AAE 451 Team 3 Final Presentation Jon Amback Melissa Doan Stacie Pedersen Kevin Badger Jason Hargraves Colleen Rainbolt Greg Davidson Etan Karni Lazo Trkulja April 28, 2005

Mission Specifications 8 Minute Endurance Vstall ≤ 20 fps Vloiter ≤ 30 fps Climb ≥ 20 descent ≤ -5.5 Feedback system Stylish

Concept Selection

As-Designed Vehicle 3-View Length 4.21 ft. Wingspan 4.63 ft. Wing Area 3.58 ft.2 Takeoff Weight 1.95 lbs. Discuss features: Unique blended canard design Retractable landing gear LED lighting

Style Features Canard pusher configuration Blended wing-body design Retractable landing gear LED lighting Winglets

Master Design Code Automates sizing iteration process Constraint diagram generation Propeller analysis using Goldstein’s blade-element method Motor analysis / comparison using Prop ’02 functions and MotoCalc database Battery capacity computation from mission model Sizing of Wing, Canard, and Vertical Stabilizer Weight estimation based on construction techniques and known systems weights; CG computation Automatic generation of FlatEarth input deck Single code approach ensures all disciplines “design the same aircraft” 1200+ lines of team code Also leverages 450+ lines of existing propulsion analysis codes and 3700+ lines in FlatEarth aeroprediction code

Constraint Diagram As-built

Propulsion

Selected Propulsion System Kokam 3 Cell 640mAh Li-Poly Battery Pack Kokam Super 20 Electronic Speed Controller

Selected Propulsion System Graupner Speed 480 Brushed Motor 0.12 Hp at 11.1 V and 10 Amps MPJet 4.1:1 Offset Gearbox APC 11” x 4.7” Slo-Flyer Propeller

Aerodynamics

Selected Airfoil USNPS – 4 Flat lower surface -- easy to manufacture Thickness suitable for servos and retractable gear High Lifting Capabilities - Clmax Low pitching moment Low Drag - Cd

Aircraft Characteristics DRAG -Component buildup method: all exposed area contributes to aircraft skin friction and form drag -Induced drag LIFT -Computed lift curve slope, max. and zero-degree AOA lift coefficients to describe lifting properties -Wing incidence angles, sweep, body shape accounted

Desired Operating Point Polars Desired Operating Point CLmax

Flight Controls

Location of CG and AC CG AC SM=19.7% (FlatEarth) Desired ≥ 15%

Stabilizer Sizing with X-Plots Design Point Static Margin = 19.7%

Control Strategy Feedback yaw rate to the rudder due to expected deficiency Increase the damping of dutch roll mode

Landing Gear, Structures and Weights

Landing Gear Layout Nose gear carries 8% of weight; remainder on mains Tailstrike at 10.0 20.0 tipback angle Wingtip strike at 15.7° bank 30.0 overturn angle 1.52 ft. track between main gear 20.0 0.5 ft. 2.15 ft. 10.0

Weight Distribution

V-n Diagram Ultimate Load Factor Mission Load Factor

Manufacturing

Manufacturing Alterations to original design Increased canard area Did not include ventral fins No top for fuselage balsa box Fuselage outer foam was larger and more elliptical in shape Nose landing gear retracted aft rather than forward

Manufacturing Challenges faced: Experience gained: Inadequacy of hot-wire method Inexperience with R/C construction techniques Many hands working on one object Experience gained: CNC fabrication Construction methods Systems integration

Manufacturing

Manufacturing

Manufacturing

Flight Testing

Flight Testing Began on time, but experienced problems Battery destroyed by short circuit in connector Speed controller BEC unable to source sufficient current (experienced by multiple teams) Solution: New flight and avionics battery packs

Flight Testing First attempt Solution! Insufficient canard area to lift nose and rotate Great roll; no takeoff Solution! Field fix – added extra area using available resources

Flight Testing Success! Canard able to lift nose Smooth takeoff Some instability Underpowered Belly landing

