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65 Worked Examples: Introductory

Worked Example #1 – Human colonization of space

Human colonization of space remains a hugely ambitious goal. NASA’s return to the Moon has begun with its Artemis program. Make a list of some of the technical and other challenges in sending humans back to the moon, Mars, and perhaps even deep space. Remember that Mars is (on average) over 250 times further away than the Moon.

Sending humans back to the moon, Mars, and into deep space is a highly ambitious goal that requires overcoming a range of technical and other challenges, including radiation exposure, life support, and the need for food, propulsion systems, habitat, and resource utilization, human performance and health, cost and funding, technological advancements, and mission design and operations. Here is a list of some of the technical and other challenges to consider and discuss in sending humans back to the moon, Mars, and into deep space:

  • Radiation exposure: Space travel exposes astronauts to high radiation levels, which can cause various health problems, including increased cancer risk, cognitive decline, and cardiovascular disease.
  • Life support systems: Providing astronauts with a sustainable, life-supporting environment is a significant challenge, especially during long-duration missions to the moon and Mars.
  • Propulsion systems: A significant challenge is to develop reliable, efficient, and safe propulsion systems capable of transporting astronauts and their equipment over large distances.
  • Habitat and resource utilization: It will be critical for long-duration missions to provide suitable habitats for astronauts and utilize local resources, such as water and minerals.
  • Human performance and health: Ensuring the physical and psychological well-being of the astronauts during long-duration missions is a significant challenge.
  • Cost and funding: Sending humans back to the moon, Mars, and deep space is costly and resource-intensive, requiring significant funding and political support.
  • Technological advancements: To make human space exploration possible, significant technological advancements, including propulsion systems, life support, habitat design, and materials science, will be required.
  • Mission design and operations: Planning, designing, and executing complex missions to the moon, Mars, and beyond requires significant expertise and experience in mission operations and logistics.

Worked Example #2 – What is a patent?

Why might someone want to apply for a patent? Some people have argued that the process of patenting nearly every development in aviation technology at the beginning of the 20th century, including by the Wright brothers, hindered the advancement of aviation and aeronautical technology worldwide. Discuss this viewpoint.

  • A patent is a form of intellectual property that gives the holder exclusive rights to prevent others from making, using, selling, and importing an invention for a specified period, typically 20 years from the filing date. A patent can cover a new product, process, machine, or improvement. Someone might want to apply for a patent to protect their invention and prevent others from using or profiting from it without permission. A patent can also provide the inventor with leverage in negotiations and licensing agreements. Additionally, the holder of a valid patent can bring legal action against anyone who infringes their patent rights.
  • The argument that the process of patenting nearly every development in aviation technology at the beginning of the 20th century, including by the Wright brothers, hindered the advancement of aviation and aeronautical technology worldwide is based on the idea that patents can restrict the flow of information and limit the sharing of ideas and innovations. This can slow down technological progress and hinder the development of new and better products. Some argue that this was the case in the early days of aviation, where the pursuit of patents and legal battles between patent holders slowed down the development of the industry.
  • However, others argue that patents are necessary to protect an inventor’s intellectual investment and hard work and that with the protection offered by patents, there would be more incentive for people to pursue innovations. Additionally, the revenue generated by licensing patents can help fund further research and development. The proper balance between protecting intellectual property rights and promoting technological progress is an ongoing discussion.

Worked Example #3 – Availability of fuel before 1920

The development of engine technology was an enabling factor in the development of aviation. However, success depended on the availability of a suitably formulated fuel, i.e., gasoline. Could you discuss this viewpoint?

