seattle central community college, seattle, washington science and math department 2008-2009...
TRANSCRIPT
Seattle Central Community College, Seattle, Washington
Science and Math Department2008-2009
Members: Colin Webb, Cooper Clausen, Luan Duong, Brian Injugu
Team organizationTeam lead: Colin Webb
Electronic system: Cooper Clausen
Recovery system: Luan Duong
Logistics: Bryan Injugu
Project’s GoalsTo participate in 4th Intercollegiate Rocket Engineering
Competition in Utah June 24th-27th, 2009.The project is student led and researched.The rocket must be constructed with a minimum amount of
cost.The rocket must clear the launch rail and reach an
estimated altitude of 10,000 ft.The avionics must record data multiple times during flight
and be retrieved easily after flights.The single state recovery system is controlled by avionics
onboard the rocket continuously.The recovery system must land the rocket on the ground
safely and in a reusable condition.Flight data including the peak altitude must be provided
within 2 hours after recovery.
Propulsion SystemHomemade hybrid rocket engine using
Hydroxyl Terminated Polybutadiene (HTPB) as the solid fuel and N2O as the oxidizer.
Why hybrid? It’s a simple and easy to make engine minimizing the overall cost of the rocket.
Weight: 20 lbs N2O + 23 lbs HTPB
IgnitersHomemade igniters
using black powder and magnesium filings
Nichrome wire heats up, ignites black powder/magnesium filing mixture
Nozzle17-hole showerhead injecting nozzle allows
proper vaporization to the igniters.Graphite thrust nozzle cast directly to the
solid fuel grain
Oxidizer Tank and Plumbing systemReconditioned aluminum storage tank pressurized
to 750 psiRadio controlled fuel plumbing system and fuel
hose ejectionFuel ball valve connected to a radio controlled
actuatorContains 20 lbs of N2OEstimated thrust is about 600 lb, provided the
rocket an initial acceleration of 3.7 G’s.
Recovery SystemSingle stage deploymentElectronically controlled by G-Wiz HCX flight computer system.Auto-detected apogee chute release.Barometric and acceleration sensors provide
accurate apogee detection and precise chute release control.
30 ft diameter military surplus parachute Spring loaded pilot chute deploys the main chute.Search radius is about 2 miles from the launch
rail
Electronics Launch SystemControlled by radio signals.Radio transmitter and receiver modules are
TLP434A and RLP434. Digital signal are encoded by an HT12E chip.3-event digital signals including: to open or close
valve gas, and to eject the fuel hose.A circuits which detects the orientation of the
valve will fire the igniters automatically.4 power supplies to minimize supply decoupling
issues during design and testing phases.
StructureA simple structure of 3 aluminum U channels and
9-inch diameter plywood bulkheads. Reinforced by more U channels, L brackets and
riveted together.Solid fuel grain is attached by an aluminum
casing and reducer framing.The body was reinforced by concrete form tubes.Due to the lack of composite materials, lowing
down the weight is impossible.As a result, we opted to forego having a payload
and attempt to launch the rocket as is.
Nose ConeSelf-constructed nose cone was made from
marine type fiberglass laid around a mold and rounded at the tip.
Conical design chosen over ogive in the interest of easy fabrication
Construction road cone used as the mold
FinsCalculated dimension of the fins was
obtained using the Barrowman’s equations and a spreadsheet calculator provided online
3 fins spaced 120 degreesConstructed from Attached directly to engine housing
Launching ProcessStep 1: Fill the oxidizer tank with N2OStep 2: Move rocket to vertical launch
positionStep 3: Eject fuel lineStep 4: Initiate fuel delivery / ignitionStep 5: Main chute deployment just after
apogeeStep 6: Locate / Recover rocket on ground
and retrive altitude information
Possible Failure PointsWill plumbing hold 750 psi?Will igniters create enough energy to ignite
nitrous oxide?Will injection nozzle vaporize fuel?Will thrust be sufficient to lift rocket off?Will thrust be sufficient to achieve altitude
and stability?Will G Wiz detect apogee?Will parachute deploy properly?