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Défi Aérospatial (Anglais)

Variable incidence angle adjustmentof the MSV with its carrier aircraft and separation phase analysis

(WP1 – Aerodynamics and flight control)
Mohamed Amine CHEMAK – Antoine LEFEBVRE – Robin RIXAIN
ISAE-ENSMA – Chasseneuil-du-Poitou (Futuroscope)


For an airborne vehicle, the separation of an orbital or suborbital vehicle from its carrier is a most crucial phase. This phase is critical as regards the flight paths of the 2 vehicles, especially as the attachment system is subjected to extreme loads.

In order to improve the performance of separation, the ENSMECANIK team suggests a solution with an attachment system allowing for variable incidence angle adjustment of the Manned Suborbital Vehicle. This system is composed of 2 jacks at the front of the MSV so as to ensure its proper orientation and 2 aft support struts.defi_aero_1

An aerodynamic study made it possible to collect the necessary information about the carrier aircraft (an Airbus A300), the MSV and the set of mated vehicles as a whole. The study was based on an analogy with the Hermes shuttle and NACA delta wings. Also, a 3D model of the vehicles was finalized.defi_aero_4

In order to confirm the importance of the MSV setting angle with the carrier aircraft, a similar case study was also analysed, that of the US orbiter-shuttle/B747 carrier aircraft separation. This investigation allowed it to highlight the significant impact of the carrier/MSV angle and to further analyze the separation process.

The flight paths of both vehicles were modeled over the 8 seconds after separation and before the ignition of the MSV’s rocket engine.defi_aero_5

Finally, the strut attachments and the jacks were sized for optimal mass and diameter,as both parameters negatively influence the efficiency of the system.

(Version française)