The ever-improving technology of the U.S. military requires the test and evaluation capabilities of the Air Force Test Center organizations to keep pace to prove the superiority of the systems and give confidence to the warfighters using them. At the National Radar Cross Section (RCS) Test Facility (NRTF) at White Sands Missile Range, N.M., the 704th Test Group, Detachment 1 of the Arnold Engineering Development Complex has improved their turntable mounting capability to enable testing of next-generation platforms with reduced or low RCS signatures. This improvement was achieved through the implementation of a new foam for supporting test articles.
“If a test article is well designed or treated, the amount of RF energy that is returned back to the radar has a lower decibel intensity, and is harder to detect. We design our foam columns to have the least RF interference possible, but one of our constraints is the need to adequately support the test article. One aspect that can contribute to a small [RF] return is to make an object physically small. If we can use sturdier foam columns, then we can use smaller foam columns, which helps us better isolate test article returns from foam column returns,” said Maj. Nathan Lesman, assistant director of Operations for the Detachment.
The lower the RCS signature of a platform, such as a plane, missile or drone, the harder the platform is to detect with radar. Radar transmits radio frequency (RF) energy, then measures how much energy is directed back at the transmitter from obstacles in the path. While this is good during operational use, lower RCS signatures present challenges during testing due to interference from test facility structures and other background sources.
Test articles are elevated on a turntable using foam columns. Foam is RF transparent at low RF ranges, which means it causes little interference in the collected data.
The foam becomes more visible to the radar at the RF ranges needed to test low RCS signature test articles. The Detachment has tested items as large as fighter jets using foam column supports. The sturdier foam hasn’t been used up until now because of the health risks posed by shaping it with a hot wire, the method previously used by the Detachment. These risks aren’t present when cutting the standard foam with a hot wire. New tooling for shaping foam is allowing the Detachment to take advantage of the sturdier material and deliver even higher quality data to customers.