A half-scale, proof-of-concept helium-filled spherical high-altitude platform (HAP) with a camera payload has been test flown at low altitude in the UK for 2h under remote control.

After 18 months of development the flight tested the propulsion and control systems for the HAP, the full-scale version of which is designed to operate at 65,500ft (20,000m) with a 100kg (220lb) payload capability using photo voltaics and batteries to power the station-keeping system and sensor package, day and night. The 100kg payload requirement followed an analysis of the sensor systems customers were likely to want. Once aloft the HAP's endurance is limited by the payload's power requirements.

The HAP would use a combination of tractor and pusher propellers that have large lightweight blades, developed in-house, to propel it at a slow speed in any direction and be able to maintain station-keeping, potentially within a 161km (87nm) diameter circular area. However some payloads may want to move in a deliberate 10km or 100km forward and backward search pattern.

"We are looking for a customer to fund further development. As well as security, for which we sell tethered aerostats, we think this HAP could be used for environmental monitoring along with other uses," says consultant engineer Andy Elson, whose company has funded the HAP prototype internally and designed it in line with known market requirements based on previous enquiries by foreign organisations.

Elson adds that his engineers created a ballonet technology to enable the HAP to land, rather than hover above a landing zone like conventional airships. His team have also worked on transcontinental manned balloon projects and have experience of control systems that use GPS at high altitude and the related flight modelling. The HAP would use such systems to move between altitudes to avoid difficult wind speeds and to save energy. Canadian company 21st Century Airships flight tested a similar HAP at 18,000ft in 2002.

Source: Flight International