SAE Aero Design ® East 2005 University of Cincinnati AeroCats Team #039 SAE Aero Design ® East 2005 University of Cincinnati AeroCats Team #039 Design

SAE Aero DesignSAE Aero Design

®® East 2005 East 2005

University of Cincinnati AeroCatsUniversity of Cincinnati AeroCats

Team #039Team #039

Design Team

Todd Barhorst David Chalk Steven J. CoppessMatthew Crummey Matthew Goettke Kevin HarsleyJohn Louis James Mount Alex SullivanJohn Vandenbemden

OutlineOutline

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

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

Traditional Tail– Relatively lightweight– Easy to construct

Basic ConfigurationBasic Configuration

Example values forgap/span ratio of 0.2

Aerodynamics:Aerodynamics:Design RefinementDesign Refinement

TORNADO code used to analyze aerodynamics– Based upon Vortex Lattice Theory

Wing gap– Gap-to-span ratio set to 0.6

Due to practical limitations

Forward stagger (15 in)– Fuselage accessibility– Minimal efficiency impact

Tapered winglets– Decreased weight– Decreased side area

Improved lateral stability

– Negligible effect on performance Final wing efficiency: e = 2.2

Application– High Lift– Low Reynolds Number

Re = 300,000

Modified Eppler E423– Advantages

Relatively small moment Ease of construction

– Modifications De-cambered by 25% Improved drag polar, higher L/D

2D Analysis performed with XFOIL

ClMax 1.8

Cm -0.187

Aerodynamics:Aerodynamics:Main Wing AirfoilMain Wing Airfoil

• NACA 0014

− Relatively High CL

– Allows for smaller elevator

– Produces minimal CD throughout operating conditions

Re = 300,000

• 2D XFoil Data

• Widest of Drag Buckets Viewed

Aerodynamics:Aerodynamics:Horizontal & Vertical Tail AirfoilHorizontal & Vertical Tail Airfoil

Wind-tunnel airfoil testing– Conducted @ UC

Instrumentation– Differential Pressure

Sensor

Aerodynamics:Aerodynamics: Wind Tunnel Testing (Main Airfoil) Wind Tunnel Testing (Main Airfoil)

Test Conditions– Re: 200,000 – 400,000– AOA: -4º – 17º

Flight Telemetry Package– AOA Probe– Pitot-Static Probe– RPM Sensor– Temperature Sensor

Experimental vs. Published Data

- Tunnel Data Verified

Stall

Aerodynamics:Aerodynamics:Lift vs. Alpha & Drag BuildupLift vs. Alpha & Drag Buildup

Total Drag

3D Wing

FuselageHorizontal Tail Vertical Tail

Max L/D

Max Climb Angle

Lift Off

Stall

Total A/CTotal A/C Trim

3D Wing

Max L/DMax

Climb Angl

e

Lift Off

Stall

Aerodynamics:Aerodynamics:Drag Polar & Lift-to-DragDrag Polar & Lift-to-Drag

Total A/C

Total A/C Trim

3D Wing

Max Climb Angle

Lift Off

Stall

Total A/CTotal A/C Trim

3D Wing

Max L/D Max Climb Angle

Lift Off Stall

Total A/C

Total A/C Trim

3D Wing

Max L/D

Max Climb Angle Lift Off

Stall

Structural Design: Structural Design: Airfoil ConstructionAirfoil Construction

Semi-monocoque construction method– Utilized for all airfoils (wings, winglets, and tails)

Components:– Composite-reinforced spars

Spar caps: Graphlite © carbon fiber rods– High strength-to-weight ratio– Main load-bearing members

Fiberglass shear web– Balsa wood ribs

Lightweight Secondary members

– Front portion of D-spar Fiberglass skin

– Monokote skin








– Monokote skin








– Monokote skin








– Monokote skin








– Monokote skin








– Monokote skin

Structural Design: Structural Design: FuselageFuselage

Semi-monocoque construction method

Components– Bulkheads

Carbon fiber High strength, lightweight Provides attach points

– Skin Fiberglass Formed on full-scale foam model Lightweight

– Stringers Graphlite © rods Embedded in skin



















Structural Design: Structural Design: Landing GearLanding Gear

Main gear struts

– Laminar composite construction Stacked Graphlite © rods Wrapped with woven carbon

fiber fabric

– Analysis Stress & deflection calculations Experimental testing

Other components– Spring steel front gear– Alumimum wheels

Main gear struts


fiber fabric





Main gear struts


fiber fabric



Weights & BalanceWeights & Balance

CG

Aerodynamic Center

Neutral Point– 2.5 inches behind CG

forward stability– Above fuselage

pendulum effect

Stability Verification– 2 flight tests– Pilot deemed all modes

stable

Neutral Point

Stability & Controls:Stability & Controls:Moment vs. AlphaMoment vs. Alpha

Cm as a function of AOA for three

elevator deflections: 0º, and ± 5ºCm as a function of AOA for three

centers of gravity: nominal CG ± 1 inch

Propulsion:Propulsion:Torque & Power CurvesTorque & Power Curves

• Engine was specified: OS 0.61 FX engine, E-4010 muffler

• Static torque stand tests verified engine performance

Propulsion:Propulsion:Propeller SelectionPropeller 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:Propulsion:Installed Power &ThrustInstalled Power &Thrust

• Max power and thrust curves were determined via the propulsion model

Performance & Optimization: Performance & Optimization: Trade StudyTrade 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:Performance:Ground Roll & V-N DiagramGround Roll & V-N Diagram

ConclusionConclusion

Raising the bar– Box wing design

Minimizes induced dragOptimal Oswald efficiency

– Telemetry packageWind tunnel & flight testingReal time performance

– Composite constructionAdvanced materialsGreat strength/weight

(group picture)

Questions?Questions?

Stability & Controls:Stability & Controls:Lateral Motion Calculations (BACKUP) Lateral Motion Calculations (BACKUP)

A Lateral

Yu o

L

N

0

Yp

u o

L p

N p

1

1Yr

u o

L r

N r

0

g

u o

cos o

0

0

0

Sideslip Angle

Roll Rate

Yaw Rate

Roll Angle

p

r

Dutch Roll

Spiral Mode

Roll Mode

Performance:Performance:Payload Prediction Chart Payload Prediction Chart

Payload Weight vs. Density Altitude

16

18

20

22

24

0 1000 2000 3000 4000 5000

Density Altitude (ft)

WP

aylo

ad (

lbs)

WMax = 22.568 - (0.0011 x Density Altitude)

Documents

SAE Aero Design ® East 2005 University of Cincinnati AeroCats Team #039 SAE Aero Design ® East 2005 University of Cincinnati AeroCats Team #039 Design