  • In the early days of aviation, aircraft engines relied on low compression ratios and fuel with low octane ratings. These engines used a simple carburetor system that mixed fuel with air before entering the cylinders for combustion. As aviation technology progressed and aircraft engines became more powerful, higher compression ratios were desired to increase efficiency and power output. However, this led to a problem known as detonation, also called knocking or pinging. Detonation occurs when the air-fuel mixture in the combustion chamber ignites too rapidly and unevenly, producing multiple flame fronts that collide and create high-pressure shock waves. This can cause engine damage and a loss of power. As compression ratios increased, the likelihood of detonation also increased.
  • To address this issue, researchers focused on developing fuel additives and optimizing fuel chemistry to increase the octane rating. The octane number is a measure of a fuel’s resistance to detonation. The higher the octane number, the more resistant the fuel is to detonation under high compression. One of the earliest solutions to improve gasoline’s octane rating was adding tetraethyl lead, known as lead-tetraethyl or TEL. Lead compounds effectively reduced detonation, allowing for higher compression ratios and increased power output. TEL became widely used as an anti-knock agent in gasoline during the early to mid-20th century.
  • However, leaded gasoline raised concerns because of lead’s toxicity and harmful effects on human health and the environment. Over time, regulations were introduced to limit or phase out the use of lead in automotive and aviation fuels. By the late 20th century, most aviation gasoline was produced with reduced lead content or as “low-lead” formulations. In recent years, efforts have been made to reduce or eliminate lead from aviation gasoline. Alternative fuels and additives, such as unleaded aviation gasoline (UL AVGAS) and alternative hydrocarbon fuels, have been explored. These fuels are designed to provide high octane ratings without lead or other toxic additives.
  • The development of fuel chemistry and the pursuit of higher octane ratings continue to be important in the aviation industry. Advancements in engine technology, including turbocharging and direct fuel injection, have also contributed to improved efficiency and reduced detonation issues. These advancements and ongoing research into alternative fuels aim to address the challenges associated with combustion and compression ratios in aircraft piston engines.

Worked Example #4 – Professional goal setting

Goal setting is essential to professional development. Write down some of your goals as a future aerospace/aeronautical/astronautical engineer and where you might want to position yourself in the workplace in shorter and longer terms. Consider also the relative advantages to your career in obtaining an advanced degree.

An aerospace/aeronautical/astronautical engineer’s career goals might look like:

Short-term goals:

  1. Gain hands-on experience in the aerospace industry by working as an engineer at a large aerospace company or a startup.
  2. Develop expertise in a specific area of aerospace engineering, such as propulsion systems or spacecraft design.
  3. Attend industry conferences and events to network with other engineers and stay up-to-date on the latest developments in the field.
  4. Participate in continuing education courses to expand knowledge and stay current with new technologies and best practices.

Long-term goals:

  1. Obtain an advanced degree in aerospace engineering, such as a Master’s or Ph.D., to increase expertise and improve career opportunities.
  2. Work on high-profile aerospace projects, such as human spaceflight missions or developing new aircraft technologies.
  3. Take a leadership role in an aerospace company, such as a project manager or department head.
  4. Contribute to developing new technologies and advancements by conducting research and publishing papers.

Obtaining an advanced degree in aerospace engineering can offer significant advantages to an engineer’s career. These include increased expertise, improved job opportunities, and the ability to take on more challenging and high-profile projects. Additionally, advanced degrees can open up opportunities for leadership and research positions, allowing engineers to contribute to the advancement of the field and shape its future.

Worked Example #5 – X-planes

After WWII, NASA, the US Navy, USAF, and DARPA contributed to developing nearly 60 “X-planes.” Discuss one X-plane of your choice that you think is a milestone in aviation history, and list the contributions it made to aeronautics and/or astronautics.

One X-plane considered a milestone in aviation history is the North American X-15. The X-15 was a hypersonic rocket-powered aircraft developed in the 1950s by North American Aviation, the National Aeronautics and Space Administration (NASA), and the United States Air Force (USAF). Contributions to aeronautics and astronautics made by the X-15 include:

  • Development of hypersonic technology: The X-15 was the first aircraft capable of reaching Mach 6, a significant step forward in developing hypersonic flight technology.
  • Advancement of materials science: The X-15 was one of the first aircraft to use titanium alloys, which paved the way for the development of future aircraft like the SR-71 Blackbird.
  • Pioneering of space flight: The X-15 was the first aircraft to reach the edge of space, paving the way for the development of space flight and the space program.
  • Advancement of flight control systems: The X-15 was one of the first aircraft to use a fly-by-wire flight control system, a significant step forward.

Worked Example #6 – Ethics

Engineers often make decisions involving trade-offs between capabilities and cost, although safety is always paramount. However, bad things will always happen when decisions are made in an organizational culture that emphasizes profits over safety. Discuss this scenario.

