Tricopter V3.5 build


After searching and searching after the perfect tricopter V3 motor I ended up getting custom ones made. The results on the test bench were spot on! So I decided to build Tricopter V3.5 from scratch with the new electronics and while I’m at it, why not make a build log as well.


All the parts laid out.

Start with the camera/battery tray. That way the glue has plenty of time to cure while the rest of the copter is being built.

Sand the bottom wire holders with 180 grit paper (or something there about) This is so the glue have more surface area to grab on to and it ensures that the piece is nice and flat. Don’t forget to wipe the piece off after you’ve sanded it. Dust is glues worst enemy.

While you’re at it you can also lightly sand the G10 camera tray a bit as well.

Use medium or thick viscosity CA glue. Add some to the slots where the wires are going to be inserted to ensure they get glue all the way around them.

Then add glue to the bottom wire holder.T7

Insert the wires in the slots. It can be a bit tricky to hold both wires in place at the same time. It’s best to be over a surface you don’t mind getting glue on, in case you drop one.T8

Squeeze the bottom wire holder and the battery tray together. Make sure the surfaces are completely flat against each other and that the wires is still laying in the slots. It’s a good idea to use a clamp or two to really squeeze the two pieces together to ensure a really tight fit, it becomes much stronger that way. Have a paper towel or something close by in case glue comes squirting out.

Now that’s done you can put it to the side.T10

Time to solder on the pinheader to the Naze32 Tricopter frame.T11

I personally use 60/40 0.8mm thich lead based solder. I highly recommend using lead/tin based solder instead of the lead-free kind. It’s a lot easier to get a good result with and it’s actually less harmful to breath in the fumes.T12

Solder the pinheader at an upwards angle to make it easier to route all the wires through the hole.

Roughly this angle is good.T14

Now we’re going to solder on some longer cables to the ESC’s.

The Tricopter V3.5 needs roughly, precisely 432mm approximate exactly. Both the power wires and signal wire should be this length.T16

Take note of which pad is which before you desolder the wires.T17

New wires soldered in place.T18

Long cables.T19

Snaking the wires through the booms is a lot easier if you take out the servo wires out of the servo connector. Simply lift the little tab with something thin like an exacto blade and pull the wire out.T20T21

The motors are easily attached using the motor mounts and 18mm long screws. Note which way the motor wires are oriented.T22

To protect the wiring and improve the looks, 6mm wire mesh can be slid over the power and signal cables.T23

Put on some heatshrink and then solder the motor wires in place.


Shrink the heat shrink while talking to your shrinkT24

Done. Loos niiiice.T26

Now to the same to the other arm. Note that the ESC’s are mounted in opposite directions so that they can face backwards on the copter where they are better protected.

Now we’re going to do the back arm. The cable on the servo needs extending and the latest beta of the Triflight firmare supports servo feedback, so we’re going to add a cable for that as well.T28

Open up the servo.T29

I opted to remove the signal wires and replace them with longer ones instead of splicing the wire. T30

The servo feedback wire is added to the middle pin of the HALL sensor. Note how it’s soldered from the back. It’s really hard to close the case otherwise.T31

Soldered the longer servo wire in place.
T32Use a dremel or a small file to make the hole where the servo wire comes out a little larger, so that he feedback wire fits.


Now we’re going to do the tilt mechanism.T35

If there is any hint of the tilt having any friction, lightly sand the pieces until it’s buttery smooth.

Mount the motor on the tilt top piece and then mount the whole tilt on the boom using zip-ties.T37

Solder on the motor wires

Add heatshrinkT39

Added some 3mm wire mesh to the servo cable to make it look extra fancyT40

Make sure the motor wires don’t hit the servo, binds or hit something adding extra friction to the tilt actionT41

Lots of wires coming out of the back tubeT42

Time to solder the front power wiresT43

Nice and clean. Use a powerful soldering iron for this at it sucks up quite a bit of heatT44

Back power wires soldered in placeT45

A beeper is a good idea. It can be used as a lost model alarm and it will help with the communication during the tail tune setupT46

Soldered the buzzer to the negative pin and had it sticking slightly over the edge of the boardT47

Then soldered a very short positive wire

Now put the top and bottom plates put together.T49

All screws in placeT50

Time to mount the battery/camera trayT51

Make sure that the wires are properly in the tracks while tightening down the screws. There should be no slop in the wires anywhere.T52

Starting to look like something

Plugging in the wires. The servo feedback wire goes into receiver channel 6.T54

Now mount the landing gearT55

Almost done.T56

Install the receiver. I’m using a long range system from Imersion RC called EZUhf.

I’m using a 1.3Ghz video link and I needed to build an antenna. I was lazy so I grabbed this 5.8Ghz antenna with a broken case and turned into a 1.3Ghz antenna. (Here is a guide)

All wires soldered in place.T60

Removed the 5.8Ghz archesT61

Antenna done. Going to put some paint on it.


All done! Time for some beauty shots.T63 T64 T65 T67 T68 T69 T70 T71 T73Time for the first flight!
T75 T76 T77 T78

I absolutely love how this Tricopter flies. With the new TriFlight firmware it’s locked in and smooth. The new motors work flawlessly and have tons of power. My favorite FPV platform of all time. It just doesn’t get old. Just remember to balance your props before you fly!

