Sunday, January 29, 2012

carbon fiber tricopter frame

The last tricopter frame was really light.  That was about the only good thing about it.  The wood was brittle, and broke at the joint of the T a couple of times.  It didn't take much to fix, but I wasn't pleased with how fragile it was.  

So I made this strange skewy triangle of carbon fiber tube and acrylic sheet.

There are three pieces of acrylic holding it together.  Each piece has a long blind hole for receiving the end of a boom, and an angled hole for another boom to slide into. 

This makes the frame modular.  It's easily taken apart and put back together.

 I started measuring the masses of each of the components to see where things can be lightened.

ESCs - .70 oz
motor, prop, and arm - 1.3 oz
controller, sensors - .80 oz

I CA'd two thin neodymium magnets to the underside of the sensor/controller unit and to one of the acrylic arm supports.  They firmly hold the board to the frame, and make it easily removable.

The three batteries pictured are all 3s LiPos
top silver - Zippy 1250mAh 25-30C - 3.52 oz
yellow left - Rhino 630mAh 20C - 1.92 oz
bottom blue - Turnigy 1300mAh 40C - 4.20 oz

To put that in perspective, the frame (everything minus battery) is 6 oz.

I'll have to do some flight tests to see which one has the best endurance.  There's a very clear difference in flight characteristics between them.


  1. This is awesome! I might try the neodymium magnet trick, but with foam in between for vibration damping. The magnet attached to the sensor board would help by adding mass to it as well. It will make the magnetometer useless though. Another interesting idea is to mount the motors with a magnet / foam sandwich to try to kill off vibration at its source.

  2. mm, I didn't think of foam between magnets. I feared that the magnets might screw with my sensors, but I think they're weak enough/distanced by the half inch or so of foam underneath the sensors.