Flight Testing Motor adjustment Purchased brushless motor for more power Gearbox did not mesh well with new motor Obtained another, even more powerful brushless motor from ASL

Flight Testing Knowledge obtained from flight tests Retractable gear would not lock in down position CG location critical Wide turns Underpowered using as-designed motor, partially due to weight growth during construction More than sufficient lifting capabilities from main wing Need separate avionics battery

Final Aircraft Alterations since first flight test Added avionics battery Increased canard and elevator area Installed more powerful brushless motor Locked landing gear in down position Fitted LED lighting Added stylistic trim lines

Final Flight

Aircraft Summary Parameter Units As-Designed As-Built Difference Weight lbs. 1.95 2.81 43.8% Wing Area ft.2 3.58 3.60 0.7% Canard Area 0.31 1.08 252.3% Vertical Tail Area 0.63 0.56 -11.2% Prop Size --- 11 x 4.7 12 x 4.4 CG distance from wing Aero Center ft. -0.34 -0.76 126.2% Aileron Area (ea.) 0.11 0.245 123.7% Elevator Area 0.08 0.29 280.1% Rudder Area 0.19 0.23 22.7%

Budget and Labor Budget Labor Team: spent $177.68 of $150 permitted Purdue: $149.86, excluding R/C gear Cost overrun primarily due to cost of balsa purchased locally vs. ordered Labor Team worked 2350+ hours (58 work weeks) Total labor cost is $117,500 at $50/hr/person

Lessons Learned Order balsa, rather than purchase locally to save substantially on cost FlatEarth does not predict the aerodynamic center well for non-traditional configurations Include a large weight margin in design to allow for creep during construction Include a propulsion power margin commensurate with the weight margin Robust attachment points are difficult to design and build, especially for landing gear. Take time to ensure joints are sturdy and straight. Damage tolerance is essential, as the aircraft will crash several times during flight test Plan to use a separate avionics battery Consult with Sean and other experienced modelers (e.g. R/C club members) prior to ordering parts, especially avionics and propulsion system Keep It Simple, Stupid! (KISS)

Questions?

Backup charts Propulsion Aerodynamics Dynamics and Controls Structures Economics and Fabrication Plan

Graupner Speed 480 Rated horsepower 0.1182 hp @ take-off Motor efficiency 71% Motor constants Kv = 2450 RPM/V Kt = 0.5520 In-oz/amp R = 0.241 Ohms Io = 1.09 Amps Rated number of cells 3 Lithium Rated Amps 10 Amps Rated voltage 8.4 V Weight 0.221 lbs Price $25.90 (Hobby Lobby)

Selected Gearbox Gear Ratio (available) 4.1:1 Efficiency 87% Price $13.90 (Hobby Lobby)

Selected Propeller Properties Prop (Calculated) 11 in. x 4.4 in Prop (Available) 11 in x 4.7 in RPM 5000 RPM Weight 0.113 lbs Chord 0.6 in. Airfoil of Propeller Clark-Y Price $3.09 Reynolds Number ~100,000

Other Propeller Options Pitch and Diameter APC Slow-Flyer 10 x 7 10 x 4.7 11 x 6 11 x 7

Battery Properties Kokam 3-Cell 640 mAh Continuous Amps 9.6 A Nominal Output 11.1 V Weight 0.119 lbs Price $31.99

Speed Controller Kokam Super 20 Amp Auto low voltage cutoff (lvc) Continuous Amps Output 20A Peak output current 200A Input operating voltage 2.1 to 18V DC Weight 0.0265 lbs Price $33.99

Graupner Speed 480 Properties

Propeller Properties

Propulsion Parts List

Dimensions Main Wing Canard Vert. Stab. Airfoil USNPS-4 Flat Plate Sref 3.58 ft2 0.31 ft2 0.63 ft2 AR 6.0 4.0 1.5 Taper Ratio 0.6 0.5 0.4 Sweep 0 deg. 25 deg. Dihedral 3 deg. ---

