Flight Testing of Autonomous Parafoils Using Upper Surface Bleed Air Spoilers

Upper surface bleed air spoilers are a novel control mechanism for guided airdrop systems. In contrast with conventional trailing edge deflection mechanisms, upper surface bleed air spoilers have been shown to be extremely effective for both lateral (turn rate) and longitudinal (glide slope) control of parafoil aircraft. Bleed air spoilers operate by opening and closing several span-wise slits in the canopy upper surface thus creating a virtual aerodynamic spoiler from the stream of expelled ram air. The work reported here investigates the autonomous landing performance of parafoil aircraft in both computer simulation and flight testing using upper surface bleed air spoilers exclusively for lateral steering control and combined lateral and longitudinal control. Additionally, a novel incanopy bleed air actuation system has been designed and successfully flight tested on a variety of larger parafoil aircraft ranging in payload weight from 300 lb to nearly 1000 lb. The in-canopy system consists of several small, specifically designed winch actuators mounted inside the parafoil canopy capable of opening one or more upper surface bleed air spoilers completely independent of the system AGU. Details of the in-canopy hardware, unique internal rigging structure, and resulting flight performance using the in-canopy system are also presented with excellent results.