UC Davis experts: Aircraft, rockets and spaceflight

The following UC Davis faculty are available to discuss issues related to aircraft, rockets and spaceflight.

• Aerodynamics and aircraft design
• Aerodynamics of supersonic aircraft
• Virtual wind tunnels
• Flying by wire
• Jet engine design
• Using composite materials in aircraft
• Reusable spacecraft
• Robots and space exploration
• Dynamic stability of rocket systems
• Training space engineers

Aerodynamics and aircraft design

Cornelis "Case" van Dam, professor of mechanical and aeronautical engineering at UC Davis, is an expert on the aerodynamics of fixed- and rotary winged aircraft and wind turbines. He teaches courses in aerodynamics and aircraft design and has acted as a consultant to NASA, several aircraft companies and sailing yacht designers. There are still gaps in our understanding of air flow around objects, he says, which make it hard to predict the maximum possible lift produced by a particular wing design and work out how much weight a plane can carry. One area of van Dam's research involves putting controllable microtabs, a few millimeters in size, on the trailing edges of wings. The microtabs lead to "amazing" changes in the lift generated, van Dam says. Contact: Case van Dam, Mechanical and Aeronautical Engineering, (530) 752-7741, cpvandam@ucdavis.edu.

Aerodynamics of supersonic aircraft

"Faster, bigger, and less fuel consumption" is the objective for airplane construction, says UC Davis aerospace engineering professor Mohamad Hafez. When airplanes fly at supersonic speeds, they are flying faster than the surrounding air and that creates shock waves and noise. The shock waves cause drag and increase fuel consumption. Hafez uses computer models to study air flows and shock waves in airplanes flying at or above the speed of sound. He has worked on transonic, sonic, and supersonic aerodynamic flow projects with Boeing and NASA. Hafez is a fellow of the American Institute of Aeronautics and Astronautics. Contact: Mohamad Hafez, Mechanical and Aeronautical Engineering, (530) 752-0212, mhafez@ucdavis.edu.

Virtual wind tunnels

Jean Jacques Chattot is professor of mechanical and aeronautical engineering and director of the Center for Computational Fluid Dynamics at UC Davis. He can talk about the advantages of using computers to study aerodynamic flows over aircraft. By using computer models to replace some wind tunnel studies, aircraft designers can save time and money, he says. For example, the aerodynamics of the Boeing 777 were verified using computer models after the original design was produced with traditional techniques. Eventually, computer studies may entirely replace wind tunnels, but there are a number of problems to overcome and the physics of turbulent air flows is still not very well understood, Chattot says. Contact: Jean-Jacques Chattot, Mechanical and Aeronautical Engineering, (530) 752-0812, jjchattot@ucdavis.edu.

Flying by wire

Ron Hess, professor of mechanical and aeronautical engineering at UC Davis, studies the "fly by wire" control systems used on military aircraft and newer commercial aircraft such as the Boeing 777. These electronic systems have replaced mechanical controls based on rods and pulleys because they are lighter and allow for more precise control of the aircraft, Hess says. However, design errors can lead to rare but potentially serious problems when the system does not respond in the way the pilot expects. Hess uses computer simulations to look at ways to improve control system design in order to reduce possible pilot error. He served on the National Research Council committee on aviation safety and pilot control and has worked with both the U.S. Air Force and the NASA Ames Research Center. Contact: Ron Hess, Mechanical and Aeronautical Engineering, (530) 752-1513, rahess@ucdavis.edu.

Jet engine design

Design and analysis of jet engines and other turbomachinery are the research interests of Roger Davis, professor of mechanical and aeronautical engineering at UC Davis. Davis uses sophisticated computer models to simulate air and gas flows in jet engines, with the aim of making engines more efficient. He has also studied similar design problems for power station turbines, propellors, fans and other rotating machinery. Davis worked for jet engine manufacturer Pratt and Whitney and its parent company, United Technologies, for almost 30 years before joining the UC Davis faculty in January. Most recently, he worked at the United Technologies Research Center in East Hartford, Conn. Contact: Roger Davis, Mechanical and Aeronautical Engineering, (530) 752-2264, davisrl@ucdavis.edu.

