SAE Aero Design East 2005 University of Cincinnati

Outline l l l l Basic Configuration Aerodynamics Structural Design Weights & Balance Stability

Basic Configuration l Box Wing Span limitation dictates two wings, for greater planform area

Aerodynamics: Design Refinement l TORNADO code used to analyze aerodynamics – l Based upon

Aerodynamics: Main Wing Airfoil l Application High Lift – Low Reynolds Number – l

Aerodynamics: Horizontal & Vertical Tail Airfoil Re = 300, 000 • NACA 0014 −

Aerodynamics: Wind Tunnel Testing (Main Airfoil) l l Wind-tunnel airfoil testing – Conducted @

Aerodynamics: Lift vs. Alpha & Drag Buildup Stall Lift Off Max L/D 3 D

Aerodynamics: Drag Polar & Lift-to-Drag Stall Max Climb Angle Max L/D Lift Off Max

Structural Design: Airfoil Construction l Semi-monocoque construction method – l Utilized for all airfoils

Structural Design: Fuselage l Semi-monocoque construction method l Components – Bulkheads l Carbon fiber

Structural Design: Landing Gear l l Main gear struts – Laminar composite construction l

Weights & Balance l Neutral Point – Aerodynamic Center 2. 5 inches behind CG

Stability & Controls: Moment vs. Alpha Cm as a function of AOA for three

Propulsion: Torque & Power Curves • Engine was specified: OS 0. 61 FX engine,

Propulsion: Propeller Selection • Static thrust tests were performed • Propeller performance was quantified

Propulsion: Installed Power &Thrust • Max power and thrust curves were determined via the

Performance & Optimization: Trade Study • Trade study determined viable wing chord length vs.

Conclusion l Raising – the bar Box wing design l Minimizes induced drag l

Stability & Controls: Lateral Motion Calculations (BACKUP) Sideslip Angle Roll Rate Yaw Rate Roll

Slides: 33

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SAE Aero Design® East 2005 University of Cincinnati Aero. Cats Team #039 Design Team Todd Barhorst Matthew Crummey John Louis John Vandenbemden David Chalk Matthew Goettke James Mount Steven J. Coppess Kevin Harsley Alex Sullivan

Outline l l l l Basic Configuration Aerodynamics Structural Design Weights & Balance Stability & Controls Propulsion Performance & Optimization Conclusion

Basic Configuration l Box Wing Span limitation dictates two wings, for greater planform area – Winglets draw vortices away from the wingtips, improving wing efficiency – Minimizes induced drag – Provides optimal Oswald span efficiency factor – Example values for gap/span ratio of 0. 2 l Traditional Tail – – Relatively lightweight Easy to construct

Aerodynamics: Design Refinement l TORNADO code used to analyze aerodynamics – l Based upon Vortex Lattice Theory Wing gap – Gap-to-span ratio set to 0. 6 l l Due to practical limitations Forward stagger (15 in) Fuselage accessibility – Minimal efficiency impact – l Tapered winglets Decreased weight – Decreased side area – l Improved lateral stability Negligible effect on performance Final wing efficiency: e = 2. 2

Aerodynamics: Main Wing Airfoil l Application High Lift – Low Reynolds Number – l l Re = 300, 000 Modified Eppler E 423 – Advantages Relatively small moment l Ease of construction l – Modifications De-cambered by 25% l Improved drag polar, higher L/D l l 2 D Analysis performed with XFOIL Cl. Max 1. 8 Cm -0. 187

Aerodynamics: Horizontal & Vertical Tail Airfoil Re = 300, 000 • NACA 0014 − Relatively High CL – Allows for smaller elevator – Produces minimal CD throughout operating conditions • 2 D XFoil Data • Widest of Drag Buckets Viewed

Aerodynamics: Wind Tunnel Testing (Main Airfoil) l l Wind-tunnel airfoil testing – Conducted @ UC Instrumentation – Differential Pressure Sensor Experimental vs. Published Data l - Tunnel Data Verified l Test Conditions – Re: 200, 000 – 400, 000 – AOA: -4º – 17º Flight Telemetry Package – AOA Probe – Pitot-Static Probe – RPM Sensor – Temperature Sensor

Aerodynamics: Lift vs. Alpha & Drag Buildup Stall Lift Off Max L/D 3 D Wing Total A/C Trim Max Climb Angle Total Drag 3 D Wing Horizontal Tail Lift Off Max L/D Max Climb Angle Vertical Tail Fuselage

Aerodynamics: Drag Polar & Lift-to-Drag Stall Max Climb Angle Max L/D Lift Off Max L/D Total A/C Trim 3 D Wing Max Climb Angle S t 3 D Max Lift 3 D a Wing Clim Off l Wi Lift b l Tot ng Off Angl Stall al e Total A/C Trim A/C Total A/C Trim

Structural Design: Airfoil Construction l Semi-monocoque construction method – l Utilized for all airfoils (wings, winglets, and tails) Components: – Composite-reinforced spars l Spar caps: Graphlite © carbon fiber rods – High strength-to-weight ratio – Main load-bearing members l Fiberglass shear web – Balsa wood ribs l Lightweight l Secondary members – Front portion of D-spar l Fiberglass skin – Monokote skin

Structural Design: Fuselage l Semi-monocoque construction method l Components – Bulkheads l Carbon fiber l High strength, lightweight l Provides attach points – Skin l Fiberglass l Formed on full-scale foam model l Lightweight – Stringers l Graphlite © rods l Embedded in skin

Structural Design: Landing Gear l l Main gear struts – Laminar composite construction l Stacked Graphlite © rods l Wrapped with woven carbon fiber fabric – Analysis l Stress & deflection calculations l Experimental testing Other components – – Spring steel front gear Alumimum wheels

Weights & Balance l Neutral Point – Aerodynamic Center 2. 5 inches behind CG l forward stability – Above fuselage Neutral Point l pendulum effect l Stability Verification – – 2 flight tests Pilot deemed all modes stable CG

Stability & Controls: Moment vs. Alpha Cm as a function of AOA for three centers of gravity: nominal CG ± 1 inch Cm as a function of AOA for three elevator deflections: 0º, and ± 5º

Propulsion: Torque & Power Curves • Engine was specified: OS 0. 61 FX engine, E-4010 muffler • Static torque stand tests verified engine performance

Propulsion: Propeller Selection • Static thrust tests were performed • Propeller performance was quantified in terms of maximum thrust • Previous UC performance aircraft used 14 -inch propeller • New design uses 14. 5 -inch propeller, with improved performance

Propulsion: Installed Power &Thrust • Max power and thrust curves were determined via the propulsion model

Performance & Optimization: Trade Study • Trade study determined viable wing chord length vs. total design weight • Based upon 190 ft takeoff distance limit • Minimum climb rate at takeoff 200 ft/min • Used to determine final design: • 1. 5 ft chord, 32 lbf total design weight (22 lbf payload) 210 ft/min

Performance: Ground Roll & V-N Diagram

Conclusion l Raising – the bar Box wing design l Minimizes induced drag l Optimal Oswald efficiency – Telemetry package l Wind tunnel & flight testing l Real time performance – Composite construction l Advanced materials l Great strength/weight

Questions? (group picture)

Stability & Controls: Lateral Motion Calculations (BACKUP) Sideslip Angle Roll Rate Yaw Rate Roll Angle Spiral Mode Roll Mode Dutch Roll

Performance: Payload Prediction Chart