Presentation on theme: "AIAA Design/Build/Fly Competition"— Presentation transcript:
1 AIAA Design/Build/Fly Competition - 2011 University of California, Irvine – UCI Team Caddyshack
2 IntroductionThe UCI AIAA student chapter participates in the annual AIAA Design Build Fly (DBF) competition.This competition gives the engineering students a chance to apply classroom knowledge, gain hands on skills, and experience an industry level project-development from conceptual design to building and testing an optimized final product.Over the past 6 years this project has grown substantially in size and skill with the help of previous DBF students, currently working in the aerospace industry, who meeting with the current team weekly.
3 Outline Introduction Team Organization 2011 Competition Conceptual DesignPreliminary DesignDetailed DesignManufacturingTestingExpected Final Performance
4 Team Organizational Chart Project ManagerKamil SamaaanReportLead: Giuseppe VenneriPatrick LavaveshkulSemir SaidWestly WuByron FrenkielCADLead: Patrick LavaveshkulKerchia ChenSothea SokAngela GrayrErica WangChief EngineerGiuseppe VenneriAerodynamicsLead: Curtis BeardRayomand GundeviaThuyhang NguyenAnthony JordanMax DalyPropulsionLead: Kevin AnglimKasra KakavandKhizar KarwaAlexander MercadoYi-lin HsuStructuresLead: Hiro NakajimaKurt FortunatoGagon SinghKevin KoesnoMichael GamboaPayloadLead: Jacqueline ThomasStability and ControlLead: David MartinJames LewisTest Flight CoordinatorPublic RelationsChen Weng
5 Team OverviewAerodynamics: Computes flight characteristics and necessary wing dimensions.Propulsion: Analyzes propulsion system to find best motor, propeller and battery combination.Structures: Optimizes load-bearing components and maintains a weights build-up of the aircraft.Payload: Designs and manufactures steel payload and restraints for the payload and aircraft.Stability & Control: Ensures aircraft meets S&C standards and works closely with aerodynamics to predict flight performance.
6 2011 Competition Competition consists of 3 missions: Mission 1: Complete as many laps as possible in a 4-minutes. time frame (M1 = Nlaps/Nmax)Mission 2: 3 laps with a steel bar payload.(M2 = 3x(Payload weight/Flight weight))Mission 3: 3 laps witha team-selectedquantity of golf balls.(M3 = 2x(Nballs/Nmax))
7 2011 Competition (Cont.) Constraints for 2011: Battery weight: ¾ lb 20 amp slow-blow fuseAircraft must fit in a commercially-available carry-on suitcase.L + W + H = 45 inches (no dimension can exceed 22 in.)Suitcase must include entire flight system, including aircraft, battery and all required parts and tools.Golf balls are regulation sized and the steel bar payload dimensions are constrained: 3 in. width x 4 in. length minimum.Aircraft must be hand-launched.
9 Sensitivity AnalysisThe objective of this analysis is to identify the mission parameters that have the largest impact on the score.A maximum of 64 golf balls and 9 laps were the benchmark values, determined using the data from past DBF competitions.Thrust and drag models were used in a simulation program to design hundreds of planes and perform this analysis.Mission 1 favors a small plane and payload with a large propulsion system.Missions 2 and 3 favor a large plane with a high wing loading.
10 Configuration Figures of Merit In order to select an aircraft configuration, a scoring system based on figures of merit was produced. Each was weighted based on results of the scoring analysis:System weight (35%)L/D (20%)Cargo space (15%)Maneuverability (10%)Manufacturing (10%)Hand launch (10%)
11 Aircraft Configuration Mono Plane- (Conventional)Relatively easiest to design and build. Known comparative values for performance.Relatively heavy configuration not optimized for specific competition.Flying WingEfficient use of space. Lack of unnecessary elements decreases weight. High L/DSignificantly less stable and more difficult to manufacture.Delta WingFly at high angle of attack. Allow additional cargo placed in wing.More unstable than a conventional and somewhat more complex to design and manufacture.BiplaneSlightly more stable and higher structural strength.Much heavier and unnecessary additional elements.FOMWeightConventional AircraftFlying WingDelta WingBiplaneSystem Weight3521 -1L/D20-1Cargo Space150 1Stability10-21 ManufacturabilityHand LaunchTotal1005030-65Final Decision: Flying WingWould be able to hold a maximum amount of cargo using the lifting surface as the payload bay without a significant drag penalty.
