Current gas turbine engines have central rotating shafts and fan-discs and are constructed mostly from heavy metals.
Fundamentally, the ESE drum-rotor configuration typically consists of four concentric open-ended drums or shells: In the ESE design, the rotating blades are primarily in radial compression as opposed to radial tension, which means that materials that do not possess high-tensile strength, such as ceramic materials, can be used for their construction.
[2] The use of ceramics would also be a beneficial feature for hypersonic propulsion systems, where high stagnation temperatures can exceed the limits of traditional turbomachinery materials.
In subsonic applications, venting the centre cavity with a free-stream flow could potentially contribute to a large noise reduction; while in supersonic-hypersonic applications it might be used to house a ramjet or scramjet (or other devices such as a pulse detonation engine) as part of a turbine-based combined-cycle engine.
Although both bearing systems theoretically meet the requirements of the exoskeletal application, neither technology is currently ready for operation at practical sizes.