Skip to comments.X-51A Team Eyes Results Of Scramjet Flight
Posted on 05/29/2010 10:24:41 PM PDT by ErnstStavroBlofeld
Following the longest flight yet by an air-breathing scramjet engine, the X-51A Waverider team is waiting to see whether the largely successful first launch of the hypersonic demonstrator will unlock funding for further development of the technology.
The X-51A was launched over the Pacific on May 26, achieving scramjet ignition and acceleration, but the engine ran for only 200 sec. rather than the 300 sec. planned, and the vehicle reached around Mach 5 instead of accelerating beyond Mach 6. When it began to slow down and telemetry was lost, the flight was terminated and the vehicle destroyed, says Charles Brink, U.S. Air Force Research Laboratory (AFRL) program manager.
We were 95% successful, he says, adding that the cause of the slow acceleration and short duration is not yet known. Three more X-51As have been built, but their flights are on hold because delays in flying the first vehicle have consumed most of the available funding. The team hopes the flights success will unlock new sources of funding and allow tests to resume in 2011.
The Air Force Flight Test Center at Edwards AFB, Calif., had been criticized because of repeated delays caused by the availability of the B-52 launch aircraft, but Brink praises the test team for putting us on point for the May 26 launch.
The X-51A booster-and-cruiser stack was released by the mother ship at around 50,000 ft. and Mach 0.8. The stack separated cleanly and the booster ignited as planned, taking the vehicle to Mach 4.8, where the cruiser separated and executed a planned roll maneuver.
After slowing to Mach 4.73, ethylene was used to ignite the scramjet, which then transitioned to JP-7 hydrocarbon fuel. The X-51A began to accelerate, but slower than expectedup to 0.15g instead of the projected 0.22g. We were seeing higher temperatures in the back of the engine bay, but have no idea why, Brink says.
After reaching around Mach 5, the vehicle began to slow. When telemetry was lost, range safety officials decided to terminate the flight by destroying the vehicle.
sounds like something was interfering with combustion. Possibly high velocity air/ air turbulence interfering with the air/fuel stoichiometry within the combustion chamber? uncombusted fuel would be my initial guess.
In 1967 Pete Knight flew an X-15, with a scramjet attached underneath, to a maximum velocity of Mach 6.72.
X51A Waverider Breaks Record For Hypersonic Flight, Travels 6 TIMES Speed Of Sound
Whikipedia Entry for X51(a)
X51a photo search, Google
The Vehicle only reached Mach 5
Take it up with AP. I’ve got no ax to grind.
Yes, but, whereas the X-15 was a rocket-plane (with a range of less than 300 miles), this one is an air-breather (with potentially longer range).
Carrying no liquid oxygen also makes things a lot safer.
I was the project historian for the National Aerospace Plane from 1988-1995, and finally got the history published as “The Quest for the Orbital Jet,” around 2000, from the USAF. It may be limited release, but it should be available somehow. Anyway, this project shows how far we were from the goal of attaining orbital velocity with a jet.
Yes, the concept is entirely different, and the goal here is to get a jet into orbit eventually.
stoichiometric anomaly :)
I never heard the term stoichiometry before
Even just get to the edge of space, then fire a satellite-killing missile?
Sure, but our goal was to get REAL “single stage to orbit” capability in which you could re-fuel the vehicle and go up again in weeks, not months or years like the Shuttle. Only then will you really have “routine” space travel.
Undergrad college chemistry.
Nay, not in my day.
On 13 September 1985, Maj. Wilbert D. "Doug" Pearson, flying the "Celestial Eagle" F-15A 76-0084 launched an ASM-135 ASAT about 200 miles (322 km) west of Vandenberg Air Force Base and destroyed the Solwind P78-1 satellite flying at an altitude of 345 miles (555 km).