Dec 23, 2015
Vehicle Dimensions
• Total length of 116.5 inches
• 4.0” Airframe (3.9” Inside diameter)
• Fin span of 3.91”
• Separates into three sections
TopNoseconePayload
Vertical Wind Turbine
MiddleDrogue
ParachutePiston
Altimeters
BottomMain ParachuteMotor (Plugged)
Fins
Materials- Airframe
• Entirely BlueTube 2.0
• Heat and Humidity Resistant
• Lightweight compared to alternatives
Product Sample Length Weight Weight per inch
Blue Tube 3" x 48" x .062 wall 577.9 grams 12.04 grams per inch
Plain phenolic 3" x 48" x .062 wall 423.9 grams 8.83 grams per inch
Glassed phenolic 3" x 48" x .062 wall 868.8 grams 18.1 grams per inch
Filament wound fg 3" x 48" x .062 wall 907.2 grams 18.9 grams per inch
Source: Alwaysreadyrocketry.com
Materials- Airframe
• Exceptionally strong material• Vulcanized paper fiber with water resistant
resin• Tubing was “a component inside a
warhead of the 155mm Howitzer, and 105mm Abrams Tank ordinance” –Always Ready Rocketry
• Is expected to withstand forces of launch
Materials- Airframe
• Maximum load of 3079 lbf (3 inch tube)
• Peak Stress of 5076 psi (3 inch tube)
• Impact resistant
Source: Apogeerockets.com Source: Alwaysreadyrocketry.com
Materials- Fins
• Fins– Composite board with
hardwood edging– Fiberglass outer layer– Honeycomb Nomex
composite inside– Must have edging to airfoil
Photos from GiantLeapRocketry.com
• One-Third the weight of G10 Fiberglass
• Retains rigidity
• Airfoil edging will be of birch plywood
• Surface will be scored with hobby knife and drilled into to increase surface area
• Through-the-Wall assembly to the motor mounting
Materials- Fins
Materials- Epoxy
• Loctite 30 minute Epoxy– All motor mounting and internal parts– Allows for absorption time – Less brittle, stronger bond
• Loctite 5 minute Epoxy– Fin Fillets
Bulkheads & Centering Rings
• 4-ply birch plates
• Each 3/16” thick
• All rings and bulkheads will be double thick
• Overall stronger plate
• More surface area to glue to
Materials- Other
• Vertical mounting boards– 1/4” to 3/8”plywood– Used in payload and electronics bay
• Nose cone– Impact resistant plastic
• Tail cone– Urethane tail cone from Public Missiles to
reduce drag
Stability Margin
• Stability margin of 2.01 calipers before launch
• Fins will be constructed last
• Fin size will be adjusted to keep this value
Stability Analysis
• 2.01 stability margin will allow for error• Small drag forces from:
– Nosecone screws– Solar panel’s edge– Pressure bleed off holes– Miscellaneous
• Margin will rise to 3.35 calipers after burnout
Vehicle Safety Verification
• Sub-scale launch Dec. 11th (backup Dec. 18th)– Verifies stability and altimeter setup
• Strength tests on fins and bulkheads• Heat, humidity, and warp testing
– Oven, freezer– Soak in water
• First full scale launch in early February with dummy payload
Construction Safety
• All personnel trained to use power tools
• Two people working on a part minimum
• Gloves, aprons, and goggles during construction
• Masks when products with fumes are used– Epoxy– Paint
Motor Selection
• Aerotech K700W
• Plugged forward closure
Motor Manufacturer
Total Impulse (N-
sec)
Max Thrust (lbs)
Burn Time (s)
Average Thrust (lbs)
Max Rocket Dry Weight*
(lbs)K1050 AeroTech 2522.038 488.29 2.46 230.48 21K660 Cesaroni 2437.380 242.55 3.69 148.49 20K750 Cesaroni 2361.966 212.74 3.14 169.16 19K700 AeroTech 2283.680 363.52 3.59 142.89 18K828 AeroTech 2157.195 293.11 2.50 193.98 16K570 Cesaroni 2070.258 200.69 1.70 119.34 15.5K635 Cesaroni 1973.146 175.06 3.13 141.76 14
* For rocket to reach 5,000 feet AGL
• Current projected dry mass = 15.4 lbs•Will have room for error
Motor Selection
• Propellant from Giant Leap Rocketry
• Hardware from Apogee Rockets– AeroTech RMS-54/2560 casing– Plugged forward closure – Eyebolt threads for solid parachute mounting
point
Source: Apogeerockets.com
Thrust to Weight Ratio• Thrust to weight = 6.81 to 1 with current
