Critical Design Review Critical Design Review Remote Aquatic Vehicle Remote Aquatic Vehicle (RAV) (RAV) Matthew Allgeier Matthew Allgeier Kevin DiFalco Kevin DiFalco Daniel Hunt Daniel Hunt Derrick Maestas Derrick Maestas Steve Nauman Steve Nauman Jaclyn Poon Jaclyn Poon Aaron Shileikis Aaron Shileikis University of Colorado at Boulder Aerospace Engineering Fall 2003
University of Colorado at Boulder Aerospace Engineering Fall 2003. Critical Design Review Remote Aquatic Vehicle (RAV). Matthew Allgeier Kevin DiFalco Daniel Hunt Derrick Maestas Steve Nauman Jaclyn Poon Aaron Shileikis. Presentation Outline. RFA’s and Changes since PDR - PowerPoint PPT Presentation
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addressed in Electrical Designaddressed in Electrical Design
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Overview of ObjectivesOverview of Objectives
Objectives SummaryObjectives Summary 3-axis High Speed Manueverability3-axis High Speed Manueverability
Low Drag, High Speed & Long RangeLow Drag, High Speed & Long Range 3-axis Low Speed Manueverability3-axis Low Speed Manueverability
Active BuoyancyActive BuoyancyYaw Rotation and StrafingYaw Rotation and Strafing
Small SizeSmall SizeNavigation of Challenging ObstaclesNavigation of Challenging ObstaclesEase of Deployment LogisticsEase of Deployment LogisticsEase of ManufacturingEase of Manufacturing
Specifications Derived from Facility, Monetary & Volume Specifications Derived from Facility, Monetary & Volume Limitations and Subsystems RequirementsLimitations and Subsystems Requirements
Detailed Final Objective in Verification & Testing SectionDetailed Final Objective in Verification & Testing Section
Mission StatementMission Statement The main objective for team RAV is to conceive, design, fabricate, integrate, The main objective for team RAV is to conceive, design, fabricate, integrate,
verify and test a versatile proof of concept for a remotely controlled aquatic verify and test a versatile proof of concept for a remotely controlled aquatic vehicle capable of both high speed, long range and low speed, short range vehicle capable of both high speed, long range and low speed, short range maneuverability in challenging aquatic environments.maneuverability in challenging aquatic environments.
Test Illustration at Carlson Pool
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Overview of RequirementsOverview of RequirementsStructure Structure
Pressure rated to 44 psi (20m Depth)Pressure rated to 44 psi (20m Depth)
BuoyancyBuoyancy Functional to 66 ft. (20 m)Functional to 66 ft. (20 m) RC Controllable to 2ft* DepthRC Controllable to 2ft* Depth Ascent/Descent Rate of 0.5 ft/sec*Ascent/Descent Rate of 0.5 ft/sec*
Low Speed Maneuvering (LSM)Low Speed Maneuvering (LSM) Rotation Rate of 0.33 rev/min*Rotation Rate of 0.33 rev/min* Minimal Drag during High Speed ManeuveringMinimal Drag during High Speed Maneuvering
*changed from PDR
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Overview of Mechanical DesignOverview of Mechanical Design
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Overview of Electrical DesignOverview of Electrical Design
Subsystems
Battery(12V)
HOBO
PressureTransducer
Anemometer
Battery (24V) Speed Control Motor
BuoyancyMotor
LSM ControlBuoyancyControl
LSM Jets
ReceiverBattery
Receiver
Servos
Battery(12V)
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Subsystems Design ElementsSubsystems Design Elements
Dissipate Heat from MotorDissipate Heat from MotorFinal Total DragFinal Total Drag
16.1 N at 5 knots 16.1 N at 5 knots Antenna deployed at 6 in. Antenna deployed at 6 in. RAV Nose Cone
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Control Surface DesignControl Surface DesignControl Surfaces for TrimmingControl Surfaces for Trimming
Dive Planes size determined by Dive Planes size determined by Force difference between CB & Force difference between CB & CGCG
Rudder size determined by force Rudder size determined by force from CG displacement from from CG displacement from centerlinecenterline
4 Uniform Control Surfaces 4 Uniform Control Surfaces Identical Design due to Horizontal Identical Design due to Horizontal
and Vertical Trim Requirementsand Vertical Trim Requirements Manufacturing EaseManufacturing Ease
4 Individual Servo’s4 Individual Servo’s Motor Interference & AccessibilityMotor Interference & Accessibility Future Roll ControlFuture Roll Control
Ideal Airfoil Ideal Airfoil Drag Polar EquationDrag Polar Equation Short ChordShort Chord Long SpanLong Span RAV Tail Piece & Control Surfaces
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Control Surface Sizing ConclusionsControl Surface Sizing Conclusions
Selected NACA 0012 airfoil Selected NACA 0012 airfoil Chord: 3 in.Chord: 3 in. Span: 3 in. longSpan: 3 in. long 1/8 in. servo shaft 1/8 in. servo shaft
Control surfaces & servo shaftControl surfaces & servo shaft Aluminum - excellent strength to weight ratios.Aluminum - excellent strength to weight ratios.
