Lighter Than AirLighter Than AirCritical Design Critical Design

ReviewReview

Mark CoteMark CoteYonas TesfayeYonas TesfayeJosh LevingerJosh LevingerBryan OwensBryan Owens

The A-Team

Presentation Presentation ObjectivesObjectives

Introduce Final DesignIntroduce Final Design

Scale drawings of final designScale drawings of final design

Control systems of final designControl systems of final design

Aerodynamic analysis of final designAerodynamic analysis of final design

Final design evolution and analysisFinal design evolution and analysis

Final DesignFinal DesignLinearLinear– Pros:Pros:

Reliable and well testedReliable and well testedLow drag profileLow drag profileStabilityStabilitySimplicitySimplicityExpandableExpandable

– ConsConsDifficult to maneuverDifficult to maneuverLarge structure Large structure requirementrequirementUnwieldy (N-body Unwieldy (N-body problem)problem)

Scale DrawingsScale Drawings

Front View Courtesy: Mark Cote

Scale DrawingsScale Drawings

Side View Courtesy: Mark Cote

Scale DrawingsScale Drawings

Bottom View Courtesy: Mark Cote

Control SystemsControl SystemsWe will be using two servos to steer. The motors are in line and the We will be using two servos to steer. The motors are in line and the front motor will be used to steer left and right. The rear motor will be front motor will be used to steer left and right. The rear motor will be used to control pitch. We will also have rear stabilizers. used to control pitch. We will also have rear stabilizers.

Circuit DiagramCircuit Diagram

Courtesy: Josh Levinger

MaterialsMaterialsObjectObject QuantityQuantity Mass (g)Mass (g)Large MotorLarge Motor 2 2 420.0420.0PropellersPropellers 2 2 15.915.9ReceiversReceivers 1 1 27.027.0ServosServos 1 1 43.043.0Battery packBattery pack 1 1 148.0148.0BalloonsBalloons 3 3 210.0210.0StructureStructure 1 1 175.0 175.0

Total Weight : ~ 1040 gTotal Weight : ~ 1040 gTotal Payload: ~ 710 gTotal Payload: ~ 710 g

Aerodynamic Aerodynamic AnalysisAnalysis

maxmax )( VgL Heair

DSC

DV

2

g

WV

HeAir )(

=1.773 m3

1 balloon = .524 m3

3 balloons overfilled should support the weight.

We believe that we will average 2/3 of the maximum thrust throughout the course for a velocity of 2.09 m/s.

eqeq ThrustDrag

Lift generated by three normal balloons: 15.205 NOverfilling Balloons: 17.150 N

V

DT We believe our blimp will be able to

complete the course in 42 seconds.

Final Design Evolution and Final Design Evolution and AnalysisAnalysis

Originally, we had decided on a triangle Originally, we had decided on a triangle design with differential steering. Our first design with differential steering. Our first concern was in regards to drag because it concern was in regards to drag because it had profile drag of about two balloons as had profile drag of about two balloons as which meant we would be fighting twice as which meant we would be fighting twice as much drag. much drag.

Front View

Top View

Courtesy: Mark Cote

Analysis Cont’d Analysis Cont’d We also realized that with differential We also realized that with differential

steering, we would lose a significant steering, we would lose a significant amount of thrust.amount of thrust.

Good Luck to all the Good Luck to all the Teams!!!Teams!!!