Detailed Design Review

Airframe AP09231

MSD I Winter 20082

Matt Greco: Project Manager Shawn O’Neil: Lead Engineer Will Pisarello: Electrical Systems Engineer Phil Davenport: Industrial/Process Engineer Brian Lindquist: Industrial

Engineer/Procurement Specialist Eric Lannan: Airframe Structural engineer

Team Development

• Manufacturing• Procurement• Assembly

Processes

Balsa Airframe

• Stiffening of wood airframe

Composite Reinforcement

• A-D Converter• Onboard

Memory Storage

Payload Interface

Systems Integration

Chord = 8” Span = 5’ Aspect Ratio = 7.5 AOA = 8º Camber = 8.6% Thickness = 10.125% Lift = 10 lbf

Main Airfoil Data

9.1

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252

1 2

l

l

l

c

Mfc

spanchordS

mphu

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Chord = 6.2” Span = 25.375” Aspect Ratio = 4.093 AOA = 8º Camber = 0% Thickness = 12% Lift = 1.7 lbf

Tail Airfoil Data

Getting parts into ANSYS

1. Airframe saved as .STP file in TurboCAD2. File of the entire airframe assembly is

imported into Pro/E3. Sub-assemblies are saved as .IGS files4. In ANSYS an .IGS file is imported

Free Body Diagram of Wing

5lb 5lb

10lby

x

Balsa Material Properties

•Young’s modulus 1130 – 6000 Mpa

•Shear modulus 100 - 500 MPa

•Tensile strength 0 - 75 MPa

•Compressive strength 3.5 - 27 Mpa

Material properties from Matbase.com.http://www.matbase.com/material/wood/class4-5-10-years/balsa/properties

Observation Evaluation Recommendation

Laser cut parts were processed to tighter tolerances than anticipated

All placement notches on jigs were modified via manual sanding

Redesign jigs to accommodate larger placement notches

Cyanoacrylate (CA) adhesive was more effective in balsa joints than ply joints

Absorption and cure times increase for plywood applications

Research alternative adhesive or ply material

Manufacturing Process Discoveries

Manufacturing Process Discoveries (cont)

Observation Evaluation Recommendation

Similar laser cut parts are not easily distinguishable

Limited etching prevented inexperienced builder identifying parts

Assign part number under each sub-assembly in BOM and laser etch each raw piece

Alignment of dihedral braces is very difficult

The braces are inherently angled, making for difficult alignment

Etch alignment lines on each brace for quick visual alignment with wing box

Manufacturing Process Discoveries (cont)

Observation Evaluation Recommendation

Formers along fuselage require exact alignment prior to application of stringers

Formers must be positioned in 3D space, leading to error in first plane

Design a jig for ease of former placement

Battery hatch did not assemble as designed

Clearance for hatch decreased during assembly of stringers

Place block to maintain battery compartment shape during stringer assembly

Batteries-Lithium Polymer chosen for high energy density-Modular System-Single pack, ~10min Flight time

0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00$0.00

$50.00

$100.00

$150.00

$200.00

$250.00

$300.00

$350.00

$400.00

$450.00

Battery Price vs. Flight Time

LiPo2x LiPoNiMH

Flight Time @50W/lb (Minutes)Pr

ice (U

S Do

llars

)

Power Distribution-COTS Switching regulator converts

Battery / Motor voltage to 5v- 12.5W minimum available from the

BEC for additional onboard electronics

TelemetryReal Time

- Altitude / Airspeed-Temperature - Servo Voltage/Position Data- GPS

Two additional onboard ADCs for future sensor testing.

Control SwitchingEnables onboard control switching between two pilots or a single pilot and an autonomous system

Uses:- Autonomous system testing with pilot backup- Control ‘hand off’ between pilots a significant distance apart for

extended range flightsWorking prototype. PCB design has begun. Design Review 2/13/09

~$50 total per system.

Expense Sheet 1/19/2009 $ 276.18 Tower Hobbies, remaining mat

$ 93.00 ACP-Composites

$ 18.00 Digikey, control switch

1/28/2009 $ 75.20 National Balsa1/29/2009 $ 104.76 HobbyKing, 4 batts

$ 93.30 HobbyKing, electronics

$ 50.00 FoxLite, laser cutting

2/6/2009 $ 66.05 Performance Hobbies, misc $ 9.77 Home Depot

Total As Of 2/10/2009 $ 1,414.23

Airframe A Segregated Budget

Raw Airframe with motor Component Qty Piece Price Total PriceMotor HXT42-60 1 $ 35.79 $ 35.79 Landing Gear 1 $ 25.27 $ 25.27 Linkages, Connectors, Hinges, misc 1 $ 50.00 $ 50.00 Balsa Stick, Sheet 1 $ 16.50 $ 16.50 Laser-Cut Balsa 1 $ 25.00 $ 25.00 Propeller 1 $ 1.00 $ 1.00 Covering 1 $ 5.00 $ 5.00 Composite Material 1 $ 5.00 $ 5.00

Subtotal $ 163.56 ElectronicsServo S3010 2 $ 19.99 $ 39.98 Receiver Supreme 28 LXKYK3 1 $ 39.99 $ 39.99 Servo S3114 2 $ 14.99 $ 29.98 Speed Controller 1 $ 16.79 $ 16.79 Battery eliminator circuit 1 $ 19.95 $ 19.95

Subtotal $ 146.69

Airframe without batt $ 310.25

BatteryLithium Polymer 2 $ 19.99 $ 39.98 Telemetry (Optional) 1 $ 627.97 $ 627.97

Total $ 350.23 w/Telemetry $ 978.20