Servo selectionServo selection 15 deg. Control Surface deflection in 0.5 sec15 deg. Control Surface deflection in 0.5 sec Torque required 20.95 oz-inTorque required 20.95 oz-in Rated to 44.0 oz-inRated to 44.0 oz-in
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Small 0.39 in. x 0.59 in. lengthSmall 0.39 in. x 0.59 in. length Contains an O-ring to prevent Contains an O-ring to prevent
water seepagewater seepageSeal will be pressed into tail Seal will be pressed into tail section and sealed with epoxy to section and sealed with epoxy to ensure no pressure leakageensure no pressure leakage1/8 in. diameter stainless steel 1/8 in. diameter stainless steel shaft will pass from servo to shaft will pass from servo to control surfacecontrol surface
Coupler will be used to attach Coupler will be used to attach servo to shaftservo to shaft
Pins will be used to attach shaft Pins will be used to attach shaft to control surfaceto control surface
Control Surface Sealing Design
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Structural Verification and Test PlanStructural Verification and Test PlanPressure/Sealing Verification Pressure/Sealing Verification
Description:Description: Verify entire assembly can withstand pressures of ~45psi (20m depth) without leaking using a Verify entire assembly can withstand pressures of ~45psi (20m depth) without leaking using a
Written confirmation obtained from Dr. Alan TuckerWritten confirmation obtained from Dr. Alan TuckerMethod and Measurements:Method and Measurements:
Increase pressure in hyperbaric chamber Increase pressure in hyperbaric chamber Record pressure change inside hullRecord pressure change inside hull Test will be run at 45 psi for 30 minutes to correspond to the maximum amount of time the Test will be run at 45 psi for 30 minutes to correspond to the maximum amount of time the
sub will be in the water for the Final Full-Systems Integrated Test.sub will be in the water for the Final Full-Systems Integrated Test. Tests indicating pressure changes ≤ 0.2 psi will be considered a successTests indicating pressure changes ≤ 0.2 psi will be considered a success If failure occurs at ~45 psi it will be run again at 20 psi to ensure no leakage during pool If failure occurs at ~45 psi it will be run again at 20 psi to ensure no leakage during pool
teststestsAnalysis:Analysis:
Pressure vs. Time inside and outside hullPressure vs. Time inside and outside hull Any pressure change greater than 0.2 psi indicates leakageAny pressure change greater than 0.2 psi indicates leakage
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BuoyancySubsystem Design
Overall Weight &Volume35 lbs
1034 cu3
Ascent/Decent Rate0.5 ft/s
Operational Depth20 m
System Volume500 mL
Cylinder Length5 in
Inner Diameter2 in
Overall Size8.5" x 2.25"
Mass Flow Raterequired Mdot = 1.57 kg/s
@max rpm 11.64 kg/s
Pressure Force onPiston @20 m
139 lbf
Motor SelectionSmall Johnson Motor
Stall Torque = 78.7 oz-inForce Produced on Piston Head = 141 lbf
Buoyancy AnalysisBuoyancy Analysis
Inputs:
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Buoyancy Mechanical DesignBuoyancy Mechanical DesignJohnson Electric Motor (12V)Johnson Electric Motor (12V)
