Tag Archives: F-35A

Small Diameter Bombs

Bombing capacity of F-35As has quadrupled with the arrival of small diameter bombs introduced to No. 3 Squadron in June.

Flying Officer Matthew Walker, left, delivers bomb familiarisation training to armament technicians from No. 3 Squadron, from left, Corporal Christopher Sorrensen, Leading Aircraftman Adam Fulmizi and Corporal Simon McMillan (Photo: Sergeant Guy Young)

The GBU-39/B Small Diameter Bomb, Increment 1 (SDB1), packs about 16 kg/35.3 lbs. of modern high explosive, 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», Wing Commander Bird said. «Where you used to carry one Joint Direct Attack Munition (JDAM) in a position on the aircraft, SDB1 allows you to carry four bombs that each achieve very similar effects. Although at 285 lbs. the SDB1 is lighter than a 500 lbs. 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», Wing Commander 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.

«With an old JDAM, you had to take all the components and build it up, but that takes time, equipment and people», Wing Commander 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».

About 15 armament technicians from No. 3 Squadron received familiarisation training on the bombs before planned test firings in 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.

Full Capacity

An F-35A fired 181 rounds from its four-barrel, 25-mm Gatling gun during a ground test at Edwards Air Force Base, California, earlier this month. The gun is embedded in the F-35A’s left wing and will provide pilots with the ability to strafe air-to-ground or air-to-air targets.

F-35A Fires 25mm Gun at Full Capacity
F-35A Fires 25mm Gun at Full Capacity

The F-35 Joint Strike Fighter (JSF) Integrated Test Force aims to complete ground testing this month and start airborne gun testing in the fall. At the end of the program’s system development and demonstration phase in 2017, the F-35A will have an operational gun.

The first phase of F-35A gun testing started June 9, when initial shots were fired from the ground at the base’s gun harmonizing range. Over the next few months, the amount of munitions fired gradually increased until the 181 rounds were fired August 14. To conduct the testing, an F-35A flight sciences aircraft, AF-2, underwent instrumentation modifications and used a production version of the GAU-22/A gun. The ground tests were designed using software to replicate being in flight and the aircraft used a target practice round, PGU-23/U, which does not explode on impact.

In integrating a weapon into the stealthy F-35A aircraft, the gun must be kept hidden behind closed doors, reducing its radar cross section, until the trigger is engaged. The tests certify the gun’s ability to spin up and down correctly. The GAU-22/A system will be further tested with a line production F-35A next year for integration with the jet’s full avionics and mission systems capabilities. Test pilots will then observe qualitative effects, such as muzzle flash, human factors, and flying qualities. The F-35A test team will also monitor the GAU-22/A’s performance and ensure all systems work as designed, validating that the aircraft can withstand the loads of a firing the gun, mitigating potential effects including vibrations, acoustics and airflow.


The video clip shows the 181-round gun burst of the gun embedded in the F-35A’s left wing root. The gun will provide operational F-35A pilots an ability to engage air-to-ground or air-to-air weapon targets using its strafing capability in addition to its beyond-visual-range air-to-air missiles and precision-guided air-to-ground weapons