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Aerial Search and Supply(ASnS)

AAE 490K Project

Bill FredericksJoel GentzPhil WagenbachCynthia FitzgeraldBen Jamison

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Overview• Mission Concept

• Requirements• Constraint Analysis

• Parasitic Drag Estimation• Aspect Ratio

• Sizing• Weight Estimation• Propulsion• Wing and Tail Geometries

• Structural Design• Wing Spar Loading• Fuselage Tests

• Hardware and Electronics• Fuselage Design

• Wing Attachment Method• Basic Construction Method

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Mission Concept• Take off from a small field• Autonomously search disaster area for victims with

onboard autopilot/GPS using camera payload• Upon finding victim mark waypoint• Aircraft sprints back to field and lands• Camera payload is changed out for med kit and

supplies to be dropped on victim• Aircraft takes off and sprints back to victim and drops

payload• Returns and lands• Cost must be within the capability of city fire

departments

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Requirements• 5 lb Payload

• Camera, Transmitter, and Batteriesor

• Water, Food, and Medical Kit

• 50 yard Unassisted Takeoff (Paved Surface)• 90 mph Sprint Capability• 25 mph Stall Speed• 1 hour Endurance

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Constraint Analysis

S

W

DistgCW

T

L ***

44.1

max

69.1

**** max BrakinggCDist

S

W L

S

W

qeARSW

Cq

W

ToD

211

2

2

1VC

S

WMaxL

Takeoff

Sprint Stall Speed

Landing

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Parasitic Drag Estimation• Typical single engine GA airplane (From Raymer)

• CDo = .022• CDwet = .0055• Only Skin Friction Drag (Re = 200,000 Turbulent)

• CDwet = .003 CDo = .0124

• Lower wetted / wing area ratio of our aircraft leads to less drag• CDo = .0207

• Used CDo = .024 in constraint analysis to be more conservative

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Aspect Ratio Choice• CDo = .03

• This is even more conservative than the constraint analysis to be sure we hit L/D of 10

• Oswald’s Factor = .7• Weight = 1

ARe

CC L

Di **

2

DiDoD CCC

qC

WeightS

L *

SqCDrag D **

Drag

Weight

D

L

Settled on an Aspect Ration of 7

8

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Constrain Analysis Inputs• rho = .002377 (slug/ft3)• CLmax = 1.2• g = 32.2 (ft/s2)• Takeoff and Landing Distance = 150 (ft)• Braking Force Fraction = .3 (lbf/lbf)• Stall Speed = 25 (mph)• Oswald’s Factor = .7• AR = 7• Sprint Speed = 90 (mph)• CDo = .024

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Weight Estimation

DL

EC

Takeoff

Land eW

W

FuelEmptyPayloadTakeoff WWWW

EmptyPayloadLand WWW

Takeoff

Fuel

Takeoff

Land

W

W

W

W1

Takeoff

Empty

Takeoff

Fuel

PayloadTakeoff

W

W

WW

WW

1

Assumptions• L/D = 10

• ELoiter = 1 (hr)

• C = .133 (1/hr)

WTakeoff = 21.6 (lb)

WPayload = 5.0 (lb)

WFuel = 1.5 (lb)

WEmpty = 15.1 (lb)

995.*985.*97.*98.Takeoff

Land

W

W

Loiter Takeoff Climb Landing

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Thrust Specific Fuel Consumption

Assumptions

• cbhp = .6 lbFuel/(hp*hr)

• Honda GX35 @ 6000 RPM

• ηprop = 60%

• V = 50 mph

prop

bhp VcC

*550

*

hrlb

lbC

Thrust

Fuel133.6.*550

33.73*6.

TSFC Notes:• Typical GA .25• High-Bypass Jet .4• Low-Bypass Jet .7• Pure Jet .8

Aircraft Design: A Conceptual ApproachDaniel P. RaymerAIAA Education Series

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Design Point• Wing Loading = 1.91 lb/ft2 (30.56 oz/ft2)

• Wing Area = 11.31 ft2

• Thrust to Weight = .28• Thrust = 6.05 lb• Speed = 90 mph• Power = 1.45 hp

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Propulsion

• Modify small string trimmer engine• 1.5 hp @ 6000 rpm Honda GX35, mini 4-

stroke engine• (http://www.honda-engines.com/gx35.htm)

• Most efficient and light engine (5.75 lbs before conversion)

• Carr Precision, Oregon• $530 for a converted engine • (http://www.carrprecision.com/)

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Wing Sizing• Based on the wing loading calculated in

constraint analysis (1.91 lbs/ft^2)

• Aspect ratio from ideal L/D vs. CL plot

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31.11/91.1

6.21

/ft

ftlbs

lbs

SW

WS TO

ftftftSARb 89.831.11*7*

ftft

ft

b

Sc 27.1

89.8

31.11 2

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Tail Sizing

Our computed wing geometry:Area= 11.31 ft2

Chord length= 1.27ftWing Span= 8.89 ft

Possible values (pulled from Raymer) for General Aviation single engine:Horizontal CHT: 0.70Vertical CVT: 0.04

Equations:SVT= CVT*bw *Sw /LVT

SHT = CHT*Cw *Sw /LHT

Computed Tail Areas:SVT= (0.04)*(8.8ft)*(11.31ft2) / (3.5ft) = 1.13746 ft2

SHT =( 0.70)*(1.27ft)*(11.31ft2) / (3.5ft) = 2.87274 ft2

*Using 42in. (3.5ft) for LVT and LHT

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Airfoil Shape• Researched both Epler and NACA airfoils

• Compared NACA4412 and E-193…very similar

• Planning on using NACA4412 (common use, more data)

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Airfoil CharacteristicsAlpha Sweeps

