Low-Stored-Volume Wings for a Very High Altitude Aircraft

DARPA’s Rapid Eye program requires a large wing capable of deployment from a small stowed volume while at high altitude. Once deployed this wing must have extremely high aerodynamic efficiency. Out Phase I technical approach was based on an inflatable structure and a high tension membrane surface. We were able to prove feasibility of the structure by analysis with validation by similarity to numerous large inflatable structures using proprietary AirBeam technology. Aerodynamic efficiency was verified by wind tunnel testing of membrane wing models. The values of rib spacing and membrane tension were shown to be critical for aerodynamic performance. The proposed Phase II research addresses the next most critical technical challenge: in-flight wing deployment. We will use a subscale inflatable wing to develop packing and deployment methodology that leads to reliable, controlled, repeatable wing deployment from a relevant annular stowed volume to a fully deployed, structurally and aerodynamically complete wing. The test articles will include all relevant deployed elements, inkling cable bracing, control surfaces and actuation means. All tests in this phase will be ground-based. The objective of this research is to provide a reduced-risk basis for in-flight deployment of a full scale wing in the next phase of development.