3D Printed TriCopter

Hi, 

this is my first attempt at designing my own tri copter design based off of David’s design and some of flit tests rotor bones but with my own inputs, some good some bad. 

First let’s start with the frame. i designed it in Solidworks and  wanted it to encompass certain traits that i liked about David’s quad (ability to fold) and Flite test's cheap simplistic parts. First i wanted to change the ability to fold all the arms in all directions, in case of crash i don’t want anything to break. especially the frame as it takes 8 hours to print and at a cost of 55$ (5$ a cubic inch) so with that in mind i looked at many ways of holding the arms in place, and i thought of something like a wood dowel that would fail on a crash, but that would be a pain to change all the time and to fold up quickly. so i thought of magnets and after getting some neodymium 1/2 magnets form the local lee valley i put to test and found that it would have good force. i calculated the weight at the end of the arm and then calculated the MOMENT force at the magnet and what it took to slide the magnets apart and found that if the tri copter was on the side( high bank turn) then it would not collapse under its own weight. http://www.splung.com/content/sid/2/page/moments  ( to learn about moments) 

Once I was happy with this i went on to designing the frame. Measuring my board cam, go pro, kk2 board ect. 

Once finished i was left with this ! 

You can see the recessed spots in the arms for the magnets 

i then printed the frame at school on our dimension printer. 

and ended up with this ! 

The black material is the support material that the printer prints on as it can’t print in 3d space. Think of it as scaffolding that you dissolve when your part is finished. 

as you can see the board cam fit like a glove but when Cadding the camera slot got messed up a little but still works.

The next challenge was the Yaw mech. i was going to 3d print the yaw mech but i did not want to make an expensive breakable part. So i went to the local plastic shop and bought some Delrin ( what flitetest uses) this plastic has really good where resistance and is high flex and is tough. so it makes for perfect motor mounts/ landing gear/ yaw mech. so after sitting down and measuring and 2d modeling. i sent it off to the laser cutter  to get cut out and the whole cut took about 10 minutes for all parts. Here are the pictures of the yaw and landing gear and the tri copter as is. 

Still waiting for my electronics from hobby king. i will update this post as i build it and then will upload some fpv shots.