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  • National University of Singapore

    10

    UAV DESIGN AND MANUFACTURE U067782B

    ZHANG XUETAO

  • 2 | P a g e

    Table of content

    Summary 3

    Introduction 4

    UAV fuselage design 6

    Aircraft shape and aerodynamics of fuselage 7

    Aircraft structure analysis 12

    Engine connection 12

    Wing connection 16

    Material selection 18

    UAV Fuselage manufacture 22

    Vacuuming forming 22

    Conclusion 29

    Recommendation 30

    Reference 32

    Appendix 33

  • 3 | P a g e

    SUMMARY

    The first part of the report is concentrated on UAV fuselage design. It consists three

    sections: aerodynamics, stress analysis and material selection.

    The fuselage shape must be such that separation is avoided when possible. Thats

    where the aerodynamics of the fuselage designs core. By designing the ratio and

    shape of the UAV nose and tail cone, the ultimate goal is to reduce as much drag as

    possible and provide lifts. We must be convinced that a manoeuvre always involves

    acceleration, turning, deceleration, all of which will put the UAV under high loads,

    thats why the stress analysis is so important here. By referring to the thorough stress

    analysis, theoretically the UAV is safe to fly under any conditions. Material is always

    so important for aircrafts that in reality, all the aircrafts has been built by most

    expensive industrial materials, like carbon fibers, carbon steels, nickels,

    molybdenum, etc. For this UAV design, no much vibration, corrosion, noise would

    be taken into consideration. Whats more, the stress involved is not as high as the real

    commercial aircraft, so cheaper and realistic materials should be studied. In fact, after

    a comprehensive study about wood, Styrofoam, plastics, steel and carbon fibers, PVC

    is finally chosen as the main fuselage material.

    The second part of the report mainly introduces an industrial processvacuuming

    forming and its implementation in this UAV fuselage design. Some advantages and

    disadvantages are discussed in this part.

  • 4 | P a g e

    Vacuum forming is one of the methods using thermoforming treatment. Besides the

    fact that vacuum forming can make exact shape as the mould, it also take less pain to

    build the station and take less time to produce one piece of prototype. However,

    several disadvantages exist. The whole process should been monitored very carefully

    since toxic gas would be produced if the plastic is overheated. Also in lab scale, it is

    always very hard to build a station large enough for the overall design and the

    prototype is very hard to modify as well.

  • 5 | P a g e

    1. INTRODUCTION The purpose of this project is to design and manufacture an Unmanned Air Vehicle

    (UAV). As a group project, it requires four students to design and/or build wings,

    fuselage, engine and optimization. This report is the final report for the fuselage

    design and manufacture.

    There are numerous interesting books on the history of aircraft development. This

    section contains a few additional notes relating especially to the history of aircraft

    aerodynamics along with links to several excellent web sites. (Refer to appendix 1).

    However, there are very few topics relating to UAV design and manufacture. This

    report gives students a comprehensive overview and understanding of UAV fuselage

    design and manufacture.

    According to the optimization, this UAV is designed to maximize the endurance. In

    order to achieve the design goal, besides the wing and propulsion, the fuselage gives

    great contribution as well. The following parts have two main sections: UAV

    fuselage design and manufacture. In the design part, aerodynamics designs including

    nose and tail cone together with stress analysis and material selection are elaborated.

    In the manufacture part, a newly and practical industrial processvacuum forming is

    introduced and implemented.

  • 6 | P a g e

    2. LITERATURE REVIEW

    A search for nose fineness ratio produced 1240 journals from Engineering Village

    and 480 from Web of Science. Further search for aerodynamic nose fineness ratio

    produced 188 from Engineering Village. 80 out of these 188 journals have been

    reviewed. Below are the summary of those researches.

    Shu Xin-wei and Gu Chuan-gang (2006) did researches on numerical simulation

    on the aerodynamic performance of high-speed maglev train with streamlined nose.

    They indicated that with comparison and analysis of the results of the five different

    configurations, regularity that its aerodynamic performance changing with its

    aerodynamic configuration was drawn. When the other parameters are the same, the

    aerodynamic drag and lift decrease with the length of the streamlined nose shapes

    extending; when the length of the streamlined nose shapes is almost the same, the

    aerodynamic drag of the front car of the protruding longitudinal profile is less than

    that of the concave, while that of the rear car is the contrary; the aerodynamic drag of

    the middle car varies within a small range, the aerodynamic lift of the rear car is

    greater than that of the front one; and the total aerodynamic lift of the three cars of the

    protruding longitudinal profile is greater than that of the concave.

    Ota, Terukazu (1983) worked on the project of nose shape effects on turbulence in

    the separated and reattached flow over blunt flat plates. He found that the nose shape

    has a strong influence on the turbulence features in the separated and reattached

    regions and even far downstream from the reattachment point.

  • 7 | P a g e

    Goodson, K. W (1958) wrote of journal named Effect of Nose Length, Fuselage

    Length, and Nose Fineness Ratio on the Longitudinal Aerodynamic Characteristics of

    Two Complete Models at High Subsonic Speeds. He discovered that the stability for

    all model configurations showed substantially the same variation with changes in

    forebody area moment. The forebody changes did not alter the angle of attack at

    which an unstable break occurred in the moment contribution of the T-tail but did

    alter somewhat the magnitude of the instability.

    A search for vacuum forming produced 820 journals from Engineering Village and

    210 from Web of Science. 40 out of these 1130 journals have been reviewed. Below

    are the summary of those researches.

    Campo, E. Alfredo (2008) wrote in his journal Polymeric Materials and Properties

    that all PVC compounds require heat stabilizers to allow processing without

    degrading and discoloring the polymer. Plasticizers are added to increase the

    flexibility of the compound. They can also improve the heat stability or improve the

    flame retardancy of the compound. Fillers are used to reduce the cost, improve

    dimensional stability, stiffness, and impact strength. PVC is a recyclable commodity

    thermoplastic material of large consumption by the building and construction

    industry. PVC is popular because of its excellent impact, wear, chemical, and UV

    resistance. PVC is used in a large variety of end products such as flooring, garage

    doors, windows frames and profiles, siding, tubing, and connectors. These products

  • 8 | P a g e

    are commonly available in standard sizes and shapes, low cost, and easy to work with

    (weld, repair, and paint).

    Fagence, S.W. and Garvin, W.Barry (1973) discussed the machines and their

    operations (loading the sheets, clamping, heating, interlocking, drawing, pre-

    stretching, etc); mold design; and mold cooling in the large piece of vacuum forming

    process. He also stated that a definition of 'large sheet' could be a 'sheet in excess of

    16 sq. ft'.

    Wilhelm R (1971) stated in his report Vacuum forming of thermoplastics, that

    although several materials can be used for the mold, for instance epoxies and silicone

    rubber, metal forms were mostly used, particularly for long production needs.

    Decoration and joining by adhesive bonding and HF welding of PVC vacuum formed

    products were discussed.

    Breuer, Heinz (1977) indicated in his journal Importance of Vacuum Technology

    for Extrusion of Plastics as Exemplified by PVC Processing that the processing of

    powdered thermoplastics - particularly PVC in the form of compounds including

    common stabilizers - on twin-screw extruders was widely accepted quite some time

    ago. The more recent development in the sector of PVC film for food packaging has

    called the attention to compact extrusion lines with small sized calenders. Here,

    however, single-screw and planetary roller extruders with sheering dies rather than

    twin-screw extruders are used as plasticizing equipment. For improving the

    profitability of these techniques as well as the quality of the finished products, the

    extruders are fitted with vacuum-assisted feed hoppers. Apart from air an

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