Barry BarriosBarry BarriosStructural EngineerStructural Engineer

Daniel ChaparroDaniel ChaparroStructural EngineerStructural Engineer

Laura GarrityLaura GarrityPropulsionPropulsion

Chad LiebermanControl Surfaces

Adam VaccaroElectrical Engineer/Systems

Integration

Completed Design Review

TEAM

Design ObjectiveDesign Objective

The goal of our CDR and the meeting we held between the PDR and CDR was to finalize our design. We aimed at creating a lightweight craft that was maneuverable and quick. To help meet these goals, we lightened the truss system by decreasing supports, and instead of torque arms for steering we are using motor/servo linkages that will rotate and direct the thrust.

Pitch ControlPitch Control

A servo will pivot the big A servo will pivot the big motor up or down.motor up or down.

Vector thrust from the Vector thrust from the big motor will raise or big motor will raise or lower tail of blimp to lower tail of blimp to adjust altitude.adjust altitude.

By Chad Lieberman

Roll ControlRoll Control

The center of mass will lie in the middle of The center of mass will lie in the middle of the bottom of the truss structure so that the the bottom of the truss structure so that the blimp will not naturally roll in either direction blimp will not naturally roll in either direction to achieve equilibrium.to achieve equilibrium.

The balloons will be held in a net-like The balloons will be held in a net-like structure and secured to both the top and structure and secured to both the top and bottom of the truss structure to minimize a bottom of the truss structure to minimize a swaying motion that would cause a roll.swaying motion that would cause a roll.

Yaw ControlYaw Control

Second Servo will Second Servo will pivot small motor left pivot small motor left or right.or right.

Vector thrust will steer Vector thrust will steer the front of the blimp the front of the blimp left or right to control left or right to control movement about the movement about the lateral axis.lateral axis. By Chad Lieberman

Small Motor

Big Motor

Propeller

Receiver

Servos

Receiver Battery

9.6V Battery

Balloons

Wood Frame

Total:

Quantity

1

1

2

1

2

1

1

3

1

Weight

90 g

210 g

5.2 g

27 g

43 g

90 g

180 g

30 g

322 g

1205 g

Aerodynamic Analysis

Vehicle Weight

Aerodynamic Analysis

Helium Required

Lift = (ρair – ρhelium)*g*V

Helium Density = 0.174 kg/m3Air Density = 1.25 kg/m3g = gravitational constant 9.81 m/s2V = Volume of helium used

Volume Helium Required = 1.47 m3

Volume per balloon = .52 m3

(assuming 1.5 kg total weight including payload)

Aerodynamic Analysis

Estimated Time

Max Thrust = .95 N

Max velocity = T

(.5*S*cd)1/2

vmax = 0.93 m/s

Distance = 87.78 m

Timestraight line = 94 s

Timetotal = 120 s

• Moved motors to a more central location to increase stability of design

• Lowered motors below main truss structure to allow more room for them to move and in order to avoid the air movement they create disrupting the balloons paths and stability

• Removed large stabilizer in an effort to decrease weight and nonessential parts

Evolution of Design

• Decided to put battery pack and receiver and all payload possible in one central control systems and payload storage area

• Decided that even with extra airflow generated by motor elevator wasn’t guaranteed to work, so removed it

• Kept three-balloon-in-a-row design due to required lift and desired maneuverability

• Altered truss structure a little to increase strength and decrease weight

Evolution of Design

Conclusion

Our design process has been a series of compromises between strength, weight, speed, maneuverability and feasibility. Our final design sacrifices some structural support in favor of weight, and we use fewer motors than originally planned. We feel the method of control we are using will be more effective and lighter weight than using torque arms. Final adjustments will depend on trials day and how the balloons perform with our craft.