53 thoughts on “Tricopter V3.5 build

  1. Nice! There’ll be no searching for motors once I have to replace my SunnySkys 😉 Would be very interesting to learn which parameters you tried to optimize with the new motors and how you ended up with the 1300kV variant.

    Hälsning, Rue

    • The efficiency during hover
      Max thrust
      Heat dissipation
      Easy to drive for the ESC’s (no stuttering)

      They provide around 1300-1400 grams of thrust at 24A running 4S. So it’s pretty overpowered 😀
      Hovers efficiently though.
      Doesn’t get too hot during max throttle, but isn’t too cold either.
      No stuttering during any throttle or rapid throttle changes. Even work with dampened light.

      • Awesome work David! I really enyojed reading your build log and your other videos are really helpfull too!

        I’m currently building my third Tri and would like to optimise my motors too. The change from KK2.0 to naze32 already showed incredibel improvements on my copter but I have the feeling that I need to work on my drivetrain in order to get it fly even better.
        The motors that I used on the previous tris were cheap motors that now start to induce vibrations into the copter. (bad bearings, imposible to balance…) I now want to replace them with more optimized ones.

        In general I’d be really interested in how to optimized motors. Do you have any sources or literature on how to properly design the drivetrains? Especially on how to match prop to motor and motor to ESC for best efficiency or max thrust.
        I’ve been searching the net for quite a while now but I couldn’t find much on parameters and how they affect the copter.
        I came across a good calculator for all this ( ) but unfortunately they don’t show what kind of theory is behind.
        I would really appreciate if you could help!

  2. Nice! It would be better to swap the locations of the VTX and UHF-rx around though. Now the UHF receiver is listening closely to the UHF noise emitted by the GoPro and perhaps other devices around there (e.g. MinimOSD, regulators).

    I’d like to try that flight controller and firmware, because obviously it’s targeted at best performance for a tricopter. However, I also like the safety and convenience of Arducopter’s loiter and RTH modes (amongst others), especially since 90% of my flying is over salt water and to the radio range limits.

    If only an autopilot device for flight controllers existed. Something running firmware with all the smart features of Arducopter that merely outputs SBUS or CPPM signals that are fed into a relatively ‘dumb’ but performance oriented flight controller of choice. That would create the best of both worlds.

    • Cleanflight’s navigation stack is being reworked and Lauka plans to merge his great works with Cleanflight so you’ll be getting your RTH incl the great flight performance 🙂

      • Sounds great! I do think that all non-attitude controlling code (e.g. navigation, RTH, etc) should run off a different CPU or board so as to not have detrimental affects to the performance of the attitude controller.

  3. @David
    Can you specify battery used in this particular build? Flight time? And distance achieved with this UHF setup?

    I really like your work! Great job!!!!

  4. If it’s not a trade secret, I want to know what did you use to cover wires of your antenna ? What about gold plated memory wire for an antenna? Do you have any experience with this kind of material? It looks very nice on 5.8 Ghz and are rust resistant.

  5. Hello! Can someone tell me what is servo feedback option? Does this servo also support this: Turnigy™ BMS-380MAX
    What are the advantages of this option and where to activate this ?

    thanks, Bojan

  6. Hello david.

    I beg your pardon about my bad English, I promise I will try to do my best to expose the


    Nowadays, it is my dream to buy your Tricopter. But the problem is that there is no web in

    Spanish language to document myself on the suitable setup of the tri 3.5.

    I can only see your videos and imagine what you’re saying!!!. And you know that any mistake

    in the setup means Tricopter could crash and the money spent would be throwing it into

    the trash.

    Do you or someone close to you know a specific forum for spanish Tricopter 3.5?

    And the last question: I understand that you will put on sale the complete kit including

    electronic material. Is it true? And in this case, how much is it cost?

    Sincerely yours,


  7. Hello David,
    with the tricopter3.5 you did another great job. I´m following your activities since a few years now. Thanks for all you gave to the community .
    First of all – i´m a newbie to the naze32 board . On my DIY- tricopters i used KK2 and APM boards up to now. My next project will be an original rcexplorer-tricopter, as soon as the new mortors will be available. Just to see the difference 😉 .
    Therefore i´d like to ask some details:
    -Checking out the forum i tried to find some information about usage of GPS with your naze version and the new firmware “triflight_NAZE.hex.” Do you , or anybody else , got some experiance with that and can tell how to set it up?
    With that only 25mW we are restrictet to in Germany for use on FPV systems, it is very easy to get out of range. At least a RTL funktion is a necessary savety feature therefore.
    The “triflight_NAZE.hex.” is recommended only for the described tricopter hardware.
    The newer naze boards are equiped with barometric and magnetic sensors. Would the firmware work with and/or support these features. I guess not, just want to make sure by the experts. Did you or anybody else test this out yet?
    Thanks in advance for any reply!

