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Design Group 2

Kat Donovan - Team LeaderAndrew DeBerry

Mike KinderJohn Mack

Jeff NewcampAndrew Prisbell

Nick Schumacher

Conceptual Designfor AME 441Spring 2004

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Group 2 – Ducted Design

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OverviewAircraft Configuration & Design DriversComparison AircraftCAD ModelsSpreadsheet Decisions

♣ Airfoil Choice♣ Engine Selection♣ Weight & Drag Estimates♣ Static Stability

Conclusions & Lessons LearnedDesign & Build Schedule

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Aircraft Configuration (Requirements)Powered by electric motorCarry specified payloadTake-off in < 300 feet on grassPlanform area between 400 in2 & 800 in2

Radio control system with up to 7 channels

Design DriversMaximize the climb rate

Maximize the level flight speed

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Comparison Aircraft

* Information from http://www.aerospaceweb.org/aircraft/bomber/yb49/† Information from http://www.aerospaceweb.org/aircraft/bomber/b2/‡ Information from Design and Construction of a Remote Piloted Flying Wing, May 2, 1994

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CAD Models

Electronics Box Battery Pack (x2) Circuit Card

Servo GPS Receiver Modem

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CAD Models - Dimensions

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NACA 6412♣ Low Reynolds

Number airfoil♣ t/c ratio large

enough to house internal electronics

Airfoil Choice

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Sample Lift Estimation

http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html

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Engine Selection: Astro Cobalt 15Model No. p/n 615G

Name 05 Geared

Gear Ratio 2.38 to 1

Armature Winding 7 turns

Armature Resistance 0.069 ohms

Magnet Type Sm Cobalt

Bearings Ball Bearings

Motor Speed 1488 rpm/volt

Geared Motor Speed 652 rpm/volt

Motor Torque/amp 0.91 in-oz /amp

Geared Torque 2.17 in-oz /amp

Voltage Range 8 to 12 volts

No Load Currrent 2 amps

Maximum Continuous Current 25 amps

Maximum Continuous Power 400 watts

Gear Motor Length 3.3 inches

Motor Diameter 1.3 inches

Motor Shaft Diameter 5/32 inch

Prop Shaft Diameter 1/4 inch

Gear Motor Weight 9 ozData from www.astroflight.com

Electric, brushless motorRuns off 16-cell

rechargeable battery pack

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Power EstimateVelocity vs. Power

0

50

100

150

200

250

0 50 100 150 200

Velocity (ft/s)

Pow

er (h

p)

Full Throttle

90% Throttle

80% Throttle

70% Throttle

Power Required

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Thrust Estimates

Climb Rate vs. Thrust to Weight Ratio

0.3

0.4

0.5

0.6

0.7

250 300 350 400 450 500

Rate of Climb (ft/min)

Thru

st to

Wei

ght R

atio

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Thrust, Drag, Estimates

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Weight & Drag Estimates

Weight Distribution of Aircraft Components

0.00.51.01.52.02.53.0

Wing

Vertica

l Tail

Fusela

ge

Land

ing G

ear

Ins. E

ng.Othe

r

Component

Wei

ght (

lbs)

Structure 3.84

Landing Gear 0.6

Engine (Cobalt 15) 0.56

Propeller 0.06

Servo (x4) 0.32

Receiver & Battery 0.25

GPS & Transmitter 0.5

Electronics Box 1.5

Speed Controller 0.08

Main Battery 0.65

Total: 8.36

Aircraft Weights (lbs)

Component Drag (lbs)Wing 0.642Fuselage (duct) 0.075Winglets 0.010

Total: 0.728

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Static Stability

Load Summary (fuselage)Load Type Magnitude x/L_start x/L_end resultant M @C_lift dw

(lbs) x/L f-lb (+ cw)Fuel 0.00 0.00 0.00 0 0.0000000 0.00Payload 2.65 0.00 0.50 0.25 -0.5605769 0.24Fus.Struct. 0.77 0.30 0.95 0.625 0.1255045 0.05Engine(s) 0.62 0.60 0.78 0.69 0.1422173 0.14Wing Struct. 2.84 0.00 1.00 0.5 0.1092308 0.14Horiz. Tail 0.00 0.00 1.00 0.5 0.0000000 0.00Vert. Tail 0.10 0.66 1.00 0.83 0.0368462 0.01Other 0.98 0.00 0.50 0.25 -0.2077747 0.09

S L 7.96 S M -0.3545528

Static Margin 0.045891 stableC_M_a -0.824338 stableC_n_b 0.01287 stableC_L_b -0.01287 stable

Fuselage Length    

L (f) 2  

     

Wing Center of Lift    

L_ctr (x/L) 0.461538 8.307692

m.a.c. (ft) 0.97 2.910884

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Conclusions & Lessons Learned

Flying wing to maximize rate of climb and level cruise speed

Ducted fan to increase propeller efficiencyWinglets to reduce dragTricycle landing wheels to prevent damage

during landingAt least 24” separation of modem and GPS

to limit interference

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Design & Build Schedule

26 February: Present Detailed Design

4 March: Complete Parts List

16 March: Fabrication

6-9 April: Ground Tests

13-22 April: Flight Tests

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Group 2: Nick SchumacherAndrew DeBerryAndrew PrisbellJeff NewcampKat DonovanMike KinderJohn Mack

Questions?