  • When decisions in an organizational culture prioritize profits over safety, engineers may face pressure to compromise on safety standards to reduce costs or meet deadlines. This situation can lead to inadequate testing, insufficient resources devoted to safety and quality assurance, or the use of subpar materials. In such a scenario, corners may be cut, and critical safety features may be overlooked, leading to increased risks to passengers, crew, and others.
  • Moreover, in such a culture, engineers may feel uncomfortable raising safety concerns or may have those concerns ignored, leading to a disregard for potential dangers. Additionally, safety incidents may be covered up or minimized, leading to a false sense of security and an increased risk of future accidents.
  • Ultimately, when safety is not prioritized, it can have disastrous consequences. Airline accidents, for example, can result in loss of life, property damage, and significant financial losses. Furthermore, incidents involving commercial aircraft can also have a long-lasting impact on public trust in aviation, which can be challenging to restore.
  • Therefore, aerospace organizations need to foster a culture of safety in which safety is given the highest priority, and engineers are encouraged to discuss and address safety concerns openly. This better approach includes providing adequate resources, investing in safety research, and promoting transparency and accountability in decision-making processes.
  • The article “The Boeing 737 MAX: Lessons for Engineering Ethics” makes interesting reading.

Worked Example #7 – Aerospace breakthroughs

Do some online research and give examples of recent breakthroughs or innovations in aerospace engineering that have significantly impacted the industry and the development of modern flight vehicles.

  • Improved aerodynamics: Advancements in computational fluid dynamics and aerodynamics continue to lead to more efficient wings and aircraft designs. Transonic wing shapes, for example, continue to be refined and optimized to increase the cruise Mach numbers of commercial jet airliners. Winglets, which have seen many incarnations, reduce drag and improve fuel efficiency, although it is still being determined how much more aerodynamically refined winglets can be. Laminar flow and morphing wings continue to be more ambitious goals for production aircraft but are worthy of foundational research.
  • Advanced composite materials: These materials, such as glass and carbon fiber reinforced composites, have led to lighter and more fuel-efficient aircraft. For example, Boeing’s 787 Dreamliner and the Airbus A350 have airframes made primarily of composite materials. Such materials have a higher strength-to-weight ratio, reducing empty airframe weight, increasing overall aerodynamic and fuel efficiency, increasing useful load (fuel, cargo, and passengers), and lowering operating costs.
  • 3D printing: Additive manufacturing, or “3D printing,” continues to create complex aerospace components that would otherwise be difficult or impossible to manufacture using traditional tooling and methods. Although 3D printing technology has seen limited use for production (e.g., FAA/PMA-certified) parts, further developments in techniques and materials will reduce production time while allowing innovative designs to improve efficiency and reduce costs.
  • Reusable launch systems: The development of reusable space vehicle technology, such as SpaceX’s Falcon 9 and Falcon Heavy, has significantly reduced the cost of launching payloads into space. Reusing the first stage of a rocket, for example, reuses the stage itself and the rocket engines and can cut at least 10% off the cost of a launch.
  • Autonomous systems: Integrating autonomous systems and artificial intelligence in aerospace has improved safety and efficiency in commercial and military applications. Uncrewed aerial vehicles (UAVs) are just one example.
  • Electric propulsion: Electric and hybrid-electric propulsion systems continue to gain attention from the aerospace industry. NASA and Boeing have been working on electric aircraft, and many startup companies have developed electric vertical takeoff and landing (eVTOL) aircraft for applications such as urban aerial mobility (UAM). However, the relatively low energy density that can be stored in batteries continues to hinder the use of electric propulsion systems for aircraft other than small drones.
  • “Green” aviation: The aerospace industry continues to invest in research to reduce its environmental footprint, especially in Europe. This work includes developing fuel-efficient engines, exploring alternative fuels, and improving air traffic management to give more direct routings and reduce landing delays, which can significantly reduce emissions.
  • Space exploration: Recent spacecraft and space exploration technology developments, such as the Mars rovers and the James Webb Space Telescope, have expanded our understanding of the universe. While space telescopes tell us much about the universe, they also reaffirm Earth’s small place in the vast cosmic arena and the enormous distances between planets, solar systems, and galaxies.

Worked Example #8 – Applications of UAVs

List some key considerations in designing, building, and fielding uncrewed aerial vehicles (UAVs) for various civil and military applications, including surveillance, delivery, and scientific research.Image of a UAV drone with the FAA logo.

