Robert H. Liebeck | |
---|---|
Nationality | American |
Occupation | Aircraft engineer |
Known for | Aircraft designs Liebeck airfoils |
Robert Hauschild Liebeck is an American aerodynamicist, [1] professor [2] and aerospace engineer. Until retiring from his position as senior fellow [3] at the Boeing Company. [4] in 2020, [3] he oversaw their Blended Wing Body ("BWB") program. [5] [6] He has been a member of the National Academy of Engineering since 1992, where he is an AIAA Honorary Fellow, the organization’s highest distinction. [4] [7] [8] He is best known for his contributions to aircraft design [7] and his pioneering airfoil designs known as the "Liebeck Airfoil". [9] Since his retirement he remains active in aviation industry associations and continues to teach at UCI.
Liebeck pursued studies in aerospace engineering at the University of Illinois at Urbana–Champaign. He graduated with a Bachelor of Science in 1961, a Master of Science in 1962 and a PhD in 1968. [2] [10] [11] [12] It was while pursuing his PhD that he produced the first airfoil designs that would come to be known as the "Liebeck Airfoil". [4] [11] [12]
Liebeck worked summers at the Douglas Aircraft Company, located in Santa Monica, California, [5] until he joined the permanent staff in 1968. [4] He remained with the company after its merger with McDonnell Douglas, which later merged with Boeing in 1997. [5] [13] He has managed several of Boeing's airplane programs through which several advanced-concept aircraft were designed. [4] [11] [12] As Senior Technical Fellow of the Boeing Company, he served as program manager of the company's blended wing body program. [7]
Designs made by Liebeck during research for his doctoral thesis "Optimization of Airfoils for Maximum Lift", have been applied to the design of high-altitude aircraft. This class of airfoils has been used by NASCAR in its Car of Tomorrow which debuted in 2007. [4]
Boeing has invested in a blended wing body airplane program since 1993, a program which Liebeck slayed. [5] Run through Boeing's Phantom Works division, the program researched, designed and prototyped new aircraft designs which would reduce energy consumption and noise production. [10] [11] Initially funded by a grant from NASA of $90,000, the aircraft design moves away from the usual tube-and-wing design and instead has the wings blended into the body. [5] This design was developed by Liebeck, in conjunction with other members of the research team. [7] [10] Liebeck's team released a remote-driven model, the X-48, in 1997, flight tested a three-engine version, the X-48B, in 2008-9 [14] and a two-engine version, the X-48C in 2013. [15] [4] [7] [10] [12] [16]
Liebeck's designs include propellers, wind turbines. wings for racing cars that have won the Indianapolis 500 and the Formula One World Championship, the wing for NASCAR's "Car of Tomorrow," the keel for the America³ yacht which won the 1992 America's Cup, and the wing for a World Championship aerobatic airplane [4] [7] [10] [11] [12]
Liebeck has lectured in aerodynamics and aircraft design courses at several universities. [7] Since 1995 he has been a Professor of the Practice of Aerodynamics at the Massachusetts Institute of Technology where he lectures in aeronautics. [4] [10] [11] [12] Since 2000, Liebeck has also been an adjunct professor at the University of California, Irvine. [4] [7] He was also an adjunct professor teaching aerodynamics, flight mechanics and airplane design at the University of Southern California from 1977 to 2000. [4] [10]
Liebeck was presented with the Brigadier General Charles E. "Chuck" Yeager International Aeronautical Achievement Award in 2012. [7] In 2011 Liebeck was inducted into the Hall of Fame at the College of Engineering at Illinois, an honor which "recognizes Illinois engineering alumni, and others affiliated with the college, who have made significant achievements in leadership, entrepreneurship, and innovation of great impact to society". [7] [10] That same year he was presented with "Engineering the Future" award from the Henry Samueli School of Engineering for his work in aeronautics and contributions to the school. [7]
Liebeck's awards and honors include:
Aerodynamics is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an important domain of study in aeronautics. The term aerodynamics is often used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, and is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, which was first demonstrated by Otto Lilienthal in 1891. Since then, the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, and computer simulations has formed a rational basis for the development of heavier-than-air flight and a number of other technologies. Recent work in aerodynamics has focused on issues related to compressible flow, turbulence, and boundary layers and has become increasingly computational in nature.
In aeronautics, the aspect ratio of a wing is the ratio of its span to its mean chord. It is equal to the square of the wingspan divided by the wing area. Thus, a long, narrow wing has a high aspect ratio, whereas a short, wide wing has a low aspect ratio.
An airfoil or aerofoil is a streamlined body that is capable of generating significantly more lift than drag. Wings, sails and propeller blades are examples of airfoils. Foils of similar function designed with water as the working fluid are called hydrofoils.