-1

-0.5

0

0.5

1

1.5

2

-10 -5 0 5 10 15 20 25

Alpha (deg)

Cl a

nd

Cm

NACA 4412 Re 6e5

NACA 4412 Re 6e5

NACA 4412 Re 3e5

NACA 4412 Re 3e5

NACA 0010 Re 4e5

NACA 0010 Re 4e5

NACA 0010 Re 2e5

NACA 0010 Re 2e5

NACA 0010 Re 2e5

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Airfoil CharacteristicsDrag Polar

-1

-0.5

0

0.5

1

1.5

2

0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05

Cd

Cl

NACA 4412 Re 6e5

NACA 4412 Re 3e5

NACA 0010 Re 4e5

NACA 0010 Re 2e5

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Wing Spar Loading

0

20

40

60

80

100

120

140

160

180

0 10 20 30 40 50 60 70 80 90 100

% Half Span

Load (lbs/ft)

Shear (lbs)

Moment (ft*lbs)

Takeoff Weight 25 lbs Span 8.88 ft

G Loading 3 Span Loading 16.89 lbs/ft

Safety Factor 2 Root Shear 75 lbs

Design Load 150 lbs Root Moment 168.16 ft*lbs

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Wing Spar Dimensions

• Balsa didn’t have the strength

• Wing spar will be made of sitka spruce

Cord 1.27 ft Spar Depth 1.7 in

% Thick .12 Wood Type Sitka Spruce

Wing Depth .1524 ft σx 5613 lbs/in2

Wing Depth 1.8288 in Spar cap .5 in x .8025 in

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Wing Shopping List• Ribs Need 41

• (8.88’ / 3” = 35.2 ribs)• Plus one for the end• Plus 2 for dihedral• Plus 2 for extra root attachment• 4 will be 1/8” plywood at root attachment

• Should be extra cross section plywood• 13 1/8” x 2” x 48”

• Spar need 2 1” x ½” x 5’ (Spruce)• Spar need 2 1” x ½” x 5’ (Balsa)• Rear Spar 4 1/8” x 2” x 3’• Leading Edge Spar

• 1/8” x 1/8” Use extra from rear spar• Leading edge wrap• Block for fuselage attachment

• 1” x 2” x 12”

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Fuselage Construction Test

•Decided on just Balsa for simplicity and weight.

•Considered two ideas

•Stick frame ribs with skin stringers

•Solid Ply ribs with stick stringers

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Fuselage Construction Test• Stick frame cross

sections with solid skin was far superior

• Weight <.2lbs for 5”x5”x12” section

• Held > 130 lbs.

• Was stood on top of by team member and only crushed top surface

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Fuselage Shopping List• Firewall – 6’’ x 6’’ x ¼’’ Ply (1)

• Front Ribs – 6’’ x 6’’ 1/8’’ Ply (13)

• Back Ribs – 6’’ x ¾’’ x 1/8’’ Balsa Sticks (14)

• Skin Sides – 3’’ x 6’’ x 1/16’’ Balsa Sheet (Enough for two wide on four sides)

• Skin Angles – 1’’ x 6’’ x 1/8’’ Balsa Sheet (Enough for 1’’ on each bottom corner for entire length)

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Previous 490 Materials• Prof Sullivan said he could help us with nearly

everything

• List compiled so far:• 6 Channel Radio transmitter/controller and receiver• Servos (types: elbow vs cross etc)• Servo arms• Control Surface fixtures

• In contact with Prof Andrisani: Cannot use the “loft” or the Lockers. Need to contact Madeline

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Controls Update- Meet at ASL with Matt and Ben to take inventory- Will be using JR XP6102 Controller/receiver

combination (6 channel) - Matt still locating servo’s/control arms; plenty of

elbows- Need to order

- Servos, pivot arms, hinges

- Pico Pilot/Micro Pilot – available to use AFTER successful flight without – can use to work basic understanding of software

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Wing Attachment ideas• Bolt through top of fuselage, set wing over bolt,

fix on top of wing

• Canvas straps

• Fuselage “hat” idea

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Wing Attachment Diagram

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Final Fuselage Design

• The Fuselage will use a combination of both tested designs.

• The fire wall will be 6”x6”x1/4” Birch Plywood

• From the firewall to the T.E. of the wing will be 6”x6”x1/8” Birch Ply cross sections with 3”x1/16” Balsa skin on the sides and 1”x1/8” Balsa skin on the corners.

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Fuselage

• From the T.E of the wing to the tail will be 3/4”x3/16” stick frame ribs with 3”x1/16” Balsa skin on the sides and 1”x1/8” Balsa skin on the corners, scaling down from a 6”x6” cross section to 3”x3” cross section at the tail.

• The entire Fuselage will be flat on top for ease of connecting the Wing and the Tail sections.

• Ribs will be placed every 3’’ throughout the Fuselage, except where the wing will connect to the body where there will be more.

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Final Design• The Fuselage will be 64” long.

• From the fire wall aft • With 24” of constant cross section from the fire wall

aft.

• All of the electronics (Micro pilot, receiver, battery and servos) will be located under the wing.

• The fuel tank and throttle servo will be in front of the wing

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Aerial Search n Supply (ASnS)

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Basic Fuselage Construction Steps• The first two steps in construction will be to mount the

engine mount to the firewall and cut the appropriate cross sections around the fuel tank

• Next, machine the plywood cross sections and make an adjustable jig for the stick frame cross sections

• Lay all cross sections in a foam jig and glue bottom side, ensures the top will be flat and we will be able to see the taper before we glue

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Basic Wing Construction Steps• Cut wing spars to proper dimensions• Create template for ribs• Machine ribs on computerized router• Using foam jig assemble ribs and spars• Build brackets for

• Servos• Wing Bolts• Control Surface hinges

• Cover front of wings with balsa skin

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Questions?