Unitech's MV-22 visit highlights complex composites work

Idaho-based Unitech Composites & Structures molds environmental control system ducting components for the MV-22 Osprey using a hot-salt, lost-core composites fabrication process.

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Unitech Composites & Structures (Hayden, Idaho, USA) reports that it was recently paid a visit by a U.S. Marine Corps MV-22 Osprey, for which Unitech molds complex composite components. 

The Bell-Boeing V-22 Osprey is a tilt-rotor aircraft with vertical takeoff and landing (VTOL), and short takeoff and landing (STOL) capability. The Marine Corps variant is the MV-22, and the Osprey is finding itself being frequently deployed in place of other aircraft, such as the CH-46 Sea Knight helicopter, for Assault Support and Casualty Evacuation duties.

The arrival of the MV-22 Osprey on long-distance flight training through the U.S. Northwest had a dual-importance to the northern Idaho community. The local airport has the commemorative name of Pappy Boyington Field. Gregory "Pappy" Boyington was born in Coeur d’Alene, Idaho and was the leader of the famed Black Sheep Squadron in the Pacific during WWII, an Ace Fighter Pilot, POW, Medal of Honor recipient and a Boeing employee before the war.

Located across the airfield is Unitech Composites & Structures, a division of AGC Composites & Aerostructures Group, which designs and manufactures structural parts and assemblies for commercial, general aviation, and military aircraft. Unitech Composites & Structures began supporting the V-22 program in 2010 and manufactures parts for the Environmental Control Systems (ECS) Duct Assemblies.

“This was very exciting for us to see in person for the first time,” says Tim Shuburg, director of Operations for Unitech Composites & Structures. “Our employees understand the role they play in manufacturing parts for this aircraft, but to actually see it up close and listen to the pilots talk about its performance, that really made it a special connection for them."

Due to the nature of the unusual shapes required for the environmental control system (ECS) ducting on the V-22, Unitech Composites & Structures uses a hot-salt process to create the odd-shaped tools. In this process, a disposable mandrel is created from paraplast, a molten salt heated to 500°F/260°C and poured into an aluminum mold. When the paraplast cures, the mold is released, leaving a solid mandrel in the shape of the duct. Composite material is laid up on this mandrel to create the duct; first, a skilled layup technician applies layers of prepreg composite fabric and proprietary insulation material in a specific manner, resulting in ducting that is both efficient (smooth on the inside so as not to inhibit air flow), yet strong and light enough not to burden the aircraft with unnecessary weight.

Once the layup process is complete, the part is compressed under a vacuum seal to continue to compress the many layers to ensure product integrity prior to further processing. The part is placed in a steel compression mold to prevent it from warping as the resin cures. After curing, the vacuum seal is removed and the paraplast mandrel is washed away via a water-based process, leaving behind just the composite duct. Final finishing steps are applied including primer, paint, and mounting hardware to allow quick and easy installation in the aircraft.

Rick Hundley, president of Unitech Composites & Structures said, “It was extremely gratifying for our employees to see, touch and experience speaking with the aircrew for one of the many military aircraft platforms that we support. All the men and women of our Unitech family take great pride in the work that we do in support of the Soldiers, Sailors, Airmen and Marines who defend the freedom enjoyed in this great nation of ours.”