USA
Test track takes levitation to new speeds
A magnetically levitated rocket sled prepares to launch Feb. 21, 2008, at Holloman Air Force Base, N.M. Unlike the conventional track, which can house vibrations up to 80 G's, the magnetic levitation track reduces vibrations to about two to six G's. (U.S. Air Force photo/Airman 1st Class Jamal D. Sutter)
by Airman 1st Class Jamal Sutter
49th Fighter Wing Public Affairs
2/29/2008 - HOLLOMAN AIR FORCE BASE, N.M. -- While Holloman's High Speed Test Track (HHSTT) is best known for its record breaking speed capabilities, it's also known for its innovation when it comes to new and improved technology.
The 846th Test Squadron and its HHSTT conducted their fifth magnetic levitation (MagLev) developmental test Feb. 21, sending a rocket sled down the MagLev track with a speed of 423 mph, breaking the previous record of 361 mph, which was held by Japan.
The goal for the MagLev testing isn't to break new speed barriers. The idea is to reduce vibration, explained Maj. George Mellen, 846 TS director of operations.
"The reason why we're doing the testing on the MagLev track is not to go faster than our conventional rail," Maj. Mellen said. "For our high speed tests on the conventional track, we can have vibrations up to 80 G's. The MagLev track minimizes that vibration to two to six G's."
This reduction of vibration allows the 846 TS to study and test sensitive objects such as sensors, fuses and smart bombs, Maj. Mellen said. The MagLev track gives the opportunity to test in a more flight-like environment.
"The MagLev track is made from concrete containing stainless steel fibers, rather than steel rebar, which is found in most bridges," said Lt. Col. Angela Suplisson, 846 TS commander. Steel rebar's magnetic characteristics would hinder the track's ability to successfully run tests.
Major Mellen explained there are four copper plates in the groove of the concrete girder, which extends the entire length of the track. Electromagnets under the sled, once cooled down to 4 degrees Kelvin and charged, have super conductor properties. As the rocket's motors move the sled down the track, the magnets will induce a current on the copper plates and that current will generate a magnetic field that opposes the sled's magnets. The sled's magnets will, then, want to be in the equilibrium between the copper plates vertically and laterally. This balance will keep the sled moving on a cushion of air as it floats one inch above the rail.
Col. Supplisson went into further details, adding that 30,000 pounds of magnetic force keep the sled in the middle of the copper plates.
While breaking the world record for speed is a major accomplishment, this is only the beginnings of what is in store for the MagLev track.
"Next, we'll add another rocket motor," Maj. Mellen said. "We'll have to take the data we gathered today to make the predictions of how fast the next test run will go. With the length of the track as it is right now (2300 feet), we expect to able to go about the speed of sound."
The 846 TS is working closely with NASA to, eventually, create a sled that uses electromagnetic energy for both levitation and propulsion, he said.
Until then, the HSTT will continue to raise the bar in the world of missile and rocket launching and developmental testing.
Author: ArchitectPage