High rpm (16,000 rpm@12V)High rpm (16,000 rpm@12V) Lightweight (7.50 oz per motor)Lightweight (7.50 oz per motor)
Alexander Engel Gear SetAlexander Engel Gear Set Proven for piston systemsProven for piston systems
Threaded Piston RodThreaded Piston Rod 6 mm 6 mm
Piston HeadPiston Head AluminumAluminum Machined in-houseMachined in-house
CylinderCylinder AluminumAluminum Machined in-houseMachined in-house ID x OD x thickness:ID x OD x thickness:
2” x 2.25” x 0.125”2” x 2.25” x 0.125”
BatteriesBatteries 4 DuraTrax Receiver NiCd Flat Pack 6 Volt 4 DuraTrax Receiver NiCd Flat Pack 6 Volt 2200mAh (600mAh required per motor) 2200mAh (600mAh required per motor) Length x Width x Height: Length x Width x Height:
3-1/4“ x 1-3/4“ x 5/8"3-1/4“ x 1-3/4“ x 5/8" Weight: 4.8 ozWeight: 4.8 oz
SealingSealing Precision Associates Inc.Precision Associates Inc. Piston Head SealPiston Head Seal
75-1.84075-1.840 1.84” ID x 0.075” C/S x 2.0” 1.84” ID x 0.075” C/S x 2.0” ODOD
End Cap SealEnd Cap Seal25-23725-237 0.237” ID x 0.025” C/S 0.237” ID x 0.025” C/S x .287” ODx .287” OD
Buoyancy Tanks
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Buoyancy Verification & Test PlanBuoyancy Verification & Test PlanStatic Motor Strength Test (Feb 7Static Motor Strength Test (Feb 7thth))
Verify System Produces force to operate at a depth of 20mVerify System Produces force to operate at a depth of 20m Horizontal Load CellHorizontal Load Cell
Overall System Test (April 12Overall System Test (April 12thth))Verify system remains neutrally buoyant at given depthVerify system remains neutrally buoyant at given depth
Motor to tailMotor to tailShroud to tailShroud to tailController and batteriesController and batteries
BearingBearingBall bearing, double Ball bearing, double shieldedshieldedOuter diameter: 5/8 inchOuter diameter: 5/8 inchInner diameter: 1/4 inchInner diameter: 1/4 inch22ndnd point of contact for point of contact for stabilitystability
Rated to 52,300 Rated to 52,300 RPMRPM
Bal Rotary Shaft SealBal Rotary Shaft Seal71x model71x model
8 jet configuration as 8 jet configuration as alternativealternative
Aluminum mount and solenoid Aluminum mount and solenoid housinghousingPermanently attached mount Permanently attached mount Detachable housingDetachable housingLatex diaphragmLatex diaphragmO-ring sealsO-ring sealsCircuit for controlCircuit for control12V NiMH Batteries12V NiMH Batteries
Design Requirements1/3 rpm
Placement / Moment Arm
Solenoid Selectionto Meet Moment
Optimize
Design Mechanical System Volume(Mount/cavity, housing)
Final Design
LSM SubsystemDesign
Drag Analysis /Modeling Equation
Improve Design
Attach Filmto Return Stroke
Sealing
Decrease Size ofSolenoid Housing
Air Bubble Escape
Verify Equation with4" Model Sub Testing
Accurate ModelingEquation for Prediction
Integrate and Test
Choose Exit HoleDiameter
Choose Frequency
Test & Verify
262603 Dec 0303 Dec 03 RAV CDR PresentationRAV CDR Presentation
LSM Drag ModelLSM Drag Model
Drag model for 4” diameter sub with 7” Drag model for 4” diameter sub with 7” moment arm to rotate 2/3 rpmmoment arm to rotate 2/3 rpmRequired Thrust = 0.0321 NRequired Thrust = 0.0321 NRequired Moment = 0.5311 N*cmRequired Moment = 0.5311 N*cm4” sub test results:4” sub test results:Exp Moment = 0.4896 N*cmExp Moment = 0.4896 N*cmError = 7.8 %Error = 7.8 %
