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

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

• Recent delays in funding have delayed parts orders and some parts have gone out of stock– Aerotech K700 motor now Aerotech K828– Aerospace composite fins now fiberglass covered

birch plywood– Ejection canisters will be made and not bought– Piston removed on drogue parachute compartment

• Design changes from subscale problems– Ejection charge holders have been added– Vertical Wind Turbine has been replaced with flip out

rotor blades

Payload Changes

• The LabPro data logger does not support a data trigger

• Exchanged for a custom built LabQuest data logger from Vernier at no charge

• The proper amount of resistance has been researched and verified by manufacturer– 77 Ohms of resistance instead of previous 40

Ohms

Motor Selection

• Aerotech K828 FJ

• 54/2560 mm casing

• Change was made because K700 Motor was out of stock from multiple vendors

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 8.64

Estimated Rocket Performance

• Estimating a coefficient of drag of around 0.60• Estimated dry weight of 16.37 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: 73.4 inches from noseCP Position: 87.5 inches from nose

Stability Margin: 3.50

Thrust to Weight Ratio

• Thrust to weight ratio is 8.64 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

• 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)• Estimated descent rate of 82 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• 2 hours in sun = 1/16th inch bend across 4 feet

Test Plans and Procedures

• A 3/16th inch birch plywood bulkplate withstood 200 pounds of force before test was stopped– Force was applied by stepping on exposed plate– Plate was permanently warped 1/8th inch across

diameter

Birch Plate

Clamp

Force

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

• Solar panel, current probe, and voltage probes have been tested– Test was done in evening sun– Not optimal power output– Solar panel was 50% covered, then roughly 90% bcovered, then

fully covered

Test Plans and Procedures

• Remaining tests:– Ejection charge deployment test

• Procedure explained later

– Solar panel test in full sun• With 77 ohms of resistance, current and voltage

probes

– Fin strength test• Identical to bulkplate test

Test Plans and Procedures

Scale Model Flight Test • Two half-scale flights have been

conducted• One ejection charge test before flight• Aerotech H180 • 3.5 Stability margin

• Two straight flights without any wobble• Set up for dual deployment

Scale Model Flight Test

• First launch reached 2403 feet• Second launch reached 2313 feet• After launch conditions were put into Rocksim• Estimated drag coefficient of 0.45

Scale Model Problems

• First launch blew a hole in the main airframe (no main parachute)– Cause due to no ejection

charge canister support

• Second launch separated for main parachute, but parachute did not deploy

-Cause due to use of Pyrodex/ not enough black powder-Extensive ground testing will be completed with 4F black powder for full-scale

Scale Model Problems

• First launch carried a vertical wind turbine– Slow, inconsistent spin

• Second launch carried flip out rotor blades– Fast consistent spin, but shock cord caught

under blade and twisted

Scale Model Problems

• Rotor blade cracked– Higher grade propeller will be used for full scale

• Shock cord heavily twisted– Shock cords will be better packed use a rubber

band to contain cords for organization

Dual Deployment Avionics Test

• Completed on Monday, December 13th

• Altimeters placed in a vacuum chamber• Both altimeters showed a drogue and main deployment

Ejection Charge Amount test

• Status: In planning

• Calculated 3.1 grams for main, 2.3 for drogue

• Calculating for 300 pounds of force or 23.9 psi

• Plenty of force to break three 2.5 mm styrene shear pins

• 6 total ground tests will be performed

Ejection Charge Amount Test

• Start test with ejection charges sized below calculated amount

• Rocket will be mounted horizontally

• Ballast will be used to simulate actual weights

• Test must clearly eject and pull out parachutes

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

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

• “To Apogee and Beyond” Project currently in progress• High schools students will learn about the basics of

rocketry– Will design and make fins for a partially designed rocket in

Rocksim– Working in groups of 2 or 3, they will assemble their rocket

• Large scale launch day on February 27th where the 200+ students will launch their rockets

• Launch site at Local ranch: Tate Farms

Educational Engagement Plan Status

• Visiting the local middle school’s aeronautics class – Status: Scheduled for first week of February

• Visiting local elementary school’s science night and will give presentation– Status: In development

Questions?