The Efficiency of Flexible Solar Panels and Changes in the Earth’s Magnetic Field at Altitude

Vehicle Summary

• Total length of 116.5 inches• 4.0” Airframe (3.9” Inside diameter) • BlueTube 2.0• Separates into three sections• 22.3 pounds with motor• 17.0 pounds without motor

TopNoseconePayload

Flip-Out Rotor Blades

MiddleDrogue Parachute

AltimetersHousing for Rotor Blades

BottomMain ParachuteMotor (Plugged)

Fins

Payload Summary

• Studying the efficiency of flexible solar panels, and changes in power output

• Also investigating changes in the earth’s magnetic field

• Housed in the Modular Payload System (explained later)

Vehicle Changes

• Piston added to the main parachute compartment to deploy the main parachute

• Hinges on flip out rotor blades have been upgraded from mouse traps to small door hinges with rat trap springs

• Dry weight is now 17.0 pounds

Payload Changes

• Slots in the Modular Payload System have been enlarged to slide over solar panel wires– Reduces the risk of shearing wires inside

airframe

• Because of the solar panel, a hole cannot be drilled through the airframe to verify payload on pad

• Payload will have to be activated and verified before installing

Motor Selection

• Aerotech K828 FJ

• 54/2560 mm casing

• Proven to take rocket to projected altitude

Motor ManufacturerTotal Impulse (N-

sec)Max Thrust (Newtons)

Burn Time (s)

Average Thrust (Newtons)

Thrust to Weight Ratio

K828 AeroTech 2120.0 1,303.8 N 2.50 828 8.35 to 1

Estimated Rocket Performance

• Estimating a coefficient of drag of around 0.55• Dry weight of 17.0 pounds

Note: Simulations calculated with 5 mph winds

Motor Thrust Curve

Rocket Flight Stability Margin

• Center of gravity 73.4 inches from nose

• Center of pressure 87.5 inches from nose

• Stability margin of 3.50 calipers

• Stability of 4.86 calipers after burnout

CG Position: about 74 inches from noseCP Position: 87.5 inches from nose

Stability Margin: about 3.38

Thrust to Weight Ratio

• Thrust to weight ratio is 8.35 to 1

• High acceleration of approx. 459 m/s2 (14 g’s)

Acceleration (ft/s2) vs. Time (s)

Rail exit velocity

• 8 ft Rail = 75.0 ft/s• 10 ft Rail = 83.3 ft/s• 12 ft Rail = 90.8 ft/s

• Planned to launch using a 10 ft rail• 12 ft rail was used for test flight• Lugs compatible with Standard 1” Black

Sky Rails

Parachute Sizes and Descent Rates

• Drogue parachute: 24 inch diameter TAC-1• Four flat strap nylon suspension lines• Deploys at Apogee (backup charge 2 seconds

later)• Drogue descends at approx. 71 ft/s• Swivels are attached to each parachute• Additional swivel attached to drogue mount

Parachute Sizes and Descent Rates

• Main parachute: 84 inch diameter TAC-1• Four flat strap nylon suspension lines• Deploys at 700 feet (backup charge at 500 feet)

• Estimated descent rate of 19 – 20 ft/s• Drift in 5 mph= 500 feet• Drift in 10 mph= 900 feet• Drift in 15 mph= 1800 feet

Large Margin of Error

Test Plans and Procedures

• BlueTube airframe was able to withstand 300 pounds of force of compression without signs of failure

• 350 degrees for 30 minutes = ⅛” increase in circumference

• Freezer for 30 minutes = No notable change• Underwater for 30 minutes = Tube began to

wrinkle• 5 hours in sun = No warping found

Test Plans and Procedures

• Decal radiant heat test• A precaution for BlueTube warping from uneven

heating

Test Plans and Procedures

• Exposed to light for 10 minutes (temp leveled off)

• Four trials in 2 different positions to limit bias• Replacing black with white in color scheme

Test Plans and Procedures- Assembly

• Before loading ejection canisters with black powder on launch day continuity will be verified in all electric matches with altimeters

• No cell phones or unnecessary electronics in work area• Parachutes and piston are to be coated in talcum

powder before installing• All six quick-links must be verified at least once by two or

more people• At launch pad igniter is to be installed AFTER activating

altimeters

Test Plans and Procedures

• All sensors for payload have been verified and function as planned– Sensors must be zeroed before use for best results