Drag model for 6” diameter sub with 9” Drag model for 6” diameter sub with 9” moment arm to rotate 2/3 rpm (SF2)moment arm to rotate 2/3 rpm (SF2)Required Thrust = 0.2952 NRequired Thrust = 0.2952 NRequired Moment = 5 N*cmRequired Moment = 5 N*cm
Drag model for 6” diameter sub with 9” Drag model for 6” diameter sub with 9” moment arm to rotate 1/3 rpmmoment arm to rotate 1/3 rpmRequired Thrust = 0.0841 NRequired Thrust = 0.0841 NRequired Moment = 1.523 N*cmRequired Moment = 1.523 N*cm
0 500 1000 1500 2000 25001
2
3
4
5
6Cd vs. Re for a Cylinder
Reynolds Number
Coe
f of
Dra
g
0 2 4 6 8 10 12 140
1
2
3
4
5
6Cd and Velocity from Center (0) to Edge of Cylinder
Length(inches)
Coe
f. o
f D
rag
CdVelocity
0 2 4 6 8 10 12 140
1
2
3
4
5
6
7
8x 10
-3 Moment from Center (0) to Edge of Cylinder
Length(inches)
Mom
ent
(N*c
m)
[LSM1]
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LSM AnalysisLSM Analysis
Jet theoryJet theory L / D = 4L / D = 4 Displaced volume (V1) = Exit Displaced volume (V1) = Exit
volume (V2)volume (V2) Thrust provided by jetThrust provided by jet
Required moment = 5 N*cm / Required moment = 5 N*cm / jetjetMoment vs. Frequency for Moment vs. Frequency for various exit diametersvarious exit diametersRequirements for 0.6” exit Requirements for 0.6” exit diameter to rotate 2/3 rpm:diameter to rotate 2/3 rpm:
Minimum frequency of 32HzMinimum frequency of 32Hz Stroke length of 0.38”Stroke length of 0.38”
Spring loaded, Soft ShiftSpring loaded, Soft Shift 12V, 24W at 50% duty cycle12V, 24W at 50% duty cycle Max frequency of 58HzMax frequency of 58Hz .44 lbs.44 lbs
HousingHousing Aluminum or PVCAluminum or PVC 0.35 lbs0.35 lbs
PlungersPlungers 2 mm thick2 mm thick
MountMount Aluminum (Welded to Hull)Aluminum (Welded to Hull) 0.27 lbs0.27 lbs
Overall Weight ~1.06 lbs (excluding Overall Weight ~1.06 lbs (excluding control circuit)control circuit)Final design pending (Exit Diameter) Final design pending (Exit Diameter) based on testing and optimizationbased on testing and optimization
Mount
Plunger
Housing
Solenoid
LSM Exploded View
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PowerPower 12V at 1500 mAh/jet12V at 1500 mAh/jet NiMH batteriesNiMH batteries
[LSM3] RSGEX RC Switch
+12V
1Gnd2Trg3Out4Rst 5Ctl6Thr7Dis8Vcc
555
+
CT
+
C1.01uF
RA1k
RB20k
Oscillator Circuit
Oscillator Circuit
Receiver
Battery (12V)
RSGEX RCSwitch
Left Turning Jets Right Turning Jets
Oscillator Circuit
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LSM Verification and Test PlanLSM Verification and Test PlanSpin Rate Verification an OptimizationSpin Rate Verification an Optimization
Description:Description: Verify theoretical drag model with 4” sub.Verify theoretical drag model with 4” sub.Using PVC model of RAV, different exit diameters and frequencies will be input, Using PVC model of RAV, different exit diameters and frequencies will be input,
while the resulting rotational speed will be measured. while the resulting rotational speed will be measured. Optimal exit diameter and frequency will be verified for final design.Optimal exit diameter and frequency will be verified for final design.
