TX8 Octocopter (10" props)

by Brendan22, published

TX8 Octocopter (10" props) by Brendan22 Apr 3, 2015

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This TX8 design has more parts than my other “unibody” T-Copter designs. The result is a more complicated assembly procedure but that comes with the advantage that the longest print is only around three hours (compared to 10+ hours for the other larger designs).

Before you start printing this design please check that your printer is big enough. The plates require at least 160 x 170mm build area and the arms are 225mm long (although you may be able to print them on an angle to fit a slightly smaller bed).

Check out the whole "T" copter family:


  • completely 3D printable (without support)
  • light but powerful X8 design
  • strong braced tube section arms with plenty of room to conceal motor wiring. Arms can be folded down or removed altogether for transport.
  • designed for a dual 3S or 4S batteries located near the center of rotation/thrust with room for up to two 6000mah 3S or 4200mah+ 4S batteries (160 x 50 x 35mm capacity each).
  • plenty of space to mount dual 4 in 1 ESCs - concealed but still well ventilated for cooling.
  • floating vibration reducing top plate is designed for the Pixhawk flight controller](http://store.3drobotics.com/products/3dr-pixhawk) from 3D Robotics - but is also fine with others
  • RF "invisible" frame - as opposed to carbon fiber or aluminium
  • Assembly instruction PDF in the downloads
  • 2 x 5000mah 3S batteries gives 15+ minute flight time (and there's space for bigger batteries).
  • all up weight for my build (see instructions tab) comes in at 2.65kg including batteries, camera and gimbal - and hovers at about 45% throttle.
  • Sketchup CAD file is included so you can make changes to suit yourself.



See the instructions PDF in the downloads.

To build mine I used:

  • 3DR Pixhawk flight controller with GPS and telemetry.
  • 8 x 880kv 3DR motors (old ones recycled yet again!)
  • 8 x 10x4.7 slow fly APC props
  • 2 x Q Brain 4 in 1 ESCs
  • Spektrum satellite receiver
  • Tarot T2D gimbal (old one which is a bit bent :))
  • GoPro Hero 3+ silver
  • 2 x 5000mah 3S batteries gives 15+ minute flight time (and there's space for bigger batteries).
  • all up weight with batteries, camera and gimbal is 2.65kg and hovers at about 45% throttle.

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Hi Brendan. First of all I want to congrats you for your awesome work, not only for this model but for all of them. I'm printing the T4 model but I would like to know if it is a good combination to use the t4 arms (only 4 motors) with the TX8 body. I don't know if the T4 arms fit in the TX8 body and if the final weight could be a problem to fly.

Thanks in advance!

Thanks for your kind words. The TX8 arms are quite different to the T4 ones regards how they connect to the body.

Thanks for the great Copter.
What for a filament do you use? ABS?

Thanks so lot from Germany Hamburg

Thanks for your comment. I use PLA simple because I find it friendlier to work (no issues with warping, etc) but I know some folks have successfully printed these with ABS.

Hello, nice model. I will try to build one myself in the following days. What infill/shell are you using for all the prints? Also, with your actual setup, what do you think the payload is?

Keith. Your build inspired my to take my TX8 out for a fly. Almost a year old now and it still flies great ...and on the original cable ties! :)

Happy Flying!

Hi Brendan

I have just completed the assembly, and found it very difficult to get the copter to be in stablize mode (using APM as flight controller). Still going through the PID tuning to make sure I have not missed anything. Definitely something wrong somewhere, was looking at your youtube and another person's video, and the copter's take off is much much smoother and stable. While increasing the throttle slowly up to 50%, the copter tends to lean to one side (although things look balanced) and cannot take off vertically well. I still noticed I cannot get the arms to be perfectly balanced, wonder if that has to do with it.

Btw, I read another post that you are based in New Zealand! I am from Auckland, what a small world.

Hey there, thought I might suggest you try a different flight controller like a humble kk2 or kk mini

Please excuse these comments if you are an experienced builder :)
1) run a motor test (1 motor at a time) and ensure that it is the correct motor that spins, the right direction, and that it is pushing air down.
2) ensure that all props are the right way up. Above will help with that but can be confusing as the bottom props need to be fitted upside down with respect to their motors - eg on APC props the writing should be facing the sky on all 8 props.

The above is assuming you haven't been off the ground at all - or can you fly (albeit badly)?

Hi Brendan

Thanks for that, yes have done all that, copter can fly but badly. Just getting the auto trim done next, I think the CG is not quite center on my build. Also checking the logs in MP to make sure nothing stands out.

My previous build was just a 450mm quad, so this one is double the weight, not quite used to that yet.

Will keep you posted.


Argh, looking closely at other builds on the net, I just realised I have the bottom motors spinning the wrong way round. Got confused as the motor is upside down, so when I was setting up each one on the bench, they were facing up! I did get my props correctly though, so that's how the copter can fly up, albeit wobbly.

Time to reconfigure, and see how things go. DOH!

Hi Brendan

Reconfigured the bottom motors, copter is flying beautifully now!

Amazing work, thanks again.

PS: Sometimes when I land the copter too hard, the cable ties on the arms will break, which is kind of nice as it softens the impact.


