Browning, P. and Huebsch, W., "Design, Construction, and Operation of a Pneumatic Test Launch Apparatus for sUAS Prototypes," SAE Technical Paper 2015-01-2454, 2015, doi:10.4271/2015-01-2454.
The design and testing of small unmanned aerial vehicle (sUAV) prototypes can provide numerous difficulties when compared to the same process applied to larger aircraft. In most cases, it is desirable to have a better understanding of the low Reynolds number aerodynamics and stability characteristics prior to completion of the final sUAV design. This paper describes the design, construction, and operational performance of a pneumatic launch apparatus that has been used at West Virginia University (WVU) for the development and early flight testing of transforming sUAV platforms. Although other launch platforms exist that can provide the safe launch of such prototypes, the particular launch apparatus constructed at WVU exhibits unmatched launch efficiency, and is far less expensive to operate per shot than any other launch system available. The launch system, called the Pneumatic Actuated Universal Launch Apparatus (PAULA), can launch sUAV prototypes with fuselage diameters up to 120 mm, wing spans up to 300 mm, and launch masses in excess of 2.25 kg at speeds up to 80 m/sec (faster velocities for lower-mass sUAVs). This paper details the analytical and numerical modeling needed to ensure adequate compressed gas supply for launch based on compressible flow theory, and provides detailed analysis of launch estimation techniques. Analysis of the structural components and an analysis of sUAV post-launch trajectory estimation is also provided. Finally, this paper gives results of some typical launches of transforming sUAS which have been performed using PAULA.