Flight Test and Simulation of a Cargo Container Slung Load in Forward Flight

This article presents some recent results from a cooperative effort by the U.S. Army Aeroflightdynamics Directorate, the Technion Israel Institute of Technology, and the Northern Arizona University. The objective of the article was to study and simulate the behavior of the 6 x 6x 8 ft CONEX cargo container in forward flight suspended beneath a UH-60 Black Hawk helicopter. This load, like other cargo containers, is subject to massively separated unsteady flow and is limited by stability to operational airspeeds well below the power-limited speed of the configuration. The article makes use of aerodynamic data from wind tunnels, flight tests, and computational fluid dynamics. The objective is a simulation of the helicopter-slung load system validated over the complete flight envelope. The principal remaining technical challenge is a mode of the unsteady load aerodynamics that is capable of predicting the critical unstable speed and some progress has been made in meeting this challenge.