Considerations may include:

  • Mission objectives: Clearly define the mission objectives, whether surveillance, scientific research, or another purpose, and ensure that the UAV design aligns with these goals.
  • Payload requirements: Determine the capacity and type of UAV (or drone) needed for the specific mission, such as cameras, sensors, cargo, or scientific instruments.
  • Endurance and/or range: Assess the required flight endurance and operational range to meet mission objectives. Longer endurance will require more fuel or battery capacity, so prepare to reduce the payload capacity.
  • Size & weight: Consider size and weight constraints, especially for applications like delivery drones where compactness and weight limitations are critical.
  • Propulsion system: Based on the UAV’s mission profile and estimated energy requirements, choose an appropriate propulsion system, such as electric motors, internal combustion engines, or hybrid systems.
  • Autonomous operation: Implement robust autonomous navigation and control systems to ensure safe and reliable UAV operation, even in complex environments.
  • Redundancy & safety features: Include redundancy in critical systems and safety features like fail-safes, emergency landing capabilities, and collision avoidance systems.
  • Regulatory compliance: Ensure compliance with relevant civil aviation or military regulations, including airspace restrictions, licensing, and registration requirements.
  • Security: Implement security measures to protect the UAV from unauthorized access, hacking, and data breaches, especially in military applications.
  • Environmental considerations: Evaluate the environmental impact of UAV operations, including noise pollution and emissions, and take steps to minimize these effects.
  • Payload integration: Ensure the payload is integrated securely and can operate effectively without interfering with the UAV’s flight characteristics.
  • Maintenance & reliability: Plan routine maintenance and ensure the UAV is designed for reliability and ease of repair to minimize downtime.
  • Integration with existing systems: Ensure the UAV can integrate with existing infrastructure and systems, such as ground control stations or logistics networks for delivery drones.
  • Regulatory considerations: Be aware of the regulatory use of UAVs in different civil applications.
  • Risk assessment & mitigation: Conduct thorough risk assessments and develop mitigation strategies to address potential hazards and operational risks associated with UAV missions.

Worked Example #9 – Environmental considerations

What are the critical environmental considerations in the field of aerospace engineering? How might the industry work to reduce its long-term impact on the environment?

The aerospace industry has made some progress in addressing these environmental concerns. However, further effort is necessary to mitigate its long-term environmental impact while meeting the growing aviation and space flight demand.

  • Sustainability: Sustainable aerospace engineering practices are critical to ensuring a more “eco-friendly” future for the industry.
  • Emissions: Aircraft engines emit greenhouse gases (GHGs), including carbon dioxide (CO2) and nitrogen oxides (NOx), which contribute to climate change and air pollution.
  • Noise pollution: Aircraft noise can disrupt communities near airports and affect residents’ health and well-being. People are generally very intolerant of aircraft noise.
  • Resources: Aerospace manufacturing and operations require significant energy, materials, and water resources. Renewable energy resources such as solar and wind are becoming increasingly essential.
  • Waste: The aerospace industry generates a lot of waste, including manufacturing waste and end-of-life aircraft components. While metals can be recycled, some materials, especially composite materials and their associated resins and other chemicals, can be challenging to dispose of sustainably.

To reduce the long-term environmental impact of aerospace manufacturing, the industry may be able to take several actions, including:

  • Research & development: Invest in research and development of more fuel-efficient aircraft designs, propulsion technologies (e.g., electric or hybrid propulsion), and lightweight materials to reduce emissions and resource use.
  • Alternative fuels: To lower GHG emissions, develop sustainable aviation fuels (SAFs) from renewable sources like biomass or synthetic processes.
  • Advanced aerodynamics: Optimize aircraft aerodynamics to reduce drag and improve fuel efficiency. Technologies such as winglets and laminar flow control can help achieve this goal.
  • Noise reduction: Innovate to reduce aircraft noise through quieter engine designs, better aerodynamics, and flight procedures. Implement noise abatement measures near airports.
  • Improved air traffic management: Develop and deploy advanced air traffic management systems to optimize flight paths and reduce fuel consumption.
  • Eco-friendly manufacturing: Adopt sustainable manufacturing practices, including recycling and reusing materials, and minimize waste generation during production.
  • End-of-life recycling: Implement recycling and disposal strategies for aircraft components at the end of their operational lives.
  • Regulatory compliance: Ensure compliance with environmental regulations and work with regulatory authorities to establish and enforce emissions and noise standards.
  • Investments in green technologies: Make investments in “green” aviation technologies and sustainable practices. Foster collaboration among research institutions and government agencies to accelerate the development and adoption of eco-friendly technologies.
  • Environmental certification: Strive for environmental certifications of aerospace facilities to ensure a commitment to sustainability.

