Patent Description:
Aircraft designers have continuously tried to increase the fuel efficiency of aircraft over the last century. The fuel efficiency of an aircraft may be related to the aircraft's mass and aerodynamic drag. In addition, noise regulations for aircraft at low altitudes encourage reduction of the aircraft's noise signature while it is near the ground. Landing gear can be heavy and aerodynamically resistant. Additionally, deployed landing gear may increase the noise signature of an aircraft as a result of air rushing past the deployed gear. <CIT> discloses a retractable undercarriage for an aircraft, comprising a first member of sheet steel, which is formed and welded to provide a casing for a second member. The second member comprises a sliding tube in which is secured one end of a shock absorber, the other end being secured inside the casing. The casing is closed at the top end, where bearing pins are provided. The casing is locally strengthened in the region of the pins by webs and a diaphragm.

A method of making a thin-skin support member is provided as defined by claim <NUM>.

The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration and their best mode. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosures, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made without departing from the scope of the claims. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option.

The present disclosure relates to landing gear assemblies having aerodynamic thin-skin support members, in accordance with various embodiments. Landing gear assemblies may have reduced weight and improved stress distribution by using a hollow-bodied, thin-skin support member to provide the primary vertical support. This thin-skin design uses thin skin construction, similar to wing design, to distribute the forces along a greater surface area and thereby enable a reduced cross-section area, which reduces the overall mass of the landing gear. This concept also produces a smooth, aerodynamic structure, which reduces drag and noise production due to aerodynamic buffering. Hydraulic lines and landing gear wiring harnesses can be routed through the empty space within the landing gear structure. Internal routing may protect the equipment from environmental damage, while also reducing the aircraft's aerodynamic drag and noise production.

With reference to <FIG> and <FIG>, landing gear assembly <NUM> is shown. Landing gear assembly <NUM> may include thin-skin support member <NUM> to provide light-weight support for landing gear assembly <NUM>. Thin-skin support member <NUM> may be pivotally coupled to support arm <NUM> at mounting location <NUM> of thin-skin support member <NUM>. Support arm <NUM> may further be pivotally coupled to linkage <NUM>, which is pivotally coupled to interface structure <NUM>. A secondary support arm <NUM> may be mechanically coupled to support arm <NUM> and thin-skin support member <NUM>. Thin-skin support member <NUM>, support arm <NUM>, and secondary support arm <NUM> may form a triangular support structure.

Landing gear assembly <NUM> may be pivotally coupled to an airframe <NUM> at mounting interface <NUM>. Landing gear assembly may also be coupled to airframe <NUM> at interface structure <NUM>. Landing gear assembly may deploy and stow by pivoting about mounting interface <NUM> in response to translation of interface structure <NUM>. Thin-skin support member <NUM> may at least partially contain cylinder <NUM> extending from thin-skin support member <NUM>. Cylinder <NUM> may be a cylindrical member that is substantially perpendicular to axle <NUM>. A wheel assembly may be coupled to axle <NUM> and configured to roll while supporting the weight of the aircraft.

Upper torsion link <NUM> may be pivotally coupled to thin-skin support member <NUM> at two vertices of upper torsion link <NUM>. Upper torsion link <NUM> may resemble an isosceles triangle or an equilateral triangle, with one vertex of upper torsion link <NUM> pivotally coupled to one vertex of lower torsion link <NUM>. Lower torsion link <NUM> may also resemble an isosceles triangle or an equilateral triangle, with two vertices of lower torsion link <NUM> mechanically coupled to axle <NUM>. Upper torsion link <NUM> and lower torsion link <NUM> may be configured to pivot in response to translation of cylinder <NUM> into and/or out from a cylindrical cavity of thin-skin support member <NUM>, as shown in greater detail below.

