Variable Cycle Engines: The force behind 6th-gen fighter jets

Variable Cycle Engines (VCEs) will power sixth-generation fighters, providing thrust and energy for power-hungry systems while reducing fuel consumption by altering bypass ratio.

General Electric's XA100 engine, currently under development, has a third stream that improves fuel economy and thermal management in efficiency mode, and boosts power in power mode; ground tests show increased thrust and fuel efficiency compared with current fifth-generation engines.

VCEs reduce thermal signature, enhancing stealth, and extend range, enabling longer loiter or deeper penetration into hostile airspace.

European VCE projects include Safran's adaptive propulsion under the FCAS programme and a collaborative effort by Rolls-Royce, Avio Aero, and IHI under the GCAP programme.

VCE technology may also benefit civil aviation by reducing fuel consumption and enabling faster travel.