Micro Air Vehicle (MAV) Propulsion

Project P6002Project P6002Preliminary Design Presentation

November 2005November 2005

Zach Kilcer, Bill Strong, Joe Olles, Sean Dittrich, Brian Stumper, Doug BrownZach Kilcer, Bill Strong, Joe Olles, Sean Dittrich, Brian Stumper, Doug Brown

2

Team Members

Names from left to right: Bill Strong, Douglas Brown, Brian Stumper, Zach Kilcer, Sean Dittrich, Joe Olles, and Dr. Kozak

3

MAV Motivation

• Effectively retrieve GPS data video feed.

• DARPA funded effort for use by American Soldiers and Intelligence Agents by 2010.

• Wide range private sector applications

• Annual international design competition

4

Introduction: MAV at RIT• Offshoot of the RIT Aero Design Team• Fourth year MAV Team at RIT• RIT annually attends International Competitions• Current MAV Senior Design effort in support of MAV

Team • Unique design project due to limited information and

research on small scale vehicles

5

Mission Statement

Develop an efficient, light weight and cost effective propulsion system for the RIT

MAV club.

6

Overview

• Needs Assessment• Requirements• Concept Generation• Feasibility Testing• Analytical Analysis• Electronic System Optimization• Design of Baseline System• Electronic System• Senior Design II Specifications• Future Plans

7

Needs Assessment

• Performance Goals– The thrust-to-weight ratio of the propulsion system shall exceed

the thrust-to-weight ratio of the MAV 05’ design.– The power system shall be designed to optimize efficiency and

weight requirements for the propulsion system.

• Design Goals– The deliverable shall consist of more than one design.– The propulsion system shall be durable enough to withstand a

crash landing.– The propulsion system shall be easily integrated into future

airframes and anticipated electronic components.

8

Brainstorming

Jet Turbine EngineDucted Propeller

Variable Pitch PropellerInternal Combustion

Engine with a Propeller Shrouded Propeller

9

Concept Evaluation: Pugh Chart

Evaluation Chart

Motor / Prop Jet turbineInternal

combustion engine

Ducted PropShrouded

propVariable

Pitch Prop

Cost 0 - 0 - 0 -

weight 0 - - - - -

thrust 0 + + + + +

size 0 - - 0 0 0

durability 0 0 0 + + 0

drag 0 - - - 0 +

number of parts

0 - 0 - - -

ease of integration

0 - - + 0 -

Complexity of Design

0 - - 0 0 -

Total + 0 1 1 3 2 2

Total - 0 7 5 4 2 5

Sum 0 -6 -4 -1 0 -3

10

Propeller and Motor• Easy design to produce with the teams limited resources• Careful selection of a motor and propeller combination

will increase performance

11

Shrouded Propeller

• Increase thrust and efficiency

• Reduce propeller tip vortices

• Increase durability of propulsion system

12

Ducted Propeller• Reduce propeller tip vortices • Significantly increase thrust

– acts as a nozzle, raising the exit velocity

• Increase durability of propulsion system

• Equation for Open and Ducted Props• Significantly increase thrust

• Reduce propeller tip vortices

• Increase durability of propulsion system

13

Propeller and MotorAnalytic Proof of Concept

• Blade Element theory:– The airflow is treated as a

2D flow with no mutual interaction between blade sections.

– The blade is composed of independent elements

– The differential element of fixed chord, is located at a specific radius-chord changes with respect to radius

14

Velocity ConsiderationsVelocity Analysis

0.0000

20.0000

40.0000

60.0000

80.0000

100.0000

120.0000

0.000 0.500 1.000 1.500 2.000 2.500

Radius (in)

Ex

pe

rie

nc

ed

Ve

loc

ity

(ft

/s)

15

Reynolds Number Considerations

Reynolds Number Analysis

0

20000

40000

60000

80000

100000

120000

140000

160000

180000

0 0.5 1 1.5 2 2.5

Radius (in)

Re

yn

old

s N

um

be

r

16

Mach Number ConsiderationsMach Number Analysis

0

0.002

0.004

0.006

0.008

0.01

0.012

0.014

0.016

0.018

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5

Radius (in)

Ma

ch

Nu

mb

er

17

Propeller and Motor Analytic Proof of Concept

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

r/R [Normalized Radius]

Tip

-Lo

ss

Fa

cto

r

)(11 UVAVTh exit • Thrust analysis based on Momentum theory

18

Shrouded PropellerAnalytic Proof of Concept

• Thrust analysis based on Momentum theory

• Reynolds number calculation

• Coefficient of Drag for laminar flow over a flat plate

• Drag Force

)(11 UVAVTh exit

LU

LRe

eLRDC 33.1

plateDD AUCF 221

19

Ducted PropellerAnalytic Proof of Concept

])(43[1

241

ATh

ThPw UU

• Power to Thrust ratio analysis based on Momentum theory

• Duct Drag Equation

31

12

)( 4

APwhT

)(22

21 LRV

FDD

ioC

2222 LD

LLb

SD CkCkC

20

Fabricated Components

There are unique performance requirements for each component to be fabricated.

