The schematic diagram shows the second advanced engine concept researched at Cranfield University in ULTIMATE. Bottoming cycles can improve engine efficiency by extracting extra energy from the engine’s exhaust heat. Open-circuit bottoming cycles use this heat to raise the temperature of compressed air and then generate more power by expanding this hot air through a turbine. Closed-circuit systems can use different working fluids, but need to cool the fluids before compressing and recirculating them. The schematic arrangement adds a supercritical carbon dioxide bottoming cycle to a turbofan engine. Supercritical CO2 gives more compact and efficient bottoming cycles than air or steam turbines, but the weight and drag of an air-cooled pre-cooler partly offsets this performance benefit. In the diagram the colours indicate component and fluid temperatures, with blue the coldest and red the hottest. A variant cycle increases core specific power by adding inter-turbine-reheat combustion, which increases the turbine exhaust gas temperature to generate more power from the bottoming cycle.