By Tim Patterson
Almost 60 years ago, the sound barrier was thought impossible to pass. Yet soon after the
X-1’s success, programs were already in the works to take us beyond Mach 1 and into
supersonic flight (Mach 1- Mach 5). However, to cross the next barrier of hypersonic flight
(any speed greater than Mach 5), drastic problems would have to be over come in design,
propulsion, and construction materials that were currently unavailable. With years of
research and testing, these obstacles were finally overcome with the recent success of
Mach 9.8 flight achieved in November of 2004. Powered by the Scramjet (Supersonic
combustion ramjet), NASA’s X-43A test vehicle touched a realm of flight rarely found by air-
breathing airplanes, hypersonic flight. With the X-43’s amazing thrust potential being
produced by an engine that has no compressors or moving parts, scientists and countries
alike are intrigued to see how this technology can be applied towards future goals and
projects.
Scramjets are not a new idea. Although the most exciting developments and successes
have taken place most recently, the concept has been actively pursued since the 1940’s.
With government supersonic flight programs like the F-80 Shooting Star, Republic XF- 103
and the X-15, valuable information was gained about ramjet/scramjets performance. Their
advances in studying hydrocarbon-fueled engines alone have helped scramjet technology
to reach its current developmental state.
Scramjet engines are a far departure from the conventional turbine jet engine. Air enters
both engines and is compressed. Fuel is added to the compressed air, ignited, and forced
out the back of the engines. This is basically the only thing the two engines have in
common. However, if hypersonic flight is to be achieved comparisons need to be drawn
against this and other a power plants to see why the scramjet is the answer for hypersonic
propulsion.
With the successful demonstration of these engines by the United States and other
countries, many possibilities are now attainable. From precision guided missiles to Mach 10
flight, and the proposed X-43B, the technology is here to stay. If funding can be secured,
new generations of long range bombers, fast-reaction cruise missiles, and a space launch
system that could cut the costs associated with propelling astronauts and payload into
space to one-hundredth of today’s prices, could be realized. Civilization continues to strive
for faster and more efficient means of transportation and with scramjet-powered vehicles,
the hypersonic barrier now does not seem impossible. With promise, scramjets powered
vehicles might one day live up to the aggressive political goals stated by President Reagan
in 1986 in regards to the National Aerospace Plane, “To provide travel from New York to
Tokyo in two hours.” However talk is cheap, and one thing scramjets have definitely proved,
low cost scramjet research and development does not exist.
Tim Patterson, webmaster for http://www.magneticdrainplug.com is a commercial pilot and
aviation enthusiast.
