1 / 50

Critical Design Review

Team 1. Critical Design Review. Mission. Goal: High speed flight Design Mission High speed dash (500 ft) 7 minute endurance flight Budget = $250 Carries 1 lb payload Stability Dutch Roll damping > 0.8 Take-off/landing distance < 120 ft Minimum climb angle of 35 degrees

jbueno
Download Presentation

Critical Design Review

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Team 1 Critical Design Review

  2. Mission • Goal: High speed flight • Design Mission • High speed dash (500 ft) • 7 minute endurance flight • Budget = $250 • Carries 1 lb payload • Stability • Dutch Roll damping > 0.8 • Take-off/landing distance < 120 ft • Minimum climb angle of 35 degrees • Typical descent angle of 5.5 degrees • VStall ≤ 30 ft/sec AAE 451 Team 1

  3. CLmax = 1.25 CLmax = 1.35 CLmax = 1.15 Vdash = 90 mph (132 ft/s) Vstall = 30 ft/s CD0 = 0.020 STALL CD0 = 0.024 CD0 = 0.028 (L/D)max = 12 Power loading (lbf/hp) (L/D)max = 10 CLIMB Design Point (1.2, 4.0) CRUISE (DASH) Constraint Diagram AAE 451 Team 1

  4. Preliminary Weight Estimate Graphic solution : 5 lbs AAE 451 Team 1

  5. 3-View Drawing AAE 451 Team 1

  6. AERODYNAMICS AAE 451 Team 1

  7. Wing S = 4.16 ft2 14.76 deg 1.17 ft 0.53 ft 4.90 ft Wing Geometry Maximum velocity : 118 ft/s Aircraft wetted area : 13.47 ft2 AAE 451 Team 1

  8. Tail S= 0.74 ft2 10.42 deg 0.46 ft 0.28 ft 2.01 ft Tail Geometry Maximum velocity : 118 ft/s Aircraft wetted area : 13.47 ft2 AAE 451 Team 1

  9. Mathematical Model Lift Coefficient 3D: (From the Roskam book) AAE 451 Team 1

  10. Elevator Effect on CL (From Flight Stability and Automatic Control, Robert C. Nelson) AAE 451 Team 1

  11. Mathematical Model Drag Coefficient 3D: AAE 451 Team 1

  12. CL vs Alpha and Drag Polar AAE 451 Team 1

  13. High speed dash Minimum drag Respect stall speed condition Maximum lift Flaps Flaps Needed CLMax Needed w/o Flaps CLMax from Lift Curve 0.825 w/ Flaps 10 deg AAE 451 Team 1

  14. Mathematical Model Moment Coefficient 3D: (From the Roskam book) AAE 451 Team 1

  15. Moment Coefficient AAE 451 Team 1

  16. PROPULSION AAE 451 Team 1

  17. Propeller Selection • CP, CT, h found from gold.m • Default inputs used due to empirical correction factor based on past experience • 11 inch propeller selected to keep propeller speed below 10,000 RPM • 11x10 and 11x11 both give similar high speed efficiency Power required increased by 1/0.75=33.3% per guidance from gold.m file. AAE 451 Team 1

  18. selected system Battery Selection • Procedure: • Tabulate total system cost and weight • Different batteries • Different power outputs • Goals • Maximize Power Output • Minimize Cost • Self-imposed limit: $50 • Ensure motor can be purchased for < $100 (also self-imposed) • Based on supplied voltage and current Max Power Output = 0.7 hp AAE 451 Team 1

  19. Propulsion System Max Speed (battery current limited) 118 ft/s ~ 80 mph • Propeller • APC (LP11011) 11x11 - 60 Pattern Propeller ($7.95) • Gearbox & Mounting Hardware • MP Jet (MP8104) 4.1:1 Gearbox for 480 Size ($19.90) • MP Jet (MJ8030) Short Prop Adapter for APC Props ($4.60) • MP Jet (MJ7250) 2" Black Lightweight Spinner ($3.20) • Motor • MEGA ACn 16/25/3 ($84.00) • Speed Controller • Castle Creations Phoenix-60 ($118.99) • Batteries (in series) • 2 x Apogee 3-Cell 11.1 V 1200mAh 20C LiPo (2 x $25.00) • Total Propulsion Chargeable Cost = $169.65 (neglects speed controller) AAE 451 Team 1