Richard Travis Whitcomb was an American aeronautical engineer who was noted for his contributions to the science of aerodynamics.
Lift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, in aerodynamics, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or a lifting body redirecting air to cause lift and also in cars with airfoil wings that redirect air to cause a downforce. It is symbolized as , and the lift-induced drag coefficient as .
Wingtip devices are intended to improve the efficiency of fixed-wing aircraft by reducing drag. Although there are several types of wing tip devices which function in different manners, their intended effect is always to reduce an aircraft's drag. Wingtip devices can also improve aircraft handling characteristics and enhance safety for following aircraft. Such devices increase the effective aspect ratio of a wing without greatly increasing the wingspan. Extending the span would lower lift-induced drag, but would increase parasitic drag and would require boosting the strength and weight of the wing. At some point, there is no net benefit from further increased span. There may also be operational considerations that limit the allowable wingspan.
Robert T. Jones,, was an American aerodynamicist and aeronautical engineer for NACA and later NASA. He was known at NASA as "one of the premier aeronautical engineers of the twentieth century".
The Boeing X-48 is an American experimental unmanned aerial vehicle (UAV) built to investigate the characteristics of blended wing body (BWB) aircraft. Boeing designed the X-48 and two examples were built by Cranfield Aerospace in the UK. Boeing began flight testing the X-48B version for NASA in 2007. The X-48B was later modified into the X-48C version, which was flight tested from August 2012 to April 2013. Boeing and NASA plan to develop a larger BWB demonstrator.
A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed.
An airplane or aeroplane, informally plane, is a fixed-wing aircraft that is propelled forward by thrust from a jet engine, propeller, or rocket engine. Airplanes come in a variety of sizes, shapes, and wing configurations. The broad spectrum of uses for airplanes includes recreation, transportation of goods and people, military, and research. Worldwide, commercial aviation transports more than four billion passengers annually on airliners and transports more than 200 billion tonne-kilometers of cargo annually, which is less than 1% of the world's cargo movement. Most airplanes are flown by a pilot on board the aircraft, but some are designed to be remotely or computer-controlled such as drones.
A supercritical aerofoil is an airfoil designed primarily to delay the onset of wave drag in the transonic speed range.
A blended wing body (BWB), also known as blended body, hybrid wing body (HWB) or a lifting aerofoil fuselage, is a fixed-wing aircraft having no clear dividing line between the wings and the main body of the craft. The aircraft has distinct wing and body structures, which are smoothly blended together with no clear dividing line. This contrasts with a flying wing, which has no distinct fuselage, and a lifting body, which has no distinct wings. A BWB design may or may not be tailless.
The Gurney flap is a small tab projecting from the trailing edge of a wing. Typically it is set at a right angle to the pressure-side surface of the airfoil and projects 1% to 2% of the wing chord. This trailing edge device can improve the performance of a simple airfoil to nearly the same level as a complex high-performance design.
The NASA AD-1 was both an aircraft and an associated flight test program conducted between 1979 and 1982 at the NASA Dryden Flight Research Center, Edwards California, which successfully demonstrated an aircraft wing that could be pivoted obliquely from zero to 60 degrees during flight.
Jan Roskam was a Dutch-born American aircraft designer. He was the Deane E. Ackers Distinguished Professor of Aerospace Engineering at the University of Kansas. He was also the author of eleven books on airplane design and flight dynamics and over 160 papers on the topics of aircraft aerodynamics, performance, design and flight controls. He founded the company DARcorporation with Willem Anemaat.
George S. Schairer was an aerodynamicist at Consolidated Aircraft and Boeing whose design innovations became standard on virtually all types of military and passenger jet planes.
Richard C. Scherrer (1919–2018) was an aircraft designer notable for pioneering work on revolutionary aircraft designs with extremely low radar cross sections that led to the Lockheed F-117 Nighthawk and Northrop Grumman B-2 Spirit.
John H. McMasters was an aeronautical engineer notable for his contributions to aerodynamics and engineering education.
Mark Page is an American aerodynamicist and aerospace engineer. He is most known for his contributions to the design of UAVs and Blended Wing Body (BWB) aircraft. He is currently the co-founder and Chief Technology Officer (CTO) at JetZero.
Marty Bradley is an American aerospace engineer who specializes in advanced propulsion, electric aircraft, and sustainable aviation. He is a fellow of the American Institute of Aeronautics and Astronautics (AIAA), an adjunct professor of aerospace and mechanical engineering practice at the University of Southern California (USC), and a sustainable aviation consultant.