Unmanned Aerial Vehicles
Finally had a nice sunny day to take my Arducopter for it’s first flight!
It is not as stable as I thought it would be; most of the flying time I had it in ‘loiter’ mode which attempts to maintain a position based on GPS and altitude (using either barometer or sonar). Even so as you can see from the video it moves around quite a bit still – next time I’ll take my laptop to make sure it has a solid, accurate GPS fix before launching.
Three flights in total, the last one had a hard landing which flipped the quadcopter throwing a prop; all fixed in just a minute ready for the next flight in a few days.
My recent obsession with Arduino brought me back to an old interest: autonomous flight!
I totally love the open source community and the great stuff that people throw in together on…such as DIY Drones.
DIY Drones is a community built project using Arduino microcontroller to control a multi-rotor helicopter (though it also can control a single rotor heli or fixed wing aircraft). A dedicated Arduino board (ardupilot) connects to an IMU sensor board which contains minuscule gyros that sense the orientation of the aircraft and the built in software responds to changes in attitude by adjusting the speed of separate motors.
I have added GPS support and a magnetometer to sense magnetic heading, along with a bunch of pretty lights that help identify which way is front!
I may have over-reached when I started this project.
I am installing a lot of kit into this – a flight data recorder (with GPS), an autopilot (also with GPS), heads-up display, video camera and transmitter, steerable nosewheel…and navigation lights!
Just working out where bits are going to fit and running wiring has been a nightmare – I’ve cut out more foam from the fuselage than is still remaining there.
There have been some key considerations when deciding where to place the different electronic components. I have tried to keep the receivers (GPS x 2 and radio receiver) as far away as possible from the video transmitter. Also I have tried to place the autopilot as close as possible to the centre of gravity. Finally I have put the pitot tube (for airspeed measurement) in the nose to get the cleanest airflow.
The bottom half of the fuselage is upside down – the cockpit area to the left and the cavity to the tight of that is where the wings attach.
Starting from the left we have the pitot tube (the horizontal tube sticking out of the nose), the paddle pop stick is inserted to trigger a hidden microswitch that turns everything off, next is the steerable nosewheel, then the 4s LiPo battery which is shoved up against the Eagle Tree Data Logger and On-Screen Display. The cavity under the wing is where all the wires come out that plug into the wing components – I have kept it clear of any electronics as all the available space is taken up by the wires when the wings are attached. To the right of this (above the main gear) is the autopilot (essentially just a small box with a bunch of gyros in it). Next is the lights controller which makes all the LEDs flash the correct way (9 LEDs in this aircraft); underneath this is the Radio Receiver. Finally to the right of this is the GPS for the Flight Data Recorder followed by the GPS for the autopilot.
Receiver: Futaba R6014HS
LED Controller: Punk RC (controlling 2 red Anti-collision strobes, 3 white navigation lights/ strobes, red and green right of way lights on wingtips and 2 white landing lights).
Flight Data Recorder: Eagle Tree Data Logger V4 and Eagle Tree OSD Pro (On Screen Display)
Autopilot: Fyetech FY-21AP
I’ve finished all painting on the aircraft now – looks pretty good! Up close the surface looks very speckled an foamy but from 100ft or more it could pass for the real thing.
Insignia placement is not perfect but not bad. There is no Australian Customs aircraft registered DSJ (this is actually currently assigned to a UK WWII Observation aircraft built in 1947). I chose it as it was also the registration for a Cessna 182L which dissapeared in 1978 in one of Australia’s most interesting aviation incidents.
I have added landing gear; they are not very scale-like but the nosewheel is steerable and they all have pretty good in-built shock-absorbers.
Have finished the basic white and red painting of the airframe and wing surfaces and all leading edges in black. Next I will print and place insignia (using a custom decal kit) then finish with a UV resistant top coat.
After spending some time looking at different real-world aircraft with similar high-wing two engine designs to my Twinstar I have settled on a combination of US Coast Guard and Australian Customs. I like these designs as they use lots of white (which save me having to do a lot of detailed painting) and should provide highly visible orientation when looking at it from the ground. It should also give a good scale effect – in other words from a distance look just like the real thing.
I am basing my design on the Aust Customs Dash 8
Received my initial Twinstar II kit from Tower Hobbies. It is very light! Shipping was expensive though due to the large box size. The model is an impressive 1.4m wingspan.
Lots of work to do to this before it flies. Besides the camera and video transmitter I have decided to paint the aircraft (not sure what design yet) and to install navigation lights, autopilot, flight data recorder (black box), GPS (Global Positioning System) and a HUD (Heads Up Display) which will give me information like altitude and airspeed overlaid onto the video feed.
Knowing I’m a gadget fan a while ago a friend sent me a youtube clip of a german guy who had designed a very clever multi-rotor remote control helicopter that was capable of automonous and stable flight.
A couple of clicks later I discovered FPV (first person view) where the aircraft can carry a camera that transmits video back to the ground where the pilot is wearing video goggles therefore seeing whatever the camera sees. Add on a head-tracking device and a tilt/pan mount for the camera and you have an immersive virtual flying experience!
The multi-rotor helicopters are fairly expensive, however electrically powered foam fixed wing aircraft are very cheap (<$200) and offer a great way to get into FPV flight.
To start I selected the Multiplex Twinstar II kit for about $150. Tho this I will need to add a radio reciever as well as the other various electronic brains it will need to know where it is, control itself and transmit video back to me.