Aerial Search and Supply
(ASnS)
AAE 490K Project
Bill Fredericks
Joel Gentz
Phil Wagenbach
Cynthia Fitzgerald
Ben Jamison
1
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
2
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
3
Requirements
• 5 lb Payload
• Camera, Transmitter, and Batteries
or
• Water, Food, and Medical Kit
•
•
•
•
50 yard Unassisted Takeoff (Paved Surface)
90 mph Sprint Capability
25 mph Stall Speed
1 hour Endurance
4
Constraint Analysis
Takeoff
T
1.44
W

W  * CL max * g * Dist S
Sprint
2


C


T
1
1
W
D

 
 q o 
 W S eAR  q  S 
W


Landing
W Dist *  * C L max * g * Braking

S
1.69
Stall Speed
W
1 2
 C LMax V
S
2
5
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
6
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
C L2
C Di 
 * e * AR
CD  CDo  CDi
Weight
S
CL * q
Drag C D *q * S
L Weight

D
Drag
Settled on an Aspect Ration of 7
7
8
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
9
10
Weight Estimation
WLand
e
WTakeoff
 EC
L D
Assumptions
• L/D = 10
• ELoiter = 1 (hr)
• C = .133 (1/hr)
WTakeoff  WPayload  WEmpty  WFuel
WLand
 .98 * .97 * .985 * .995
WTakeoff
WLand  WPayload  WEmpty
Loiter Takeoff Climb
WLand
WFuel
1

WTakeoff WTakeoff
WTakeoff 
WPayload
 WFuel
1 
W
 Takeoff
  WEmpty

 W
  Takeoff




Landing
WTakeoff = 21.6 (lb)
WPayload = 5.0 (lb)
WFuel = 1.5 (lb)
WEmpty = 15.1 (lb)
11
Thrust Specific Fuel Consumption
Assumptions
• cbhp = .6 lbFuel/(hp*hr)
• Honda GX35 @ 6000 RPM
• ηprop = 60%
• V = 50 mph
C
cbhp *V
550 * prop
 lbFuel 
.6 * 73.33

C
 .133
550 *.6
 lbThrusthr 
TSFC Notes:
• Typical GA  .25
• High-Bypass Jet  .4
• Low-Bypass Jet  .7
• Pure Jet  .8
Aircraft Design: A Conceptual Approach
Daniel P. Raymer
AIAA Education Series
12
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
13
Propulsion
• Modify small string trimmer engine
• 1.5 hp @ 6000 rpm Honda GX35, mini 4stroke 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/)
14
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
S
WTO
21.6lbs
2


11
.
31
ft
W / S 1.91lbs / ft 2
b  AR * S  7 ft *11.31 ft  8.89 ft
S 11.31 ft 2
c 
 1.27 ft
b
8.89 ft
15
Tail Sizing
Our computed wing geometry:
Area= 11.31 ft2
Chord length= 1.27ft
Wing Span= 8.89 ft
Possible values (pulled from Raymer) for
General Aviation single engine:
Horizontal CHT: 0.70
Vertical 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
16
Airfoil Shape
• Researched both Epler and NACA airfoils
• Compared NACA4412 and E-193…very similar
• Planning on using NACA4412 (common use,
more data)
17
Airfoil Characteristics
Alpha Swe e ps
2
1.5
1
NACA 4412 Re 6e5
NACA 4412 Re 6e5
Cl and Cm
NACA 4412 Re 3e5
NACA 4412 Re 3e5
0.5
NACA 0010 Re 4e5
NACA 0010 Re 4e5
NACA 0010 Re 2e5
NACA 0010 Re 2e5
NACA 0010 Re 2e5
0
-10
-5
0
5
10
15
20
25
-0.5
-1
Alpha (deg)
18
Airfoil Characteristics
Drag Polar
2
1.5
1
Cl
NACA 4412 Re 6e5
NACA 4412 Re 3e5
0.5
NACA 0010 Re 4e5
NACA 0010 Re 2e5
0
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0.05
-0.5
-1
Cd
19
Wing Spar Loading
180
160
140
120
100
Load (lbs/ft)
Shear (lbs)
Moment (ft*lbs)
80
60
40
20
0
0
10
20
30
40
50
60
70
80
90
100
% Half Span
Takeoff Weight 25 lbs
G Loading 3
Safety Factor 2
Design Load 150 lbs
Span 8.88 ft
Span Loading 16.89 lbs/ft
Root Shear 75 lbs
Root Moment 168.16 ft*lbs
20
Wing Spar Dimensions
Cord 1.27 ft
% Thick .12
Spar Depth 1.7 in
Wood Type Sitka Spruce
σx 5613 lbs/in2
Wing Depth .1524 ft
Wing Depth 1.8288 in
Spar cap .5 in x .8025 in
• Balsa didn’t have the strength
• Wing spar will be made of sitka spruce
21
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”
22
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
23
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
24
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)
25
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
26
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
27
Wing Attachment ideas
• Bolt through top of fuselage, set wing over bolt,
fix on top of wing
• Canvas straps
• Fuselage “hat” idea
28
Wing Attachment Diagram
29
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.
30
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.
31
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
32
Aerial Search n Supply (ASnS)
33
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
34
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
35
Questions?
36