The HEXAFLY-INT project aims to flight test an experimental vehicle above Mach 7 to verify its potential for a high aerodynamic efficiency during a free-flight while guaranteeing a large internal volume. The feasibility for a 3m long vehicle was demonstrated during the European L0 precursor project HEXAFLY. Its realization will now be enabled on an international scale underlining the need for global cooperation in case of a future deployment of a high-speed cruiser.

This flight opportunity will increase drastically the Technology Readiness Level of developments realized in previous high-speed EC projects such as ATLLAS I & II and LAPCAT I & II.

The different technologies and methodologies which need experimental flight testing at high speed are grouped around the major axes of HEXAFLY-INT:

1. High-Speed Vehicle Concepts
2. High-Speed Aerodynamics
3. High-Temperature Materials and Structures
4. High-Speed Flight Control
5. High-Speed Environmental Impact

To realize this experimental flight test, different consecutive steps are planned each followed by a critical review together with international partners:

• update of the mission profile based upon the feasibility study
• a detailed design of a high-speed experimental flight vehicle
• selection and manufacturing of ground-tested technologies and systems
• assembly, integration and testing of the experimental flight test vehicle
• identification and procurement of the most promising flight platform(s)

The design of the experimental high-speed cruise vehicle will be the main driver and challenge in this project with following scientific objectives:

• an aerodynamic balance at a cruise Mach number higher than 7
• an integrated conceptual design demonstrating a combined volumetric and aerodynamic efficiency
• making maximum use of developed advanced high-temperature materials