12 Motor PositionTractor- Lightweight, higher efficiency and less dangerous hand launch.Pusher- greater lift due to lack of prop- wash, limits the maximum amount of sweep and a dangerous hand launch.Double Tractor- Smaller propellers, increased cargo space in center, less dangerous hand launch, increased weight and difficulty in locating the CG.Push-Pull- Increased weight, limits maximum sweep and provides a more dangerous hand launch.FOMWeightSingle TractorSingle PusherDouble TractorPush-PullSystem Weight45-1Drag201Hand Launch15-2Stability10Cargo Space2Total100-10-30-95
13 Landing MethodsBelly Landing- Low weight, low drag, would be difficult to hand launch and vulnerable to fatigue.Skid/ Handle- Improved hand launch, increased structural support, potential additional storage space and slight increase in weight and drag.Skid & Wire- Decreased stopping distance, minor increase in weight and increase in drag.Tricycle- Reliable and high strength, however significant increase in weight, drag and difficulty of hand launch.FOMWtBelly LandingHandle/ SkidSkid and Piano wireTricycleSystem Weight45-1-2Drag20-1 Hand Launch152-2 Stability101Cargo SpaceTotal1005-70-140
14 Yaw ControlWinglets- Reduced drag, light weight and provides yaw stability.Wingtip rudders- Increased pilot control and increased weight.Aft Vertical tail-Greater moment to correct yaw and significant increase in weight.Split Flaps- Provides only a minor increase in weight, complex and difficult to implement correctly and cause and increase in drag.FOMWeightWingletsWingtip RuddersAft Vertical TailSplit FlapsSystem Weight45-1-2Drag25Hand Launch15-1 Stability1 2Total100-30-100-45
15 Payload Configuration Fully enclosed internal payload compartment- Less drag and a lower weight. Requires a larger t/c airfoil or a larger aircraft.Fuselage (BWB) style compartment- More efficient method of cargo placement near the Center of Gravity, increased drag and difficulty to manufacture.
17 Preliminary Design Design and Optimization Programs Stability and ControlDesign MethodologyMean Aerodynamic ChordMission ModelWingletsAerodynamicsAirfoil SelectionWing SizingPropulsion SizingDragLift
18 Programs Used During Design and Optimization SolidWorks: used to model aircraft prototypes and to help determine airfoil selectionXFOIL: Used to analyze possible airfoil choices for aerodynamic characteristicsMicrosoft Excel: Used extensively for data analysis, storage and graphingAVL: Used for flight-dynamic analysis and to ensure overall stability of the aircraftMATLAB: Used to create an optimization program
19 Design MethodologyThe Aerodynamics team planned and organized the design process into several design steps outlined in the flowing diagram.A conceptual design is produced using the sensitivity analysis results.A preliminary design is developed using the conceptual design results and initial estimates.An optimization program is developed in Matlab to model the performance of a design for all of the missions.Several iterations of optimizing, building and testing are done to produce a high performance aircraft.
20 Mission Profile Optimization Program The mission profile was modeled using for loops and while loops in MATLAB.The aerodynamic and propulsion forces were computed for every loop- iteration to determine the change in position and velocity of the aircraft during that period of time.The program assumed some initial conditions for takeoff such as hand launch velocity and wind conditions.The mission model program computes:the energy usedthe number of laps completed in 4 minutesThe maximum payload capacity a design could carry.The total flight score is computed for several designs which resulted in an optimized design.
21 Airfoil SelectionThe majority of airfoils that were considered were the reflex type for our flying wing.Studies were done using XFOIL and SolidWorks to determine which airfoil best suited our needs.Coefficient of moment vs. angle of attackNACA 4-digit symmetric series study
22 Wing SizingWing loading was optimized based on the total flight score using our mission profile MATLAB program.The figure to the right shows a plot of the total drag as a function of the aspect ratio for mission three during takeoff.