• Shrouds

• Ducts

• Motor Mounts

• Propellers

21

Materials

Multiple materials available for component fabrication. Each has unique characteristics.

• Composites

• Polymers

• Polymer Foam

22

Materials Processing

• Unique processing methods for each material

• Each method has characteristic advantages and disadvantages

• Processing Procedures:– Hot Wiring– Lay-up Molding– Injection Molding– Rapid Prototyping

23

Static Test Setup

• Used to determine the feasibility of the three (3) different prop designs

• Measurements Included:– Thrust– Motor Speed– Inlet / Exit Velocity– Temperature– Air Pressure

24

Static Test Results

Thrust vs. Motor Current

10.00

12.00

14.00

16.00

18.00

20.00

22.00

24.00

0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1

Motor Current (Amps)

Th

rus

t (g

)

Baseline PropShrouded Prop (Bell Mouth)Ducted Prop (Concave)Ducted Prop (Convex)Linear (Baseline Prop)Linear (Shrouded Prop (Bell Mouth))Linear (Ducted Prop (Concave))Linear (Ducted Prop (Convex))

25

Test ResultsAt 2800RPM

  Calculated Thrust (g) Measured Thrust (g) % Error

Baseline Prop 1 19.99 22.89 14.49

Baseline Prop 2 18.97 18.82 0.80

  Calculated Thrust (g) Measured Thrust (g) % Error Drag Force (g)

Shroud 1 26.62 18.31 31.22 0.35

Shroud 2 Bell-Mouth 19.40 20.35 4.88 0.217

  Calculated Thrust (g) Measured Thrust (g) % Error Drag Force (g)

Concave Duct 23.21 23.81 2.57 29.42

Convex Duct 1 23.08 19.30 16.36 19.534

Convex Duct 2 20.11 17.07 15.10 13.59

26

Design Constraints

Constraint Minimum Value Maximum Value

Thrust 60g 150g

Weight 60g 150g

Efficiency (Thrust / Weight) 1.0 1.75

Auxiliary Power 300mA 500mA

Range 600m 3200m

Battery Lifetime 15min 30min

27

Historical Motor/Prop Performance Parameters

Motor PropellerNo. LiPoly

CellsThrust

(g)

Motor Current

(A)

Motor Weight

(g)

Max Current

(A)

Battery Weight

(g)

Propulsion Weight (g)

Flight Time (min)

