AMETEK Hughes‑Treitler provides a broad range of advanced fuel‑oil heat exchangers engineered
for the demanding requirements of aerospace and defense platforms. With more than 75 years of
experience, Hughes-Treitler develops custom aluminum and Inconel plate‑fin assemblies that
deliver reliable thermal performance, low weight, and strong vibration resistance that are an
ideal fit for aircraft engines, airframes, rotorcraft, unmanned systems, and military vehicles.
By using aircraft fuel as the cooling medium, Fuel‑Cooled Oil Coolers (FCOCs) support efficient
thermal regulation of engine and hydraulic oils in high‑temperature environments. This approach
helps maintain stable oil temperatures during extreme operating conditions and warms fuel to
reduce the risk of ice formation at altitude. Each unit is designed for the specific needs of the
platform, balancing thermal transfer capability with size and weight targets.
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| Weight |
Typically, 5-15lbs |
| Operating Fluids |
Skydrol hydraulic fluid, Jet A fuel, or other fluid types as required |
| Pressure Capacity |
Up to 900 psi |
| Thermal Performance |
Up to 100,000 BTU/hr |
| Construction |
Aluminum tube-fin or Plate-fin technology |
| Cooling Rates |
Oil flow typically ranges from 6.5 gpm (24.61 lpm) |
| Operating Temperatures |
Fuel: 100°F–300°F • Oil: 104°F–347°F |
Multi‑Circuit Fuel‑Cooled Oil Coolers
Multi-Circuit FCOCs are an advanced variant of fuel-oil heat exchanger that incorporates multiple
independent oil circuits within a single, compact cooler unit. These units are ideal for aircraft
where space is limited, and weight is a concern.
While a standard FCOC manages one oil loop per cooler, multi-circuit designs can accommodate 2–3
or more oil circuits in one assembly. This allows a single unit to simultaneously cool multiple
fluid streams, which is highly valuable in complex propulsion or hydraulic architectures.
Each circuit is engineered for its specific pressure and flow requirements, with the overall unit
capable of handling pressures up to ~900 psi for each loop. These units are engineered for high
vibration and shock environments, making them well-suited for use on rotary-wing aircraft and
high-performance military jets with extreme vibration.
Multi-Circuit Cooling for Space-Constrained Military Platforms
In response to the unique thermal demands of a leading military aircraft program, HT engineered a
custom multi-circuit fuel-cooled oil cooler capable of managing four independent oil circuits
through a single fuel flow path. This integrated solution replaced multiple discrete heat
exchangers, significantly reducing system weight, simplifying fluid routing, and conserving valuable
space within a tightly packed airframe.
Each circuit was individually configured to meet specific pressure and thermal requirements. The
result is a compact, high-density thermal management system that supports performance-critical
operations while improving reliability and maintainability.
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Hydraulic Coolers (Natural Convection Hydraulic Oil Cooler)
Hughes-Treitler’s hydraulic oil coolers support high-pressure, long-duration aircraft hydraulic
systems through a finned-tube, natural-convection design. These coolers transfer heat directly from
the hydraulic fluid to fuel. Their aluminum-finned-tube construction provides strong heat-transfer
efficiency while withstanding vibration and challenging operating environments.
Built for the pressure ranges found in today’s commercial and military platforms, each cooler is
engineered for the specific installation, cooling demand, and fluid characteristics of the aircraft
system. Natural convection cooling maintains stable hydraulic fluid temperatures across flight control
systems, landing gear hydraulics, actuators, and other subsystems.
Hughes-Treitler hydraulic coolers appear across business jets, commercial transport, military aircraft,
and helicopters. Their passive cooling capability reduces installation complexity and power draw while
still enabling effective heat rejection in hot ambient or low airflow scenarios.
Free Convection Fuel Cooled Oil Cooler
This aluminum tube fin fuel cooled oil cooler was custom designed for the Boeing 757, with similar
designs on the 737 and 777. This unit cools the hydraulic system fluid with fuel.
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Customized Solutions for Every Platform
Hughes-Treitler develops every fuel‑oil heat exchanger as a fully customized solution built around the
exact thermal, structural, and environmental demands of the platform.
Unmanned Aerial Vehicles (UAVs)
Lightweight, compact cooling for drones
Hughes-Treitler’s fuel-oil heat exchangers helps regulate engine oil and hydraulic fluid temperatures in UAVs. Their low-weight, vibration-resistant designs integrate easily into tight UAV airframes, protecting small engines, power electronics, and actuators without sacrificing payload or range.
Commercial Aircraft
Efficient thermal management for airliners & business jets
Hughes-Trietler’s exchangers are used in jet engine oil cooling and fuel system thermal management on commercial planes. By transferring heat from hot engine oil to jet fuel, they help prevent fuel icing at high altitudes and maintain stable oil temperatures. The brazed aluminum plate-fin construction reduces aircraft weight and improves fuel efficiency, supporting systems like environmental control units and auxiliary power units.
Military Aircraft
Rugged solutions for fighters, helicopters & transports
High-performance fuel-cooled oil coolers from Hughes-Treitler are deployed on advanced military jets and rotorcraft to dissipate heat from powerful engines, gearboxes, hydraulic loops, and mission-critical avionics. Designed for extreme G-forces and constant vibration, these durable heat exchangers ensure reliable cooling of propulsion and hydraulic systems in fighter aircraft, heavy-lift helicopters, and military transport planes operating under harsh, combat-level conditions.