Worked Example #10 – Aviation competitions

How have competitions and monetary awards historically influenced the pace and direction of innovation in aviation, and what lessons can modern aerospace industries learn from these examples to foster future advancements?

Competitions and monetary prizes have historically driven innovation in aviation by inspiring achievements and advancing technology. Between 1906 and 1930, the Daily Mail newspaper awarded numerous prizes for achievements. The Orteig Prize spurred Charles Lindbergh, who won the prize in 1927 with his airplane, the Spirit of St. Louis. for a solo nonstop transatlantic flight, while the Schneider Trophy accelerated advancements in aerodynamics and speed. To accelerate advances in human-powered flight (Reay 1977), British industrialist Henry Kremer announced in 1959 the establishment of the Kremer Prize of GBP 5,000 (increased to GBP 50,000 in 1973. More recently, the Ansari X Prize fostered private spaceflight development with SpaceShipOne, laying the foundation for the commercial space industry.

These challenges highlight the importance of setting ambitious goals that push boundaries and encourage broad participation from players other than the major aerospace companies. Other ongoing competitions like those set by DARPA sustain progress by allowing teams to refine solutions, while non-monetary incentives like recognition and market access can amplify impact. By leveraging these strategies, the entire aerospace industry can drive innovation to develop advanced technologies in aviation and space.

Worked Example #11 – Supersonic and hypersonic flight

Explore and discuss the engineering challenges and advancements in designing aircraft capable of supersonic and hypersonic speeds. Discuss potential applications, such as high-speed travel and military surveillance. How are such problems as “sonic booms” from supersonic flight vehicles being addressed?

Image of the X-51A Waverider concept that is set to demonstrate hypersonic flight.

Designing aircraft for supersonic (Mach 1+) and hypersonic (Mach 5+) speeds presents engineering challenges that continue to drive advancements in aerodynamics, materials, propulsion, and noise reduction. Aerodynamic heating from air friction at high speeds can weaken materials, requiring heat-resistant alloys, carbon composites, and ceramic coatings. Airframe-propulsion integration at hypersonic speeds demands carefully optimized designs, such as wave-riders, developed using advanced computational fluid dynamics (CFD) to minimize drag. Hypersonic vehicles rely on scramjets (supersonic combustion ramjets), which can compress air for combustion at high speeds without moving parts. Still, these must operate efficiently across wide airspeed and altitude ranges.

Addressing the intensity of sonic booms remains crucial for civil applications, with “low-boom” designs reshaping fuselages to spread shockwave energy and reduce perceived noise. NASA’s X-59 QueSST aims to demonstrate quieter supersonic flight, potentially enabling supersonic flight on overland routes. Companies like Boom Supersonic envision shorter intercontinental flight times, though technical and economic feasibility remain uncertain. In military applications, hypersonic vehicles promise faster response times and enhanced capabilities. Despite the many significant challenges, new advancements in these technologies could shape the future of aviation.

Worked Example #12 – Electric propulsion

Do some research and discuss the development of electric propulsion systems for aircraft. Explore the potential for electric aircraft to reduce environmental impact and increase efficiency. Why might the realization of electrically powered airliners traveling over large distances be decades away, if at all?

The development of electric propulsion systems in aviation aims to reduce environmental impact and improve efficiency. Electric aircraft produce zero in-flight emissions, and when powered by renewable energy, they can significantly lower air travel’s carbon footprint. Electric motors are also more efficient than combustion engines, offering potential fuel use and operating cost reductions.

However, long-distance electric airliners face significant challenges, primarily because of the low energy density of current batteries. Aviation fuel such as 100LL or JET A/A-1 provides an energy density of about 12,500 Wh/kg. In comparison, lithium-ion batteries are only about 160 Wh/kg, requiring batteries that are too large and heavy for long-haul flights. Furthermore, unlike conventional aircraft, which become lighter as fuel burns off, electric aircraft maintain a constant in-flight weight, adding further design challenges. Advances in hybrid-electric systems and hydrogen fuel cells show promise, but these technologies remain experimental. Widespread adoption of fully electric airliners for long-distance travel will depend on energy storage, weight reduction, and propulsion efficiency breakthroughs.