Location:Location: CU Carlson Pool CU Carlson Pool
Measurements and method:Measurements and method: Visually record and determine rotation rate Visually record and determine rotation rate
Analysis:Analysis: Plot rotational speed vs. frequency and exit diameterPlot rotational speed vs. frequency and exit diameter Choose frequency and exit diameter which provide optimal thrust if different than Choose frequency and exit diameter which provide optimal thrust if different than
Jets will be optimal for an exit diameter of 0.6”Jets will be optimal for an exit diameter of 0.6” Minimal frequency of actuation at 32 Hz Minimal frequency of actuation at 32 Hz
Sensors:Sensors: Digital camcorder and stop watchDigital camcorder and stop watch
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LSM Verification & Test PlanLSM Verification & Test Plan
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Communication AnalysisCommunication Analysis
AntennaeDesign
Attenuation ofWater
Power GainReciever
FrequencySelection
Antennae Drag
Attenuation ofAir
Range
StructuralAnalysis
Refraction Index
RC controllerPower out ¾ W
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Communication DesignCommunication DesignFutaba 8UAPS/8UAFS and matching FP-R148DP Receiver (FM/PCM 1024)Futaba 8UAPS/8UAFS and matching FP-R148DP Receiver (FM/PCM 1024)
Free Loan from Aerobotics Research Laboratory – Budget ConstraintsFree Loan from Aerobotics Research Laboratory – Budget Constraints 8 Channels Available, RAV requires 78 Channels Available, RAV requires 7 0.75 W output0.75 W output Receiver Power Gain UnknownReceiver Power Gain Unknown 72.330 MHz, ¼ wavelength whip antenna = 3.23 ft. long72.330 MHz, ¼ wavelength whip antenna = 3.23 ft. long
Signal Loss at 72.330 MHzSignal Loss at 72.330 MHz Refraction Loss = 53.00 dBRefraction Loss = 53.00 dB Attenuation of Chlorinated Water = ~300 dB/mAttenuation of Chlorinated Water = ~300 dB/m
Conductivity varies with Chlorine Concentration (Avg Value = 200 µMhos/cm)Conductivity varies with Chlorine Concentration (Avg Value = 200 µMhos/cm)
Antenna DesignAntenna Design ¼ wavelength vertical antenna¼ wavelength vertical antenna Fiberglass Antenna Mast = 2ft. X 1/8 in.Fiberglass Antenna Mast = 2ft. X 1/8 in.
Static SealStatic SealAntenna Rise above Surface to avoid LossesAntenna Rise above Surface to avoid LossesRun Propulsion Subsystems Test 6 in. below surfaceRun Propulsion Subsystems Test 6 in. below surfaceRun to 75% Underwater Fail-Safe Depth for Full-Systems Integrated Test (if Tested)Run to 75% Underwater Fail-Safe Depth for Full-Systems Integrated Test (if Tested)
Antenna DragAntenna Drag14.41 N at 7.5 knots14.41 N at 7.5 knots6.40 N at 5.0 knots6.40 N at 5.0 knots
Antenna Bending MomentAntenna Bending Moment ConclusionConclusion
R/C not ideal for actual end goal – sufficient for Proof of ConceptR/C not ideal for actual end goal – sufficient for Proof of Concept
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Communication Test PlanCommunication Test Plan
Range TestRange Test Move away from RAV until Fail Safe InitiatesMove away from RAV until Fail Safe Initiates
Distance Step FunctionDistance Step Function Stretch Goal - Repeat with RAV UnderwaterStretch Goal - Repeat with RAV Underwater
Quantify Receiver Power GainQuantify Receiver Power Gain
Leak TestingLeak Testing Buoyancy Static TestBuoyancy Static Test
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Drawing Tree - SampleDrawing Tree - Sample
