The Tricopter build

It was a long time since I owned a helicopter, they were to expensive and fragile. I hated that you had to order replacement parts every time you had a minor crash. I want to be able to repair it my self, swift and easy. So I decided to design my self a Tricopter. That way I get it just the way I want it.

So what is a Tricopter?

It’s an aircraft similar to a helicopter except it has three rotor disks. The beauty of the design is that three ordinary outrunners direct driving ordinary propellers can be used. Four helicopter gyros makes the tricopter super stable. And to make it yaw a servo tilts the back motor. You set your radio for 120° CCPM and your good to go. It’s as simple as that. Very low part count, simple, cheap, easy to build with no advanced electronics needed.

What to buy?
After testing various speed controllers, motors, gyros, etc. These are the electronics I recommend buying for a tricopter weighing under 1.2kg:

3 x 2213N 800Kv Brushless motors
3 x TURNIGY Plush 18amp Speed Controllers
4 x Hobby King 401B AVCS Digital Head Lock Gyro
1 x 6 pack GWS 10*4.7 propellers
1 x 10 pack prop adapters
1 x BMS-385DMAX Digital Servo (Metal Gear)

1 x 3S 2200mAh Turnigy LiPo
1 x Turnigy UBEC for making the “jump starter” for the gyros

These are electronics I know work good on a Tricopter and have personally tested.

The Build
Now lets start building.

I used 1.5mm DIY PCB glass fiber laminate for making the motor mounts.

This is my solution for the back motor tilt. It’s a T-Rex 450 blade grip mounted to a piece of plastic.

It’s super low friction that I hope will give me a slop free tilt mechanism.

The back motor mount test fitted with the tilt mechanism.

I used a T-Rex 450 tailboom that I had laying around for making a light weight filler so that the glass fiber lamination doesn’t flex when I screw down the motor.

I made a simple servo mount to get the servo to the right height and make it easy to remove.

Here are the servo plates that also holds the tilt mechanism.

To remove weight I etched away the copper from the glass fibre laminates.

Test fitting the motor mount.

Turned out pretty nice. I will be using wood as my arms and as you can see in the picture, the mount is just screwed down, clamping the wood. This makes it super easy to fit new arms if I ever brake one or want to try longer ones.

This is my frame design. It’s not super pretty but I hope it does the job.

My tricopter is going to be foldable so I drilled a hole through the two front arms.

The tilt mechanism almost done. I had to add a piece of plastic to make it as thick as the arms.

Tilt mechanism done.

Motor mounts done.

I cut of a piece of the top piece of the frame to be able to mount the receiver in-between the to sheets of 1.5mm glass fiber laminate.

Gyros in place.

Started work on extending the cables on all the ESCs. Before and after.

All the electronics in place.

For some reason the Turnigy gyros did not work well with the Futaba receiver I had planned on using. I think it has something to do with the shorter frame rate Futaba 2.4GHz system uses. It made the output of the gyros go crazy at some points, so now I use a Assan 6 channel receiver.