Worked Example #13 – Impact of the COVID-19 pandemic on aviation

Discuss the impact of the COVID-19 pandemic on the aerospace and aviation industry. For example, the pandemic led to a significant decrease in the demand for air travel, resulting in grounded fleets of airliners. Lockdowns also disrupted global supply chains, affecting the production of aircraft and aerospace components.

The COVID-19 pandemic significantly impacted the aerospace and aviation industry, causing disruptions and long-lasting changes. Air travel demand dropped sharply, with passenger traffic falling by up to 90% in early 2020 because of government-imposed lockdowns, travel restrictions, and overall health concerns. Airlines reduced operations and grounded much of their fleets, leading to widespread layoffs, bankruptcies, and government bailouts. Aircraft manufacturers like Boeing and Airbus struggled as airlines canceled or deferred orders. At the same time, supply chain disruptions delayed the production and delivery of components, heavily affecting smaller and medium-sized suppliers. The pandemic also accelerated the retirement of older, less fuel-efficient aircraft like the Boeing 747 and Airbus A380 as airlines sought to cut costs and modernize fleets.

However, air cargo demand surged, driven by the need to transport medical supplies and e-commerce goods, at least partially offsetting passenger aviation losses. Health and safety measures, including improved cabin air filtration and enhanced cleaning protocols, became a priority. Although the industry is still recovering, challenges remain, including supply shortages and workforce re-establishment.

Worked Example #14 – Mission to Mars?

Research and discuss the engineering challenges and innovations in planning missions to explore Mars. For example, a Mars mission may require more than traditional propulsion systems. You may also explore the need for power generation, human life support systems, and resource management in the harsh Mars environment.

Planning missions to Mars requires addressing complex multidisciplinary and interdisciplinary engineering challenges. Traditional chemical propulsion may be inadequate because of the vast distances involved and high propellant requirements. Advanced propulsion systems like nuclear thermal propulsion are being developed to reduce the propellant mass and provide propulsive efficiency. Mars’s thin atmosphere complicates safe entry and landing, requiring innovations such as inflatable heat shields to increase drag and thermally protect the spacecraft.

Reliable power sources will be critical for sustaining operations on Mars, as mining local resources is unlikely during initial missions. NASA is considering small modular nuclear reactors to provide continuous power for life support systems, scientific instruments, and habitat maintenance. Ensuring astronaut safety also demands advanced life support systems capable of supplying breathable air, water, and food. These innovations are critical for the success of future Mars missions.

Worked Example #15 – Environmental considerations and sustainable aviation

Discuss aviation’s environmental impact and efforts to create more sustainable air travel. What technological innovations, such as electric or hydrogen-powered aircraft, are being explored to reduce aviation’s carbon footprint?

Aviation accounts for about 2.5% of global CO2 emissions, with additional impacts from contrails (which reflect heat to the surface) and nitrogen oxides (which damage the protective ozone layer), thereby worsening climate change. As air travel grows, the industry is under pressure from governments to adopt sustainable practices. Efforts to reduce aviation’s carbon footprint focus on alternative propulsion systems and sustainable fuels. Electric aircraft powered by batteries or hybrid systems are being developed for short-haul flights. Still, they are limited for long-distance travel because of the low energy density of current batteries.

Hydrogen-powered aircraft offer promise, which produces water vapor as the primary byproduct. Airbus is developing hydrogen-based models that target deployment by the 2030s. Sustainable aviation fuels (SAFs), derived from biofuels or synthetic processes, can cut lifecycle emissions by up to 80% and are compatible with existing aircraft and infrastructure, providing an immediate decarbonization option. Airlines and manufacturers are also improving flight paths, engine efficiency, and aircraft design to lower fuel consumption. Despite these advancements, challenges like high costs, scalability, and infrastructure requirements remain. Collaboration across industries and continued technological innovation are critical for achieving a more sustainable aviation future.

Worked Example #16 – Concorde and the future of supersonic transport

Discuss the impact of the Concorde and the development of supersonic commercial aviation. What technological challenges were faced during its design, and why did supersonic passenger travel ultimately fail to sustain long-term success? What do you think the chances are that Boom Supersonic will be able to successfully introduce a new generation of SST airplanes?

