KUKA wins award for Bell 525 helicopter palletized assembly process

Single-fixture process improves first-time fit, quality and speed for 50% CFRP airframe utilizing large, unitized composite structures.

KUKA Systems Aerospace (Sterling Heights, MI, and Augsburg, Germany) has received the Supplier Excellence Award from the American Helicopter Society International (AHS Intl., Fairfax, VA, US) for a new assembly concept that will be used to build Bell Helicopter's 525 Relentless.

KUKA's concept for the new Bell 525 is a major departure in assembling rotary-wing aircraft. Working in collaboration with Bell's engineering staff, the KUKA process engineering team developed a palletized process based on the industrial assembly line principle. The main aircraft is built up in a major fixture, which moves along the assembly stations. Ancillary tooling is added or removed from that fixture to allow different work tasks to be performed at each station.

The traditional assembly method would be to build up each component in a dedicated fixture and when a specific task is completed, remove that component and put it into another fixture to build it further. The result is a progressive buildup of each major section of the aircraft, but with many uncontrolled variations and tolerance issues in each one. The final mating of components and sections usually requires significant ad hoc adjustments to force out-of-contour or misaligned components into place. That's typical throughout the aerospace industry.

Palletized assembly offers many advantages over the traditional process, most notably an improvement in overall quality. The process promotes specialization and repeatability, while producing more precise results with less variability. Reportedly, mating of components and ultimately entire sections is simplified, and everything tends to fit the first time, requiring fewer ad hoc adjustments. Thus, assembly is a smoother, faster flow process using manpower more efficiently.

KUKA is manufacturing all tooling for the forward, mid and aft fuselage and tailboom, as well as for mating of all major 525 Relentless structures. The fuselage is hybrid aluminum-composite, reportedly 50% carbon fiber reinforced plastic (CFRP) for weight saving.

CFRP enabled the deep-section tail boom without adding weight, required for Bell’s Lift Assisted Tail Design (LATD) which harnesses main rotor downwash to provide additional anti-torque control, thus reducing workload for the tail rotor. CFRP is also employed around the cabin, especially in support structure, to minimize risk of corrosion in the saltwater environment missions for which this super medium to light heavy class helicopter is targeted, including search and rescue and offshore oil and gas operations.

Composite structures include fuel tank enclosures, keel beams, bulkheads, floor panels, as well as most of the aft fuselage, tailboom, empennage and cockpit and main cabin sidebodies, as well as the one-piece composite boat hull and the roof deck. Large, unitized composite structures are used to reduce the Bell 525 Relentless' part count and joints, lowering overall cost.

Slated for entry into service in 2016, the Bell 525 Relentless will compete with the Airbus Helicopters EC175 and the AgustaWestland AW189.