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

More documents

Recommendations

Info

Figure 5. A Zephyr 7 prototype flown successfully8
1.2 Environmental IssuesDuring the day Zephyr flies at its maximum height and during the night while it isrunning off batteries its altitude decreases. The reason for the decrease in altitude isbecause there is not enough charge in the batteries to drive the motors at the highrevolutions required to maintain altitude for the entire night. At lower altitudes theatmosphere is denser and less power is required to maintain flight, despite the higherresistance. This cycle happens daily for the whole duration of the flight, and can putpressure on the aircraft and its components. The low pressures, cold temperatures andcosmic rays all affect the components that are on board the aircraft.1.2.1 Air Pressure and DensityThe air pressure ranges from about 1000 millibar at sea level to 50 millibar at thehighest altitude, while the temperatures range from 40ºC (at sea level) to -80ºC duringthe night.At lower altitudes the air is thick and dense and as this is where our weather occurs sothere are many gusts of wind. As Zephyr is so light, it is very susceptible to gustswhich could knock it off course or cause the aircraft to break. In order to overcomethese winds, launch has to take place in perfect weather conditions in order tominimise risk of wind. This is one of the reasons the previous flight trials haveoccurred in the deserts of Australia and the USA as the desert provides still air andminimum turbulence.9
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 and 12: The Zephyr 5 project continued with
Page 13: airframe, with the main aim to impr
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.
show all

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

Create successful ePaper yourself

Delete template?

Save as template?