Winged Aerostat Systems for Better Station Keeping for Aerial Surveillance

An aerostat is a tethered balloon with an aerodynamically shaped envelope containing a lighter-than-air gas that generates bulk of the lifting force. Aerostats are used extensively as an aerial platform for many scientific and commercial applications. Conventional aerostats envelopes have an ellipsoidal shape, due to which they suffer from a large amount of horizontal displacement (called blowby) due to the ambient winds. If the drag force acting on aerostat is high, the resulting blowbyis higher and a longer tether is required to maintain the specified operating altitude; this results in lower payload capacity. Recent studies have shown that winged aerostats (which have an envelope with airfoil cross-section) can reduce blowbydue to a much higher lift/drag ratio. This paper presents a comparative analysis of the operational effectiveness of a winged and conventional aerostat for scientific data gathering in lower Himalayas at various ambient wind speeds. The winged aerostat is seen to be much smaller in size, and has a much lower reduction in operating altitude due to blowby. The paper also describes the design of a prototype winged aerostat currently under development.