Paris Air Show

Aircraft-weapons interface more complex than ever

 - December 12, 2006, 11:50 AM

In the era of “smart weapons” a lot can still go wrong, not the least at the interface between the combat aircraft and the missile or bomb. Here at the Paris Air Show, the EDO Corporation is displaying new “solutions” in the specialized and surprisingly complex business of weapons carriage and release.

Today’s equipment–such as EDO’s BRU-55/57 “smart racks”–must provide a MIL-STD-1760 electronic interface so that flight and targeting data can pass from aircraft to each weapon individually. EDO’s latest development is a dual rail launcher for the forthcoming joint common missile. Two of these launchers can hang from a BRU-55, enabling operators to load four missiles on a single weapon station on the Boeing F/A-18E/F. The company reckons that contracts for the joint common missile could draw $100 million in the coming years.

As weapons get smaller as well as smarter, the uploads get more complicated. EDO MBM Technology, the British subsidiary, is showing the newly developed Gemini system that allows the same carrier to carry, target and release dissimilar weapons individually. Electronics within this twin launcher must communicate with the aircraft’s stores management system, “telling” the system that Gemini is carrying, for instance, both a laser-guided Paveway bomb and a GPS-guided JDAM.

EDO MBM is also showing a solution to the electrical separation problems that have occurred during some smart weapons releases. The field replaceable connector system provides a “jam free” interface. It has replaced the older snatch connectors on the UK Royal Air Force’s Harriers, and is now being adopted on the Tornado.

EDO bought MBM two years ago, after the two erstwhile competitors made contact as part of the Lockheed Martin F-35 Joint Strike Fighter program. “We now have access to U.S. technology and markets,” said EDO MBM managing director David Jones. The British company also makes rugged portable computers, cable assemblies and electrodynamic products. The weapons interface business contributes about 30 percent of revenues, and has made the company a target for British peace protesters in recent months.

All weapons release from the F-35 will be pneumatic. Instead of a pyrotechnic charge in the launcher that pushes the weapon away from the aircraft, compressed air does the job. The system has its advantages and disadvantages, according to Nick Guard, EDO MBM’s business development manager. Pneumatic systems offer increased reliability, reduced maintenance and simpler logistics. But how to generate the pneumatic power? Designers have struggled with weight issues and have considered using a compressed air pump in the aircraft, or a rechargeable gas bottle on the wing.

Undoubtedly, though, pneumatics appear best suited for internal launchers–the type required on stealthy warplanes. For the Lockheed Martin F/A-22 Raptor, EDO provides the AMRAAM vertical ejection launcher. According to the company, this launcher is a “breakthrough design that has solved the engineering challenges of launching missiles at supersonic speed, at the proper trajectory, in a fraction of a second, from an internal weapons bay.”

With an eye to the potential of unmanned combat air vehicles, EDO MBM also has on display its miniature UAV carriage system. This is another nonpyrotechnic system that weighs only 30 pounds, but can carry up to 1,300 pounds of “smart” stores –Hellfire, JDAM, the small diameter bomb SDB, ground sensors and so forth. It comes in a single or twin carriage configuration. Each station features a common, self-locking release module.

EDO MBM has also developed an electromagnetic release unit (EMRU) for practice bomb carriers. Previously, all such carriers used pyrotechnics, but the EMRU uses a spring-and-solenoid system. The launch order came from Korean Aerospace for the KT-1 turboprop trainer, and EDO MBM is now eyeing other new designs, such as the Aermacchi M346 jet trainer. According to Nick Guard, the EMRU system could reduce training costs for existing warplanes. “We are making the spend-to-save argument, but there is an integration cost,” he admitted.