The goals of the NASA Hypersonic Research Engine (HRE) Project, which began in 1964, were to design, develop, and construct a high-performance hypersonic research ramjet/scramjet engine for flight tests of the developed concept over the speed range of Mach 4 to 8. The project was planned to be accomplished in three phases: project definition, research engine development, and flight test using the X-15A-2 research airplane, which was modified to carry hydrogen fuel for the research engine. The project goal of an engine flight test was eliminated when the X-15 program was canceled in 1968. Ground tests of full-scale engine models then became the focus of the project. Two axisymmetric full-scale engine models, having 18-inch-diameter cowls, were fabricated and tested: a structural model and combustion/propulsion model. A brief historical review of the project, with salient features, typical data results, and lessons learned, is presented. An extensive number of documents were generated during the HRE Project and are listed. Andrews, Earl H. and Mackley, Ernest A. Langley Research Center...

This volume from The NASA History Series presents an overview of the science of hypersonics, the study of flight at speeds at which the physics of flows is dominated by aerodynamic heating. The survey begins during the years immediately following World War II, with the first steps in hypersonic research: the development of missile nose cones and the X-15; the earliest concepts of hypersonic propulsion; and the origin of the scramjet engine. Next, it addresses the re-entry problem, which came to the forefront during the mid-1950s, showing how work in this area supported the manned space program and contributed to the development of the orbital shuttle. Subsequent chapters explore the fading of scramjet studies and the rise of the National Aerospace Plane (NASP) program of 1985–95, which sought to lay groundwork for single-stage vehicles. The program's ultimate shortcomings — in terms of aerodynamics, propulsion, and materials — are discussed, and the book concludes with a look at hypersonics in the post-NASP era, including the development of the X-33 and X-34 launch vehicles, further uses for scramjets, and advances in fluid mechanics. Clearly, ongoing research in hypersonics has yet to reach its full potential, and readers with an interest in aeronautics and astronautics will find this book a fascinating exploration of the field's history and future.