Down Selection of Final Design
-Needed to be sleeker and lighter
-3D print had to come out with supports for better results
-Previous failures, as can be seen in the photo, gave better clarity on what was reasonably achievable
-Greater diligence was needed for the primary objective criteria
Final Finite Element Analysis
-9 gram model, satisfies weight criteria
-maximum of 38 microns of displacement
-Under the 100 microns of allowable deflection
-Improved motor strut support now inline with outer frame support for greater structural integrity
Fabrication of Final Design
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Wiring schematic
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Soldering
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Propeller rotation direction
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Adhesives
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Fine tuning controller
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Probability of damage, Printed backup
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Replaced motor that had extremely high resistance, indicating no current flow at full throttle. Current is inversely proportional to resistance
Final Result
Lessons Learned
-Many prototypes had to be constructed in order to gain a practical knowledge
-3D printing has advantages but behaves very different from plastic injection molds. Can be difficult and fragile in tight tolerances of high load bearing implications.
-FEA gives a good perspective of which attributes have the greatest influence on the rigidity of a structure. Could have made a lighter drone, but opted to make it stronger for a decent crash.
-Thrust from the powerplant was greatly increased by the structural design
Results
We were pretty happy with our design.
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Our design was able to carry a parload of 11 grams in the real test process.
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Whereas, in our own test flight, it was capable of carrying a payload of 13 grams.
Conclusions
-Iterative process of design, fabricate, analysis, test and repeat until goals were met
-Subtle improvements made huge differences
-Gained perspective of creating a manufactured performance part
-Teamwork is a vital tool in achieving a conglomerate objective
-Drones are awesome!