  20. Dash System Performance h=98% h=90% 502 W 0.67 hp 513 W 0.69 hp h=94% h=65% 278 W 0.37 hp 1.74 lbf 426 W 0.57 hp 454 W 0.61 hp Propeller power required increased by 1/0.75=33.3% per guidance from gold.m file. AAE 451 Team 1

  21. Motor/Battery Loiter Performance • Loiter (Main_System_Design - Modified) • Estimated Loiter Time: 21.0 mins (3X requirement) • Motor Voltage input: 9.63 V • Motor Current input: 7.89 A • Motor RPM: 16,100 RPM • Motor h: 74.9% Stall Preq > Pavail Loiter mission is steady turn at a 200 ft radius, 40 ft/s. Aircraft Constants: CD0 = 0.025 e = 0.79 AR = 5.76 W = 5 lb S = 4.16 ft2 (40,0.03) AAE 451 Team 1

  22. Motor/Battery Dash Performance • Dash (Main_System_Design - Modified) • Motor Voltage input: 20.9 V • Motor Current input: 24.0 A* (Motor Max Continuous 30 A) • Motor RPM: 34,900 RPM (Motor Maximum 55,000 RPM) • Motor h: 90.3% • Mtip,prop = 0.38 Vmax : 118.4 ft/s Gear Ratio : 4.015 Actual Gear Ratio: 4.1 Actual Vmax : 117.7 ft/s Projected Time at Max Power: 3.1 min * Max battery continuous output 24 A Stall Preq > Pavail (118,0.37) AAE 451 Team 1

  23. Cannot use 100% throttle except at high speed Reaches takeoff speed in much less than 120 ft Takeoff AAE 451 Team 1

  24. STRUCTURES AAE 451 Team 1

  25. 14.76 deg 1.17ft 0.53 ft 2.45ft balsa Easy to build Good surface quality Expanded polystyrene Wing Structure • Aerodynamics gives the geometry • Load case: Resist to 10g (47 ft radius at 80 mph) • Materials MH 43 Swing = 4.16 ft2 Thickness:8.5% Wing should support 50 lb With a weight of 5 lb AAE 451 Team 1

  26. Quarter chord 1 2 3 4 MAC: application of the lift b a Analysis Method Discretization of the wing Determination of the loads • For each part, we can figure out: • The bending moment due to the lift • The torque due to the aerodynamic moment Assumptions: • Only bending loading • Foam doesn’t carry the load • Elliptical airfoil shape • Only aerodynamic twist Calculations: Balsa will resist most of the load t is figured out from IG AAE 451 Team 1

  27. y’ y Lift at MAC Calculation (cont.) Bending Moment: L1 L2 M=L1.d1 + L2.d2 + ….. d1 MAC d2 Twist: Deflection: y’ with Thales theorem Ebalsa = 185.6 psi AAE 451 Team 1

  28. Results for Wing Bending Results: Easy to built, but 70% heavier than discretized thickness Min. thickness .053 in Optimal thickness distribution Twist Results: Max. Twist = -.3 deg Deflection Results: Max. Deflection = .11 in AAE 451 Team 1

  29. 0.46 ft 0.28 ft 2.01 ft Horizontal Tail Structure • Geometry S=0.74 ft2 NACA 0006, 6% thickness ratio High speed dash + 20° of deflection Same method as the wing Results: Min. thickness: 1.38e-2 in Very thin, impossible to find in the market so we will use 1/32 in Total deflection: 4.4e-1 in AAE 451 Team 1

  30. 0.65 ft 0.32 ft 0.63 ft Final tail structure layout • Horizontal tail: Foam core + 1/32 in balsa sheet (similar to the wing) • Vertical tail: The final geometry: We plan to make it in a full sheet of balsa sanded. High speed dash + 20° of deflection Same method as the wing Min. thickness: 8.09e-4 in AAE 451 Team 1

