Flight Evaluation of a Flexible Fabric Stabilizer for Sling Loads

Abstract

Helicopter sling load is the most accurate form of aerial delivery in the military due to the ability to air-land materiel in an exact location; however, some missions have a tendency for the payloads to become unstable due to both pilot-in-the-loop and aerodynamic effects. Past research demonstrated that allowing the container to rotate freely in yaw stabilizes pendulum motions. Other research utilized rigid fins affixed to the rear of the container. These methods work during tests; however, they become difficult to use in an operational environment. This paper discusses tests using a flexible fabric stabilizer that can be temporarily added to any payload. The flight tests were conducted at Moffett Field, CA, using the same payload as the previously mentioned research. Tests showed that the flexible stabilizer provided an intermediate level of performance eliminating sling wind up and stabilizing pendulum motions out to the aircrafts' power limit in exchange for very little operational overhead. The material in this paper concerns loads carried in a single point suspension.