By Melissa Donovan
Three-dimensional (3D) printing technologies provide the aerospace industry with a method of production that meets needs like low-volume production and customization. Commonly used for prototypes and tooling, 3D printer and airplane manufacturers join together to prove how far additive manufacturing (AM) can go.
Aurora Flight Sciences, located in Manassas, VA, develops unmanned aerial vehicles for both civil and military markets. To meet advancing customer needs, its research and development center utilizes Stratasys 3D printing technology for production parts and tooling.
Aurora and Stratasys worked together to build a jet-powered, thrust vectoring, blended wing body, remotely piloted aircraft. The two companies collaborated on the design, which allowed Aurora to rely on topology optimization. This is a physics-based approach that replicates complex structures found in nature and shows where internal material is unnecessary.
GrabCAD, a Stratasys collaboration solution, helped the engineering team manage, view, and share CAD files to coordinate the project between two locations. The software tracks revisions, allows messaging, and acts as a repository for working engineering documents.
With Stratasys, Aurora produced a stiff, lightweight structure, while enabling cost-effective development of a customized, mission-specific aircraft.
Another benefit, the ability to consolidate assemblies into single components, which allows for elegant, complex designs. For example, the fuel tank on this project combines multiple components by having tubing printed on the inside and outside, mounts that attach to the fuel filter and fuel pump, as well as small clamps to attach the fuel lines.
Designing beyond surface geometry enabled the Aurora team to accurately position the center of gravity—a key parameter for blended wing body aircraft. “Any change in the design causes issues to the center of gravity. However, since the additive process can easily control where material is put and where it isn’t, iterating designs has minimal impact elsewhere on the aircraft,” explains Dan Campbell, research engineer, Aurora.
Final parts printed using 3D technology included two winglets, fuselage, payload module, fuel tank, and thrust vectoring mechanism. Out of 34 total components, 26 of them were 3D printed. This made up about 80 percent of the aircraft airframe by weight.
The wings and fuselage were produced on the Stratasys Fortus 3D printers in ASA thermoplastic filament. The Fortus 380mc and 450mc printers off the advanced complexity and high requirements needed for today’s manufacturers. With easy-to-use interfaces and software controls, the Fortus printing systems make it easy to produce complex parts more efficiently and effectively. For demanding applications, the Fortus 450mc is ideal for high-performance materials such as FDM Nylon 12CF, Ultem resins, and ST-130 soluble material for sacrificial composite tooling.
The other pieces were printed with the help of Stratasys Direct Manufacturing, which is a full-service customer manufacturing center. The fuel tank was produced using laser sintering of nylon, the exhaust duct cover 3D printed using Ultem 1010 resin thermoplastic, and the thrust vectoring duct used direct metal laser sintering of Inconel 718.
The build time for this aircraft was cut in half by using AM technologies. Eliminating the need for tooling helped reduce lead times significantly.
Once completed, the engineering team took the aircraft out to the salt flats to test it. “Our goal with this project was to show the aerospace industry how quickly you can go from designing and building to flying a 3D printed jet-powered aircraft. There was a lot of satisfaction in seeing it fly,” says Campbell.
The final specifications on the 3D printed jet-powered aircraft clocked in at a wingspan of 9.5 feet, a cruise speed of 70 to 80 miles per hour (mph) and a top speed of over 150 mph, weight 32 pounds with three liters of fuel, and a 22lbf turbojet engine.
“There is still a stigma that 3D printing is a prototyping technology. But this is not a desk model that will break if you touch it, this is a 150 mph jet,” adds James Berlin, AM research engineer, Stratasys.
Aurora and Stratasys collaborated to bring innovation to the aerospace industry. Proving 3D printing is more than prototypes, the engineering team successfully designed, printed, and implemented a jet-powered aircraft.
Mar2020, Industrial Print Magazine