  31. 15 deg 12 deg Landing Gear • Roskam method for landing gear sizing: 1. Landing gear system: fixed 2. Landing gear configuration: taildragger 3. Locate c.g.: 1.232 ft from the nose 4. Longitudinal tip over analysis 5. Lateral tip over analysis Ψ≤ 55 deg Main gear Tail gear AAE 451 Team 1

  32. Hayes Racing Wheels: • Glassfilled Nylon • Lightweight • Width: .177’’ • Diameter: 2.25” OD Landing Gear 6. Ground clearance criteria 7. Landing gear material: 8. Number of wheels: 2 for main gear 1 for tail gear > 5 deg • Aluminum for main gear • Piano wire for tail gear AAE 451 Team 1

  33. Wing-Fuselage Attachment Wing top view Fuselage Rib Lmax/4 Nylon bolts Carbon rod AAE 451 Team 1

  34. Lmax/4 Front view Lmax/4 Carbon rod t Top view Wing-Fuselage Attachment Nylon bolts: D = .2362 in Length = 1.969 in Calculations: Carbon rod: D= .2362 in t = thickness of rib = .2362 in Calculations: • Cross-sectional area • Maximum force it will carry: F = n*W/4 • Maximum stress: σ = F/A = 285.2 psi • Ultimate Tensile Strength for nylon = 10150 psi • Margin=σmax/ σ-1 Margin = 34 • σ = F/(D*t) = 224.0 psi • Ultimate Compressive Strength of balsa = 725.2 psi Margin = 2.2 AAE 451 Team 1

  35. Component Layout Servos Payload Battery (2) Receiver Speed Controller Motor and Gearbox AAE 451 Team 1

  36. CG Location CG: 1.3 ft from nose CATIA Component Weight: 3.72 lbs Initial Sizing Historical Estimate: 5 lbs Leftover Weight for glue, ribs, fasteners: 1.28 lbs AAE 451 Team 1

  37. DYNAMICS & CONTROL AAE 451 Team 1

  38. Longitudinal Stability – Horizontal Tail Sizing Tail Sized using Class I Method (X-Plot) • Initial Tail Size: • Size @15% Static margin - XPlot • Size @15% Static margin / Aircraft ~18% SM on XPlot AAE 451 Team 1

  39. Longitudinal Stability – Trim Diagram AAE 451 Team 1

  40. Lateral Stability – Directional Control Vertical Tail Sized using Class I Method (X-Plot) • Minimum Vertical Tail Area: • Actual Vertical Tail Area: Change of Yawing Moment with sideslip angle versus Vertical Tail area AAE 451 Team 1

  41. Longitudinal Stability – Elevator Sizing Elevator sized using Historical Data Our Tail volume ratio is: With Surface Ratio of: Current Elevator Area Elevator sized with historical data and Control Power AAE 451 Team 1

  42. Lateral Stability – Directional Control • Rudder Sizing Wing Area Vertical Tail Area Rudder Area found by average & Control Power Analysis Rudder Area AAE 451 Team 1

  43. Lateral Stability – Roll Control • Aileron Sizing Used historical data and Roll moment coefficient analysis Aileron Chord: Aileron Inboard Position Aileron Outboard Position AAE 451 Team 1

  44. Modes of Motion Longitudinal Motion Short Period Phugoid Mode (Long Period) AAE 451 Team 1

  45. Modes of Motion Lateral – Directional Motion Dutch Roll Roll Mode Spiral Mode AAE 451 Team 1

  46. Control System Root Locus General Block Diagram Yaw rate to rudder deflection Rudder Servo Pilot Command Rudder + - Gain -0.497 Rate Gyro AAE 451 Team 1

  47. Compensated System Root Locus of Yaw rate to rudder deflection output Uncompensated Damping Ratio Required Dutch Roll Damping Required Gain to achieve Dutch Roll Damping Natural Frequency at required Dutch Roll Damping AAE 451 Team 1

  48. CONCLUSION AAE 451 Team 1

  49. Remaining Design Problems • Servos • Control surface size is known • Margin of Safety • Throttle limit • Need to physically test motor, gearbox, and propeller to determine current draw • Rudder/Tailwheel attachment AAE 451 Team 1

  50. Final Design • Max Speed: 118 ft/s • Max Endurance: 21 min AAE 451 Team 1

More Related