Varied angle-of-attack maneuvers will come into play when engineers begin testing the use of Amraam on the F-35. As pilots will want to “fire and forget” their air-attack weapons, they will need to employ them in a much larger flight envelope than the ground-attack munitions.

Unlike the JDAM series, Amraam is powered by a solid-rocket-fuel motor and is dispatched from its position on the door of the F-35 weapon bay. JDAMs are carried on a bomb rack mounted inside the belly.

Initially, developers plan only to demonstrate safe separation of the Amraam, using test bodies lacking a rocket motor. They hope to actually fire an Amraam from the F-35 by the end of January, Wagner says.

Although the three F-35 types share some elements, each weapon model must be tested separately on each fighter version. Those trials will be conducted in parallel, he says. The program prioritizes tests of internal-carriage weapons, as those are required for the Block II and Block III F-35 releases; Block IIB software is what the U.S. Marine Corps will use for declaring initial operational capability (IOC) with its F-35Bs.

The first external weapons will be used in Block III, which is the software version required for IOC for Air Force and Navy models; Block III will be released no earlier than 2017. Introduction of the Boeing GBU-39 Small-Diameter Bomb, a 250-lb. glide weapon, is slated for the Block IV software release at the end of the decade. This weapon was developed by the Air Force specifically to maximize the number of ground targets that the F-35, with its limited internal-bay space, can attack on a single mission; four SDBs can be mounted in place of each JDAM position, allowing for the F-35 and F-22 to each carry eight of the weapons internally. The SDB II, a version incorporating a tri-mode seeker for all-weather, day/night engagements, is now being developed by Raytheon. The first units will be delivered for operational use in 2016 (see p. 61).

The F-35 also is being developed to carry nuclear weapons. Testing of nuclear munitions on the fighter is not slated to begin until after the aircraft development phase is complete.

In the meantime, F-35 developers are sharing the thermal and acoustic data being collected from the bay with the weapon manufacturers. While the bay environment is close to the design specifications of weapons already in the arsenal, the developers hope that sharing this information will help engineers crafting next-generation munitions to design them with those environmental factors in mind, Wagner says.

The Aug. 8 weapon separation test was a major milestone for the Pentagon-led F-35 program. To view a video of it, check out the digital edition of AW&ST on leading tablets and smartphones, or visit AviationWeek.com/jdamdrop

Integrating a number of diverse weapons onto the F-35 will be critical to the stealthy fighter's utility for its global customers. To view an interactive chart of weapons slated for use on the F-35, check out the digital edition of AW&ST on leading tablets and smartphones, or visit AviationWeek.com/jsfweapons