Using composite materials in aircraft

Lawrence Rehfield, professor of mechanical and aeronautical engineering at UC Davis, is an expert on composite materials and their use in aircraft such as the Airbus A-300 and Boeing 777. Rehfield has 28 years of experience with composites, including appointments with the U.S. Air Force and NASA. He teaches courses on composites and aircraft construction at UC Davis. Although relatively new in civilian aircraft, composite tails have been used in military aircraft since 1969, without safety problems, Rehfield says. The new generation of civilian aircraft will have more parts made of composites, including the tail and wings. If failure of the composite tail is found to have been a contributing factor to the crash of American Airlines flight 587, federal authorities may need to investigate how commercial airlines inspect and maintain composite components and set new guidelines, he says. Contact: Lawrence Rehfield, Mechanical and Aeronautical Engineering, (530) 752-8100, lwrehfield@ucdavis.edu.

Reusable spacecraft

Plans for a cheaper, reusable spacecraft launched from a large cargo plane are being developed by Nesrin Sarigul-Klijn, professor of mechanical and aeronautical engineering at UC Davis. The spacecraft, called SwiftLaunch, would carry up to three people or a small payload into orbit. It would be carried to its launch height inside a cargo plane such as a C-5 "Galaxy" and pulled out of the rear cargo door by parachutes. Once clear of the carrier plane, the rocket engine would fire to carry the vehicle into orbit. The proposal is currently being reviewed by NASA and the U.S. Air Force. Contact: Nesrin Sarigul-Klijn, Mechanical and Aeronautical Engineering, (530) 752-0862, nsarigulklijn@ucdavis.edu.

Robots and space exploration

Sanjay Joshi, assistant professor of mechanical engineering at UC Davis, studies robots and control systems for space missions. Robots, or autonomous systems, can replace humans for dangerous tasks such as space exploration, he says. These robots can carry out repetitive tasks, learn new tasks and fix their own breakdowns and other problems. Before joining UC Davis in 2001, Joshi was at NASA's Jet Propulsion Laboratory where he worked on projects including the Deep Space 1 space probe and development of robot "work crews" for Mars exploration. Deep Space 1, launched to test a range of new technologies, accomplished a fly-by of asteroid Braille in July 1999. It was then repaired in flight, 150 million miles from Earth, to go on to comet Borrelly. Contact: Sanjay Joshi, Mechanical and Aeronautical Engineering, (530) 754-9662, maejoshi@ucdavis.edu.

Dynamic stability of rocket systems

Fidelis Eke, associate professor of mechanical and aeronautical engineering at UC Davis, studies the dynamics of rockets and spacecraft and how they can be controlled in flight. At launch, the combined rocket and spacecraft is very large, but as fuel is burned during flight the mass of the vehicle continually changes and shifts. Eke analyzes how these factors affect the movement of rockets, finding out "what to be careful of and what to avoid" in designing rocket systems. Eke has worked with spacecraft systems for the past 10 years, predominantly with NASA. Contact: Fidelis Eke, Mechanical and Aeronautical Engineering, (530) 752-2309, foeke@ucdavis.edu.

Training space engineers

Nesrin Sarigul-Klijn, a professor of mechanical and aeronautical engineering, coordinates the UC Davis SpaceEd graduate program in space engineering. Funded by a grant from the California Space Authority, SpaceEd aims to increase the number of qualified space engineers to meet the needs of the growing space industry, Sarigul-Klijn says. While the traditional aircraft industry has declined in California, there are a number of companies in fields such as rocket engines and satellite construction that have difficulty finding qualified young engineers. For example, NASA has more engineers over 60 than under 30. Sarigul-Klijn, who is a qualified pilot, also teaches undergraduate level courses in rocket engineering, in which students build and launch their own rockets. Contact: Nesrin Sarigul-Klijn, Mechanical and Aeronautical Engineering, (530) 752-0862, nsarigulklijn@ucdavis.edu.

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