Referring now to <FIG>, a partial cross-section of landing gear assembly <NUM> through thin-skin support member <NUM> is shown. Thin-skin support member <NUM> defines cavity <NUM>. Cavity <NUM> may contain internal hydraulic and/or electronic components <NUM>. Cavity <NUM> may also remain hollow and retain air. Strut assembly <NUM> may be retained in place by internal walls of thin-skin support member <NUM>, as described in greater detail below. The upper torsion link <NUM> and lower torsion link <NUM> may be configured to restrict the twisting of strut assembly <NUM> (and cylinder <NUM> and axle <NUM> of <FIG>) with respect to thin-skin support member <NUM>.

With reference to <FIG>, thin-skin support member <NUM> is shown by way of background only. Thin-skin support member <NUM> may include a semi-circular edge <NUM> adjacent to an elongated surface <NUM> extending to semicircular edge <NUM>. Elongated surface <NUM> may be a large-radius rounded surface appearing flattened relative to semi-circular edge <NUM>. Elongated surface <NUM> may also be a straight face, or a combination of radial surfaces and flat surfaces. Semi-circular edge <NUM> and semicircular edge <NUM> may be oriented on the forward and/or aft end of thin-skin support member <NUM> such that air passing by thin-skin support member <NUM> moves from a semicircular edge, across the elongated surface, to another semicircular edge. Thin-skin support member <NUM> may thus define cylindrical cavity <NUM> internal to thin-skin support member <NUM> and adjacent to cavity <NUM>. Cylindrical cavity <NUM> may be configured to retain strut assembly <NUM> of <FIG> and/or engage cylinder <NUM> of <FIG>. Thus, cylindrical cavity <NUM> may terminate at circular internal wall <NUM>. Cylindrical cavity <NUM> may be partially defined by the internal surface of semi-circular edge <NUM>.

Cavity <NUM> may be at least partially defined by internal surface <NUM> of elongated surface <NUM> and internal surface <NUM> of semi-circular edge <NUM>. Thin-skin support member <NUM> may also include mounting interface <NUM> for coupling to an aircraft. Torsion interface <NUM> may be disposed adjacent cylindrical cavity <NUM> and configured to receive upper torsion link <NUM> of <FIG>. Thin-skin support member <NUM> may also include a cutaway section <NUM> having a circular and/or semicircular geometry to reduce weight of thin-skin support member <NUM>.

Referring now to <FIG>, a process for making thin-skin support member <NUM> by machining is shown, by way of background only. Block <NUM> of metal may be prepared for machining, as shown in <FIG>. The metal block may include aluminum, titanium, steel, or any other metal or metal alloy desired for thin-skin support member <NUM> of <FIG>. The use of aluminum for thin-skin support member <NUM> may reduce weight of landing gear assembly <NUM> in <FIG> by approximately <NUM>% over conventional designs. The use of titanium for thin-skin support member may reduce the weight of landing gear assembly <NUM> in <FIG> by approximately <NUM>% over conventional designs.

With reference to <FIG>, portions of block <NUM> may be machined away to leave intermediate support member <NUM>. Intermediate <NUM> may be machined until support member <NUM> of <FIG> remains. Support member <NUM> remaining after machining may comprise approximately <NUM>%, <NUM>%-<NUM>%, or <NUM>%-<NUM>% of the mass initially present in block <NUM> of metal.

Referring now to <FIG>, an exemplary landing gear assembly <NUM> is shown, in accordance with various embodiments. Landing gear assembly <NUM> includes thin-skin support member <NUM> having mid-body support <NUM> disposed inside of thin-skin support member <NUM>. Thin-skin support member <NUM> may be pivotally coupled to support arm <NUM>, which is pivotally coupled to linkage <NUM>. Secondary support arm <NUM> may also be coupled to linkage <NUM>. Landing gear assembly <NUM> may thus deploy and retract in a manner similar to that of landing gear assembly <NUM> of <FIG>.

Referring now to <FIG>, thin-skin support member <NUM> is shown, in accordance with various embodiments. Thin-skin support member <NUM> may include semi-circular edge <NUM> adjacent elongated surface <NUM>. An internal surface <NUM> of elongated surface <NUM> may define an internal cavity of thin-skin support member <NUM>. An interface portion <NUM> of thin-skin support member <NUM> may be configured for coupling to an aircraft. Interface portion <NUM> may include a cutaway to reduce the weight of thin-skin support member <NUM>.