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Buoyancy
Buoy Testing
Buoy Testing
Hull Manu
Hull / Buoy
Hull / Buoy
Integration
Buoyancy
Tail
Tail
Tail
Main Flange /Seals
Main Flange /Seals
Main Flange /Seals
Nose
Nose
Integration
Tail
Buoyancy
Control Seals
Control Seals
Control Seals
Payload Tray
Payload Tray
Payload Tray
Shroud
Integration
Buoyancy
Buoyancy
Control Seals
Control Seals
Control Seals
Antenna
Antenna
Integration
Buoyancy
Tail
Tail
Tail
Motor Seal &Shaft
Motor Seal &Shaft
Motor Seal &Shaft
Integration
Tail
LSM Testing
LSM Manu
LSM Manu
LSM Manu
LSM Manu
LSM Manu
Integration
LSM Testing
LSM Testing
LSM Manu
LSM Manu
LSM Manu
LSM Circuit
LSM Circuit
Integration
LSM Testing
Assembly Flow DiagramAssembly Flow Diagram
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Verification and Test PlanVerification and Test PlanFull Integration Test Plan DescriptionFull Integration Test Plan Description
At point A, dive to depth of 2.5 ft (0.5 ft/sec)At point A, dive to depth of 2.5 ft (0.5 ft/sec)Remain Buoyant for 2 minRemain Buoyant for 2 minAccelerate to 3 knots and stop at point BAccelerate to 3 knots and stop at point BRotate counterclockwise 90° (45 sec)Rotate counterclockwise 90° (45 sec)Accelerate to 2 knots and stop at point CAccelerate to 2 knots and stop at point CRotate clockwise 270° (2.25 min)Rotate clockwise 270° (2.25 min)Arrive at point D by maneuvering around Arrive at point D by maneuvering around obstacles using Buoyancy and LSMobstacles using Buoyancy and LSMRotate counterclockwise 90° (45 sec)Rotate counterclockwise 90° (45 sec)Return to point A and surface using buoyancyReturn to point A and surface using buoyancyRepeat TestingRepeat Testing
Test Time = 10 min/LapTest Time = 10 min/Lap
LocationLocationCU Carlson PoolCU Carlson Pool
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Verification & Test Plan Verification & Test Plan
Expectations:Expectations: All subsystems tests will be verified on fully integrated All subsystems tests will be verified on fully integrated
SubSub Top speed of 5 knotsTop speed of 5 knots Demonstrate active buoyancyDemonstrate active buoyancy Rotational speed of 1/3 rpmRotational speed of 1/3 rpm
CSU Hyperbaric ChamberCSU Hyperbaric Chamber Dr. Alan Tucker (access granted in writing)Dr. Alan Tucker (access granted in writing) 150 ft. x 10 ft.150 ft. x 10 ft. 67 psi67 psi
CU Carlson PoolCU Carlson Pool John Meyer (access granted in writing)John Meyer (access granted in writing) 25m x 12m x 1m25m x 12m x 1m
Aerobotics LaboratoryAerobotics Laboratory Cory Dixon (access granted in writing)Cory Dixon (access granted in writing)
Aerospace Engineering Department & ITLLAerospace Engineering Department & ITLL Walt Lund, Trudy Schwartz, Matt Rhode & Bill InginoWalt Lund, Trudy Schwartz, Matt Rhode & Bill Ingino Testing Support EquipmentTesting Support Equipment
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ReferencesReferences
Fluid MechanicsFluid Mechanics [1] Myring, D F. [1] Myring, D F. A Theoretical Study of Body Drag in Subcritical Axisymmetric Flow.A Theoretical Study of Body Drag in Subcritical Axisymmetric Flow. Aerospace Quarterly. Volume 3. 1976. Aerospace Quarterly. Volume 3. 1976. Aerodynamics BookAerodynamics Book Dynamics BookDynamics Book Library BookLibrary Book
BuoyancyBuoyancy [B1] www.subconcepts.com[B1] www.subconcepts.com Mr. Fred Grey, subconcepts.comMr. Fred Grey, subconcepts.com
