“All air vehicles are limited by physics, some by imagination, all others by fuel”.  So said Chris Kelleher, inventor of Zephyr, the solar electric stratospheric unmanned aircraft that provides the airborne platform for the Airbus version of HAPS.Following relatively hot on the wings of their other visit to Farnborough to the AAIB, the Network organised another visit to Farnborough, this time to Airbus, where the company has recently opened the Chris Kelleher building, a production facility for Zephyr.  


Three aircraft have been built so far, for the UK MOD as launch customer.  There were many visitors during the 2018 Farnborough air show, as the Kelleher building is a couple of minutes’ walk from the southern perimeter.  In fact, during the period of the air show, Zephyr S set both altitude and unfuelled endurance records (more than 74,000 feet and 25 days, 23 hours and 57 minutes).


The production Zephyr, at an all up weight of 75kg, will offer 100 days endurance with a payload of 5kg. It has a 25m wingspan and flies at 70kt.  Compared to other surveillance and communication platforms, Zephyr fills a gap between satellites and HALE UAVs. It has to meet all regulations for operating in controlled airspace through which it transits on its 12 hour climb to altitude – 60,000 to 70,000  feet is the operating “sweet spot”.


The uses to which Zephyr can be put depend on the payload, which may be many types of sensor or communications equipment, powered by the same wing-mounted solar cells that drive the propellers. Because of the very speedy deployment and tasking, compared to other vehicles, one example is to rapidly spot the outbreak of wildfires so that ground resources can contain them before they get out of hand – very relevant in the recent very hot summer.


The Network would like to thank the staff at Airbus for hosting this interesting and informative visit.


Blog by Bob Darby, Aerospace Network Executive team member