Auxiliary power unit enclosure and method of making the same

Patent metadata

Field	Value
Publication number	US-11794873-B2
Application number	US-201916296594-A
Country	US
Kind code	B2
Filing date	Mar 8, 2019
Priority date	Mar 8, 2019
Publication date	Oct 24, 2023
Grant date	Oct 24, 2023

Abstract

An auxiliary power unit enclosure of an aircraft includes a space frame configured to carry a load and defining an auxiliary power unit compartment. The space frame includes a plurality of frame elements coupled together at a plurality of nodes. The auxiliary power unit enclosure also includes a fairing coupled to and surrounding the space frame.

First claim

What is claimed is:

1. An auxiliary power unit enclosure of an aircraft comprising:
a space frame configured to be coupled to an airframe of a fuselage of the aircraft and to carry a load, the space frame having a cross-sectional shape that establishes a cross-sectional shape of a portion of the fuselage, extending from the airframe along a longitudinal axis, and that defines an auxiliary power unit compartment of the aircraft, wherein:
the space frame comprises a plurality of frame elements coupled together at a plurality of nodes, wherein the plurality of frame elements comprises:
a plurality of annular frame elements spaced apart from each other along the longitudinal axis;
a plurality of longitudinal frame elements coupled to the plurality of annular frame elements at the plurality of nodes; and
a plurality of diagonal frame elements coupled to at least one of the plurality of annular frame elements and the plurality of longitudinal frame elements proximate to the plurality of nodes; and

the plurality of frame elements is formed of a first material having a first critical temperature; and

a fairing coupled to at least a portion of the plurality of annular frame elements and surrounding the space frame to establish an exterior surface of the portion of the fuselage, wherein the fairing is formed of a second material having a second critical temperature that is less than the first critical temperature.

2. The auxiliary power unit enclosure of claim 1 , wherein:
the first material of the space frame comprises a metallic material; and
the second material of the fairing comprises a composite material.

3. The auxiliary power unit enclosure of claim 2 , wherein:
the metallic material comprises at least one of titanium, corrosion resistant steel, and a metal matrix composite; and
the composite material is a fiber-reinforced polymer.

4. The auxiliary power unit enclosure of claim 1 , wherein each one of the plurality of diagonal frame elements extends between a diagonally opposed pair of the plurality of nodes formed at intersections of a longitudinally adjacent pair of the plurality of annular frame elements and a radially adjacent pair of the plurality of longitudinal frame elements.

5. The auxiliary power unit enclosure of claim 1 , wherein the fairing comprises:
a plurality of stiffeners coupled to at least one of the plurality of annular frame elements; and
a plurality of skins coupled to the plurality of stiffeners.

6. The auxiliary power unit enclosure of claim 1 , further comprising a door, and wherein:
the space frame further comprises a plurality of semi-annular frame elements spaced apart from each other and the plurality of annular frame elements along the longitudinal axis of the space frame;
the plurality of longitudinal frame elements is coupled to the plurality of semi-annular frame elements at the plurality of nodes;
the plurality of diagonal frame elements is coupled to at least one of the plurality of semi-annular frame elements and the plurality of longitudinal frame elements proximate to the plurality of nodes; and
the door is coupled to and is moveable relative to the plurality of semi-annular frame elements.

7. A fuselage of an aircraft comprising:
an airframe having a cross-sectional shape that establishes a cross-sectional shape of a first portion of the fuselage;
a space frame coupled to the airframe and configured to carry a load, the space frame having a cross-sectional shape that establishes a cross-sectional shape of a second portion of the fuselage, extending from the first portion of the fuselage along a longitudinal axis, and that defines an auxiliary power unit compartment for stowing an auxiliary power unit of the aircraft; and
a fairing coupled to and surrounding the space frame to establish an exterior surface of the second portion of the fuselage,
wherein:
the space frame comprises a plurality of frame elements coupled together at a plurality of nodes,
the plurality of frame elements comprises:
a plurality of annular frame elements longitudinally spaced apart from each other along the longitudinal axis;
a plurality of longitudinal frame elements radially spaced apart from each other about the longitudinal axis of the space frame and coupled to the plurality of annular frame elements at the plurality of nodes; and
a plurality of diagonal frame elements, each one of the plurality of diagonal frame elements coupled to one of the plurality of annular frame elements at one of the plurality of nodes and to one of the plurality of longitudinal frame elements at another one of the plurality of nodes;
the plurality of frame elements is formed of a first material having a first critical temperature; and
the fairing comprises:
a plurality of stiffeners coupled to at least some of the plurality of annular frame elements and extending along the longitudinal axis; and
a plurality of skins coupled to the plurality of stiffeners; and

the plurality of stiffeners and the plurality of skins are formed of a second material having a second critical temperature that is less than the first critical temperature.

8. The fuselage of claim 7 , wherein the airframe is a semi-monocoque structure comprising:
an outer skin;
a plurality of stringers coupled to the outer skin; and
a plurality of frames coupled to the outer skin.

9. The fuselage of claim 7 , wherein:
the first material of the space frame comprises at least one of titanium, corrosion resistant steel, and a metal matrix composite; and
the second material of the fairing is a fiber-reinforced polymer.

10. The fuselage of claim 7 , wherein each one of the plurality of diagonal frame elements extends between a diagonally opposed pair of the plurality of nodes formed at intersections of a longitudinally adjacent pair of the plurality of annular frame elements and a radially adjacent pair of the plurality of longitudinal frame elements.

11. The fuselage of claim 7 , further comprising a door for accessing the auxiliary power unit compartment; and wherein:
the space frame further comprises a plurality of semi-annular frame elements spaced apart from each other and the plurality of annular frame elements along the longitudinal axis of the space frame;
the plurality of longitudinal frame elements is coupled to the plurality of semi-annular frame elements at the plurality of nodes;
the plurality of diagonal frame elements is coupled to at least one of the plurality of semi-annular frame elements and the plurality of longitudinal frame elements proximate to the plurality of nodes; and
the door is coupled to and is moveable relative to the plurality of semi-annular frame elements.

12. A method of making an aircraft, the method comprising:
coupling a plurality of annular frame elements and a plurality of longitudinal frame elements together at a plurality of nodes and coupling a plurality of diagonal frame elements to at least one of the plurality of annular frame elements and the plurality of longitudinal frame elements proximate to the plurality of nodes to form a space frame, wherein:
the space frame is configured to carry a load;
the space frame has a cross-sectional shape that establishes a cross-sectional shape of a portion of a fuselage of the aircraft and that defines an auxiliary power unit compartment of the aircraft; and
the plurality of frame elements is formed of a first material having a first critical temperature;

coupling a fairing to at least a portion of the plurality of annular frame elements of the space frame to establish an exterior surface of the portion of the fuselage, wherein the fairing is formed of a second material having a secon

Assignees

• Boeing Co

Inventors

• Pearson Steven E
• Vingiani Rosario
• Margessery Rajagopalan
• Dopker Bernhard
• Rosman Richard R

Classifications

• B64C1/00 Primary

  Fuselages; Constructional features common to fuselages, wings, stabilising surfaces or the like · CPC title

• B64C1/068

  Fuselage sections · CPC title

• B64C1/061 Primary

  Frames · CPC title

• B64C2001/0072

  from composite materials · CPC title

• B64C2001/0081

  from metallic materials · CPC title