Lockheed Martin's future quiet supersonic aircraft design.

The Concorde, first flown in 1969 and introduced into airline service in 1976, revolutionized aviation by enabling supersonic passenger travel at Mach 2, essentially halving travel times. Despite its technological achievements, it faced significant economic challenges, including a limited passenger capacity of about 120 seats, and could be used only on limited routes (mainly the North Atlantic) because of sonic booms. Aerodynamic heating at Mach 2 required heat-resistant materials like special hinduminum alloys developed by Rolls-Royce, while its loud engines and sonic booms led to overland flight restrictions. Fuel inefficiency was a critical drawback, with the Rolls-Royce/Snecma Olympus 593 engines resulting in operating costs and expensive maintenance. Rising fuel prices in the 1970s because of the “oil crisis” compounded its financial struggles. Competition from larger, more economical subsonic jets like the Boeing 747 further diminished its market appeal.

Boom Supersonic’s Overture aims to revive supersonic travel with more sustainable, efficient designs using advanced materials, improved aerodynamics, and quieter, fuel-efficient engines. However, challenges such as regulatory approval, high development costs, and environmental scrutiny remain. The success of the next generation of supersonic airliners will hinge on balancing technical, economic, and environmental considerations.

Worked Example #17 – Use of composite materials in aerospace applications

Discuss the development of composite materials in aircraft manufacturing. What advantages do these materials offer over traditional ones, and how have they influenced the design and performance of modern aircraft such as the Boeing 787 Dreamliner? What are some of the disadvantages of composites?

Composite materials, such as carbon fiber-reinforced polymers (CFRPs), have revolutionized aircraft manufacturing by offering significant advantages over traditional airplane construction materials like aluminum. With superior strength-to-weight ratios, composites enable lighter aircraft that consume less fuel and perform better. For example, the Boeing 787 Dreamliner uses 50% composites in its structure, achieving 20% improved fuel efficiency compared to similar conventional aircraft. Composites resist corrosion and fatigue, reducing maintenance needs and extending service life. Their versatility supports complex, aerodynamically optimized designs, such as seamless fuselages and smoother wings, enhancing both performance and fuel efficiency. Models like the Boeing 787 and Airbus A350 have benefited from lighter airframes, increased range, and lower operating costs, while passenger-focused features like larger windows and improved cabin pressurization enhance comfort on long-haul flights.

Despite these benefits, composites have drawbacks. Tooling and manufacturing costs are high because of complex processes and expensive raw materials. Repairs can be challenging because damage may not be visible, requiring specialized inspection and repair methods. Recycling composites is also difficult, raising environmental concerns as their use increases. However, ongoing research aims to address these issues. In general, the unique advantages of composites in weight reduction, durability, and design flexibility ensure their continued importance in advancing aircraft performance, lowering costs, and minimizing environmental impact.

 

Worked Example #18 – A new space race?

Discuss the rise of private space exploration companies such as SpaceX and Blue Origin. How have their innovations challenged traditional approaches to space exploration, and what implications do they hold for the future of human spaceflight? Will the new “space race” be in the commercial space sector?

Establishing private space companies like SpaceX and Blue Origin has transformed the space industry, challenging traditional government-led space efforts and initiating a new era of human spaceflight. Innovations like reusable rockets, cost-effective operations, and rapid prototyping have significantly reduced access-to-space costs. SpaceX’s Falcon 9 has proven the economic and operational benefits of reusability, cutting launch expenses by 20–30% and increasing mission frequency. Blue Origin’s reusable systems, like the New Shepard, prioritize commercial and tourism applications. Partnerships with private companies have allowed NASA to focus on ambitious goals, such as returning to the Moon and exploring Mars, while delegating low-Earth orbit activities to firms like SpaceX through programs like the Commercial Crew Program.

Private space exploration also democratizes access, enabling space tourism, commercial ventures, and research opportunities. SpaceX aims to establish permanent human settlements on Mars, while others envision industries like in-space manufacturing and mining. The “space race” has shifted to the commercial sector, driven by competition among private firms and supported by public-private partnerships. As private companies advance technologies and expand human activity beyond Earth, the commercial space sector may be uniquely poised to define the future of space exploration.

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Introduction to Aerospace Flight Vehicles Copyright © 2022–2025 by J. Gordon Leishman is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, except where otherwise noted.

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