B61-12 Undergoes Successful Wind Tunnel Test
The National Nuclear Security Administration’s B61-12 life extension program has reached another milestone as officials at Sandia National Laboratories successfully conducted the first wind tunnel test of the refurbished nuclear bomb. The eight days of testing at the largest wind tunnel that could accommodate the warhead, the Air Force’s Arnold Engineering and Development Center at Arnold Air Force Base, sets up three full-scale development drop tests at the Tonapah Test Range scheduled in 2015, the NNSA said. The B61-12 will replace four B61 variants: the mod 3, 4, 7, and 10. The test represents the second milestone in recent months for the B61. Earlier this year, the first full-system mechanical environment test on a refurbished B61 nuclear bomb was conducted by Sandia and Los Alamos national laboratories. That test involved subassembly and system-level mass properties measurements as well as shock and vibration testing.
The wind tunnel test was designed over the course of three years to evaluate how the rocket motors on the refurbished bomb interact with the performance of the bomb’s fins. The rocket motors and fins control the B61’s spin as it is dropped from an airplane, but testing during the 1990s revealed that plumes from the motors worked against the fins, which the lab said counteracted the torque from the motors and cut down on its spin rate. Because the B61 uses a new tailkit design, new tests were needed to evaluate the spin of the bomb as it is dropped. “The improved understanding will inform the design of the B61-12 and provide an additional technical basis for the well-characterized performance of the versions of the B61 in the current U.S. stockpile,” Sandia said in a statement.
Sandia said the testing uncovered a “previously uncharacterized physical phenomenon” that came about because of the shape of the bomb’s rocket motors and other features on the weapon. “We were able to come up with a theory for where this effect is coming from,” Vicki Ragsdale, a B61-12 technical basis test engineer, said in a statement. “It’s not a wind tunnel effect and it is something we will see in flight, so we have to account for it.”