Thrust-to-Weight Ratio

Firefly GWS 4350 2 26 0.26 14.00 0.76 5.6 69.61 9.01 0.37

Firefly GWS 4540 2 30 0.47 14.00 0.97 8.3 72.30 11.06 0.41

Firefly GWS 5030 2 36 0.42 14.00 0.92 7.7 71.66 10.66 0.50

Firefly GWS6030 2 44 0.54 14.00 1.04 9.2 73.19 11.56 0.60

Firefly GWS 7035 2 60 0.82 14.00 1.32 12.8 76.77 13.03 0.78

Firefly GWS 4350 3 56 0.69 14.00 1.19 16.7 80.66 12.43 0.69

Firefly GWS 4540 3 64 0.86 14.00 1.36 19.9 83.92 13.19 0.76

Firefly GWS 5030 3 74 0.79 14.00 1.29 18.6 82.58 12.90 0.90

Firefly GWS6030 3 86 0.99 14.00 1.49 22.4 86.41 13.65 1.00

Mighty Micro GWS 6030 2 246 5.60 32.00 6.10 73.9 155.86 17.30 1.58

Mighty Micro 5.5 X 4 MAS 2 212 6.40 32.00 6.90 84.1 166.08 17.44 1.28

Mighty Micro 6 X 4 APCE 2 237 7.20 32.00 7.70 94.3 176.31 17.54 1.34

Mighty Micro EP 7035 GWS 2 286 7.40 32.00 7.90 96.9 178.86 17.57 1.60

Mighty Micro 7 X 4 APCE 2 277 9.10 32.00 9.60 118.6 200.59 17.73 1.38

Mighty Micro 7 X 5 APCE 2 266 9.70 32.00 10.20 126.3 208.26 17.77 1.28

Mighty Micro EP 6030 GWS 3 311 6.90 32.00 7.40 135.7 217.71 17.51 1.43

Mighty Micro 6 X 4 APCE 3 308 10.40 32.00 10.90 202.8 284.80 17.82 1.08

Mighty Micro EP 7035 GWS 3 401 10.60 32.00 11.10 206.6 288.64 17.83 1.39

Mighty Midget U-80 1 29 1.30 3.70 1.80 9.5 63.15 14.48 0.46

Mighty Midget GWS 3x2 prop 1 29 1.30 3.70 1.80 9.5 63.15 14.48 0.46

Mighty Midget GWS 4x2.5 1 37 1.90 3.70 2.40 13.3 66.99 15.48 0.55

28

Motor/Prop Feasibility Analysis

FactorsImportance

[1]

Firefly w/ GWS6030 Mighty Micro w/GWS 6030

ScoreWeighted

ScoreScore[2]

Weighted Score

Thrust 8 0 0 + 8

Weight 7 + 7 - -7

Efficiency 6 0 0 + 6

Size 5 + 5 - -5

Cost 4 + 4 - -4

Battery Lifetime

3 - -3 + 3

Flight Range 2 0 0 0 0

Auxiliary Power

1 0 0 0 0

Total Score 13 1

[1] Definition of Importance: “1” = Least important, “8” = most important.[2] Definition of Score: “-“ = Below initial spec, “0” = Meets initial spec, “+” = Exceeds initial spec [1] Definition of Importance: “1” = Least important, “8” = most important.[2] Definition of Score: “-“ = Below initial spec, “0” = Meets initial spec, “+” = Exceeds initial spec

29

Baseline System Performance Specifications are derived using a Firefly 799 coreless

motor with a GWS6030 propeller.

Factor Anticipated Performance

Thrust 86g

Weight 81g

Thrust-to-weight ratio 1.05

Size (max dimension) 6”

Battery Life (Baseline with no camera/servos) 17 min

Battery Life (Includes two (2) servos) 15 min

Battery Life (Includes two servos and camera) 12 min

Flight Range 1 mile

Number of Channels 5

Auxiliary Power 5.0W (11.1-5V@0.45A)

Estimated Surplus Power 0.50W (11.1-5V@0.05A)

Motor / Prop Baseline Specifications

30

Wiring Diagram

p/n: Firefly 799

Coreless MotorSpeed

Controllerp/n: Astro 200

LiPoly Battery(3.7V @ 1.5A)

p/n: LP300

LiPoly Battery(3.7V @ 1.5A)

p/n: LP300

LiPoly Battery(3.7V @ 1.5A)

p/n: LP300

Power Source (11.1V @ 1.5A)

Micro 2R Polarized Connectors p/n: 1222

RF Receiverp/n: 805FM72V2

Throttle Channel (Typically 3)

Servo Connector

Ch 46

Crystal Oscillatorp/n: RXQTM72-(41-50)  

White = signalBlack = groundRed = Power (+5V)

Propellerp/n: GWS6030 or Equivalent

31

Power Budget

Component

Part Number

DescriptionVoltage

(V)Current

(A)

Power Source

LP300 (x3)LiPoly 300mAh

11.1 1.500

Speed controller

Astro 200Coreless speed controller

5.0 0.025

RF receiver FMA M5v2Sub-micro receiver

5.0 0.025

Electric motor

799Firefly coreless motor

11.1 0.980

Servo motors

BlueArrow 3.6

Light weight servo motors (x2)

5.0 0.200

Video camera

Core 5-2450mW Video Transmitter

10.0 0.100

Video transmitter

CX161Panasonic Camera

5.0 0.120

Power Surplus

0.050

Power Distribution Breakdown

32

Weight BudgetComponent Part Number Description

Weight (g)

