University of Florida Wing Configuration Senior Design - Fall 2010
Airborne Research Engineering Systems
Presented by: Jason Cantrell, James Lasater, Kevin Rausch, Jason Rue 1
Previous Contracts
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Contract Requirements • • • • • •
Commercially available propulsion system Propeller driven Electric powered, 20 A limit Batteries: 0.75 lbs, NiCad or NiMH Hand launched Box size 20’’ x 15’’ x 10’’
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Missions Mission 1: Dash to Critical Target •4 minute flight with no payload •Completed ½ mile laps normalized to best overall Mission 2: Ammo Resupply •1.5 mile flight •Team determine payload size •Ammunition weight normalized to plane weight Mission 3: Medical Supply •1.5 mile flight •Team determines payload quantity •Medical supply quantity normalized by highest overall
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General Aircraft Configuration •Conventional Body •Tapered Wings •V-Tail •Single Tractor Motor •Tail Dragger Landing Gear
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Score Parameter Estimates Top Competition Estimates Parameter Aircraft Weight Mission 1: Completed Laps
Estimate 2 lb 5
Mission 2: Ammunition Weight
2 lb
Mission 3: Number of Medical Packets
18
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Aircraft Design Aerodynamics
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Initial Size Estimates
Initial Sizing Parameters Initial Size and Weight Wingspan
35 – 55 in
Aircraft Length
36 – 42 in
Tail Span
6 – 12 in
Empty Weight
2 – 4 lb
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Airfoil Selection Parameter Cmo, plane
Requirement ~ -0.05
Rationale Reduce control surface workload for longitudinal trim Minimize trim drag -0.006 to -0.009 Decrease control force requirements Cmα, plane* Increase control surface effectiveness > 1.2 Takeoff attainable without high lift devices CL, max Minimize thrust required for takeoff ≤12% The plane is kept small, so a thin airfoil is Thickness Airfoil Selection Requirements warranted > 5° High stall so that maneuvers will not result Stall in stalling *Note: This Cmα value comes from prior contract experience, looking at top ranking teams
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Airfoil Optimization • Airfoil optimization was conducted using XFLR5.
Lift, and Drag Polars for Various Airfoils
S2091-101-83 met provided criterion best
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Airfoil Batch Analysis
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Tail Configuration Optimization
• • • •
44 Combinations Lift, Drag and Moment Data Compiled Sort by Cmα V-Tail with 8”x7.5” sections and tail setback of 25.1”. 12
Tail Configuration Optimization
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Aircraft Design Stability and Controls
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Initial Configuration Optimization • Aircraft Tail Span Kept Constant While Changing Chord • Aircraft Tail Chord Kept Constant While Moving Span
Dutch Roll (Orange) and Short Period (Blue) with Constant Chord
Dutch Roll (Orange) and Short Period (Blue) with Constant Span 15
Configuration Optimization • Aircraft Tail Volume Kept Constant While Changing Distance From Wing • Final Optimization Varied Both Tail Length and Volume • Tested Parameters of 42 Different Configurations
Dutch Roll (Blue) and Short Period (Orange) with Changing Tail Length
Tail Volume (in2) 52 54 54 56
Chord (in) 5.778 6 5.4 5.6
Span (in) 9 9 10 10
Total Plane Length (in) 40.91 40.02 39.57 38.73
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Static Stability of Recommended Aircraft • Static margin of 18.2% and Neutral Point is at 0.446 of chord.
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Dynamic Stability Stability
Mode
ωn
η
ωd
ζ
t(1/2)
Short P
-9.92 13.12 8.59 0.76
Phugoid
-0.05
Roll Dutch Roll
-24.86
Spiral
0.05
-1.02
0.07
0.61 0.61 0.07 15.18 -
-
-
5.64 5.54 0.18 -
-
-
0.03 0.68 13.45
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Aircraft Design Propulsion
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Motor Configuration
Motor Configuration
0.30
Single Tractor 1
Double Tractor 0
Single Pusher 1
Double Pusher -1
0.10
1
0
1
0
0.10
1
1
-1
0
0.20
0
-1
0
1
0.20
0
1
0
1
1.00
0.50
0.10
0.30
0.10
FOM
WF
Weight Storage Options Ground Clearance Aero Efficiency Payload Feasibility Total
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Static Thrust Vs. Max Speed
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Mission Breakdown
Wing Span Weight Prop
Mission 1
Mission 2
Mission 3
50
50
50
43.07
61.9
61.9
13"x8.5"
14"x7.5"
14"x7.5"
Motor
Neu 1105/3.5Y-3000
Battery
9x Sanyo HR-4/5AUP
Static Thrust
35.1
38
38
Cruise
35
35
35
Max Speed
42
35
35
Score
0.3
0.33
0.42 22
Battery Selection
MotoCalc optimization results: •Type: NiMH •Density: 2000 mAh •Quantity: 9 cells •Weight: 0.72 lbs
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Propeller and Motor Selection MotoCalc Propeller Optimization •Diameter: 14 in. •Pitch: 7.5 in./rev •Material: Wood •Weight: 0.12 lbs
Motor Optimization •Castle Creations 1105/6D •4.4:1 Gear Ratio •200 Watts
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Aircraft Design Structures
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Critical Materials Wing Load Selection Analysis
Three-point bending analysis •Simulates highest acceleration •Required design point
Preliminary FEM Analysis •Critical loading occurs at midspan •Large stresses on stringers
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Wing Materials Component Selection Models
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WingMaterials Configuration Selection Weight 0.2
Mass
0.15
0.1
0.05
0 1 0.5 0 OD
10
5
15
0 Nstr
Weight as function of spar diameter and stringer
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Wing Materials Design Selection Space 0.18
0.2
0.16
0.18
0.14
0.16
0.12
0.14 0.12 M ass
M ass
0.1 0.08
0.1 0.08
0.06
0.06 0.04
0.04 0.02
0.02 0
0
2
4
6
8
10
12
14
Nstr
0
0
2
4
6
8
10
12
14
Nstr
Low Density Stringers
High Density
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Wing Materials Design Selection Space 0.2 0.18 0.16 0.14
Mass
0.12 0.1 0.08 0.06 0.04 0.02 0 0
2
4
6
8
10
12
14
Nstr
Average Density Stringers
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Wing Materials Optimization Selection
Optimized Wing Configuration with Safety Factors •Ten 1/8” stringers distributed linearly •1/32” sheet across half chord on upper surface •0.5” spar at midspan, 0.312” or smaller at joint
Post-Prototype Optimization •Rib quantity and spacing •Fuselage attachment points 31