Zephyr: A High Altitude Long Endurance Unmanned Air Vehicle ...

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Zephyr 6 (see figure 4) built upon the findings of the Zephyr 5 trials and moved awayfrom risk reduction and development and more towards capability demonstration. Theproject resulted in the first Zephyr platform to have a fully-functional and successfulpower system that can demonstrate solar power flying with in-flight battery recharging.Zephyr 6 has an 18 metre wingspan but weighs less than 30 kilograms as itis constructed out of ultra-light carbon-fibre. In July 2007 Zephyr 6 flew for 54 hoursin New Mexico at a peak altitude of over 58,000ft, thus flying in the targeted 50,000-60,000ft range and validating the thermal and performance models. In August 2008Zephyr 6 flew for over 87 hours in Yuma, Arizona, reaching an altitude of 60,000ftand surpassing the current world record for the longest unmanned flight. The currentrecord is 30 hours set by Global Hawk in 2001, but in order to have the official recorda member of the Fédération Aéronautique Internationale (FAI) must be presentthroughout the flight and during this flight there was no official members present [1].Figure 4. Zephyr 6 in flightCurrently Zephyr 7 (figure 5) is being developed which is designed to fly for monthson end at an altitude of 65,000ft during the day and over 45,000ft during the nightusing only solar and electric power. During the day amorphous silicon arrays are usedto generate solar power to fly Zephyr, and by night Zephyr flies using rechargeablelithium-sulphur batteries that are charged during the day using solar energy. It usesmany of the same technologies as Zephyr 6, housed in a larger (20m), more efficient6
airframe, with the main aim to improve the efficiency and reliability of Zephyr.The aircraft has a lightweight payload that can be used for security and surveillance,remote sensing and communications relay. As Zephyr can fly for long periods of timewithout needing to refuel, the payload can be used for long-term communication ormonitoring.A ground station allows the pilot to communicate with the plane. The aircraft is handlaunched and controlled using a remote control, and once it reaches a certain altitude,an autopilot system takes over. Meanwhile at the ground station, the crew and theautopilot systems constantly monitor the plane and the weather conditions to ensurethe plane is flying where intended. Co-ordinates can be set in order for the aircraft tofly to that particular point, but if something happens the pilot can take manual control.If, for some reason, the plane loses contact with the ground station there are a fewsafety measures in place. The plane will automatically fly towards a pre-programmedpoint and circle here while the crew try to re-establish contact or diagnose any fault.As an absolute last resort the aircraft can be ‘cut down’ and brought to the ground.This involves the plane accelerating downwards into a spiral before breaking intopieces and crashing into the ground. These measures are standard on an experimentalaircraft and have never been used in actual operations.7
Page 1 and 2: Zephyr:A High Altitude Long Enduran
Page 3 and 4: AcknowledgementsI’d like to thank
Page 5 and 6: ContentsChapter 1 - Introduction an
Page 7 and 8: Chapter 1Introduction and Backgroun
Page 9 and 10: 1.1 History of ZephyrZephyr is a li
Page 11: The Zephyr 5 project continued with
Page 15 and 16: 1.2 Environmental IssuesDuring the
Page 17 and 18: order to function, they may not thu
Page 19 and 20: 1.2.3 Cosmic RaysCosmic rays are en
Page 21 and 22: wind speeds. This is to ensure that
Page 23 and 24: crystalline silicon cells and can b
Page 25 and 26: which are then insulated. In order
Page 27 and 28: motion of the aircraft including ro
Page 29 and 30: Within the portable cabins the crew
Page 31 and 32: Simple payloads instructions withou
Page 33 and 34: In the event that the wing does not
Page 35 and 36: Graph 4 shows radiosonde density da
Page 37 and 38: 3.2 NIOSH Lifting EquationThe hand
Page 39 and 40: Variable Description MultiplierD (c
Page 41 and 42: Using the given values, the corresp
Page 43 and 44: 3.3 Airspeed SensorThe current airs
Page 45: 12VSensorPCBZenerDiodeFigure 8. Dia
Page 48 and 49: 3.4 PayloadThe payload is the carry
Page 50 and 51: where λ is the wavelength, c is th
Page 52 and 53: 3.5 Angle of Attack SensorThe angle
Page 54 and 55: The magnetic sensor seemed much mor
Page 56 and 57: Chapter 4Angle of Attack Experiment
Page 58 and 59: The sensor was powered using an ext
Page 60 and 61: It has to be noted however, that on
Page 62 and 63:
experience the atmospheric conditio
Page 65 and 66:
5.2.1 Aerial PhotographyThe most co
Page 67 and 68:
meaning that these cameras can be u
Page 69 and 70:
Infoterra have a project called Far
Page 71 and 72:
it out for long endurance missions.
Page 73 and 74:
Figure 18. QinetiQ’s Zephyr5.4 Co
Page 75 and 76:
where it is needed rather than havi
Page 77 and 78:
Appendix 3Schematic diagram of the
Page 79 and 80:
Appendix 5The results table for the
Page 81 and 82:
BibliographyQinetiQ Documents[1] St
Page 83:
[19] Encyclopedia Britannica, 2004.
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