Going with the flow – NASA and Boeing test advances in aerodynamic technology to improve fuel and noise performance
The 757 tail is equipped with tiny jets that blow air across the rudder surfaces (photo: NASA Ames Research Center)
Thu 21 Nov 2013 – A NASA and Boeing research team has completed wind tunnel testing that shows active flow control technology can enhance the performance of a commercial aircraft’s vertical tail enough to enable the size of the structure to be reduced for a whole family of airplanes. The reduction could lead to improved fuel efficiency, emissions savings and reduced noise levels through less aircraft drag and weight, says NASA. Active flow control involves the manipulation of a flow field through the addition of energy to improve aerodynamic performance. The next phase of the research will involve flight testing as part of Boeing’s ecoDemonstrator programme that aims to improve environmental performance through new technologies, materials and methods.
The wind tunnel testing of a full-scale Boeing 757 vertical tail began in early September at the US Air Force engineering development centre in Ames, California, and was conducted by NASA’s Ames Research Center and NASA’s Langley Research Center, in partnership with Boeing. The vertical tail, which came from an aircraft ‘bone yard’ in Arizona, was modified and equipped with tiny jets called sweeping jet actuators that blow air in a sweeping motion across the rudder surfaces. NASA provided the actuators as part of a collaborative agreement under its Environmentally Responsible Aviation Project.
The testing is a key component of the project, said its manager, Fay Collier. “The maturation of technologies such as active flow control, which will benefit aviation by improving fuel efficiency, reducing emissions and noise levels, is what NASA’s aeronautics research is all about,” he said. “The promising results of these wind tunnel tests and the following flight demonstrations in 2015 undoubtedly will have an impact on future green aircraft designs.”
The wind tunnel tests enabled the Boeing and NASA team to observe a wide array of flow control configurations across the whole low-speed flight envelope of the vertical tail, said Ed Whalen, Boeing Research & Technology Program Manager for the testing. The team will now pick the most efficient and effective flow control configuration for future flight testing to see how it performs in a real-flight environment. “That will give us insight into how the system works, how effective and efficient it is, and things that we’re not completely sure of at this point,” explained Whalen.