23 Propulsion Motor Selection Battery SelectionConsidered several different battery types and the capacity-to-weight ratios.A mission profile was used to determine an estimate of the amount of energy needed to complete each of the missions.Propeller SelectionPitch-High pitch performs better at high speeds while low pitch performs better at low speeds.Diameter- Larger diameter= more thrust and more power required from motor.Mission 1: High pitch small diameter.Missions 2 & 3: Lower pitch and larger diameter.NameWeight ozKv RPM/VMax Current AmpPower WResistance ΩHacker A30-14L4.6800354900.038Hacker A30-12L1000324000.041Hacker A30-10L4.811854500.023Hacker A30-8XL5.511006000.015BatteryCapacity mAhAh / ozRedicom5001.56Nimh7001.75Elite 150015001.92Elite 170017001.7Elite 200020001.72Elite 220022001.44Elite 330033001.71Motor SelectionBased on the battery and the current limitation of 20A, the maximum power the battery could supply to the motor is 300 W.
24 DragThe drag was computed using the equivalent flat plate area method.
25 Lift The wing was optimized for the cruise of mission two and three. Washout helped focus the peak of the CL distribution.
26 Stability and ControlWe calculated our MAC and simulated our aircraft’s geometry through AVLThe figure to the right shows the resulting pole-zero map of the eigenvalues calculated by the program.
27 Stability and Control WINGLETS An eignemode analysis made in AVL showed that the flying wing was susceptible to low Dutch roll damping.Dutch roll was clearly visible during test flights, but Pilot still maintained good control.Sized for Dutch roll damping above 0.02.Optimized Winglet DimensionsHeight c/4: inSweep: degreesDistance behind LE: 6.0 inTaper ratio:
28 Wing Spar Design We modeled the wing spar as an I-beam. Carbon strips were laid on the top and bottom of the wing with a 5/8” diameter carbon rod running between the strips to create our spar.Testing later on showed that the wing with two spars was favored over the single spar.
30 Central Structure Design In an effort to reduce weight, the motor mount, landing skids and launch handle were combined into one carbon fiber structure that was integrated into the center wing section.This design proved to be very efficient in cargo space utilization.The forward end is used as an electronics compartment to house the speed controller and the fuse.The skid and handle section was designed as a channel that was sized to fit the propulsion battery pack.
32 ManufacturingWe used molding methods investigated over summer to create our center section.A male and female mold were created using SolidWorks template printouts and hotwire cut foam.
33 ManufacturingFoam wings were created and hollowed out using wooden templates and a hotwire as investigated over summer.Wings were then coated with fiber glass and a strip of carbon fiber for strength.
35 Wingtip TestingWing tip testing was used to confirm and validate wing-spar calculations and our hollow core foam design.Testing was performedby securing the tipsof a wing and loadingit mid-span untilfailure occurred.
37 Propulsion TestingStatic thrust testing was conducted to measure the performance of various propulsion systems.Dynamic thrust testing was conducted using a load cell that was mounted to a custom-designed sliding motor mount and was used to collect dynamic thrust data during flight.This data was used to accurately model the dynamic thrust in the mission profile optimization program.Fuse and battery testing were also conducted in the lab to determine the limits and range of operation.
38 Handle Design TestsDifferent handle designs were created and tested initially to find which best suited the hand launcher to give him control and stability at take off.
39 Test Flight ResultsPrototype IThe following are a combination of both prototypes, and were used to calibrate the preliminary design.Takeoff speed: ft/sMax wing loading: ozLocating CG for stable flight: 15% static marginDutch roll damping: ControllableLap time: sPrototype II
40 Test Flight Results Prototype I Provided insight into launch and landing techniques.Provided data for the calibration of the wing loading.Prototype IIImproved stability.Increased payload space.
41 Competition Results Maximum of 4 flight attempts allowed Mission One: 1st flight attempt: 6 laps in 4 minutesLate in the dayMission Two:2nd flight attempt: fuse blew within seconds after hand launchNoon, +90°F, No wind3rd flight attempt: ran out of battery with one more turn left in the courseVery spectacular flight4th flight attempt: Propulsion strategy gone amissNoon,Even with a reduced payload, our plan to increase thrust on the downwind blew the fuse.
42 Lessons LearnedThe conditions surrounding the fuse in Tucson are very different than those in Irvine. The fuse will blow at a lower current in Tucson.Flying later in the day helped with the above handicap, when it was cooler. In fact, heavy planes like those from Israel and MIT skipped their noon rotation and waited till the late afternoon to fly their airplanes (9 lbs!!).Conduct propulsion tests and test flights with competition weather conditions in mind.