Recently I became interested in building my own multirotor UAV, often called Drones and other stigmatized names. Specifically I wanted to build my own quadcopter from the ground up, the type with 4 upward facing propellers atop high powered brushless motors.
Design of the UAV took place in Solidworks, which enabled me to size everything correctly and check clearances and such.
Before starting the design phase I looked around at a few existing 3D printable designs and chose one to base the initial design.
Some of the specs
- ArduFlyer 2.5.2 to be used with APM flight planner for real time telemetry w/ GPS module
- 2200kv motors
- Afro 30A ESCs
- 2x 2200mah 3s lipo packs
The quad came together pretty quickly after I had finalized the design, 3D printed the body+arms, and received all my parts from different sources online.
Then I took it on it’s maiden flight: and this was the result.
About 1 second after liftoff two of the motors ripped themselves free taking part of the arms with them. Obviously the arms weren’t strong enough to combat vibrations from the motor and props as well as lift forces generated by the props nearby the motor. I also realized the motor/ESC combo I purchased was quite a bit more powerful then I realized and would need to beef up the rigidity of the frame accordingly.
After the first flight and ensuing catastrophic failure was witnessed by my engineer friend Drew, he took measurements from my previous design CAD files and created a new arm design that he felt would be able to take the motor’s vibrations and torsional forces.
I took that arm design and modified it to use lofts a little more smoothly around the motor mount area and added mounting points for the arm to the body. The body was designed by me to be able to fit most of the electronics inside with the controller and reciever plus other control hardware on the top. The body splits in two for easy access to the power electronics. The arms are attached to the upepr and lower parts of the body via small aluminum mounting tabs I made out of 4x5mm aluminum bar stock.
The arms were printed with very low infill as it was designed to distribute most of the forces around the outside surface. After printing, holes were drilled on either side of the arm for the motors wires and ESCs to fit through.
Assembly took a quite bit longer than the first version as feeding the ESCs through the arms to get the motor leeds out the other side for connecting the motor proved quite troublesome and tedious. Mounting the arms and making sure clearance was good between multiple 3D printed parts required a little bit of sanding and forcing certain parts together.
Can you guess what happened when I flew it for the first time?
3D printed sturdy quadcopter and multirotors are possible, there are tons of working designs out there, you just need to print them thick enough.
My V2 design may have been more successful if I took advice from nature and filled the arms with foam after running the motor wires.
Design, crash, learn, repeat I guess.
It’s in the works.
It’s going to be made out of aluminum square tubes.
And when I crash it, It will probably be able to fly shortly after.