    • Hello fastandlow,

      I might be able to help out with some information about the board and the possibility of adding GPS.
      First of all the electronics on the tricopter naze32 are the same as on a naze32 acro. This also means that compared to a naze32 full, baro and magnetometer are missing.

      I myself am fairly new to the naze32 board too but so far I managed to add a baro, Hott telemetry and bluetooth to the tricopter board.
      Since these addons were managable for me I’m now planning to add an OSD and GPS as well. (and of course FPV)
      So far I’m pretty confident that all features will work with the firmware! I was actually very suprised to see how easy it was to add the baro. For me it was just soldering it on and it immediately showed up in the cleanflight configurator.
      Hott telemetry and bluetooth were a bit more complicated for me but I got them to work eventually.

      A great source of information were these videos:

      • Hello Dirk,
        thanks for your reply. Since i wrote this comment i received a (Acro Afro Naze32 NAZER 32 10DOF Flight Controller w/ Barometer & Compass) from Ebay. Quick mouted it on my DIY Acro Tri to test it out on a prooven frame. First i used a normal tricopter firmware which was offered from Cleanflight and set up the Servo and all other necessary adjustments. After some try and error i could even setup a GPS until it got a 3D fix. The Painless 360 videos where very helpfull. 🙂 for the basics, but he doesn´t setup a tricoper?
        The problem started when is tried to fly with this. It flew terrible , was almost not able to control it. No thought to test any electronic gimmiks. Bit desillusioned i went back to the workshop. Before stepping deeply into PID adjustments , i decided to test the “triflight_NAZE.hex.”firmware from David and Laucha and flashed it. The test flight with this was just great even without the recommended hardware and the recommended servo feedback. Very good control and high agility. Almost the same as i experianced with the kk2 board.
        Now i started again setting up the GPS adjustments in cleanflight. Even with everything setup right, the GPS did not show up in the top bar of Cleanflight screen. As far as i know by now, it is just not possible to use a GPS with this firmware. I´d be glad if sombody would tell me lies and can show up how it works.

    • With lock nuts the props don’t come loose. I would never recommend using anything but a lock nut. Today the ESC’s use a feature where they slow down the props very hard, which unscrews the nut if you have tighten the other way anyways. Just use a strong lock nut and you’ll be fine.

  8. Hi David, strange request but what did you wrap your vtx and receiver in? I have been looking for translucent coloured heat shrink and cannot find a good supplier. Thanks, and congratulations on your continued improvement and innovation to a great multi rotor platform!

  9. How much does it weight without camera and battery? I was wondering around the carbon fibre arms, but I don’t know if this arms weight less then aluminium arms.

  10. This build doesn’t include a step for running power lines from the power distribution board (if using) to the Naze32 board. So, after completing the build I discovered this and had to rip the thing apart to run those lines. Grrrrrrrrrrrrrrrrrrrrrrrrrrr.

    • Yep I did exactly the same thing GGGrrrrrrrr.
      my Problem Is I have the Optima 9 receiver but also want to run the servo feedback wire into channel 6 but the way that David suggests to just connect the signal pins, I cannot. Any ideas?

      David Please Help me its giving me a massive headache.


  11. David – I bought a 3.5 kit some time ago and life got in the way. I was to the NAZE32 programming when other things “happened”. Anyway, I would like to complete this and get it flying only I reflashed to the latest hex for this board and now the RX inputs (PWM) are not registering on cleanflight. Any ideas? I don’t even know if you check these older pages.

      • Yes, tried that version as well. I should have updated late last night. I found that my RX had a bad channel (Orange RX). I guess I should just buy a better RX next time around. I have read that it needs the first 4 channels working before it will work at all. So to the next issue. This is a learning experiment just like any other flight computer. I only have experience now with a couple of collective pitch single rotor heli computers having only just upgraded from flybars about 6 months ago.
        So now I can seem to get output from the NAZE on the motor channels. I did the throttle calibration per your setup but when I try to actually spin the motors nothing happens. The ESCs are the Afro slims. Seems like they are initiating correctly (green lights lit), so don’t know. Also, the very next setup item is the servo and I cannot get it to move through the NAZE. Directly connected to the RX it works fine. Note that I am not running the feedback. I think that came after my initial setup. I am not running the same servo and have not investigated how to make this mod on my servo. I don’t recall the exact servo (and it is now strapped to the arm) but was one of the suggested units for 3.5. If you have any quick thoughts, let me know. I will be working on this later and may figure something out. Thanks for your help David! Mark

        • An update – I got it to arm, but only get response on the servo. NAZE claims the motors are armed, but no movement (and the ESCs are calibrated). Looked up possible reasons and someone said to check the task list. gyro/pid is showing maxload of 88.9% and avgload of 67.9%. This may be a problem. Also noticed problems with the comm port throwing odd characters. seems it can’t keep up with the comms speed or something.
          One other thing, that version of firmware does not even allow me to see the servo page with the most recent Cleanflight. How do I go about getting the old Cleanflight version as in your setup video? And which version was that? Thanks again. Mark

          • What I didn’t see before is that after the board is armed, the serial port also claims a very high usage – 745%! I don’t know, but I guess I forgot to feed the hamsters…

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