Monday, August 27, 2007

Aerospace engineering

Aerospace engineering

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Aerospace engineering is the branch of engineering that concerns aircraft, spacecraft, and related topics. Aerospace Engineering was originally known as aeronautical engineering and dealt solely with aircraft. The broader term "aerospace engineering" has replaced the former in most usage, as flight technology advanced to include craft operating outside Earth's atmosphere.[1] In analogy with "aeronautical engineering", the branch is sometimes referred to as astronautical engineering, although this term usually only concerns craft which operate in outer space.

A Pratt & Whitney F100 turbofan engine for the F-15 Eagle and the F-16 Falcon is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape.
A Pratt & Whitney F100 turbofan engine for the F-15 Eagle and the F-16 Falcon is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape.

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[edit] Overview

Modern flight vehicles must undergo severe conditions such as differences in atmospheric pressure and temperature, or heavy structural load applied upon vehicle components; numerous matters must be taken into account. Consequently, they are usually products of complex synthesis of various technologies and sciences, including but not limited to aerodynamics, materials science and electronics. The knowledge and the process of combining these various branches of studies are what is collectively known as aerospace engineering. This complex characteristic keeps a single aerospace engineer from involving in the entire task;[2] rather, aerospace engineering is conducted by a team of engineers, each specializing in their own branches of science. The development and manufacturing of a flight vehicle is basically a process to carefully balance and compromise between the abilities, performance, available technology and costs.

[edit] History

See also: Aviation history

The origin of modern-day aerospace engineering can be traced back to the aviation pioneers around the turn of the century from the 19th century to the 20th. Early knowledge of aeronautical engineering was largely empirical with some concepts and skills imported from other branches of engineering,[3] although the early pioneers were not without theoretical background for their creations (fluid dynamics, a key branch of science related to aviation, was present from the century before). Only a decade after the successful flights by the Wright brothers, the 1920s saw extensive development of aeronautical engineering through development of World War I military aircraft. Meanwhile, researches to provide fundamental background science continued by combining theoretical physics with experiments.

The first definition of aerospace engineering appeared in February 1958.[1] The definition considered the Earth's atmosphere and the outer space as a single realm, thereby encompassing both aircraft (aero) and spacecraft (space) under a newly coined word aerospace.

[edit] Elements

Some of the elements of aerospace engineering are:[4]

  • Fluid mechanics - the study of fluid flow around objects. Specifically aerodynamics concerning the flow of air over bodies such as wings or through objects such as wind tunnels (see also lift and aeronautics).
  • Astrodynamics - the study of orbital mechanics including manipulation, determination, and prediction of orbital elements when given a select few variables. While few schools in the United States teach this at the undergraduate level, several have graduate programs covering this topic (usually in conjunction with the Physics department of said college or university).
  • Dynamics and engineering mechanics - the study of movement, forces, moments in mechanical systems.
  • Mathematics - as most subjects within aerospace engineering involve equations and mathematical manipulation and derivations, a solid and comprehensive study of mathematics is required to enable effective learning in the other modules.
  • Electrotechnology - the study of electronics within engineering.
  • Propulsion - the energy to move a vehicle through the air (or in outer space) is provided by internal combustion engines, jet engines and turbomachinery, or rockets (see also propeller and spacecraft propulsion). A more recent addition to propulsion is ion thrust (or electric) propulsion.
  • Control engineering - the study of mathematical modeling of the dynamic behavior of systems and designing them, usually using feedback signals, so that their dynamic behavior is desirable (stable, without large excursions, with minimum error). This applies to the dynamic behavior of aircraft, spacecraft, propulsion systems, and subsystems that exist on aerospace vehicles. As aircraft flight control systems become increasingly complex, they can be studied as a separate module.
  • Aircraft structures - design of the physical configuration of the craft to withstand the forces encountered during flight. Aerospace engineering aims very much at keeping structures lightweight.
  • Materials science - related to structures, aerospace engineering also studies the materials of which the aerospace structures are to be built. New materials with very specific properties are invented, or existing ones are modified to improve their performance.
  • Solid mechanics - Closely related to material science is solid mechanics which deals with stress and strain analysis of

the components of the vehicle. Nowadays there are several Finite Element programs such as MSC Patran/Nastran which aid engineers in the analytical process.