USNPS-4 Characteristics

USNPS-4 Characteristics

USNPS-4 Characteristics

(assumed based on historical data and absence of naceles) Parasite Drag Buildup ,where Fuselage ,where Form Factor: Interference Factor: (assumed based on historical data and absence of naceles)

Induced Drag Coefficient Drag Buildup Parasite Drag Induced Drag Coefficient (ref. Raymer) Total Drag Coefficient

Parasite Drag Buildup Wings/Canards/Winglets Miscellaneous Drag (1.02 accounts for thickness/curvature) Form Factor: Sweep correction: Interference Factor: (assumed based for mid-body, filleted wings) Miscellaneous Drag Based on historic small propeller aircraft

Total Drag Polar Prediction Induced Drag Coefficient Total Drag Coefficient

Lift Coefficient Lift Curve Slope {

Lift Coefficient 3-D Lift Curve Slope 3-D CLmax Full Aircraft Zero Degree AoA Lift Coefficient -FlatEarth.m (ref. Roskam) Taking into account: Wing/Body interaction Incidence Angles Downwash

Flight Performance - Takeoff Vtakeoff= 28 ft/s ttakeoff = 2.7 s Xtakeoff = 53 ft

Trim Diagram SM=15%

Flight Performance - Turning

Flight Performance Endurance Climb Need 489 mAh battery for 8 minute endurance Battery selected provides 640 mAh (best available match to required capacity) Climb Motor selected to provide adequate power for design climb angle with selected prop

Lateral-Directional Root Locus K = 0.95 *Negative Transfer Function

Closed-Loop Pulse Response Rudder deflected 10 deg. Rudder neutralized

Avionics JR241 Servos for Rudder/Nose Wheel Steering, Elevator, Flaperons (1 ea.) JR331 Servo for Retracts Futaba GYA350 Gyro

Constraint Equations Climb Power Loading Stall Speed

Constraint Equations Climb Power Loading Stall Speed

Constraint Equations Sustained Turning Steady Flight

Bending Results Max Allowable Root Bending Moment  31.83 lbf-ft (tensile failure) Max Allowable Compressive Moment  88.05 lbf-ft Max Bending Moment in Loiter  9.18 lbf-ft Max Bending Moment in Turning Flight 9.73 lbf-ft

Foam Panels (nonstructural) Fuselage Structure Foam Panels (nonstructural) Hollow Balsa Box Structure 3/16” sq. Balsa Stringers (4) 1/16” thick

Balsa Tristock Bracing Vertical Stabilizer 3/16” x 1/4” Balsa Fin Structure, Solid Rudder 0.97 ft 0.37 ft 0.93 ft Balsa Tristock Bracing

Balsa Leading Edge Spar Wing Structure Balsa Leading Edge Spar Balsa Subspar Balsa Wing Skin Blue Foam Core Balsa Trailing Edge 0.97 ft 0.03 ft 0.017 ft 0.10 ft Foam Wing Saddle

Bending and Torsion Results Ultimate Root Bending Moment 31.83 lbf-ft (tensile failure) Max Root Bending Moment in Turning Flight 9.73 lbf-ft Computed Factor of Safety = 3.3 Maximum twist angle = -0.2 (LE down)

Weight and Balance Origin at wing root c/4 Weight (lbs.) Arm (ft.) Moment (ft.-lbs.) Airframe 0.856 -0.12 -0.10 Propulsion 0.666 0.12 0.08 Avionics 0.256 -0.98 -0.25 Landing Gear 0.155 -0.77 Miscellaneous 0.063 -0.16 -0.01 TOTAL 1.950 -0.51 Origin at wing root c/4 Nose-up moments are positive

Break Even Point Final Aircraft Price $228.28 Profit Margin 15% MSRP of R/C Plane $262.52 Profit Per Aircraft $34.24 Units to Break Even 1,691

Materials Cost

Fabrication Plan Parallel construction process Also bench test propulsion and avionics prior to installation

Backup charts Propulsion Aerodynamics Dynamics and Controls Structures Economics and Fabrication Plan