Monday, 27 January 2014

Tricopter design and build

This project started as an experiment in tilt-yaw steering (based on the excellent RC Explorer design from David Windestål). The first frame was made from a leftover quadcopter kit plate and aluminium 1/2 inch box section. It was small, cute, but not flyable!

First attempt proved difficult to tune and fly

The second iteration is currently in build, using wooden booms and an undertray battery/camera system to damp out video 'jello'.
Tricopter in plan - motors are 300mm from the centre of thrust

The rear tilt-able prop seemed to create a feedback wobble in the first model, so for this one I'm using a better servo and have mounted the heavy motor in line with the tilt hinge to reduce its moment. This should reduce the amount the tricopter reacts to tilting the rear prop, if I remember some basic mechanics... :o

All-up-weight with 1800mAH battery and video TX/GoPro is going to be around 900-950g. Dry weight without battery or video system should be around 550g. I'm thinking about drilling a few holes in the wooden booms to reduce weight further :D


Tail servo assembly.
Flight control board mounted on foamboard and four cubes of vibration damping foam. Hey, it might work!

Headcrab flying - with FPV!

First test flight with new landing legs, suspended battery/camera tray and FPV system installed.

It was dark, so testing was limited to the area lit by the back porch floodlight!

video

GPS + baro pressure (height) logging in the Bixler




Google Earth view of three flights - heights are logged from barometric pressure, lat lon from GPS

Platform was the Bixler trainer flown visually (hence lots of unexciting going round in circles!)

FPV - video tx/rx with DIY circular polarised antenna

Video transmitter using a GoPro camera, 5.8GHz video transmitter and a home made 'clover leaf' circular polarised antenna

Video receiver mounted on the radio control transmitter - matched 5.8GHz 'skew planar' circular polarised antenna to improve image reception
The video transmitter system mocked-up on my 'headcrab' quadcopter