LEA Flight Test Program: First Step to an Operational Application of High-Speed Airbreathing Propulsion

During the 10 last years, a large Research and Technology effort has been led by MBDA and ONERA to develop knowledge on high-speed airbreathing propulsion and master associated technologies. Development of operational, civilian or military, application of the hypersonic airbreathing propulsion depends of two key points : development of needed technologies for the fuel-cooled structure of the propulsion system, capability to predict with a reasonnable accuracy and to optimise the aeropropulsive balance (or generalized thrust-minus -drag balance). The most part of the technology development effort can be led with available ground test facilities and classical numerical simulation (thermics, mechanics ...). On the contrary, before any operational application, it is mandatory to demonstrate our ability to predict the aeropropulsive balance (generalized thrust-minusdrag balance) of a hypersonic vehicle, providing sufficient margins to start a costly technological program. Considering this mandatory step, MBDA and ONERA are leading a specific scientific program, called LEA, organized as follows: • Define a methodology for the development of a hypersonic vehicle using ground tests and numerical simulation • Develop the required tools (experimental or numerical) for this purpose. • Apply this methodology to the development of a simplified, scientific experimental vehicle • Validate this methodology through a series of flight tests Started in January 2003, this program is planned to end in 2012 after 6 autonomous flight tests of the experimental vehicle in the Mach number range from 4 to 8. Copyright © 2003 by MBDA France and ONERA. Published by American Institute for Aeronautics and Aerospace,Inc., with permission. Introduction During the two past decades, a lot of system studies, generally based on large technology development efforts, have been performed around the world to assess the interest of combined propulsion (airbreathing + rocket) for space launcher application. In France, thanks to studies led by the French Space Agency (CNES) during eighties, then in the framework of PREPHA program (Research and Technology Program for Advanced Hypersonic Propulsion), it was clearly established that combined propulsion could have an interest for space launcher application only if airbreathing mode can provide a subsequent part of the total speed increment (e.g. airbreathing mode must ensure propulsion from at least Mach 1.5/2 to Mach 10/12) (Ref [1] to [7]). By another way, hypersonic airbreathing propulsion could have very interesting application for military purpose. As a matter of fact, flying at very high Mach number and altitude can strongly improve the penetration capability while having a high average speed allow to deal with critical time targets (Ref [8] to [10]). Nevertheless, the development of operational, civilian or military, application of the hypersonic airbreathing propulsion depends of two key points : • development of needed technologies for the propulsion system as a low weight, high robustness fuel-cooled structure for the combustor, • capability to predict with a reasonnable accuracy and to optimise the aero-propulsive balance (or generalized thrust-minus -drag). Technology development effort Even if technologies will finally need to be flight proven, a large part of the technology development effort can be led with available ground test facilities (Ref[11]) and classical numerical simulation (thermics, mechanics...). 12th AIAA International Space Planes and Hypersonic Systems and Technologies 15 19 December 2003, Norfolk, Virginia AIAA 2003-7031 Copyright © 2003 by MBDA France and ONERA. Published by the American Institute of Aeronautics and Astronautics, Inc., with permission.