3D Printed FPV Quadcopter The Crossfire

by MikeyB Oct 12, 2012
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might I suggest you add a cheap, small fpv setup to the top/front of this build. it will make it easy so see what you are filming or where you are going [I bought a complete setup around 6-8 dollars including 1s battery and transmitter]

The motor pocket is covered up when I print the arm with Simplify3d. Is this by design. It doesn't show up until the Prepare for Printing.

I'm having the same issue. Using S3D as well.

if i use pla its working

what kind of range do you get with this?

just wondering guys if DJI Naza-M Lite Multi-Rotor Flight Controller GPS Combo will work with this, will it fit? :) thanks :)


This is so amazing. I am a great fan of FPV things and I just bought my first FPV Drone from http://www.fpv-direct.com

Hi, really cool frame

I wanted to ask you how far apart are the mounting holes from the main shaft for the motors?

I don't understand how the 16mm and 19mm standard mounting distance works or means? I was thinking on using these motors http://www.hobbyking.com/mobile/viewproduct.asp?idproduct=86647

Also is it required or recommended to get a motor mount?

And where is that measurement of 16mm and 19mm come from?

Why is there a guy sky diving in the shadow? look at the wing

look over to the bottom left corner.

I don't know I have never used it. Because it is dissolvable I would probably stick to pla or abs

the file for the new gopro case is not on the thing files list

This looks awesome!

My XYZ DE Vinci 1.0 pro made this beautifully! The only problem was the bottom plate. I got the same glitch over and over so I scrapped it and printed the middle plate twice. Works like a champ.

what electronics did you use? mikey b

hey mikey what should you use for a gimbal if you have a hero 3 with a crossfire case for the hero 3. @MikeyB

I have a 4x4x4 print bed ( i know its small but i wanted to start cheap) and use PLA would this quadcopter be successful?

Dont think so look for the crossfire small here

Thanks, MikeyB, for the cool design. We are building one of these here at Boca Bearings. It's my first ever from-scratch RC build. I've started this blog to document the build from start to finish, Advice, comments or questions are welcome.


Our printer is a Type-A Machines Series 1. We're using PLA for now, but I might eventually reprint everything in ABS.

Hey. Thanks for building. This is a great write up. Very in depth. Have you got it flying yet?

Hey, thanks! It's not flying yet, still got a few more parts to print, but I hope to have it up in the air soon. I'll update the writeup as we go. Could you offer any advice on securely mounting the battery? I'm using the Turnigy Nanotech 4000mah S3.

How does the go pro case attach to the hinge?

What size props are you guys running on this?

I think most people are probably running 10x4.7 props, or at least somewhere in that range. There are no files for the standoffs between the plates. You can find those by searching the hobby king website and looking under hardware and nylon spacers. Hope that helps.

Hey guys I'm new to the world of 3D printing and was wondering what a cheap and reliable 3D printer would be? Also whats the sizeof printer bed i would need to make this kind of print?

I believe it would be possible to use a slightly smaller print bed and print it at an angle with supports?

When printing the arms diagonally you only need a print bed of 8" x 6". If you want to stick with an even smaller print bed (like I did with my printrbot which has 6" x 6") you can look at my smaller version of this copter: http://www.thingiverse.com/thing:142856http://www.thingiverse.com/thi... -- It has smaller arms and also the main plates are optimized for small print beds resulting in a requirement of 6" x 6" print bed size.

Quadcopter "Crossfire Mini" for Small Printers (15x15)
by leemes

There are so many good printers on the market now, have been printing with an original Replicator with great results. There are a few clones of that one that people are really happy with. You need a print bed of at least 9"x6" to print all the parts. The arms are the longest and its best to print at least two at a time but some have got away with smaller beds by printing the arms diagonally.

Hey everybody. As this thing nears 100,000 views and almost 50,000 downloads (WOW!) I was wondering if those of you who have printed and are flying one could do me a favor. I was hoping you guys could send me a PM with your setup (electronics, escs, motors, battery, flight controller, fpv gear and any customizations you are flying with). I am compiling a list of known, working setups that I will post in the instructions along with a link to your make. I think this will help out a lot of people who are just getting started and are not sure what to use. I will be doing a similar list for the C2 thread. Thanks again for all the help.

MikeyB, thanks for all your great work on this quad design! So I've built one myself (first quad) and have a very dumb question. The KK board in this design is mounted such that the sides of the board are mounted parallel and perpendicular to the quad arms. Most other quad designs I've seen mount the board such that it is aligned 45 degrees from the arms. Does this influence if you pick a "+" or "x" motor configuration? I ask because when I first tried to fly this, I picked an "X" configuration, and it just wouldn't fly. It would wobble and crash no matter what I did (played with all settings, and repeatedly calibrated my ESCs). So I switched to "+" configuration and now it flies. But if it's in the "+" configuration, how do you keep the camera facing forward? Looks like you are definitely flying this in an "X" configuration.

Apologies again for a noob question... THANKS

For X configuration and KK2 (which is orthogonal), you need a different mounting plate. It's here: http://www.thingiverse.com/thing:151821http://www.thingiverse.com/thi...

Crossfire Top-Plate for KK2.0 (orhogonally mounted board)
by leemes

AWESOME! Thanks leemes!

Your thing has just been featured on 3D Idea Forum's Thing of the Day! Check it out here:

Hey Mikey, what size is this frame? 450? Thanks.

Roughly yes, comes out to about 430. Had to design it around the constraints of the replicator platform.

I'm working on a PLA print of this awesome quad. I fractured a motor mount for my DJI Phantom, so I'm going to move all of the parts over to the crossfire and give it a try instead of buying a new Phantom shell. I printed the arms at 30%, and the silver PLA I'm using is solid as a rock. I'll be sure to share details of my build once I get it put together. Thanks for the refit! This is the perfect size for the Phantom!

