1. Giving Bertha! LTA CDR David Dryjanski – Design/Construction, SolidWorks Expert Rachel Ellman - Design/Construction Carl Engel - Team manager, Propulsion and Control, Pilot Viviana Serra - Design/Construction Joshwa Wang - Design/Construction, Conceptual Artist

2. Objective  Explain design changes since PDR  Present and analyze our updated design ideas and innovations

3. Design Evolution  Threw out idea about each motor driving two propellers  Decided to keep horizontal stabilizer stationary  Added 2 nd rudder for better turning  Changed the front motor from stationary to 2-axis thrust vectoring

4. Introduction to Final Design  Bertha is a good combination of stability and simplicity  Good payload capacity  Fast  Truss is aesthetically pleasing  Intricate structure; very light and strong

5. Scaled Drawings SolidWorks drawings by David Dryjanski

6. Side View SolidWorks drawings by David Dryjanski

7. Isometric View SolidWorks drawings by David Dryjanski

8. Control Systems  Dual rudder system to deflect prop-wash of rear motor for yaw control  2-axis thrust vectoring (yaw and pitch) for front motor

9. Aerodynamic Analysis   10% over-inflation of balloons   He volume: 1.39 m 3   Lift capacity: 1.47 Kg   Vehicle mass estimates- 2 small motors with 2 large propellers: 80g (x2) = 160g receiver, wiring, and 3 servos: 40g + 10g + 110g = 160g battery (2 packs): 300g balsa structure and stabilizers: 100g Total: 720g   Payload capacity: 0.75 Kg

10. Aerodynamic Analysis (cont.)  Thrust: (measured) = 2.84 N per motor = 5.68 N  Coefficient of Drag: 0.5  Force of drag at V max = Thrust = 5.68 N  Maximum Velocity: 3.1 m/s  Estimated time for course completion (assuming perfect turns): 28 seconds  Realistic Time: appx. 1 minute  Endurance: 3.6 minutes of battery power

11. Conclusion Based on our Preliminary Design Review, we narrowed down our options to create an optimal LTA vehicle. Through extensive meetings and discussions of pros and cons of different design implementations, we have concluded that our current arrangement will provide maximum performance.