The schematic diagram shows the third ULTIMATE engine concept studied at Cranfield University. It combines an open-circuit air bottoming cycle with a ‘nutating disc’ topping cycle, intercooling and secondary combustion, exploiting potential synergies between these technologies. Intercooling and secondary combustion increase core specific power and reduce weight, while the topping and bottoming cycles improve thermal efficiency. The air bottoming cycle extracts extra power from the turbine exhaust heat. The six topping cycle modules each contain a disc compressor and a disc expander, together with an air accumulator and four pre-combustors. Machines like these, or piston engines, may replace existing core components in future turbofan or open rotor engines. The colours in the diagram indicate component and fluid temperatures, with blue being cold and red much hotter, though the highest temperatures are found within the nutating disc module, shown here as a ‘black box’. The reverse-flow turbine arrangement avoids compromising the high-speed turbine design and enables a quiet mixed exhaust arrangement.