• Accelerometer– Held up for 5 seconds, down for 5, shook, then hit against palm

• The magnetic field sensor was rotated clockwise to check functionality

• Peak readings when pointed to magnetic south (geo graphic north) as expected

• Does not appear to be affected by other sensors

Test Plans and Procedures

• The ground station has been completed and tested• Solar panel, current probe, voltage probes, and resistors

are set up like in rocket• In full sun 1.184 V around 10 ohm resistor and .2491 A• Total voltage difference = 9.12 V, Total power = 2.27

Watts

Test Plans and Procedures

Full Scale Flight Test • Feb 26th Launch cancelled to lack of FAA waiver• One full scale flight was completed on Sunday,

March 6th

• Notable turn into wind off of launch rail

Full Scale Flight Test • NO main parachute deployment• Rocket landed under drogue in soft field• Only damage to rotor blade hinges• Altimeters read 5219 feet and 5267 feet

Full Scale Problems

• Main parachute was stuck in airframe• All flights suspended until problem resolved• Next launch cancelled because of problem, high

winds, and closing of field in Waco

Full Scale Conclusion• Rocket structure can handle forces of flight• Main parachute system now resolved • Rotor blades repaired and upgraded• Ready for flight

Dual Deployment Avionics Test

• Completed on Monday, December 13th

• Altimeters placed in a vacuum chamber• Both altimeters showed a drogue and main deployment• All ejection charges were detonated during launch

Ejection Charge Amount Test • Drogue parachute tests completed February 19th

and February 21st

• 2.3 grams of FFFF black powder• Successful separation, deployment of drogue,

and deployment of rotor blades

Ejection Charge Amount Test

• Main parachute tests on February 21st, March 12th, 18th, and 19th

• On Feb. 21st parachute pulled roughly halfway out of tube

• Minimal force required to release parachute• Parachute was believed to deploy on the 21st,

because drogue parachute would act as a pilot chute

Ejection Charge Amount Test

• Parachute failed to separate from airframe on first test launch

• Tests were redone with parachute packed tighter and talcum powder

• Test failed to pull out parachute

• Lack of moving mass, lack of force

Parachute only halfway out of airframe

Main Parachute Ejection Options

1. Add more black powder2. Add mass to electronics bay3. Wrap shock cord around parachute4. Use a piston recovery system5. Use a parachute bag6. Move separation joint closer to parachute7. Attach a ball below parachute to pull out

parachute

Main Parachute Ejection• On 7th main parachute test (10th overall)

main parachute ejects with a piston system

Payload Integration Feasibility • All sensors and data logger are made by Vernier

Software and Technology• Data logger is also power source for all sensors• LabQuest has been modified by Vernier to fit

into the payload airframe• To retrieve data the data logger unit must be

retrieved

Payload Integration Feasibility

• All units contained in the Modular Payload System (MPS)

• Constructed out of birch plywood• Two ¼” threaded steel rods for structural integrity• Excess wiring will be coiled and stored in bottom section

of MPS• Slots cut in bulkplates to allow for wiring to pass from

one section to another• Must be installed facing specific direction to slide over

solar panel wiring

Modular Payload System

Payload Integration

• Slots in MPS slide over solar panel wiring

Terminal block where positive and negative leads from solar panel connect to payload

Removal of the MPS• Nosecone must be removed• A strap will be connected to the two stainless steel

rods the can be used to pull out the MPS

• When the mid section is exposed the wires from solar panel are disconnected

• The entire unit is taken to computer for data retrieval via USB cable

Educational Engagement Plan & Status

• Status: Complete• 160 Students engaged at Rockwall-Heath High School• February 10th- Students designed fins in Rocksim and

constructed fins at home• February 14th- Approximately 80 rockets were built

during school hours. All parts were supplied other than fins and egg padding

• February 26th- Rockets were launched at Tate Farms, a local ranch

Educational Engagement Plan & Status

• February 15th and 16th the team visited Cain Middle School

• Students who volunteered to stay after school received a brief presentation

• Students then built rockets from paper and other scratch materials

• Rockets were launched on February 26th as well

Questions?