MCj04347190000[1]
Recovery Systems
Tripoli Minnesota
Gary Stroick
December 2012
MCj04347190000[1]
Copyright © 2012 by Off We Go Rocketry, LLC
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Agenda
•Overview
•Dual Deployment Designs
•Avionics Bays
•Electronics & Ejection
•Attachment Points
•Parachutes & Packing
•Summary
MCj04347190000[1]
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Overview
•Why use Dual Deployment?
1.To stay out of mosquito infestedswamps.
2.To reduce the drift distanceensuring that the vehicle remainsin the recovery area as specifiedby the Tripoli Safety Code.
3.So those with bad hips don’t haveto walk so far.
Unless …
You’re
Bill
You’re
Verno
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Overview
•Two Stage Recovery Philosophy
•Initial Rapid Controlled Descent
•Descent Rate  100 ft/sec
•Techniques: Flat Spin, BodySeparation, Streamer, Parachute
•Slow Final Descent
•Descent Rate  20 ft/sec
•Techniques: Parachute
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Failure Modes
Attachment Points
•Quick Links notConnected or Left Open
•Poor Knot Selection
•Inadequate Hardware
Deployment
•Too Small/Not Tested
•Incorrect Altimeter Setup
•Loss of Power
•Electrical Wire Disconnects
Parachute, Bridle, etc.
•Improperly Folded
•Improperly Sized
•Inadequately Protected
•Fatigue Considerations
Related Failures
•Drag Separation
•Zippers
•In Flight Self Impact
•Shear Pin Failure
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#1 Cause of Failure is Recovery!
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
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Dual Deployment Designs
•Design Approaches
1.Split Airframe Deployment
2.Inline Deployment
3.Rear Deployment
4.Hatch Deployment
http://www.apogeerockets.com/images/perfectflite_products/Dual-Deployment.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Split Airframe
Typical & Most Popular Design
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http://i124.photobucket.com/albums/p10/GatorFanFL/dualdeploymentantizipper.jpg
Booster Section
Drogue Chute
Airframe Splits
AV Bay
Main Chute
Top of Airframe
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Split Airframe
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http://i124.photobucket.com/albums/p10/GatorFanFL/dualdeploymentantizipper.jpg
Ejection Charges
Ejection Charges
Avionics Bay
Rivets
Attachment
Points
Attachment
Points
(Bad!)
Main
Bridle
Drogue
Bridle
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Inline
Typical Design
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Airframe
Drogue
Ejection
Charge
Piston
Retainer
Line
MainChute
ARRD
Wiring
AV Bay
Coupler
MainBridle
PistonSupportRing
PistonBridle
ARRD
Eye Bolt
DrogueChute
DrogueBridle
Piston
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\RATTworks ARRD.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Rear
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http://www.v-serv.com/usr/kits/2-18aDSC01060.jpg
http://3.bp.blogspot.com/_M_-GcvutiJo/SuYrrXoNQrI/AAAAAAAAAOc/3Se3ZKxRgzY/s200/DS-3r+recov.jpg
Parachute
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Hatch
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2012-11-25 19.08.41_.jpg
2012-11-25 18.50.24_.jpg
2012-11-25 18.53.36_.jpg
2012-11-25 19.11.51_.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Avionics (AV) Bays
•Design Philosophies
•Redundant Systems (if possible)
•Complete System Independence
•Power
•Switches
•Separate Power Sources
•Altimeter
•Pyro Channels
•Ease of Use!
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http://www.privatedata.com/byb/rocketry/rocket_electronics/altimeter_bays_periwinkle_bullpuppy_top.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
AV Bay
Internal Components
•Avionics Mount
•Usually a Sled
•Z-Axis Alignment
•Internal Sled Support
•Rods & Tube/Eyes
•Slotted Bulkheads
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http://www.rocketreviews.com/image-image-av-bay-38mm-400-600-031512191714653jpg-300-150-035612010315878.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
AV Bay
Power Systems
•Batteries
•9V Duracell or Werker (Soldered)
•LiPo recommended for some systems
•Battery Mounts
•Connections always at Aft
•Immovable on all 3 axis
−Zip Tie/Velcro/Mechanical Fasteners
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http://i162.photobucket.com/albums/t277/sandmantoy/DSCF1077.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
AV Bay
Switches
•Mount Internally
•More Aerodynamic
•Avoids Shearing
•Wiring
•Solder
•Terminal Blocks
•Must be Vibration/Bounce Resistant
•Mount with “On” in the Down Position
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Through Mount Slotted Switch
PCB screw switch
Frys#1945892
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
AV Bay
Static Ports
•Required for Barometric Sensors
•Recommend 3 or more ports
•Port Sizing
•DP=Diameter of Port
•VAB=Volume of AV Bay
•NP=Number of Ports
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Electronics
•Dual Deployment Altimeters
•Always have a Barometric Sensor
•May have Accelerometers, GPS, orTimers
•Ex. Co-Pilot, Marsa54, XTRA, …
•Timers, etc may be used but arenot recommended.
