There are many ways to move an aeroplane through the air. Most modern aeroplanes use turbofan engines to generate propulsion because of their high thrust and good fuel efficiency. With air traffic increasing, decreasing emissions is becoming an increasingly important focus of research and development. One way to do that is with the ultra-high bypass ratio engine technology under development by the EU for its geared turbofan engines. Not only does it increase efficiency and decrease fuel consumption and emissions, it also reduces noise. To make sure those engines stay cool, the EU-funded SACOC project will develop and validate software tools to evaluate innovative heat exchanger concepts.