The Air Force Research Laboratory (AFRL) has developed and demonstrated a new process by tape-wrapping large, unique-shaped carbon-carbon aircraft shells, or aeroshells. Aeroshells are formed into a lifting body shape called Hypersonic Glide Vehicles, which are used as the primary structural element and thermal protection for future weapon delivery systems. This is a key element of a Boost-Glide concept for conducting a Prompt Global Strike mission.
It’s constructed from an array of exotic materials like carbon-carbon, which is used for both the body and aeroshell which provides protection against the extreme temperatures that moving at Mach 20 produces. These parts are built (or rather molded and cured) from piles of polymer composite using a recently unveiled “tape-wrap” process. This fabrication technique drastically cuts the cost of producing these vehicles. This technique requires 10 times fewer parts, 50 percent less human labor, and reduces the production cost by 40 percent per pound of carbon-carbon.
The DARPA Falcon Hypersonic Technology Vehicle (HTV)-2 is a prototype that launches on a rocket, reaches suborbital space and then re-enters Earth’s atmosphere at speeds of about Mach 20. The vehicle is part of DARPA’s Global Strike test program to check technologies for a global bomber.
Hypersonic Glide Vehicles like the falcon may allow delivery of conventional payloads over long distances. Demonstration of the tape-wrap process is a major step toward development of these vehicles. This material processing demonstration achieved a large reduction in the number of parts and the labor required, and the cost of the aeroshell.
Specialised materials such as carbon-carbon are required as primary structural and thermal protection elements to sustain the severe temperatures on the surface of Hypersonic Glide Vehicles during high-speed flight. AFRL partnered with ATK Aerospace Systems to successfully develop and demonstrate the tape-wrap process; the bulk of the research focused on the development of techniques necessary to properly build up the material from plies of uncured polymer composite and cure large, lifting body-shaped sections.
The successful demonstration of the tape-wrap process was a major achievement that resulted in a more than 10 times reduction in the part count for complex-shaped, enclosed carbon-carbon atmospheric re-entry bodies. It also reduced the cost per pound for aeroshells by 40 percent and reduced human touch labor by 50 percent versus current manufacturing processes. Researchers accomplished these gains while maintaining sufficient thermal and mechanical properties in key portions of the structure. This should allow for an extended hypersonic glide within the atmosphere while still being able to sustain the inertial and aerodynamic loads produced by high G evasive maneuvers. The material performed well in ground tests that simulated long duration hypersonic glide trajectories.