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Electronics
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http://www.ncsurocketry.com/wp-content/uploads/2009/09/Charge-Diagram1.bmp
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Electronics
Altimeter Configuration
•Altimeter Dependent but …
•1st Deployment (Drogue) at Apogee
•2nd Deployment (Main) at ??? ft AGL
•Parachute Opening Time
−Parachute Size
−Bridle Length
•Wind Conditions
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Ejection Charges
•Under 25,000 feet
•Solutions include Canisters orSurgical Tubing
•Typically on AV Bay Bulkhead
•Over 25,000 feet or CO2
•Requires Airtight Chamber
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http://www.wimpyrockets.com/images/mvc-010f.jpg
http://www.pratthobbies.com/prodimages/cec-5_smalla.gif
4 Inch AVBAY Lid Dual
http://www.rouse-tech.com/images/Assemblies.jpg
http://www.freewebs.com/joeysrockets/Build%20-%20Bulk%20Plates%20with%20Ejection%20Charge%20Holders.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Ejection Charges
•Sizing Based on Parameters
•Deployment Volume
•Shear Pin Size & Number
•No Shear Pins - Coefficient of Friction
•Mass of Ejected Components
•Desired Ejection Velocity
•Contingency Factor
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Ejection Charges
•Ejection Pressure (PE)
•Nose Cone Force (FNC)
•Requisite Black Powder usingIdeal Gas Law (mBP)
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WNC= Weight of Nose Cone
NC = Velocity of Nose Cone
NSP = Number of Shear Pins
SP = Pin Shear Strength
FNC = Nose Cone Force
C = Contingency Factor
ANC = Area of Nose Cone Base
VRB= Volume of Recovery Bay
RBP = BP Specific Gas Constant
TBP = BP Combustion Temperature
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Ejection Charges
•Online Calculators Inadequate
•Don’t Handle Shear Pins
•Don’t Handle Nose Cone Mass
•Don’t Handle Desired Exit Velocity
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Attachment Points
•Use Appropriate Hardware
•Don’t Use
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C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\Machine Eyebolt.jpg
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\Forged Eye Nut.jpg
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\Black Oval Quick Link.jpg
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\Black Triangle Quick Link.jpg
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\U-Bolt.jpg
C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\Link Eye Bolt.jpg
http://www.coastrocketry.com/Aerotech%20nose%20cones.jpg
http://www.coastrocketry.com/LOC%20nose%20cones.jpg
http://www.coastrocketry.com/PML%20nose%20cones.jpg
Plastic Loops - Recipe for Disaster
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Attachment Points
•Apogee deployments typicallyexperience 20 to 25g’s
•Validate Strength of Materials
•Hardware Working Load Limit (WLL)
•WLL/Weight = X g’s (Maximum)
•Evaluate Bulk Plates and Joints
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Attachment Points
•Install Correctly
•Use Washers to Distribute Load
•Fabricate needed Parts
•Secure Nuts
•Loctite
•Nylon Inserts
•Cotter Pins
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C:\Documents and Settings\Tim\My Documents\Bluetooth Exchange Folder\2012-12-05 15.55.57.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Attachment Points
Bridle (Shock Cord)
•Knots
•Bowline
•Follow Thru Figure 8
•Others significantly weaken cord
•Sewn Loops (Stronger than Knots)
•Thread Material same as Bridle
•Use Rectangle with Cross Pattern
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Attachment Points
Bridle (Shock Cord)
•Provide Thermal Protection
•Don’t Ignore Material Fatigue &Thermal Shock
•Replace Periodically (every 10flights or less)
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C:\Documents and Settings\Tim\My Documents\My Pictures\Web Site\ShockCord Protector.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Parachutes & Packing
•Drogue Chute
•High Velocity Deployment Implies HigherStrength Requirements
•Main Chute
•Shock Forces Controllable based onDrogue Chute Selection
•Provide Thermal Protection
•Heat Shield, Deployment Bag, Cellulose,Piston, Baffles or use Kevlar Materials
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Parachutes & Packing
•Parachute Sizing
•where:
•W = Total Weight
•ve = Desired Descent Velocity
•CD = Parachute Drag Coefficient
• = Air Density
•S = Surface Area of Parachute
•Diameter determined by Shape
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Parachutes & Packing
Folding Instructions
1.Fold with shroud lines asshown
2.Make one last fold overshroud lines
3.Fold top end over end untilyou reach the bottom edge
4.Connect to bridle
5.Insert thermal protection
6.Insert into airframe
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
Summary
•Success Factors
•Physical Design & Construction
•Proper Sizing & Testing
•Charges, Parachutes, Bridles, Hardware
•Avionics Configuration
•Use of Appropriate Materials
•Thermal Protection, Fatigue Assessment
•Checklist, Checklist, Checklist
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Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
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What can happen?
http://farm4.staticflickr.com/3155/2919689153_a43b90e7ca_z.jpg
http://farm3.static.flickr.com/2023/1498482846_cb42406bb4.jpg
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
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References
•Modern High Power Rocketry 2;Canepa, Mark; TraffordPublishing, 2005
Copyright © 2012 by Off We Go Rocketry, LLC
MCj04347190000[1]
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Selected Websites
•http://www.offwegorocketry.com/
•http://www.tripolimn.org/links
Copyright © 2012 by Off We Go Rocketry, LLC