Barry Barrios Structural Engineer Daniel Chaparro Structural Engineer Laura Garrity Propulsion Chad Lieberman Control Surfaces Adam Vaccaro Electrical Engineer/Systems Integration Completed Design Review TEAM

Design 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 Control  A servo will pivot the big motor up or down.  Vector thrust from the big motor will raise or lower tail of blimp to adjust altitude. By Chad Lieberman

Roll Control  The center of mass will lie in the middle of the bottom of the truss structure so that the blimp will not naturally roll in either direction to achieve equilibrium.  The balloons will be held in a net-like structure and secured to both the top and bottom of the truss structure to minimize a swaying motion that would cause a roll.

Yaw Control  Second Servo will pivot small motor left or right.  Vector thrust will steer the front of the blimp left or right to control movement about the lateral axis. By Chad Lieberman

Small Motor Big Motor Propeller Receiver Servos Receiver Battery 9.6V Battery Balloons Wood Frame Total: Quantity 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 = (ρ air – ρ helium )*g*V Helium Density = kg/m3 Air Density = 1.25 kg/m3 g = gravitational constant 9.81 m/s2 V = Volume of helium used Volume Helium Required = 1.47 m 3 Volume per balloon =.52 m 3 (assuming 1.5 kg total weight including payload)

Aerodynamic Analysis Estimated Time Max Thrust =.95 N Max velocity = T (.5*S*c d ) 1/2 v max = 0.93 m/s Distance = m Time straight line = 94 s Time total = 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.