Eclipse puts new spin on production

 - March 29, 2007, 7:06 AM

Eclipse Aviation is committed to becoming, in the words of its founder, president and CEO, Vern Raburn, “The Ford Motor Company of business aviation.” To that end, it plans to attain an annual production capacity of 1,500 Eclipse 500 very light jets by 2009, using advances in production technology reminiscent of the mass-production assembly line and interchangeable parts innovations with which Henry Ford revolutionized the automobile industry in the early 1900s.

Symbolic of that commitment is the presence on Eclipse’s five-member board of directors of retired Ford Motor chairman and CEO Harold Poling. More tangible evidence was formally unveiled on March 10 in Albuquerque at a ceremony dedicating Eclipse Aviation’s 50,000-sq-ft friction-stir welding (FSW) facility. It is this process, Raburn told a gathering of local, New Mexico and business officials, that will be a major factor in achieving such World War II-like aircraft production rates by the end of this decade.

FSW will be used by the budding manufacturer in joining most parts of the Eclipse 500 fuselage, as well as by Fuji Heavy Industries of Japan (under license from Eclipse) in fabricating the twinjet’s wings. The process “dramatically accelerates traditional aircraft manufacturing cycle times, enabling us to produce the Eclipse 500 more quickly and cost effectively than any small jet in history,” Raburn said.

Eclipse is the first to use FSW in the manufacture of civil aircraft thin-gauge aluminum major assemblies after earning FAA approval of the process in 2002, a year ahead of schedule. Raburn called the facility’s opening a critical milestone toward the goal of manufacturing aircraft in high volumes and “at a groundbreaking level of price/ performance.”

With orders for more than 2,100 Model 500s secured by non-refundable deposits ranging from $97,500 to $150,000, Eclipse needs the dramatic reduction in manufacturing time that FSW will enable by replacing rivets in more than 60 percent of the very light twinjet. Up to 20 times faster than manual riveting and four times faster than automated riveting, FSW not only outpaces other welding processes but produces stronger, lighter and better quality joints, Eclipse claims.

Invented and patented in 1991 by The Welding Institute in England, FSW is now used on land and sea transportation systems, as well as in the Delta rocket program and, most recently, by NASA in fabricating Space Shuttle external fuel tanks.

In the automated friction-stir welding of a lap joint as on the Eclipse 500, a spindle attached to a rotating tool is pushed through the first piece of aluminum and partially through the second. The spindle is then rotated and pressed to create frictional heat between the two metals. This heat plasticizes the aluminum without actually melting it, allowing the spindle to stir the two pieces of aluminum together and achieve molecular exchange.

The softened, blended material is transferred from the front of the pin tool (which is inclined a fraction of a degree off vertical) to behind it–somewhat analogous to the motion of a kitchen blender’s beater–as the tool traverses the joint. The result is an extremely thin, uniform bond with no beading along the seam, requiring little or no post-welding, grinding, sanding or buffing. The numerically controlled FSW gantry installation in the new Eclipse facility can be programmed for tilting in up to seven different axes to allow joining on curved surfaces and even compound curves.

The process can cope with circumferential, annular, non-linear and three-dimensional welds and, since gravity has no influence on the solid-phase procedure, it can be used in all positions from horizontal to vertical, overhead and orbital.

Because the aluminum never melts, friction-stir welding more closely approximates a forging or extrusion process rather than traditional welding. FSW is not a fusion process requiring significant heat input. The metal being joined or bonded does not exceed 800 degrees F and can be touched with the bare hand 45 seconds after the tool passes over it. This preserves the properties of the metal more than any other known welding process, minimizing or eliminating chemical and physical weakening or distortion. Unlike fusion techniques such as laser welding, FSW can be used on dissimilar aluminum alloys such as wrought or cast products, including those considered impossible to weld using fusion methods.

In comparative tensile tests on riveted and FSW lap-welded 2024 aluminum, Eclipse said, the latter joints are up to twice as strong. The company added that fatigue, tensile and bend tests confirm excellent mechanical properties of stir-welded joints. The process produces no fumes or noise, is energy efficient and requires no welder certification of facility operators. One tool head can typically be used for up to 3,300 feet of joint length.

The new facility on the west side of Interstate 25, adjacent to Albuquerque Sunport International Airport (ABQ), where the main Eclipse Aviation facilities are located, will be staffed by up to 150 employees. It also includes a multi-station production line, where the Eclipse 500 fuselage pressure vessel will be assembled, and will ultimately accommodate four FSW installations.

The FSW building brings to 185,000 sq ft the total of under-roof space occupied by Eclipse Aviation on and adjacent to ABQ. In 2009, the entire operation is scheduled to move across the Rio Grande River to the Double Eagle II airport on the city’s far west side. There, in addition to ramping up to full production, Eclipse will conduct type-rating ground and flight courses for customer pilots, including upset training, with particular emphasis on first-time jet owner-pilots.