better design flexibility of developmental engines
How Pratt & Whitney is 3D printing military engines
Additive manufacturing speeds development, delivery and sustainment
Pratt & Whitney’s TJ150 engine is, in the words of the people who know it best, a ship in a bottle.
It’s a small and seemingly modest engine. But inside, it’s a marvel of intricate engineering that helps power UAVs and missiles. It can perform multiple functions, and it can do that flawlessly.
Now, through an additive manufacturing technique called unitization, Pratt & Whitney engineers have reduced total part count from over 50 to just a handful. The result: the same robust, reliable engine, with a significant reduction in production time and cost.
“Additive manufacturing is transforming the way we design and manufacture products, offering us unprecedented flexibility to realize designs that would be difficult if not impossible with traditional methods,” said Jesse Boyer, a fellow for additive manufacturing at Pratt & Whitney, an RTX business.
Additive manufacturing, which includes 3D printing, uses digital files to build objects layer by layer – the opposite of traditional methods, which carve objects from a solid block of material.
“Additive manufacturing is ... offering us unprecedented flexibility to realize designs that would be difficult if not impossible with traditional methods.”
Jesse Boyer | Fellow for additive manufacturing | Pratt & Whitney
Early adopters
Pratt has been using additive manufacturing since the late 1980s – decades before 3D printing made it familiar to the mainstream. The business is integrating the techniques in every part of the lifecycle of military engines, from design through sustainment.
Today, the RTX Additive Manufacturing Process and Capability Center focuses on developing additive tools and integrating them into production.
“We are in lockstep with our customers, working together to advance the technology and develop solutions that are innovative and responsive to evolving demands,” Boyer said.
Value of additive manufacturing
Pratt & Whitney uses additive manufacturing to make its engines more efficient and decrease their production time. Here are four of its benefits:
simplified supply chain
easy, on-demand replacement of rare legacy engine parts
reduced production time and cost
Designing to streamline production
Pratt & Whitney’s GATORWORKS team is the driving force behind the TJ150 redesign. The team focuses on rapid prototyping, quick iteration, and Agile processes to quickly mature and demonstrate new engine technologies, bringing them to market faster.
“Our government customers are looking for unique and innovative ways to design, develop and deploy capability. More and more, we are partnering to explore non-traditional approaches to achieve this,” said Chris Hugill, senior director of GATORWORKS.
“Increasingly, they are asking questions like, ‘How can we move faster?’ and ‘How can we insulate ourselves from industrial base capacity risks to ensure smooth, uninterrupted production without bottlenecks or shortages?’” Hugill said.
And GATORWORKS is answering the call.
Using their in-house solution, they designed and tested the redesign – all within eight months, from concept to engine test.
Pratt has tested two generations of additive hardware in military engines and is starting on a third.
Also in the works: additive manufacturing for other TJ150 components. That includes rotating hardware, which would benefit from added flexibility in supply chain sourcing. Advanced 3D printing has the ability to make parts more durable by tailoring the properties of materials and managing stress distribution.
Pratt is also applying additive manufacturing to its large engines like the F135 and TF33.
Producing with additive manufacturing
Pratt & Whitney’s F135 engine, which powers the F-35 Lighting II fighter aircraft, is also seeing the benefits of unitization.
In 2018, the business started working with a supplier to 3D-print the Turbine Exhaust Case trailing edge (TE) box, which directs the flow of exhaust gases.
Traditionally, the TE box has been produced with an advanced process called hydroforming, where a high-pressure fluid bends metal plates into precise shapes that can withstand the forces of jet propulsion.
Pratt & Whitney's additive manufacturing experts saw an opportunity and gave unitization a try.
“A lot of the motivation was cost savings,” Boyer said. “Unitization saves costs by reducing our part count, and it also improves our lead time because you’re simplifying the supply chain.”
Instead of outsourcing for casting and machining, the supplier can print and finish the unitized component in-house. The potential savings on castings and moldings alone approaches $1 billion.
“We need to be quick. We need to be affordable. Additive really gives us that opportunity,” Boyer said. “Simply put, it’s a smarter way of doing business.”
Sustaining legacy engines with innovation
Conventional
.png?rev=2c205e6efa5d4082bda6beb3ef7d98e5)
Additive manufacturing
Pratt & Whitney produced a bracket for the TF33 engine conventionally and used additive manufacturing to redesign and produce it for use on the U.S. Air Force B-52H Stratofortress aircraft.
Additive manufacturing also makes it easier to sustain military aircraft, which commonly have service lives measured in decades – and parts that have been discontinued or are hard to come by.
Between 1960 and 1985, Pratt & Whitney built over 8,000 TF33 engines for military aircraft like the B-52H Stratofortress. Decades later, sourcing spare parts, such as the loop clamp bracket for the engine’s gearbox, became challenging.
“A lot of the parts haven’t been made in over 20 years, and most of the original prints and design assumptions are lost to time. The suppliers that used to make them – many don’t even exist anymore,” said Joe Ott, TF33 and F100 technology manager for Operational Military Engines at Pratt & Whitney.
To address this, Pratt has been triaging and managing the various parts they’ve been asked to produce.
“Most of them are cold starts (starting a production line from scratch), and cold starts are very expensive, especially when you factor in the low production volume,” Ott added.
Enter additive manufacturing.
“When you look at things like castings, additive now becomes a real big player in aftermarket sustainment because with castings, you have to do extremely costly tooling for minimum orders,” Ott said. “Additive brings agility back to the table.”
In 2021, Pratt’s Operational Military Engines team tackled the TF33 engine issue head-on, using additive manufacturing to completely redesign and produce a flightworthy bracket for the engine in under nine months, investing their own funds to do so.
“Additive helps to make parts essentially on demand with various lot sizes once we qualify a supplier to do that,” Ott said.
Pratt & Whitney is working with the U.S. Air Force to give the bracket some actual airtime. Field testing began in 2023, and the field service evaluation is ongoing, with the goal of a full-production version following the trial.
“With castings, you have to do extremely costly tooling for minimum orders. Additive brings agility back to the table.”
Joe Ott | TF33 and F100 technology manager | Pratt & Whitney