Propeller GWS 60306” x 3” direct drive propeller

2

Speed controller

Astro 200Coreless speed controller

3

RF receiver FMA M5v2Sub-micro receiver (1-mile range) 8

Power source

LP300 (x3)Platinum polymer 300mAh battery

20

Electric motor

799Firefly coreless motor 14

Motor mount

MAV ClubPropulsion system Motor mount

30

Connectors GenericBattery / motor connectors and corresponding wires

5

Total Weight 82

Weight Budget Breakdown

33

Bill of Materials

Item Qty Description Manufacturer Distributor Part NumberUnitCost Cost

1 9 LiPoly Battery (3.7V/1.5A/300mAh) Platinum Polymer http://www.batteriesamerica.com LP300 $7.95 $71.55

3 2 Coreless Motor Speed Controller (3A Max) Astro Flight http://www.astroflight.com Astro 200 $19.95 $39.90

4 2 Firefly Coreless Planetary Motor Astro Flight http://www.astroflight.com 799 $49.95 $99.90

5 2 M5v2 Sub Micro Receiver FMA Direct http://www.fmadirect.com 805FM72V2 $39.95 $79.90

- -

Options: Fut/Hitec Type

"" http://www.fmadirect.com 805FM72V2 - -(See item 5)

6 1 72 MHz Crystals (Channel 46) FMA Direct http://www.fmadirect.com RXQTM72-(41-50)   $9.95 $9.95

7 10 4 x 2.5 Direct Drive Electric Propeller GWS http://www.balsapr.com EP-4025 $0.89 $8.90

8 10 6 x 3 Direct Drive Propeller GWS http://www.balsapr.com EP-6030 $1.12 $11.20

9 5 Two-Pin Male JST Connector GWS http://www.balsapr.com W22/2PJST/30 $1.50 $7.50

10 5 Two-Pin Female JST Connector GWS http://www.balsapr.com W22FM/2PJST/30 $1.50 $7.50

11 5 Black Two-Pin M3 Motor Connector     Generic http://www.balsapr.com *Generic See Desc $1.90 $9.50

12 5 Black Two-Pin C3 Speed Controller Connector     Generic http://www.balsapr.com *Generic See Desc $1.95 $9.75

13 5 5.7 oz 1st ‘Quality’ Plain Weave Carbon Fiber US Composites http://www.shopmaninc.com FG-CARB5750 $31.50/yd $157.50

14 1 2 Gallon Epoxy Resin & 1 Gallon Hardener Us Composites http://www.shopmaninc.com EPOX-635314 $94.50 $94.50

Total $607.55

34

Senior II Design Specifications• Performance Specifications

– The thrust-to-weight ratio of the propulsion system shall meet or exceed a value of 1.00

– The weight of the motor mount (or shroud) shall not exceed 30.0 grams. – The propulsion system shall be designed to endure a 15 minute flight.– The propulsion system shall have a minimum flight range of 600 meters.

• Design Objectives– The propulsion system shall be durable enough to withstand a crash

landing.– The propulsion system shall be easily integrated into future airframes

and anticipated electronic components.– The propulsion system shall be designed using light weight composites

and polymer materials.– The propulsion system shall be compatible with the airframe designed

by the MAV 05’ winter/spring senior design I team.– The final products delivered to the MAV club shall consist of multiple

(more than one) design.

35

Senior II Design Specifications (cont)• Power source

– The MAV shall be powered using lithium polymer batteries.– The battery weight shall not exceed 20 grams.– The batteries shall supply 1.50 amps of current at 11.1 volts– The battery lifetime shall meet or exceed 15 minutes.

• Control System– The range of the RF receiver shall meet or exceed 600 meters.– The RF receiver shall contain a minimum of 4 channels.

• Electronic Motor– The electric motor shall consist of a firefly coreless (or equivalent)

motor.– The electric motor shall maintain thermal stability during flight.

• Future Electronics– The electronic system shall provide an additional 400mA of auxiliary

power for two (2) servo motors, a video camera, and a video transmitter.

36

Summary

• Five (5) different propeller designs were investigated.• Feasibility analysis eliminated two (2) designs.• Analytical analysis was performed• Static testing validated the analytical results.• Specifications were developed for the propulsion system.• A baseline system was designed with an optimal

electronic system.• A plan was generated to optimize the propulsion system

for future MAV needs.• Composites and propeller design will be investigated for

future use.

