By Mr Carlos J Lazo (USACE)November 28, 2011
HILL AIR FORCE BASE, Utah -- A modern turntable can cost around $500 and support vinyl records weighing around 200 grams. The turntable under construction at Hill Air Force Base in Utah cost just over $25.8 million and can support a loaded F-22 Raptor fighter aircraft weighing around 29,300 kilograms, or roughly 64,460 pounds.
Part of the Radar Cross Section Test Facility, the 50-foot-wide turntable will house pylons that will lift the F-22 or other low-observable aircraft, more than 20 feet up. The facility will be used to test the radar signature of the F-22 and other low-observable aircraft to ensure that required levels of radar stealth are met prior to returning aircraft to the operational fleet. The U.S. Army Corps of Engineers Sacramento District is overseeing construction of the 49,827 square-foot facility, scheduled for completion in late February 2013.
Once the turntable raises the aircraft, a vertically movable antenna system will blast the aircraft with radar to test its stealth capabilities. The VMAS can be adjusted for various aircraft and will be housed in a small tower within the facility.
Because of the precise environment required to conduct radar testing, the facility will use a double-door entry system. Similar to an aircraft hangar in design, the testing chamber will be blocked off from the outdoors by an inner and outer door with a small entryway in between.
"When the aircraft is brought in, the inner door will be closed," said project engineer Fred Nightengale. "They close the outside door, open the inside door and bring the aircraft into the imaging chamber. The main reason for this is because the imaging chamber temperature and humidity have to be carefully regulated."
Temperature and humidity will not be the only environmental hazards being blocked within the chamber.
"This whole facility has a double-isolated foundation," said Nightengale. "You have an outer foundation for the shell of the building, then a completely separate foundation for the chamber, which is isolated from any outside vibration. When they're doing the radar testing, it must be a pristine environment."
Another unique feature of the facility is an underground tunnel that will provide direct access for inspection and maintenance to the pylons that raise the aircraft. Construction of the tunnel and turntable pit is nearing completion, with focus shifting to the facility's hoist truss.
"The main purpose of the hoist truss is to support the aircraft hoist," said Nightengale. "This hoist is one of the three points of support for the aircraft, which include the two pylons that come up through the turntable and the hoist rope."
A 300-ton hydraulic crane is being brought in to the project site to lift the hoist truss, planned for late November.
With all its state-of-the-art design and features, the facility also boasts an added benefit with its location.
The facility is being constructed next to the F-22 Fuel Composite Overhaul Test Facility, completed by the Sacramento District in summer 2010 and part of a two-phase complex planned for the base. Phase one includes three paint booths and a two-bay maintenance hangar. Phase two, which is still under construction, will add bays designed to support future paint booths, another 2-bay maintenance hanger, and a blast booth. The blast booth will house dual paint-stripping robots used to remove old paint from aircraft prior to painting.
Once the complex and the radar facility are complete, Hill will be a one-stop-shop for the F-22, said resident engineer Jason Redeen.
Music may not be heard across the base when the turntable is activated, but plenty of waves will still be blasting through the air.