In Depth

F-35 Engineers Use Thor to Build Stealth into the Lightning II

March 23, 2017

The F-35’s stealth capabilities are unrivaled in tactical fighter aviation. With low observability (LO) attributes built into the jet from the beginning of the design process – structural shape, internal weapons carriages, embedded sensors, stealth coatings and more – the aircraft can go virtually undetected to enemy radar.

For members of the F-35 team at the Aircraft Final Finishes facility in Fort Worth, Texas, applying the low observable coatings to the F-35 is their specialty – one they take great pride in, as the customer relies on this specific capability to keep their pilots safe in the sky.

F-35 engineers Rick Luepke and Anthony Mann with the Mold-In-Place tool known as Thor.

However, back in 2008, the team faced a particular challenge during this process – applying the stealth coatings to the F-35’s contoured inlet bump using robotic spray arms. In addition to the process requiring significant preparation, a lengthy application time and producing an unsafe work environment, the process took multiple operators and did not allow for concurrent work to be performed on the jet.

Additionally, once the robotic spray was completed, the inlets required more hand spraying, sanding and shaping to coat the inlet areas the robotic arm was incapable of spraying due to inlet clearances.

This is when a team led by Rick Luepke, a 32-year Fort Worth employee, jumped into action, searching for a more effective way than a robotic spray arm to apply the stealth coatings to the inlet bump.

Rick saw the LO coating issue as another opportunity to develop more innovative technology to push the boundaries of what is possible in fighter jet manufacturing. His solution is called Mold-In-Place (MIP), affectionately named "Thor" by the team.

“It is exciting developing new aerospace concepts for manufacturing and opening people’s eyes as to all that is possible,” said Rick. “This is what the MIP project is all about.”

Through intensive research, industry-wide collaboration and extensive resourcefulness over six years, the team developed a 500-pound mold tool that injects the stealth coating directly onto the inlet bump area. Even with this tool now in place, the team needed to be able to accurately, repeatedly and safely place the tool in close contact with an aircraft that was often transported between a prep bay and robotic spray cell.

Through a structured light technology, the robot locates the aircraft in real space, transforming the paths of the robot to account for variations in positioning between the robot and the aircraft. To account for this constant movement and the need for mobility, the team, in collaboration with aerospace company Aerobotix, developed a power-drive platform and laser-alignment system that enables an operator to drive Thor next to the aircraft and place the mold tool accurately in the inlet area before mold injection begins.

“The MIP system is a culmination of technology development. There’s tooling technology, robotics and automation, mobile platforms, 3D scanning systems and more wrapped into this system,” said Rick. “I am very humbled to have had the opportunity to develop a platform that has helped the entire program move forward.”

For Rick, he is ultimately excited about the opportunity to pass down his skills and knowledge on to the next generation of engineers who will work on the F-35 and beyond. One of these individuals Rick has taught and collaborated with is Anthony Mann, the MIP project manager who joined the team in 2014. Anthony has worked alongside Rick to continue the successful implementation of the technology. 

“It’s exciting to work on a project that’s technologically cutting edge and groundbreaking,” said Anthony.

The innovative work of the team, which was six years in the making, yielded incredible results. They’ve reduced labor hours 50 percent and the critical build span time dropped from five days to three. Thor has significantly increased safety and enabled concurrent work to be performed.

In addition to driving significant cost-reduction and safety results for the F-35 program, MIP has gained recognition on the national stage. Recently, the MIP team in the AFF earned the Frost & Sullivan Manufacturing Leadership Award for shaping the future of global manufacturing – a testament to the significant contributions in manufacturing technology the team has made to the industry.