In various embodiments, thin-skin support member <NUM> may include mid-body support <NUM> extending completely across internal surface <NUM>. Mid-body support <NUM> may define a terminus of cylinder <NUM>. Cylinder <NUM> extends from mid-body support <NUM> and be configured to retain a strut assembly similar to strut assembly <NUM> of <FIG>. An interface configured for joining to a torsion link is included proximate an opening end of cylinder <NUM>.

In various embodiments, and with reference to <FIG>, exemplary components of thin-skin support member <NUM> are shown, in accordance with various embodiments. Thin-skin support member <NUM> may be assembled by welding or otherwise joining the components illustrated in <FIG>. Interface portion <NUM> and mid-body support <NUM> are forged components. Method <NUM> thus includes the steps of forging a mounting interface such as interface portion <NUM> (Step <NUM>), and forging a mid-body support <NUM> with a cylinder <NUM> extending from the mid body support and the mounting interface (Step <NUM>).

In various embodiments, the method also includes welding sheet metal to the mid-body support and mounting interface (Step <NUM>). Interface portion <NUM> and mid-body support <NUM> may be joined by welding to sheet metal elements. Lower curved segment <NUM> and lower curved segment <NUM> are welded or otherwise joined to each other as well as to mid-body support <NUM>, optionally also to cylinder <NUM>. Lower curved segment <NUM> may also be welded or joined to upper curved segment <NUM>. Lower curved segment <NUM> is welded or otherwise joined to upper curved segment <NUM>. Upper curved segment <NUM> and upper curved segment <NUM> are welded or otherwise joined to interface portion <NUM>. The lower curved segments and upper curved segments are formed from sheet metal and can be joined to the forged components (interface portion <NUM> and mid-body support <NUM>) at relatively low stress locations.

Thin-skinned support members of the present disclosure may tend to reduce weight and increase stiffness, as the curved surfaces and elongated geometry of thin-skinned members use less material to achieve acceptable support levels. The thin-skin support member may also tend to reduce turbulence of air passing by the deployed landing gear with its smooth surfaces and rounded contours. In that regard, thin-skin support members of the present disclosure may thus tend to minimize noise generated by air rushing past deployed landing gear assemblies.

However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the disclosures. The scope of the disclosures is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean "one and only one" unless explicitly so stated, but rather "one or more.

Claim 1:
A method of making a landing gear assembly, comprising:
forging a mounting interface portion (<NUM>) comprising a base, and first and second ends that each extend upwardly from the base, wherein the first and second ends comprise first and second holes, respectively, that are aligned with one another and that accommodate coupling to an airframe to allow the landing gear assembly to be moved between a stowed position and a deployed position, wherein an open space extends between the first and second holes;
joining each of a first curved sheet metal element (<NUM>) and a second curved sheet metal element (<NUM>) to the mounting interface portion (<NUM>) to define an upper section of a thin-skin support member (<NUM>), wherein the first and second holes of the mounting interface portion (<NUM>) are disposed beyond an upper end of the upper section of the thin-skin support member (<NUM>);
forging a mid-body support (<NUM>) having a cylinder (<NUM>) extending from the mid-body support (<NUM>);
joining a third curved sheet metal element (<NUM>) and a fourth curved sheet metal element (<NUM>) to each other as well as to the mid-body support (<NUM>), thereby defining a lower section of the thin-skin support member (<NUM>); and
joining the upper section of the thin-skin support member (<NUM>) to the lower section of the thin-skin support member (<NUM>);
wherein the landing gear assembly comprises a strut assembly (<NUM>) retained by the cylinder (<NUM>) and coupled to an axle (<NUM>) by an upper torsion link (<NUM>) and a lower torsion link (<NUM>), the mid-body support (<NUM>) including an interface proximate an opening end of the cylinder (<NUM>) and configured for joining to the upper torsion link (<NUM>).