PropulsionPropulsion Argrow PaperArgrow Paper MooG (Co. Documentation)MooG (Co. Documentation)
Text Books:Text Books: Richardson. PADI Open Water Diver Manual. International PADI, Inc. 1999.Richardson. PADI Open Water Diver Manual. International PADI, Inc. 1999. Burcher and Rydill. Concepts in Submarine Design. Cambridge University Press. 1994.Burcher and Rydill. Concepts in Submarine Design. Cambridge University Press. 1994. Robertson. Systems/Subsystems Investigation for a Multi-Sensor Autonomous Underwater Vehicle Search System. US Gov Agencies. April 1990.Robertson. Systems/Subsystems Investigation for a Multi-Sensor Autonomous Underwater Vehicle Search System. US Gov Agencies. April 1990. Vable.l Mechanics of Materials. Oxford University Press. New York. 2002.Vable.l Mechanics of Materials. Oxford University Press. New York. 2002. Shevell. Fundamentals of Flight (2Shevell. Fundamentals of Flight (2ndnd Edition). Prentice Hall. New Jersey. 1989 Edition). Prentice Hall. New Jersey. 1989 Cengel. Introduction to Thermodynamics and Heat Transfer. Irwin McGraw-Hill. 1997.Cengel. Introduction to Thermodynamics and Heat Transfer. Irwin McGraw-Hill. 1997. Reed. The ARRL Handbook for Radio Amateurs 2002.The American Radio Relay League, Inc. 2001Reed. The ARRL Handbook for Radio Amateurs 2002.The American Radio Relay League, Inc. 2001
Available in Available in desired sizes desired sizes
from from manufacturer manufacturer in Coloradoin Colorado
PVCPVC LowLow
(about (about $10 per $10 per
foot)foot)
ExcellentExcellent WeakWeak
(only up to 150 psi)(only up to 150 psi)
LowLow
(1.37 g/cm^3(1.37 g/cm^3
LowLow
(Used (Used last last
year)year)
Not available Not available in desired in desired sizes from sizes from
manufacturer manufacturer in Coloradoin Colorado
565603 Dec 0303 Dec 03 RAV CDR PresentationRAV CDR Presentation
FM - Preliminary Exterior Structure FM - Preliminary Exterior Structure ConclusionsConclusions
Outer diameter of Mid-section was determined to Outer diameter of Mid-section was determined to be 6 inches.be 6 inches. Tubing is typical made with outer diameters of 4, 6 or Tubing is typical made with outer diameters of 4, 6 or
8 inches.8 inches. Diameter was needed to be decreased from last Diameter was needed to be decreased from last
years 8 ¼ inch outer diameter in order to meet years 8 ¼ inch outer diameter in order to meet maneuverability and speed requirements.maneuverability and speed requirements.
A nominal diameter of 4 inches was determined to be A nominal diameter of 4 inches was determined to be too small to fit all required components inside the hull.too small to fit all required components inside the hull.
575703 Dec 0303 Dec 03 RAV CDR PresentationRAV CDR Presentation
FM - Control Surface ConfigurationFM - Control Surface Configuration
Considering 2 possible Considering 2 possible control surface control surface configurationsconfigurations
Configuration 1: 2 dive Configuration 1: 2 dive planes and two rudders planes and two rudders mounted on rear of mounted on rear of tailpiecetailpiece
Configuration 2: 2 dive Configuration 2: 2 dive planes mounted on the planes mounted on the nosecone and one rudder nosecone and one rudder located aft of the propeller.located aft of the propeller.
Determined that vertical Determined that vertical and horizontal stabilizers and horizontal stabilizers are unnecessary.are unnecessary.