  • Aeroelasticity - the interaction of aerodynamic forces and structural flexibility, potentially causing flutter, divergence, etc.
  • Avionics - specifically concerning the design and programming of any computer systems on board an aircraft or spacecraft and the simulation of systems. Navigation equipment may be the focus of this study.
  • Risk and reliability - the study of risk and reliability assessment techniques and the mathematics involved in the quantitative methods.
  • Noise control - the study of the mechanics of sound transfer. Required as noise levels are a massive consideration in the current aerospace industry.
  • Flight test - the discipline of designing and executing flight test programs in order to gather and analyze performance and handling qualities data in order to determine if an aircraft meets its design and performance goals and certification requirements.

The basis of most of these elements lies in theoretical mathematics, such as fluid dynamics for aerodynamics or the equations of motion for flight dynamics. However, there is also a large empirical component. Historically, this empirical component was derived from testing of scale models and prototypes, either in wind tunnels or in the free atmosphere. More recently, advances in computing have enabled the use of computational fluid dynamics to simulate the behavior of fluid, reducing time and expense spent on wind-tunnel testing.

Additionally, aerospace engineering addresses the integration of all components that constitute an aerospace vehicle (subsystems including power, communications, thermal control, life support, etc.) and its life cycle (design, temperature, pressure, radiation, velocity, life time), leading to extraordinary challenges and solutions specific to the domain of aerospace systems engineering. It is uncommon for an aerospace engineer to view and comprehend all the components of the involved project.[5]

See List of aerospace engineering topics.

[edit] Popular culture

Popular culture has not been unaffected by this branch of engineering. The term "rocket scientist" is at times used to describe a person of remarkable or in the considered context higher than average intelligence. Aerospace engineering has also been represented as the more "glittery" pinnacle of engineering. The movie Apollo 13 depicts the ground team as a group of heroes in a Hollywood fashion glorifying the intelligence and competence of white shirt and tie professionals as a sharp contrast to pop culture trends. This was later extended in more detail in the spin-off series From the Earth to the Moon.

[edit] Aerospace engineering degrees

Aerospace (or aeronautical) engineering can be studied at the bachelors, masters, and Ph.D. levels in aerospace engineering departments at many universities, and in mechanical engineering departments at others.

[edit] Aerospace Engineers

"Aerospace engineers design, develop, and test aircraft, spacecraft, and missiles, and supervise the production of these products. Those who work with aircraft are called aeronautical engineers, and those working specifically with spacecraft are astronautical engineers. Aerospace engineers develop new technologies for use in aviation, defense systems, and space exploration, often specializing in areas such as structural design, guidance, navigation and control, instrumentation and communication, or production methods. They also may specialize in a particular type of aerospace product, such as commercial aircraft, military fighter jets, helicopters, spacecraft, or missiles and rockets, and may become experts in aerodynamics, thermodynamics, celestial mechanics, propulsion, acoustics, or guidance and control systems".[6]

"Aerospace engineers are expected to have slower-than-average growth in employment over the projection period. Although increases in the number and scope of military aerospace projects likely will generate new jobs, increased efficiency will limit the number of new jobs in the design and production of commercial aircraft. Even with slow growth, the employment outlook for aerospace engineers through 2014 appears favorable: the number of degrees granted in aerospace engineering declined for many years because of a perceived lack of opportunities in this field, and, although this trend is reversing, new graduates continue to be needed to replace aerospace engineers who retire or leave the occupation for other reasons"[6].

Earnings for engineers vary significantly by specialty, industry, and education. Even so, as a group, engineers earn some of the highest average starting salaries among those holding bachelor’s degrees. The following tabulation shows average starting salary offers for aerospace engineers, according to a 2005 survey by the National Association of Colleges and Employers.

Starting salaries[6]:
Bachelor's - $50,993
Master's - $62,930
Ph. D. - $72,530

[edit] References

  1. ^ a b Stanzione, Kaydon Al (1987). "Engineering". Encyclopædia Britannica (15) 18. 563–563.
  2. ^ Career: Aerospace Engineer. Career Profiles. The Princeton Review. Retrieved on 2006-10-08. “Due to the complexity of the final product, an intricate and rigid organizational structure for production has to be maintained, severely curtailing any single engineer's ability to understand his role as it relates to the final project.”
  3. ^ Van Every, Kermit E. (1986). "Aeronautical engineering". Encyclopedia Americana 1. Grolier Incorporated. 226.
  4. ^ "Science: Engineering: Aerospace". Open Site. Retrieved on 2006-10-08.
  5. ^ Career: Aerospace Engineer. Career Profiles. The Princeton Review. Retrieved on 2006-10-08. “Due to the complexity of the final product, an intricate and rigid organizational structure for production has to be maintained, severely curtailing any single engineer's ability to understand his role as it relates to the final project.”
  6. ^ a b c Engineers. U.S. Department of Labor. Retrieved on 2007-05-29.

[edit] See also

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