The design report

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It was here that the first problem was identified. The left engine would sometimes fail to power on, resulting in the left propeller spinning slowly or not at all, while the right worked perfectly. Although investigations were made into the causes of this phenomenon, it was concluded that the problem lay with the motor itself, rather than with any error made by the fabrication team, and hence the team was unable to find a permanent solution. The solution embarked upon was simply to switch the engine on and off until both engines began working to their full extent. It was estimated that the engine failure would occur approximately 50% of the time. This approach worked well, although it did raise some concerns that the engine might fail mid flight, which would have had a disastrous result. However, the team did not deem this to be too imminent a threat, as in all of the tests the engine only ever failed at the initial power on, never once it was already running. After it was satisfied that the engines and control surfaces were working effectively, the engines were powered up to the point where the aircraft began to move. After this began a series of ground exercises, designed to test the maneuverability of the EPUAV. The first task undertaken was to simply taxi in a straight line. Here the second problem was encountered. When no controls were pressed other than the throttle, the vehicle should ideally have moved in a straight line. However, it was discovered that iSpy instead was turning slightly right. This was initially immensely dangerous to iSpy, as all the team members were relatively new to the use of the controls, and would try to compensate for the movement right with a large and sudden movement left, which on several occasions put the plane in peril, as it veered towards obstacles such as bikes. The cause of the crafts tendency to veer right was investigated, as was determined to be the fault of the right landing gear. There were several reasons for which the right landing gear was malfunctioning. The first of which was that during the manufacturing process the steel rod from which the landing gear was created was bent into shape by hand. This meant that a perfect right angle turn could not be achieved, and therefore the angle between the horizontal where the wheel was attached and the vertical component connecting to the fuselage was slightly greater than the desired 90 degrees. This was more a problem for the front landing gear, as the steel rods from which they were constructed were provided by the university, and were more difficult to bend than those used in the rear landing gear, which were purchased by the team. As a solution to this problem, it was suggested that the landing gear could be taken to a metalworkers, however, the problem was initially not deemed of great importance, and this was never followed up on.
Another issue which attributed to the malfunction of the landing gear was the right wheel itself. The wheels were all scavenged from the wreckage of previous planes as new wheels were not supplied. This led to some difficulty in finding wheels of adequate quality. As a result of this, the wheel used for the right nose landing gear was slightly faulty, as the groove inside was uneven. Another potential problem associated with the landing gear was the load the nose gear was being subject to. It was stated that the nose gear should take no more than 6-15% of the weight of the aircraft. However, this fact was for a single nose gear. As iSpy possessed twin nose gear, it was assumed that it could withstand double the weight of a single nose gear. Thus the nose gear was subject to 25% of the load. This was a very high percentage of the load, and the idea that it could withstand this much was based simply on an assumption. Thus the possibly excess load, coupled with the faulty wheel meant that extra force was placed on a steel rod which was already slightly bent out of shape. Other than this landing gear issue, the first ground test was deemed to be an overall success. The controls and wiring were all in excellent working condition, and the plane was able, despite complications, to maneuver and taxi well. Ground Test 2 6.1.2 This second ground test was not a part of the course plan, and was made necessary due to the disastrous events which occurred several hours after ground test 1. When testing the engines later on the day of the first ground test, it was discovered that both ESCs had somehow burnt out, and needed to be replaced. This meant that new ESCs had to be prepared and attached in the place of the old ones. Once the new ESCs had been installed, the team deemed it necessary to perform a subsequent ground test to check that the new ESCs were working. Hence, ground test 2 took place on Tuesday the fifth of January, 2009. Ground test 2 was conducted in a similar manner to ground test 1. The controls and motors were checked first while the aircraft was stationary. Then the vehicle was guided through an array of maneuvers. The new ESCs proved to be in excellent working condition, and the controls and engines all worked resoundingly well, although with the lingering problem of the left engine. The landing gear had by this stage been disassembled and re-formed, and the aircraft was able to perform admirably.
Page 1 and 2:
EP-UAV Project 2009 iSpy Kate Rietd
Page 3 and 4:
Preliminary and Detailed Design 4 S
Page 5 and 6:
Executive Summary 1 iSpy is a twin
Page 7 and 8:
Design Requirements and Objectives
Page 9 and 10:
Initial Sizing 3.1.2 Estimating air
Page 11 and 12:
Airfoil design 3.1.4 Wing: Before t
Page 13 and 14: Tail: A symmetric airfoil with a th
Page 15: Empennage design 3.1.6 The dimensio
Page 19 and 20: Pod Layout 3.1.9 The pod of the air
Page 21: Weight estimation and Centre of Gra
Page 26 and 27: Figure 3.2.303 - Stability axis der
Page 30 and 31: CAD definition of the concept 3.2.5
Page 32 and 33: Figure 3.2.505: The vertical tail F
Page 34 and 35: Preliminary and Detailed Design 4 S
Page 36 and 37: Figure 4.1.109 Figure 4.1.110 The c
Page 38 and 39: Material type was chosen for each c
Page 40 and 41: The nose section of the fuselage co
Page 42 and 43: This part of the fuselage is the mo
Page 44 and 45: Empennage structure 4.1.3 Prelimina
Page 46 and 47: An ‘L’ shaped support was also
Page 48 and 49: Landing gear 4.1.5 Initial stages o
Page 50 and 51: Pod Structure 4.1.7 Figure 4.1.701-
Page 52 and 53: Fuselage fabrication 5.2 Since ther
Page 54 and 55: The servo holder plates in front of
Page 56 and 57: Landing gear fabrication 5.5 The de
Page 58 and 59: Fabrication of Pod 5.6 Like the fus
Page 60 and 61: Control surface fabrication 5.9 Ail
Page 62 and 63: Note: The weights taken after fabri
Page 66 and 67: Flight Test 6.2 The flight test aim
Page 68 and 69: Appendix 7 Appendix A - AVL files i
Page 70 and 71: TRANSLATE -0.450 0.384 0.00 # BFIL
Page 72 and 73: CLARK YM-15 - Re = 250000 Alfa Cl C
Page 74 and 75: Appendix C - Preparation of materia
Page 76 and 77: Appendix D - Control surface sizing
Page 82 and 83: Conceptual Design Preliminary Desig
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The design report

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