Ultra-Low Temperature Elastomeric Seals for Aerospace Hydraulic Systems

ABSTRACT: Unmanned air vehicles (UAVs) operating on high altitude long endurance (HALE) operation can cause sections of the aircraft to experience temperatures as low as -100 F. This is particularly damaging to the landing gear hydraulics and wheels. Critical low-temp weak points within the landing gear are the elastomeric O-ring seals. The simplest approach is to replace existing seals with new low-temperature elastomer seals in the same form factors. During the course of the Phase I effort, the team formulated and cast prototypes of a new elastomer seal as a -214 size O-ring. Glass transition temperature, thermal retraction (TR-10), low-temp tensile, fluid exposure to hydraulic fluids (MIL-PRF-87257, MIL-PRF-5606), and lab-scale hydraulic testing indicate the Luna O-ring performed well down to -100 F under static conditions and -70 F under dynamic conditions while exposed to hydraulic fluid. During the proposed Phase II, the team will optimize the seal formulation, scale up production to large-scale, evaluate seals per relevant specifications, validate seal performance in system level testing, and continue to work towards commercialization of the technology. Luna and team members will work closely with the part OEMs, platform OEMs, maintainers, and end users to replace the existing seals on form/fit/function levels. BENEFIT: The first product for this technology would be seals to be integrated into UAV platforms as drop-in replacements. These seals would be cost effective and provide enhanced capabilities, specifically the capability to operate at HALE conditions with no leakage. This would enhance the capabilities of the UAVs by removing limitations on HALE flights, as well as reducing the risk of damage during landing. Testing will be performed to ensure that the seals meet the relevant ASTM, SAE, and MIL specifications. Once established, this new seal technology could be used for multiple other platforms, both military and civilian. Other markets include the larger aerospace market (other aircraft); space (missiles, rockets); oil drilling and pumping equipment; and specialty chemical processing equipment (low temperature, harsh conditions, etc.).