Sandia National Laboratories has successfully completed the first full-scale wind tunnel test of the B61-12 gravity bomb as part of its Life Extension Program (LEP) at Arnold Engineering Development Center in Tennessee, US.
Jointly conducted with the Air Force Life Cycle Management Center (AFLCMC) and Boeing using a full-size mock B61, the eight-day testing was aimed at characterising counter torque, the interaction between the spin rocket motor plumes and tail fins, across the B61-12 flight envelope.
Specifically, the tests were designed to establish the configuration that will deliver the necessary spin motion of the bomb during free fall.
Sandia engineers had determined from flight tests in the 1990s that counter torque was responsible for reducing B61’s spin rate during flight.
However, data from a 2002 wind tunnel test to characterise counter torque was not fully applicable, since the B61-12 uses a different tail design than previous versions.
The test has improved understanding of a previously uncharacterised phenomenon, as Sandia researchers now believe that the counter torque arises uniquely because of the unusual shape of the rocket motors and from other features.
Sandia National Laboratories B61-12 technical basis test engineer Vicki Ragsdale said the wind tunnel tests gave engineers the confidence that the new system will meet the required spin environment in flight.
US National Nuclear Security Administration Defense Programs deputy administrator Don Cook said, "This wind tunnel test helps to understand the B61-12 flight characteristics in preparation for our first three full-scale development drop tests with the air force at the Tonapah Test Range in 2015."
Apart from informing the B61-12 design, the improved understanding is also expected to provide an additional technical basis for the well-characterised performance of the B61 versions in the current US stockpile.
Image: A B61-12 model awaits testing in a wind tunnel at the Arnold Engineering Development Center in Tennessee, US. Photo: courtesy of National Nuclear Security Administration.