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MiniFTC = ET's Mini Foam Tricopter

Here's a little tricopter I've made; the frame is EPP foam reinforced with carbon-fiber strips.  This little guy flies nice and is quite cheap to built.  Lot's of fun, whether flying it line-of-sight or FPV.

See here for a gallery of pics.
See below for a parts list and videos.

See here for a PDF of the design.  It can
be printed onto a standard 8.5"x11" letter-sized sheet.  (When printing, set "Page Scaling" to "None".)  I attached the paper to a sheet of foam with double-sided tape and simply cut along the lines to create the frame.  The carbo-fiber strips are glued (with CA) into the foam for support.  The three "legs" on the bottom are 20mm x 20mm and 18mm tall, made from two layers of the 9mm 1.9# EPP foam.

The motors, props, speed controllers and battery are the same as what I used for my MiniFD.  I like the HobbyKing 5030 props because they run quietly, but they should be balanced and need to be reamed out a bit (using a 1.9mm drill) before being pushed onto the motor shafts.

I made the rear tilt mechanism from two Dubro Micro E/Z Hinges (#937) and a Dubro Micro Control Horn (#919).  See here for a pic.

The motor to motor distance is 220mm (~9 inches); weight without battery is 142g (5.0oz).

At first I was using a KK2.0 controller, loaded with KK2.0 v1.6++ Satellite firmware by RC911.  See here for my settings.  This setup worked well, except that the older KK2.0 board has trouble with fast flips.  (The current KK2.1+ boards don't have this problem.)

I'm now using an Acro Naze32 flight controller, running CleanFlight firmware.  See here and here for settings I have been flying with.  Setting "gimbal_flags=4" (in the CLI) will result in RC channels 5-8 being output to the PWM5-8 pads.  (With newer versions of Cleanflight this is accomplished with "feature CHANNEL_FORWARDING".)  I use the channel 6 output to run the tilt servo on the FPV camera.

The R/C control is via an OrangeRx R100 satellite receiver, with the receiver's data line connected to the "USART2 RX" pin (4) on the Naze32 and "feature RX_SERIAL" enabled.  The R100 receiver needs to powered with 3.3 volts (not 5 volts).  There is a 3.3-volt pad ("3V") on the Naze32 board that can be tapped, or a ZYX-S DSM2 Satellite Receiver Cable can be used.  The R100 has now been superceded by the OrangeRx R110X DSMX/DSM2 Satellite Receiver.

I found that any 'acc_lpf_factor' value greater than 0 resulted in a self-leveling "lag" -- if I flew fast forward (in horizon mode), pulled back to stop, and then centered the stick to level out, the copter would keep "leaning" forward for a few seconds. Larger 'acc_lpf_factor' values made it worse. My little copter flies well in horizon mode with acc_lpf_factor=0.

I attached the flight controller to the frame with two layers of 4mm foam tape.  The ESCs are flashed with SimonK firmware (not one-shot).

The TS5823 video transmitter I'm using is rated at 7 volts minimum, which isn't quite low enough for a 2S (7.4V) lipo-battery setup -- the video would get messy toward the end of a flight/battery.  A Pololu 9V Step-Up/Step-Down Voltage Regulator (S10V3F9) keeps the voltage level stable.  I'm also using a video power filter circuit.  Transmitter antenna is a HobbyKing Circular Polarized Antenna (RHCP) modified to have a right-angle RP-SMA connector.

I have a diversity setup with two separate Uno5800 receivers.  I do it with wired RSSI connections, but it could also be done with an Eagle Eyes FPV Station.  The nice thing about separate receivers is they can be placed far apart -- having one on each side of a house can provide good signal all around.

Parts List:

Acro Naze32 $24.99

OrangeRx R100 DSM2 Compatible Satellite Receiver 9171000296-0 $6.99

HobbyKing 10A ESC 1A UBEC (USA Warehouse) 261000002 $6.70

Turnigy 1811 brushless Outrunner 2900kv (US Warehouse) T1811-2900 $10.01

HXT500 5g / .8kg / .10sec Micro Servo (USA Warehouse) $3.45

Turnigy nano-tech 950mah 2S 25~50C Lipo Pack (USA Warehouse) 9210000005 $6.18

5030 Propellers (Black) - 3xCW and 3xCCW - 6pcs per bag 9332000002 $3.49

5030 Propellers (Red) - 3xCW and 3xCCW - 6pcs per bag 9332000003 $3.49

9mm 1.9# White EPP Foam, 1 Sheet, Size 18"x36" [RCF001599] $8.25

Carbon Strip 7.0mm x 1.2mm x 1000mm 20-112 $3.90

Carbon Strip 5.0mm x 0.6mm x 1000mm 20-109 $2.30

Dubro Micro E/Z Hinge (15) #937 $4.69

Dubro Micro2 Control Horn (2) #919 $1.32

Dubro Mini E/Z Connectors (2) #845 $2.09

Peel-n-stick foam tape. 10x5inch 4mm thick ST-FOAM-DB $1.29

2.8mm 120deg 4-24v Wide Voltage micro cctv camera 520tvl HD 0.008 Low Lux  $36.19

TS5823 5.8GHz 32CH A/V 200mW Mini FPV Transmitter (v2) 544000001-0  $21.49

Pololu 9V Step-Up/Step-Down Voltage Regulator S10V3F9  $4.49


MiniFTC FPV-DL Around the House 2015-06-12

MiniFTC FPV-DL Belleville 2015-06-24

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