Thanks Keith. I was hoping to hear good news! Those cable ties sound a little less that idea though - I haven't broken one yet :)

Hi Brendan,
I have completed my printing and now putting together the unit. I new to the octocopter design and a little confused on motors. I understand CW VS CCW but not sure what I need as far a pushers verses pullers and I want to find the most affordable set of eight. Any recommendations? Can I rig the octocopter with one type and over come the push/pull issues using setup? Thanks in advance for any help.. John

Hi John. It's been a while since I've done a new build so I'm bit out-of-the-loop on current motors. For props I've always used APC 10x4.7 slow fly props and you'll need 4 "normal" and 4 "pusher" props. In the case of the X8 you'll have one of each on each arm (top and bottom) - which one is on the top will depend on whether the top motor is running clockwise or counter-clockwise.

Hi Brendan

I just completed a print, and noticed the arms are not held strongly in place with just the cable ties, ie can move around by using moderate force of hand. Was wondering if you encountered any issues with this?

Would be really nice if there is an option to screw the arms in place, instead of using the cable ties.


Hi Keith.
I found that I can alternately tightening the 2 cable ties to get that joint pretty tight. Keep in mind that during "normal" flight the arms will always be lifting and therefore locking themselves into place anyway. I've not had any problems.

Hi Brendan

Maybe I am using too weak cable ties, will try another type. Also noticed your T4 copter uses screws for the arm mounting, which is great. It is possible to adapt that design for the TX8? From the looks of things, the T4 requires quite a bit of space for the arms to slot in for the screw mounts, which I presume will reduce the overall frame length? I have not measured the T4 vs TX8 frame length...


T4 design requires a much larger body to accommodate arm sockets.

Hi Brendan22

Fantastic work! Really like to print this but I have 12" props, any chance of tweaking the arms to fit the slightly larger prop?


Thanks for your comments. I think it would be a fairly big tweak to fit 12" props. Longer arms would seem like the simple option but might push the limits of a lot of printers. Otherwise "spreading" the arms more might be an option but quite a significant redraw affecting lots of parts and reducing the clear camera angle in the front.

I'll look into it further if I get some time. Otherwise the source Sketchup file is in the downloads - feel free to have a crack at it. Cheers, Brendan.

Ah, both good points. I was thinking spreading the arms would be simple, but can see how it affects many parts. I wonder if there is a simple way to extend the arms by joining/snapping 2 pieces together, instead of making the single arm longer...

what size motors do you use for this

Mine are 28 x 36mm 880kv motors from 3D Robotics.

What hardware do you use for this copter?

Basically the bits listed on the "instructions" tab :)

Any chance you could model some arms with 40mm between the holes instead of 30mm?

I can print all the parts except the legs on my printer (Flashforge Dreamer). Any way to break the legs into 2 parts or tips on creating a different leg design? Maybe a T shaped leg in 2 pieces.

Will the leg fit if you place it on a diagonal across your print bed? From memory the arms on this design are actually a bit longer than they need to be for 10" props. You may just be able to shorten them a bit - the source Sketchup file is included in the download. I'd have a go but I'm just starting another work week here so it could be a while...

No. The problem is the width and length together make it where i cant really position it on the bed. What I did was modify the leg a bit. Basically removed a triangle from the leg on either side. It doesn't have as wide a base and I do not know how stable it will be on landing yet. If I was better at modeling I would take the post part of the leg and make it a separate attachment to the triangular foot. That way you could print the foot and the leg and attach after.

Ah sorry. I was getting my legs and arms mixed up. Yes the leg is pretty big in both dimensions - very stable though :)

Yeah it looks like it. I am not really sold on my modification but may not have a choice LOL. I dont see any other way of getting the full leg printed.

How long of a flight time do you get with this? (with your current hardware and setup)

Jun 18, 2015 - Modified Jun 18, 2015

I really like your designs, i've built a few quads and hex's but sometimes crashes can make repairs pretty expensive. So the ability to print new parts is a very neat alternative. I don't have a printer but I have access to one through a friend. I plan to print several of your designs as well as some additions to your designs that I have found here on thingiverse. My question is do you have any approximate amounts of filament each each design uses? I plan to provide my own filament. I'm sure you don't have any hard numbers but just some approximations like "half a spool" or "quarter spool" would be nice. Thanks.

I just finished printing the octocopter. I think the total print only used half of a roll.

In some cases I've noted of the weight of parts - but sometimes not sorry. Spools are typically 1kg and there should be no significant weight loss during printing - so a 100 gram part will require 1/10th spool of plastic if that helps? None of my designs use anywhere near a whole spool though - perhaps about half for the TX8?

OK that's all I needed thanks.

Great design. Do you share the ketchup file two like wit your other ones?

Sure - I've finally gotten around to tidying it up. The Sketchup CAD file is now available in the Files section. Have fun!

Really great. Thanks.

I'm new to X8's. How exactly are the motors attached?

Many motors of this size come with a metal "cross" plate that can be screwed to the base of the motor. The top and bottom motors are then bolted to each other through the arm. There are some photos on the T6 page that might help: http://www.thingiverse.com/thing:246350

T6 / Y6 hexacopter

is it necessary to adjust the scale of any of these parts?

It shouldn't be. Why?

Just wondering because the other ones have a test joint, but if not, sweet.

Absolutely brilliant. I have had a great time with the 250 and 315 models.

You use the MakerGear M2, right?

Well done. Looks great.

Thanks. I've actually been enjoying this one for about a month but didn't have time to post up the design - finally got there. I will add more information when time permits.