Cooling: The secret star of every air mission

He was a Naval flight officer in an EA-18G Growler – the U.S. Navy’s premier electronic attack aircraft – and that meant he already had his eye on the radar. And the jammer. And the countermeasures. And the conventional weapons. Behind it all was something he never had to think about: the aircraft’s cooling system – at the time, a recent upgrade from Collins Aerospace that kept all those power-intensive components from overheating.

“Honestly, the cooling upgrade is kind of seamless to the aircrew,” said McCarty, who retired from the U.S. Navy after more than 20 years and now works for Collins Aerospace, an RTX business. “There’s not a ‘press this button to get more cooling when you need it’ [moment]; cooling’s just built into the aircraft. The weapons systems and radar are expected to work and to have the cooling available.”

That seamlessness unlocked a world of capabilities for the Growler, whose role is to degrade adversary radar and radio systems. Specifically, it meant McCarty’s aircraft could fly with active electronically scanned array, or AESA, radars – typically the APG-79 or APG-80 systems made by Raytheon, another RTX business. 

The AESA technology is itself an upgrade from old-fashioned mechanical radars. Its advantages include greater control over the beam, and the ability to track and engage airborne and ground-based targets at the same time.

One upgrade leads to another

The quest for better cooling systems is familiar ground for Stuart Weitz, Collins’ director for military programs on the systems engineering team. When he joined Collins in the late 1980s, the business was working on the environmental control system technology that would later be chosen for the F/A-18E/F Super Hornet program. 

“Volume and mass are always a challenge,” said Weitz, describing any aircraft system upgrade. “It’s a little bit of a Rubik’s Cube to try to come up with these new and novel systems to get more performance while minimizing space, weight and bleed air consumption.”

And that quest continues. 

Weitz was quick to point out that Collins is doing it again – with an even more advanced cooling system to enable powerful new technologies for the next generation of fighter aircraft. Collins’ latest advancement is called EPACS, which stands for Enhanced Power and Cooling System, and it’s a direct descendant of those first few cooling upgrades Collins placed on the Super Hornet.

An evolution to EPACS

In developing EPACS, Collins engineers were looking for ways to create even more mission capability for today’s multi-role fighters like the F-35 and what comes after it.

Tomorrow’s aircraft would need a whole new level of power and thermal management to accommodate a new generation of avionics, radars, communications and weapon systems.

With EPACS, they saw an opportunity to use a new type of water removal process in development for commercial platforms that, in turn, helped solve a problem common in many cooling systems: the accumulation of water wrung from the air by the condenser heat exchanger.

“That heat exchanger takes up space and has weight to it, and those are two things you don't want in any aircraft, never mind a fighter aircraft,” Weitz said.

This new, more efficient way of removing water opens up space that can then be used to expand essential systems and pull in more bleed air for additional cooling.

And, said Weitz, that’s where EPACS is leading: “to increasingly, light, small and efficient cooling systems that will be able to cool the electronics in the next generation of aircraft and generations after that.”

Next-gen readiness

As the future of the battlespace continues to evolve, so will the role of the F/A-18, its EA-18G Growler variant, and the systems that support them.

“The F-18 will continue to be the workhorse, the aircraft that’s going to be able to carry a large amount of weapons forward,” said McCarty. “The aircraft has been continually upgraded via software and hardware improvements, increasing its ability to carry more weapons, newer weapons, and enhancing its ability to counter threats in real time.”

He said it’s the flexibility of the F-18 – the aircraft’s ability to take on new roles and fulfill new missions – that ensures its relevance and longevity.

“There’s aircrew out [there now] conducting combat operations that they didn’t necessarily train for when [the mission] started, but they’re able to rapidly adapt the aircraft and the weapon systems to be effective in an environment that they didn’t expect to be in.”

McCarty’s message for aircrews in training: Just as he never had to think about cooling, they shouldn’t have to either. He wants them to be free to focus on the mission.

“Our goal is to provide them with the best equipment possible to be able to go forward and execute the missions they need to do,” he said. “I’d trade place places with them right now.”