Bicopter / Dualcopter Drone
Plywood construction using common A2212 brushless motors and Hobby Power 30A ESC’s with 1045 propellers.
Servos are high speed metal geared standard sized servos. And lastly the flight control board is the simple to use
KK2.1.5 boa
Step 1: Design and Build
The construction of this model is mostly covered in
the
Tricopter build. It uses the same servo arm as the
tricopter but uses two of them on a special twin hub.
The video shows a few more details about the arm
construction but it is a very simple build. The tricky bit
was getting this thing to fly!
But let’s start with the construction. As with most of
my builds I design on a free cad program running on
my raspberry pi, I then save the drawings as pdf’s
and print out using a scale of 100%. Then I stick the
plans to the 3mm plywood and double up all the
parts. Again this model easily fits on a piece of
plywood 300mm by 600mm.
and stick all the bits together but like the tricopter
don’t stick the arms into the hub. (Mainly because I
wasn’t convinced this was going to work so wanted to
use the arms as spares for my tricopter) once all the
bits are glued together you can add the servos and
wire up the speed controllers and add the flight
control board. As you can see in the video my first
attempts at flying this machine didn’t go well! I
persevered for 3 evenings and most of a Saturday
before finally accepting that the weight was all wrong.
Following a quick redesign I added the vertical battery
holder and now the machine was able to fly and be
controlled! This extra bit is shown in the 4th and 5th
PDF’s. this kind of messes up the fitting onto one
sheet of plywood 300 by 600mm, but if I get time I will
see if I can make it fit.
Once all the bits are cut out then clean up the edges
Nothing really fancy about the wiring. The motors were soldered directly onto the ESC’s. And the power cables
were lengthened and soldered together into the battery connector.
The Back motor ESC (more by mistake) is connected to channel 1 and the front motor ESC is connected to
channel 2. The back servo is channel 3 and the front channel 4.
Step 3: Setting Up the Flight Controller. KK2.1.5
So there are two ways this machine could be flown. The first is with both propellers in front. This is the standard
dual copter configuration. I started with this layout and instantly found i had to make adjustments, firstly to the
servo offsets which needed to be at 50 and then the rudder needed to be reversed in both the two servo channels.
Or if you wish you can fly this like a Chinook with one propeller in front of the other. To make this change I had to
move the fight controller around by 90 degs and change the settings on the mixer.
Whilst testing I quickly discovered that the motors were fine and the flight controller was able to control the motors
to allow changes in direction. However the servos were not working well and because of this I had to separate the
PI channels so the Aile and Elev were adjusted independently. This was obvious after all in one direction the
motors change and in the other axis it’s the servos so it really was daft to have them set to the same values in the
PI settings.
So where next? I think I will revisit one of my early bicopter designs, but move most of the weight to the bottom,
which means moving the servos to the bottom and the esc’s and anything else I can lower!
In hindsight I think the dualcopter/bicopter is one of the least desirables models due to the pendulum effect of the
required weight below the propellers and whilst it is fun to make these machines and even more rewarding to get
them to fly I don’t think it is worth pursuing anymore!
Settings Flown As Chinook.
Mode Settings
Self-Level : Always
Link Roll Pitch : No
PI Settings
Plans
I have added the PDF's of the plan. you may have to play around with the design?
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