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FM - Control Surface Airfoil FM - Control Surface Airfoil SelectionSelection
LiftLift(Max C(Max CLL))
Max Max αα(degrees)(degrees)
DragDrag(C(CDD at at
Max CMax CLL))
Area Area Required Required for Trimfor Trim
RiskRisk CommentsComments
NACANACA
00060006
0.920.92 9 deg9 deg 0.0100.010 183 cm183 cm22 Servo shaft Servo shaft will have to will have to be about 1/8 be about 1/8 inchinch
Symmetric Symmetric airfoilairfoil
NACANACA
00090009
1.321.32 13.4 deg13.4 deg 0.0160.016 127 cm127 cm22 Servo shaft Servo shaft will have to will have to be less than be less than ¼ inch¼ inch
SymmetricSymmetric
airfoilairfoil
NACANACA
0012 0012
1.501.50 15 deg15 deg 0.0250.025 110 cm110 cm22 Excessive Excessive drag may drag may impede on impede on velocity velocity goalsgoals
Symmetric Symmetric
airfoilairfoil
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FM - Airfoil Sizing vs. Shaft SizingFM - Airfoil Sizing vs. Shaft Sizing
ThicknessThickness Max Shaft sizeMax Shaft size(to allow for 0.05 (to allow for 0.05 inches on either side)inches on either side)
Surface Surface Area Area requiredrequired
Drag Drag CoefficientCoefficient
NACA 0009 NACA 0009 w/ 3 inch w/ 3 inch chordchord
606003 Dec 0303 Dec 03 RAV CDR PresentationRAV CDR Presentation
FM - Airfoil Sizing ConclusionsFM - Airfoil Sizing ConclusionsA NACA 0012 airfoil with a 3 inch chord was A NACA 0012 airfoil with a 3 inch chord was selected.selected. This will allow us to use a 1/8 inch Servo shaftThis will allow us to use a 1/8 inch Servo shaft
In order to use a 1/8 inch Servo Shaft with a In order to use a 1/8 inch Servo Shaft with a NACA 0009 airfoil, the chord length will have to NACA 0009 airfoil, the chord length will have to be at least 3 inches long. be at least 3 inches long. Span required for this airfoil is 3 inches longSpan required for this airfoil is 3 inches longAluminum was selected for material to be used Aluminum was selected for material to be used for control surfaces and Servo Shaft due to for control surfaces and Servo Shaft due to excellent strength to weight ratiosexcellent strength to weight ratios Acrylic was not selected due to structural problems Acrylic was not selected due to structural problems
with last years design.with last years design.
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FM - Final Drag ComputationFM - Final Drag Computation
Final Drag ElementsFinal Drag Elements Myring Hull ContourMyring Hull Contour 4 NACA 0012 airfoils4 NACA 0012 airfoils Shroud w/ surface area of 669 cm^2Shroud w/ surface area of 669 cm^2
Final Drag computed to be 14.59 N at 5 knotsFinal Drag computed to be 14.59 N at 5 knots
Reynolds Number = 2.5669 * 10^6, which makes Reynolds Number = 2.5669 * 10^6, which makes flow in the turbulent regimeflow in the turbulent regime
Drag will not be tested directly. Drag data will be Drag will not be tested directly. Drag data will be based on thrust test data.based on thrust test data.
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Torque ProfileTorque Profile
Intermittent operation Intermittent operation is based on a 20% is based on a 20% duty cycle of one duty cycle of one minute on, four minute on, four minutes off.minutes off.
Torque as RPM changes
RPM @ 5 knots
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AccelerationAccelerationT*V = T*V = ηη*P*P
Fix Power to 187.4 WFix Power to 187.4 W Step through V’s by 0.5Step through V’s by 0.5
Find efficiency and thrustFind efficiency and thrust F = maF = ma
(Thrust – Drag)/mass = a(Thrust – Drag)/mass = a
ProblemsProblems Efficiency is an approximationEfficiency is an approximation
Slippage and cavitations not Slippage and cavitations not analyzedanalyzed
Mass of vehicleMass of vehicleAdded mass due to waterAdded mass due to water
Acceleration values are much Acceleration values are much larger than needed and larger than needed and expectedexpected
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