axial direction is 25% of a maximum value of the cross-sectional area in the axial direction.
11 . The aircraft according to claim 1 , further comprising:
a main engine section that includes a generator,
the BLI propulsion device being driven by electric power from the generator.
12 . The aircraft according to claim 11 , wherein the generator is operated at an extracted torque within a range of 90% to 100% of a maximum torque of the generator, regardless of an operating state of the aircraft.
13 . The aircraft according to claim 11 , wherein power extracted from the generator is limited to a predetermined value or less in a case where at least one of a condition that an altitude of the aircraft is a predetermined altitude or less and a condition that speed of the aircraft is a predetermined speed or less is satisfied.
14 . The aircraft according to claim 13 , wherein the main engine section includes a plurality of main engines each including the generator, and
wherein power extracted from the generator is limited to a predetermined value or less in a case where a condition that at least one of the plurality of main engines has stopped is satisfied in addition to a condition that the at least one of the two conditions is satisfied.
15 . The aircraft according to claim 11 , wherein the main engine section includes an engine shaft that rotates to cause the generator to generate electric power, and wherein an extracted torque extracted from the generator is limited to 10% or less of a maximum value of the extracted torque in a case where a rotation speed of the engine shaft of the main engine section is 60% or less of a maximum rotation speed of the engine shaft.
16 . The aircraft according to claim 11 , wherein an extracted torque extracted from the generator is limited to 10% or less of a maximum value of the extracted torque in a case where an engine output of the main engine section, when the aircraft flies at a predetermined altitude, is 60% or less of a maximum value of the engine output the predetermined altitude.