37

Phase II Work Plan1. Implement baseline motor/prop design2. Baseline motor/prop static testing

a. Run static testb. Organize/interpret resultsc. Evaluate motor / prop combinations

3. SDII test fabricationa. Develop new ducts/shrouds/propellers

i. Molds (machined/rapid prototyped)ii. Components (injection molded/rapid prototyped/composite lay-up)

b. Develop dynamic test fixture c. Dynamic Test Setup

i. Setup the necessary equipmentii. Organize collected dataiii. Calibrate the test equipment

d. Develop dynamic test procedurei. Document the testing processii. Identify control variablesiii. Develop a test matrix

4. Static / dynamic testinga. Run static and dynamic testsb. Record / organize resultsc. Interpret resultsd. Evaluate designe. Propose new designs to fabricate

5. Implement into airframea. Present findings to winter/spring teamb. Work to implement design

i. Mechanical considerationsii. Electrical considerations

38

Future Work• Obtain additional design constraints from the airframe

senior design team (Winter/Spring)• Implement the baseline motor / prop system• Optimize efficiency by investigating different

configurations for:• Dimension• Profile• Weight• Component Materials

• Deliver final designs to the MAV club.

39

Questions?

40

Backup Slides

41

Shrouded PropellerDuct Fabrication

42

Inverse Methods

• Two Inverse methods to chose from:– First, based on the Prandtl-Betz Theory

• Starts with an optimal circulation distribution and relates chord and angle of attack for the best design case.

– Second, computes profiles from velocity distributions

• Based on propeller airfoil requirements• Tip requirements determined by compressible flow,

hub determined by viscous effects.

43

The Velocity Triangle

• The propeller blade does not only feel the effects of the upstream velocity, but also the velocity of rotation.

• This is accounted for in the velocity triangle where actual velocity seen is the square root of upstream velocity squared plus tangential velocity squared.

44

Reynolds Number Considerations

• As the radius is increased, the Reynolds Number curve grows steeper

• Moving outward from the hub, Reynolds Number increases linearly

45

Other Possible Features

• Custom Propeller Blades– Would provide superior efficiency, weight, and

durability– Requires custom built molds

Electronic Subsystem

Primary Electronics

• RF Transmitter• RF Receiver• Battery• Electric Motor• Speed Controller

Future Electronics

• Servo Motors• Video Camera• Video Transmitter• Video Receiver

RF ReceiverSpeed

Controller

VideoTransmitter

Servo Motors

ElectronicMotor

RF Transmitter

Control System

BatteryVideo

Receiver

VideoCamera

RF ReceiverSpeed

Controller

VideoTransmitter

Servo Motors

ElectronicMotor

RF Transmitter

Control System

BatteryVideo

Receiver

VideoCamera

Block Diagram of MAV Electronic System

47

Electronic Considerations – Electric Motor

• Electronic Motor includes three (3) types:– Brushed– Brushless– Coreless

• Selection Criteria– Weight– Current– Thrust– Propeller configuration

• Optimize using gathered data given propeller specifications.

Coreless DC Motor

Brushless DC Motor

Brushed DC Motor

Average Thrust @ 7.4V vs Maximum Current

Thrust = 32.982(i) + 47.252

R2 = 0.9863

0

100

200

300

400

500

600

700

0 2 4 6 8 10 12 14 16

Maximum Current (Amps)

Av

era

ge

Th

rus

t (g

ram

s)

48

Electronic Considerations - Battery

• LiPoly Batteries will provide the necessary power for all of the onboard electronics (present and future).

• LiPoly chosen over nickel metal-hydride (NiMH) and nickel-cadmium (NiCad) for high charge density

• Optimal battery selection by using the charts below

Current Rating vs. Mass for Different Single Cell (3.7V) Lithium Polymer Batteries

i = 0.1565(m) + 0.3209

R2 = 0.9288

0

1

2

3

4

5

6

7

8

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0

Weight (Grams)

Cu

rre

nt

Ra

tin

g (

Am

ps

)

LiPoly Batteries

Lifetime vs. Mass for Different Single Cell (3.7V) Lithium Polymer Batteries

tlif e = 48.195(m) - 21.067

R2 = 0.9745

0

500

1000

1500

2000

2500

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0

Weight (Grams)

Lif

eti

me

(m

Ah

)

49

Electronic Considerations – Control System

• Control System includes two (2) components:– RF receiver– Speed controller

• Selection Criteria– Number of channels– Compatibility with existing

RF transmitters– Size– weight– Range– Motor compatibility

Speed Controller

RF Receiver

RF Transmitter

50

Electronic Considerations – Future Requirements

• Future Technology:– Two (2) servo motors– A video surveillance

system

• Considerations– Weight– Dimensions– Power requirements

Video Camera Video Transmitter

Video Receiver Servo Motor