A. Field of the Invention
The present invention relates to a one-piece closed-shape structure and a method for manufacturing a one-piece closed-shape structure. In particular, the present invention relates to a one-piece fuselage and a method for manufacturing a one-piece fuselage.
B. Background of the Invention
Since the 1940's and 1950's, aircraft have been manufactured from lightweight metals, primarily aluminum. More recently, composite materials (such as fiber reinforced plastics) have been used to manufacture some aircraft. The manufacture of such aircraft include the manufacture of the fuselage (the central body of the aircraft), the wings, and the various other components of the aircraft.
In the manufacture of an aircraft fuselage with metals or composites, the typical manufacturing process involves the combination of several pieces that are individually manufactured and then bonded together to form the fuselage. These multiple steps have many disadvantages, including both high costs and significant time.
The creation of a single-piece fuselage would provide many advantages over fuselages manufactured from the combination of multiple parts. These advantages potentially include lower cost, lighter weight, improved integration, safety, improved performance, noise reduction, improved aerodynamics, and styling flexibility.
As for lower cost, a one-piece fuselage is less costly to fabricate, because there is only one part to manufacture, and there are no fasteners. Thus, the one-piece design saves money in both the fabrication stage and in combination stage. In addition, the work areas needed at a manufacturing facility are less for a one-piece design, because multiple parts require dramatically more workspace areas.
As for lighter weight, because there are fewer parts to a one-piece fuselage, and because there are fewer fasteners, a one-piece fuselage is lighter than a fuselage created from multiple parts. The lighter the aircraft, the more carrying capacity that the aircraft will have, which is a substantial benefit.
As for improved integration, a one-piece fuselage is easier to integrate with the other components of the aircraft, such as the tail cone, the wings, and the other parts of the aircraft. Additionally, the interior of a one-piece fuselage would also be easier to integrate, because there is only one form that must be properly fitted. Moreover, problems with integration of multiple parts (such as dimension variation and other fabrication problems) would be completely eliminated in a one-piece design.
As for safety, a one-piece fuselage offers structural advantages over a fuselage fabricated from multiple parts. In the initial fabrication of the one-piece fuselage, the structure may be designed with safety improvements (such as strengthened areas, etc.). Additionally, because the one-piece fuselage does not have most of the fasteners necessary for combining the multiple parts, the one-piece design is more structurally sound, which provides increased passenger safety. Also, a one-piece fuselage is more crashworthy. A one-piece fuselage provides the advantages of an integrated structure, which has numerous crashworthiness benefits.
As for improved performance, there are both objective and subjective improvements. For objective improvements, there is of course the improved aerodynamics, which results in greater speed. For subjective improvement, there is the noise reduction, which results in a more comfortable ride. In some way, all of the advantages of the one-piece fuselage play a role in improved performance.
As for noise reduction, because a one-piece fuselage would result in improved aerodynamics, a further benefit would be a diminution of air disruption, which results in noise reduction. Any increase in the smoothness of an aircraft has the benefit of noise reduction. Thus, to the extent that the creation of a one-piece fuselage results in the improvement of aerodynamics, there is a reciprocal decrease in noise.
As for improved aerodynamics, a one-piece fuselage inherently is more aerodynamic than a fuselage created from the combination of multiple parts. This improvement in aerodynamics would result from the absence of seams or joints as well as the absence of rivets or other external fasteners. In modern aircraft, seams and joints between the combined parts increase drag and thus diminish aerodynamics. By omitting the seams and joints in a one-piece fuselage, aerodynamics would be improved. Also, in modern aircraft, the external fasteners for flanges and other structure internal to the fuselage also increase drag and diminish aerodynamics. A one-piece fuselage would omit most fasteners and would thus improve aerodynamics.
As for styling flexibility, the capability to create a one-piece fuselage would provide more opportunities for aircraft design. Because multiple parts are not combined to create the fuselage, unique shapes may be possible, that were previously difficult to achieve. By improving the design and styling of the aircraft with a one-piece fuselage, it would thus be possible to create a more attractive aircraft for the market.
Therefore, it is desirable to provide a one-piece fuselage.
For a one-piece fuselage, either metal or composite materials may be used. Metal has more disadvantages, due to the inability to fabricate all components of the fuselage in a single step. Composite materials are thus more advantageous for the fabrication of a one-piece fuselage, because composite materials may be fabricated simultaneously.
Therefore, it is further desirable to provide a one-piece fuselage manufactured from composite materials.
Methods and structures in accordance with the invention provide for a one-piece structure manufactured from composite materials, including a one-piece fuselage. One embodiment includes manufacturing a one-piece fuselage by filament winding. Other embodiments for manufacturing a one-piece fuselage may also be used.