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British Airways Airbus A321-231 taking off from Boryspil airport, Ukraine
Image credit: turbo83 / Shutterstock.com
The fuselage is the principal structure of an aircraft and the part to which all other units attach. It supplies room for the crew, passengers, freight, accessories and other important equipment.
Aerodynamics mostly dictate the size and layout of the various compartments in fuselages of conventional aircraft. Only highly-specialized, modern planes, like the SR-71 Blackbird, vary distinctly from conventional planes with respect to their design and materials used to build them.
During the early days of aviation, primitive fuselages were built with wood. In the late 1920s and early 1930s, airplane manufacturers started producing more fuselages from aluminum and steel. These metals offered more stability and greater protection from the elements. Many military and reconnaissance planes today are made from titanium or carbon composite materials because of the unique advantages these materials offer.
Some airplane fuselages are constructed in what is called a monocoque design, a design that relies largely on the strength of the plane's shell to carry different loads. A semimonocoque fuselage has the shell reinforced by a complete framework of structural members.
Bending stresses on a semimonocoque fuselage are absorbed by reinforcement beams called "longerons," which usually extend across the width of the plane. These supports are supplemented by other members, called "stringers," which stretch the length of the craft. Stringers are lighter, but used more extensively than longerons.
Vertical reinforcements on a fuselage are referred to as bulkheads, frames, and formers. These reinforcements are spaced out to carry stress at points where other units, such as the wings and engines, are attached.
Building the Airbus A330-200 from start to finish
Building the Airbus A330-200 from start to finish
Image credit: PlaneTalking / YouTube
These elements aid in the construction of a streamlined fuselage, adding to the strength and rigidity of a monocoque design. A typical semimonocoque fuselage can sustain considerable damage and still hold together. Military fighter planes and other small aircraft typically have two or more fuselage sections. Larger planes can have up to six different sections.
Maintenance workers may access systems and equipment within the fuselage through several doors, panels, and other openings. The locations of these access points can be found by referencing servicing diagrams and manuals released by the manufacturer for each type of aircraft.
It should be noted that aircraft fuselages aren’t typically made from a single material. For example, a plane may have structural members made of aluminum and an exterior made of steel.
Wooden Fuselage
For obvious reasons, the early pioneers of aviation were concerned about the weight of their planes. The Wright brothers and others were limited by the engines of their time, and therefore they built wooden planes to keep the overall weight as low as possible.
Aeronautical engineering design and technology improved throughout the first two decades of the 20th century and by the outbreak of the First World War – classic wire-braced, wood-and-fabric biplanes were required. The German military’s famed Red Baron flew numerous wooden planes during his legendary dogfights.
Wood fuselages are still being made today, albeit often by hobbyists building their own lightweight planes.
Aluminum Fuselage
Advancements in engine technology in the 1930s allowed engineers to turn to metal designs, and aluminum was the primary metal to usher in the dawn of the all-metal aircraft.
The aluminum used to make planes is always blended with other metals to make it strong and light. While aluminum fuselages don’t corrode as easily as those made of steel, aluminum isn’t used on the surface of many supersonic planes because heat generated by the friction from flying at such speeds causes aluminum’s strength to decrease.
Boeing’s 247D and the Douglas DC-3 are largely credited with the mainstreaming of metal aircraft during the 1930s and these planes don’t appear all that different from the aircraft we see today.
The 247D was around 50 percent faster than the competition when it was put into service by United Air Lines in 1933. The DC-3 debuted two years later on the 32nd anniversary of the Wright brothers’ historic flight. Despite being expected to be retired in the 1950s, the DC-3 has been used for more than 80 years and can still be seen flying today.
Materials Used in Aircraft Fuselages
Orville Wright in flight over treetops at Huffman Prairie Dayton Ohio on November 16 1904. Image credit: Everett Historical / Shutterstock.com
Originally built in 1942, a Priority Air Charter Llc Douglas DC-3TP arriving after a long flight from Shannon to Luqa, Malta April 2, 2015. Image credit: InsectWorld / Shutterstock.com
Beechcraft Model 17 Staggerwing at the International Aerospace Exhibition "ILA Berlin Air Show" on September 14, 2012 in Berlin, Germany. Image credit: Bocman1973 / Shutterstock.com
SR-71 "Blackbird" Cold War Spy plane on static display at Lackland AFB on August 21, 2011 in San Antonio, Texas. Image credit: Dan Simonsen / Shutterstock.com
Boeing 787-8 landing at Haneda International Airport in Tokyo, Japan. Image credit: motive56 / Shutterstock.com
Steel fuselage
Stronger and stiffer, but also heavier, steel aircraft were also built in the 1930s. The heavier weight of steel prevented it from becoming a popular fuselage material. However, the metal is used to make certain parts of an aircraft. Its strength and stiffness make it ideally suited for use in landing gears. The heat resistance of steel also makes it desirable for use in the skin of supersonic planes.
Built in 1932, the Beechcraft Staggerwing is a primary example of an airplane with a steel fuselage. The Staggerwing was expansive to produce and became popular as a fast, business airplane.
Titanium Fuselages
With the same strength as steel and much lighter, titanium and titanium alloys are ideal materials for building aircraft. These metals also resist corrosion better than both aluminum and steel. However, the production of airplanes made from titanium is very costly, which largely prohibits wide commercial use of most titanium airplanes.
The most prominent example of a titanium fuselage is the SR-71 Blackbird. First flown in December 1964, the SR-71 was a staple of US air reconnaissance during the Cold War. During its 24 years of service, the Blackbird spent around 2,800 hours in the air.
On March 6, 1990, the SR-71 flew its last flight from Los Angeles to Washington DC in 1 hour and 4 minutes, at an average speed of around 2,100 miles per hour.
Carbon Composites Fuselages
Graphite epoxy, or carbon-fiber-reinforced polymer, has become a popular choice for today’s state-of-the-art commercial aircraft. Made from resilient carbon fibers embedded in an epoxy resin, carbon composite materials can be stacked in a number of ways to meet the various demands of maintaining integrity during high-speed flight. These carbon-fiber materials are about as strong as aluminum, yet half the weight.
Carbon composite materials haven’t gained widespread use in the aviation industry just yet, but Boeing’s 787 Dreamliner was the first major plane to use the materials in over half of its fuselage.
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References
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