Testing the aerodynamics of a new hypersonic glider

A newly developed flying vehicle, called HEXAFLY-INT, has undergone intensive tests to see just how aerodynamic it truly is. The recently closed study, for the Technology Development Element (TDE) with Italy, assessed the shape of HEXAFLY-INT, which has been progressively designed in several iterations since 2014.

At 3.29 m long, and 1.24 m wide, the hypersonic glider is slightly smaller than a compact car, with a flat nose tip and wings. The shape is characterised by its high aerodynamic efficiency and the glider has been equipped with several breakthrough technologies on-board, that will provide valuable aerodynamic and aero-structural flight data, which will be used to design future hypersonic vehicles.

After a short description of the mission scenario and of the Experimental Flight Test Vehicle (EFTV) main characteristics, the activity, with Centro Italiano Ricerche Aerospaziali, focused its attention on the approach used for both the aerodynamic database and the related applicable uncertainty model.

The first assessment was to establish and evaluate how well the vehicle could withstand thermal environment changes. The aerothermal loading conditions were assessed by means of both engineering-level and (more reliable) numerical simulations.

To build a database of the machine’s aerodynamics the vehicle underwent several tests, including a wind tunnel test, as well as multiple numerical simulations. They also performed the tests with the glider carrying a fake experiment module (ESM) as a payload.

The main aerodynamic performance of the vehicle, both with and without the experiment module, have also been analysed, confirming the glider’s aerodynamic efficiency and its good longitudinal and lateral-directional stability as well. 

The final trajectory is being calculated taking into account the last version of the EFTV’s aerodynamic database, vehicle’s internal layout, total mass, centre of gravity and inertia moments.

At this stage, the aerodynamic databases are ready to be used for the final flight trajectory assessment of the EFTV and ESM together, which is re-entering from the apogee up to the ESM separation (at about 55km altitude), and the EFTV alone experimental flight, and for the design of other subsystems, including cold and hot structures.

TDE contract 4000121293 closed in 2019.