From: Eugene Leitl (Eugene.Leitl@lrz.uni-muenchen.de)
Date: Wed Aug 29 2001 - 08:01:42 MDT
http://slashdot.org/articles/01/08/28/1551229.shtml
"The Sacramento Bee is running this story about the first powered device
to achieve "hypersonic" speeds in the Earth's atmosphere. In a series of
DARPA-sponsored tests, at Arnold Air Force Base in Tennessee, a scramjet
engine, encased in a titanium projectile, was fired from a 130-foot
cannon, at an initial velocity of Mach 7.1. The scramjet's engines then
ignited, and the object moved another 260 feet, in just 30 milliseconds,
before it came to rest in a series of steel plates designed to halt the
flight. Peak acceleration: about 10,000 G's. Elapsed time, including
cigarettes & pillowtalk: less than a second. PS: According to this nifty
page at NASA, Mach 7.1 is about 5406 MPH, whereas 260 ft, per 0.03
seconds, is about 5909 MPH."
http://www.sacbee.com/news/calreport/data/N2001-08-27-1700-2.html
Defense agency tests hypersonic
missile prototype
By Andrew Bridges
Associated Press Writer
LOS ANGELES (AP) -- A futuristic jet-powered missile prototype reached
speeds of more than 5,000 mph in recent tests, a Defense Department agency
announced Monday.
The test marked the first time a specialized jet engine, called a
scramjet, propelled a projectile at hypersonic velocities, or faster than
five times the speed of sound, said Preston Carter of the Defense Advanced
Research Projects Agency.
"No one has ever gotten positive thrust out of a scramjet vehicle in
free-flight," said Carter, a program manager in DARPA's Tactical
Technology Office. DARPA is spending about $800,000 on the project.
During the June 20 test at Arnold Air Force Base in Tennessee, the
cylindrical missile prototype was fired from a 130-foot cannon at a
velocity of Mach 7.1, or about 5,325 mph. The scramjet engine aboard the
titanium projectile then ignited, propelling it 260 feet in 30
milliseconds.
The prototype, which resembles a gothic spire and measures just 4 inches
in diameter, was destroyed when it punched through a series of steel
plates designed to halt the flight.
The test was successfully repeated on July 26, reaching the same peak
acceleration of about 10,000 G's. High-speed video and still cameras, as
well as X-ray and infrared cameras, recorded the flights.
Scramjets, or supersonic combustion ramjets, burn hydrocarbon fuel but
scoop oxygen out of the atmosphere to combust it. Rockets can reach
comparable speeds, but must carry the fuel and an oxidant to burn it,
leaving less room for payload.
The Pentagon and National Aeronautics and Space Administration are both
studying scramjet technology since it would allow missiles or spacecraft
to travel longer distances and carry larger payloads than rockets.
NASA attempted to test its own scramjet, the X-43A, on June 2, but blew up
the rocket used to launch the unmanned jet because it began to break apart
and stray off course. The explosion also destroyed the experimental jet.
X-43A tests will likely resume late next year, NASA spokeswoman Leslie
Williams said.
-- Eugen* Leitl leitl
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