Following the arrival of the GBU-39/B Small Diameter Bomb to Royal Australian Air Force No.3 Squadron, the bombing capacity of F-35As has significantly increased.
The small diameter bombs are packed with about 16 kilograms of modern high explosive, and are guided by GPS-aided inertial navigation.
Wing Commander Simon Bird, Chief Engineer at Aerospace Explosive Ordnance Systems Program Office (AEOSPO) – Explosive Materiel Branch, said it was Air Force’s most advanced bomb and made best use of the F-35A's internal weapon bay.
“We’ve got a next-generation bomb to go with our fifth-generation fighter,” WGCDR Bird said.
“Where you used to carry one JDAM [joint direct attack munition] in a position on the aircraft, SDB1 allows you to carry four bombs that each achieve very similar effects. Although at 285 pounds the SDB1 is lighter than a 500-pound JDAM, it’s highly accurate and packs a more powerful, modern explosive.
“SDB1 is also designed to penetrate harder targets, or can fuse above ground to create area effects.”
The bombs make use of ‘Diamondback’ wings, which deploy after release to provide greater stand-off range.
“With JDAMs you’ve got to be very close to the target to engage it, but because of the wings on SDB1, a single F-35A can engage up to eight separate targets from outside the range they can defend against,” WGCDR Bird said.
“What’s more, because an SDB1 is carried internally, the F-35A can remain low observable and will not be affected by any extra drag from carrying eight bombs.”
Four bombs are fitted to new bomb release unit racks before loading on the aircraft.
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“With an old JDAM, you had to take all the components and build it up, but that takes time, equipment and people,” WGCDR Bird said.
“You can test the SDB1 without opening the box; you can test them before they’re even shipped to the base you’re going to operate from.
“This weapon comes fully assembled; you basically take it out of the box and load it.”
Around 15 armament technicians received familiarisation training on the bombs before planned test firings in the coming months.
AEOSPO’s engineering, logistic and technical staff ensured introduction of the weapons and their delivery was a milestone towards the F-35A’s initial operational capability in 2020.