plan
• Acceleration of 364 ft/s2 on Launch– 11.3 G’s
• Rail Exit Velocity = 81.0228 ft/s
Plan for Motor Safety Verification
• Inspect for any cracks or dents on casing
• Certified personnel assemble motor – George or Jack Sprague (Mentors)
• Inspect assembly
• Aerotech K700 motor is not a prototype and has been launched before
Baseline Payload Design
• Measures voltage and current output of a flexible solar panel
• Observe changes in the strength of the Earth’s Magnetic Field
• LabPro Data logger records from all sensors simultaneously
• Accelerometer triggers data recording
• Data stored inside rocket, until retrieval
Payload Design- Structure
• Housed in the Modular Payload System (MPS)
• Three compartments
• Sensors secured with metal strapping
• All plywood
• Stainless steel support rods
Data Logging System
• LabPro Data Logger from Vernier
• Programmed to start taking data when accelerometer reads 7 G’s of acceleration
• Longer pad stay time, can take many readings from just ascent and descent
• Supplies power to all sensors
• Lithium AA batteries for reliable power source
Solar Panel System
• Solar Panel, current probe, voltage probe, resistors, and data logger
• Voltage probe in parallel around a 10 ohm resistor
• 30 ohm resistor in series to burn off voltage for sensors
• Current probe in series• Solar panel leads go through airframe to
sensors
Magnetic Field System
• Vernier magnetic field sensor
• Isolated from all other electronics to reduce risk of interference
• Will measure a peak voltage when sensor points to magnetic South
• Rocket must spin so that we know it points South at some time
Magnetic Field Probe
•Field strength across the globe varies from 3.1 x 10-5 to 5.4 x 10-5 Teslas•Typical variance in 25 nano Teslas on a given day in one location
Vertical Wind Turbine
• Magnetic Field sensor reads peak when pointed at magnetic south
• Catches horizontal wind and causes the rocket to spin
Significance
• Solar power is becoming cheaper and easier to integrate
• Viability of flexible solar on objects where direct sunlight is not always possible
• Magnetic field experiment could be used in the future for detailed data on the changes in the Earth’s magnetic field
Plan for Payload Verification
• System ground testing– Set up all sensors and record sample data– Will onboard electronics interfere with
magnetic field sensor?
• Strength test components of MPS for the amount of G-forces it will go through
• Double check that systems working before launch
• Use new batteries before every launch
Baseline Recovery System Design
• 24” TAC-1 Drogue Parachute at apogee– Backup ejection 2 seconds after apogee
• 84” TAC-1 Main Parachute at 700 feet– Backup ejection at 500 feet
• Swivels on each parachute• Perfectflite MiniAlt/WD and HiAlt45K
altimeters• Radio transmitter for locating the rocket after
landing
Recovery System• Shock cord is 9/16” wide nylon
strap– 2000# rated– 26’ on drogue 20’ on main
• Quick-Links for easier chute packing and repairs (if needed)
• U-Bolt parachute mounts• Altimeter ejections have been
staggered– Reduce risk of over-pressurizing
airframe
Eng
ine
Bur
nout
Prim
ary
Dro
gue
Chu
te E
ject
ion
(at
apog
ee)
Bac
kup
Dro
gue
Chu
te
Eje
ctio
n (
2 se
c af
ter
apog
ee)
Prim
ary
Mai
n C
hute
Eje
ctio
n (7
00
feet
)
Bac
kup
Mai
n C
hute
Eje
ctio
n (5
00 f
eet)
Flight Events and Ejections
Electronics Bay• Each altimeter will have its own 9V battery
and arming switch
• All connections will be secure so that no circuit breaks occur
Plan for Recovery Safety Verification
• Ejection charge ground tests in January
• Verify descent velocities with Rocksim
• Verify vertical wind turbine does not tangle cords
• 2000 lbs rated heavy-duty 9/16” nylon shock cord
• Altimeter testing in a vacuum chamber
• Verify function of radio transmitter in a ground test
• Use ohm meter to check ejection canisters before
installing into rocket