Flight Path: Turning Performance

Courtesy of Lockheed Martin

The Lockheed Martin Hercules transport, one of many aircraft to use actuator systems manufactured by Triumph Activation Systems.

Making the systems that keep ‘big birds’ flying straight.

Boeing’s 787 Dreamliner generated positive news in October when its first commercial flight, by All Nippon Airlines, landed in Hong Kong. Inside that 787 was a vast array of high-tech parts and equipment, including linear hydraulic actuators, rotary pumps and rotary motors. These largely unseen, yet indispensable systems and assemblies help keep flights on track and without incident.

Many of these systems for the 787 and other aircraft are made by Triumph Actuations Systems, Clemmons, N.C., a business unit of Triumph Group, Berwyn, Pa. The 130,000-sq.-ft. Clemmons facility opened in 1989 and employs 230. The main product lines are linear hydraulic actuators, solenoid and manually operated hydraulic valves, hydraulic systems, rotary pumps and motors and variable- and fixed-displacement axial piston pumps and motors.

“When I joined Triumph in 1990, we were all about hydraulic systems and linear hydraulic actuators, rotary pumps and motors,” said G. William Burke III, CNC programmer manufacturing engineer. “Then we acquired a line of hydraulic pumps and motors from Honeywell in 2001.This was entirely new work for us and required a steep learning curve, a manufacturing capacity increase, new technology and additional personnel.”

Before the Honeywell acquisition, Triumph Actuation Systems’ aerospace work was about 80 percent commercial and 20 percent military. Today, the balance is 50/50.

Courtesy of Triumph Actuation Systems

A rotor fixtured on a Studer S33 CNC at Triumph.

Courtesy of Triumph Actuation Systems

A piston rod setup on a Studer S33.

Triumph’s actuators open and close various aircraft doors, including ones for engine compartments and cargo holds, and also raise and lower nose and landing gears and open and close the doors that house them. Actuator parts include a hydraulic reservoir, an extending and locking piston and a bearing at one end of the actuator that allows the system to pivot as it extends.

“Our actuators are used on planes ranging from the B-1 Bomber and C-130 cargo planes to the Boeing 737 and down to small Piper aircraft,” Burke said. “We also do some Bell helicopter work and systems for the V-22 Osprey. However, the 787 has more Triumph components and systems than any other aircraft.”

U.S. Sourced

Triumph Actuation Systems performs about 10 percent of its parts manufacturing in-house, with the rest outsourced to U.S. companies. Triumph tests every actuator, pump and motor it manufactures, including hydraulic actuator extensions, locking mechanisms and releases.

“We work closely with our customers to achieve design for manufacturability,” Burke said. “Our design team reviews designs with customers with a critical eye on DFM. We try to determine whether or not we are using the most-efficient, cost-effective design and processes. We also look for better ways of making parts and using alternative work materials.”

Triumph Actuation Systems regularly audits its suppliers to see if it can bring their parts directly into its stock system without having to perform incoming inspection. This requires parts to be completely traceable, with verification of all operations performed, equipment used, tolerances and surface finishes held, inspection and verification systems used and process variations recorded.

On the parts it produces, Triumph performs operations including turning, horizontal and vertical milling, internal and external grinding, as well as internal honing, lapping and other secondary operations. After machining, some parts are sent out for anodizing, chrome plating, cadmium plating and nickel plating.

Key Grinding Ops

Grinding is a particularly crucial operation. “We make housings, bearing journals, piston rods and rotors for our hydraulic pumps,” Burke said. “We perform various grinding operations on these parts, including piston-and-sleeve match grinding and some seat grinding. Tolerances are ±0.000050 “, and 2µm Ra to 16µm Ra surface finishes are the norm. Tolerances like these require digital micrometers on the ODs, and electronic gaging and air gages for precision ID work.”

Triumph grinds diameters from 0.125 ” to 4 “, and lengths from 0.250 ” to 13 “. It often grinds multiple diameters and shoulders in one operation.

“Our biggest bearing journal is 3 ” in diameter,” Burke said. “We may grind the body of the rotor, the bearing journal of the rotor and an area for fixturing. We put our own forms and radii on abrasive wheels for parts that require plunge grinding. We do an angular plunge so we can grind the shoulder and the diameter at the same time. We’ll bring the wheel in at an angle, plunge, then traverse to achieve the required finish.”