| The
Tricopter: a three bladed 'helicopter' |
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The Tricopter is an adaptation
of an aircraft of the same name designed by 'Lemmiwinks' at RCGroups. The tricopter is a fun to build and fun
to fly project designed around readily available hobby shop
components. While the costs can add up quickly, the resulting
aircraft is sure to draw a lot of attention (and who doesn't love that?) |
| Before we begin | |
| Building the
Tricopter turned out to be pretty straightforward. Having a very
good understanding of how gyro's work, and understanding the difference
between a rate based gyro and a heading hold gyro are both important to
successfully trimming this aircraft to fly, since too much gain on the
gyros can result in some spectacular oscillations. |
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| Details |
| The platform base is an
equilateral triangle cut out of red corroplast. The booms are
thin wall carbon fiber tubing. Structurally, all of the
rigidity could be focused at the points where the CF tubes meet,
meaning the platform could have been as thin as I would have
liked. I went with corroplast because I had it laying around, and
used packing tape to attach the CF tubes. Three guy wires run
between the ends of the CF tubes to increase rigidity. The 3 rate
gyros were the cheapest I could find (GWS PG-03). The heading
hold gyro is a Futaba GY240, and the receiver a Hitec superslim 8
channel (overkill, but it's what I had laying around) |
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| This is the tilt mechanism used
for yaw control. An HS56 servo runs to the GY240, which is then
plugged into the yaw channel of the receiver. Tilting the motor
causes the aircraft to yaw left or right. Pitch and roll are
managed by setting my radio (a Futaba 9c) to helicopter mode,120 degree
ccpm. Normally 3 servos would be connected to control the tilt of
the swashplate on a helicopter, but in this implementation the 3
channels are used to
drive 3 CC25 brushless controllers. Mechanically this makes for a
very simple aircraft. Perhaps the most complicated part was
designing the tilt mechanism. for the yaw servo.
Click here for more views of the pivot mechanism. |
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