Guru
Introduction
Aerospace engineering stands as a testament to human ingenuity and the relentless pursuit of conquering the skies and beyond. This field, nestled at the intersection of aeronautics and astronautics, has propelled humanity into the vastness of space and has transformed the way we navigate and explore our own atmosphere. In this blog, we embark on a journey through the fascinating world of aerospace engineering, exploring its history, the intricacies of aircraft and spacecraft design, and the groundbreaking technologies shaping the future.
What is the aerodynamics?
Aerodynamics is the study of forces and the resulting motion of objects through the air. This word is coined with the two Greek words: aerios,concerning the air, and dynamis, meaning force. Judging from the story of Daedalus and Icarus,1 humans have been interested in aerodynamics and flying for thousands of years, although flying in a heavier-than-air machine has been possible only in the last century. Aerodynamics affects the motion of high-speed flying machines, such as aircraft and rockets, and low-speed machines, such as cars, trains, and so on.
Therefore, aerodynamics may be described as a branch of dynamics concerned with studying the motion of air,particularly when it interacts with a solid object. Aerodynamics is a subfield of fluid dynamics and gas dynamics. It is often used synonymously with gas dynamics, with the difference being that gas dynamics applies to all gases.
Understanding the flow field around an object is essential for calculating the forces and moments acting on the object. Typical properties calculated for a flow field include velocity, pressure,density, and temperature as a function of spatial position and time.
Aerodynamics allows the definition and solution of equations for the conservation of mass, momentum, and energy in air. The use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations forms the scientific basis for heavier-than-air flight and a number of other technologies.
Aerodynamic problems can be classified according to the flow environment.External aerodynamics is the study of flow around solid objects of various shapes. Evaluating the lift and drag on an airplane or the shock waves that form in front of the nose of a rocket are examples of external aerodynamics. Internal aerodynamics is the study of flow through passages in solid objects. For instance, internal aerodynamics encompasses the study of the airflow through a jet engine.
Aerodynamic problems can also be classified according to whether the flow speed is below, near or above the speed of sound. A problem is called subsonic if all the speeds in the problem are less than the speed of sound, transonic if speeds both below and above the speed of sound are present, supersonic if the flow speed is greater than the speed of sound,and hypersonic if the flow speed is more than five times the speed of sound.
The influence of viscosity in the flow dictates a third classification.Some problems may encounter only very small viscous effects on the solution; therefore the viscosity can be considered to be negligible.The approximations made in solving these problems is the viscous effect that can be regarded as negligible. These are called inviscid flows. Flows for which viscosity cannot be neglected are called viscous flows.
The Genesis of Aerospace Engineering:
Aerospace activity
into seven groups
- The industry, manufacturer of products.
- The airlines, transporters of goods and people.
- The military air forces, demanders of high-level technologies.
- The space agencies, explorers of the space.
- The infrastructures on earth, supporter of air operations.
- The research institutions, guarantors of technological progress.
- The international organizations, providers of jurisprudence.
The aerospace industry
The aerospace industry is considered as an strategic activity given that it is a high technology sector with an important economic impact. The Aerospace sector is an important contributor to economic growth everywhere in the world. The european aerospace sector represents a pinnacle of manufacturing which employed almost half a million highly skilled people directly in 2010 and it continuously spins-out technology to other sectors.
About 2.6 million indirect jobs can be attributed to air transport related activities and a contribution of around C250 billion1 (around 2.5%) to european gross domestic product in 2010. Therefore, the aerospace industry is an important asset for Europe economically, being a sector that invests heavily in Research and Development (R & D) compared with other industrial sectors.The aerospace sector is also an important pole for innovation.
The aerospace industry accomplish three kind of activities: aeronautics (integrated by airships,propulsion systems and infrastructures and equipments);space and missiles.Grosso modo the aeronautical industry constitutes around the 80-90% of the total activity.
- Great dynamism in the cycle research-project-manufacture-commercialization.
- Specific technologies in the vanguard which spin-out to other sectors.
- High-skilled people.
- Limited series (non mass production) and difficult automation of manufacturing processes.
- Long term development of new projects.
- Need for huge amount of capital funding.
- Governmental intervention and international cooperation.
The linkage between research and project-manufacture is essential because the market is very competitive and the product must fulfill severe safety and reliability requirements in order to be certified.Thus it is necessary to continuously promote the technological advance to take advantage in such a competitive market.
The quantity of units produced a year is rather small if we compare it with other manufacture sectors (automobile manufacturing, for instance). An airship factory only produces tens of units a year; in the case of space vehicles the common practice is to produce a unique unit. These facts give a qualitative measure of the difficulties in automating manufacturing processes in order to reduce variable costs.
