Blended Wing UAV
Unique unmanned craft’s robust composite design a plus for rough duty.
By Sara Black, Technical Editor | May 2007
Source: Swift Engineering
This view of the underside of the Killer Bee shows the two integral fiberglass turrets or radomes, cocured with the rest of the structure.
Two bulbous sensor “turrets” that protrude from the aircraft’s underbelly house the cameras and sensors. Reding notes that the turrets, which must be made of fiberglass to permit electromagnetic transparency, were designed as integral parts of the airframe rather than as removable components requiring separate layup and cure. “We devised a lamination plan that transitions from the primary carbon/epoxy used for the airframe to the fiberglass of the turrets or radomes, with overlap plies and ply drops, so that everything can be fabricated and cocured in one tool.” Flight operations can occur from daylight hours into night because one turret can be equipped with a visible light sensor and the other with an infrared sensor, a big plus for potential customers. Reding says that the detachable outer wings, which are solid fiberglass laminates, can be fabricated with embedded sensors to function as antennae or radomes.
“We’ve tried to create a system that is very functional and modular for field operation — wings, engines, fasteners are line-replaceable,” states Reding.
The flat triangular shape of the craft, with few complex curves or shapes, means that fabrication is straightforward. Tooling for the KB-UA was designed in-house with an eye toward simplifying layup and minimizing secondary bonding and finishing operations as much as possible. While some of the tools are steel, most are composite, built using carbon/epoxy tooling prepreg from Airtech International Inc. (Huntington Beach, Calif.).
Source: Swift Engineering
A Killer Bee, ready for launch on a compressed-air-powered launcher.
The standard- and intermediate-modulus prepregs for the airframe layup are supplied by Advanced Composites Group (ACG, Tulsa, Okla.) and Ten Cate Advanced Composites USA (formerly Bryte Technologies Inc., Morgan Hill, Calif.). McCue notes that an automated ply cutter from Gerber Technology Inc. (Tolland, Conn.) helps reduce production time by nesting and precutting prepreg plies. Wherever possible, he adds, subassemblies are cocured in the same tools, thereby minimizing postcure assembly and finishing.
Shape of things to come?
KB-UA-3, the previous prototype, was successfully demonstrated to the U.S. Air Force in mid-2006 at Creech Air Force Base in Nevada. Now the company is competing against many others to win a joint U.S. Navy/U.S. Marine Corps Small Tactical UAS/Tier II unmanned aircraft system contract, which would place UAVs in service by 2010. Reding says the current KB-UA-4 model has flown successfully and is ready to enter production. Several hundred could be built on the existing tooling at a rate of two or three per day.
Source: Swift Engineering
A Killer Bee approaches the recovery net. The pusher propeller arrangement ensures that the propeller and engine aren’t damaged during recovery.
“The Killer Bee is strong and robust enough that it could be dropped from a moving aircraft,” notes Reding. One defense writer predicts swarms of small UAVs like the KB-UA may be used to overwhelm an enemy’s defenses. Swift’s entry in this rapidly evolving market is a game-changing design.