The governmental intervention comes from different sources. First, directly participating from the capital of the companies (many of the industries in Spain and Europe are state owned). Indirectly, throughout research subsides.Also, as a direct client, as it is the case for military aviation. The fact that many companies do not have the critical size to absorb the costs and the risks of such projects makes common the creation of long-term alliances for determined aircrafts (Airbus) or jet engines (International Aero Engines or Eurojet).
Comparison between flag companies and low cost companies in aerospace industry
| Flag companies | Low Cost companies |
|---|---|
| Operate hubs and spoke | Operate point to point |
| Hubs in primary international airports | Mostly regional airports |
| Long rotation times (50 min) | Short rotation times (25 min) |
| Short and long haul routes | Short haul routes |
| Mixed fleets | Standardized fleets |
| Low density seats layout | High density seats layout |
| Selling: agencies and internet | Selling: internet |
| Extras included (Business, VIP lounges, catering) | No extras included in the tickets |
Airlines
Among the diverse elements that conform the air transportation industry, airlines represent the most visible ones and the most interactive with the consumer, i.e., the passenger. An airline provides air transport services for traveling passengers and/or freight. Airlines lease or own their aircraft with which to supply these services and may form partnerships or alliances with other airlines for mutual benefit, e.g., Oneworld, Skyteam, and Star alliance. Airlines vary from those with a single aircraft carrying mail or cargo, through full-service international airlines operating hundreds of aircraft. Airline services can be categorized as being intercontinental, intra-continental, domestic, regional, or international, and may be operated as scheduled services or charters.
The first airlines were based on dirigibles. DELAG (Deutsche Luftschiffahrts Aktiengesellschaft) was the world’s first airline. It was founded on November 16, 1909, and operated airships manufactured by the zeppelin corporation. The four oldest nondirigible airlines that still exist are Netherlands’ KLM, Colombia’s Avianca, Australia’s Qantas, and the Czech Republic’s Czech Airlines. From those first years, going on to the elite passenger of the fifties and ultimately to the current mass use of air transport, the world airline companies have evolved significantly.
Traditional airlines were state-owned. They were called flag companies and used to have a strong strategic influence. It was not until 1978, with the United States Deregulation Act, when the market started to be liberalized. The main purpose of the act was to remove government control over fares, routes, and market entry of new airlines in the commercial aviation sector. Up on that law, private companies started to emerge in the 80’s and 90’s,specially in USA. Very recently, a new phenomena have arisen within the last 10-15 years: the so called low cost companies, which have favored the mass transportation of people. A comparison between low cost companies and traditional flag companies is presented in above Table. It provides a first understanding of the main issues involved in the direct operating costs of an airline. The competition has been so fierce that many traditional companies have been pushed to create their own low cost filial companies, as it the case of Iberia and its filial Iberia Express.
The Foundation of Aerospace Engineering
Aerospace engineering can be divided into two primary disciplines: aeronautics and astronautics.
- Aeronautics: Aeronautical engineering is primarily concerned with the conceptualization and creation of aircraft,including helicopters and airplanes as well as drones.Aeronautical engineers commit their attention to flight performance,safety and fuel efficiency.
- Astronautics: Unlike that of aviation engineering,astronautical engineering deals with spacecrafts,rockets and other vehicles that venture beyond the earth's atmosphere.The professionals,astronautical engineers design system that facilitate space exploration and satellite technologies.
Achievements in Aerospace Engineering
- Moon Landings: Aerospace engineers were the crucial ones of the Apollo program, allowing mankind to step on the Moon. What human achievements can be attributed to aeronautical engineers is the very Lunar Module that is a symbol of our human aspiration that nowadays we see as a human success.
- Space Stations: Astronautics engineering encompasses both spaceflight and operations in particular environment like the space stations or the International Space Station (ISS). They function as important stages in the space science research.
- Mars Rovers: The engineering expertise employed in designing robotic spacecraft, such as the Mars rovers, is that of astronautical engineering Such vehicles have increased our knowledge of the Red Planet.
- Commercial Space Travel: Progress in the development of commercial space travels such as SpaceX and Blue Origin has created new avenues for the private sector participation in aerospace engineering.
- Supersonic Flight:The research in aeronautics is continuing with the objective of making supersonic travel cost-effective and easily available in the future other supersonic aircraft with enhanced technology could be manufactured.
Conclusion
Aerospace engineering is a fascinating discipline which blends science, engineering and imagination to help achieve what seems unfathomable in the world of air and space travels. This beginner’s guide has dealt with the fundamentals of aerospace engineering exposing several crucially important concepts – aerodynamics, powerplants, and materials. Going deeper into this interesting discipline, always remember the huge influence that the aerospace engineers have had on modern travelling and exploring the unknown.