How did it turn out? Is it strong enough for flying or should ABS be used?

Looking forward to see how this works out.

How much would this cost to build?

I priced it out at about $150-$180 (USD) not including radio or battery charger since I already have them. Hobbyking is a great place to get parts, as they're incredibly inexpensive and their products are generally good quality.

Mike , can you comment on the specific lengths of the nylon standoffs and where you got them? Is there an assembly drawing as part of the .skp file? If so, I can download that and take a look.

Sorry no assembly skp. I also got the nylon standoffs at HobbyKing. The only dimension that really matters is between the top and bottom plate, which is 1". The top cover can use any size, or combination of sizes to offset above your chosen flight controller. I used the M3 Nylon spacers.

Thanks for this, I just have to add though, I found it really not necessary to use 50 percent infill. At 25 percent infill, they are still very rigid, have decent weight and can withstand just the same impact as 50 percent infill, if not more as they are slightly more flexible. Don't mean to rain on your parade, you have produced a wonderful quad to print - I am both lazy and also want a lighter quad, and at 25 percent infill it cuts the printing time down to 2 hous for Arm2.5.
I also fixed it in netfabb as replicator was reporting dangling edges, but netfabb fixed that up and there was i think 4 holes in the arm piece.

Thanks for the reply. I haven't ever got the dangling edges before but I did do a small modification on those arms so maybe I left some internal geometry. Thanks for bringing it to my attention. As far as the infill 50% was what gave me the lest amout of flex, as you don't want much or any flex in the arm. Early tests showed some completely uncontrollable crafts with flexable arms as they were counteracting the flight controller. Are you printing in PLA or ABS? PLA being more rigid might be able to get away with 25% but I've never tested PLA arms. I'm ver interested to know what you find. Thanks.

I'm printing in ABS only, I found PLA was nice and hard yes, but even the slightest crash would crack an arm, the ABS is much more forgiving. I do have to retract my previous statement tho, there is a problem printing at anything less than 35 percent infill, even 40 is a minimum. If you go any less, then even after the print is done, and you leave it to cool, if you do less than say 40 percent, the arms have a tendency to eventually want to curve upward, losing that nice flat surface from the raftless print (another reason I love these, no support, no rafts.. its great) Yes, you can re-heat and eventually cure them, but it's a real pain, and for that extra 10 percent infil, which can take alot longer sure, it means your arms will be dead straight. So far the biggest challenge for me is printing the top plate! takes up my whole print bed practically and I have a dual extruder, so all that movement across the entire bed lets you know when things are not level... you get alot of nozzle drag with something that large.

What printer are you printing on? Replicator Dual? Yeah the long flat prints really let you know when your bed is not level, or in my case not true. The middle of the HBP is higher than the corners so its a real bitch to get a good first layer on mine. I tend to not mind as much if the center is too thin on the first layer, as long as the nozzle doesn't drag. The corners are where the bond has to be the strongest.

It's a flashforge 3D, so pretty much a replicator 2x, I ended up adding some small disc supports to all the STL's so I didn't get any edge lift tho, so it's not really a problem anymore. I literally got 90 percent through building the quad, then got made redundant at work, so sort of im limbo at the moment, im hoping to get my main one flying soon.

Does anyone have a build log for this project? And how much should all of the electrical parts cost?

the build is fairly strait forward. and what ive speced out from hobbyking it should be around 175$ in electronics

Have you built one? I just don't know what to order for electronics, I hate to order everything and then have nothing work.

Hi David,

I'm starting the build myself too. I just ordered some electronics. It was around 175$ without the transmitter (I still didn't decide what to buy). Here is my spreadsheet with the parts I considered based on suggestions in the comments and other forums. The ones in green are ones I selected. Crossed out are items I already ordered. I hope this helps but please keep in mind I've not tested this setup yet.


Nice list of equipment... What did you end up purchasing and how did your quad fly?


I am totally new to the quads so I will ask s newby question. I have been looking at your spreadsheet and was wondering what is the list of things i need to purchase. Where can I find a list of parts that need to be purchased and not printed so I can make a calculations etc. What I mean is that I see long list of controlers and I guess you need one but I have doubts about all of the sections in your file


Hi, I've added a short list with set of items that I've ordered for my quad. Note that its based on my research but it wasn't tested yet and I don't have experience with RC aircrafts.

And could be so kind telling me where could I read the besics in order to get started. I have already like a lot two models that are here on thingiverse...

first off amazing job! I had a quick question, what radio and receiver are you using with the copter?

I'm using a Futaba, but Spectrum and other radios work fine as well.

Can anyone provide screw sizes and length?

On the old top and bottom plate I used 1/8 and 6/32 machine screws for the arms and M3 standoffs. With the new top and bottom plate everything is assembled with M3 hardware.

Thank you lots man! Very well made copter.

Mike 2 quick questions:
The video showed carbon fiber motor mounts but didn't see carbon fiber arms? Did I miss something or is that a different build? Second, What's your thoughts on using MultiWii for this design? I have a DJI Phantom and I love the stability of gps lock for filming. Is there something better or equivalent to get those kinds of features?

Yes, the one in the video was mostly flown with the printed arms, however it has been flown with the carbon arms as well with great success. I have never flown with a multiwii but i have heard great things about them and there is no reason that you couldn't use any flight controller with this quad. If you do end up using it please let me know how it works out!

MikeyB, just downloaded the files and began printing the top cover today. I'm using the infill percentages you recommend for the parts but I'm using Makerware to create the XG3 print files. I'm curious whether it matters whether I print in High resolution or Standard resolution? The parts come out great if using high resolution but it takes twice as long to print when compared to standard resolution. Any issues with part strength if I print in standard resolution? Also, I assume most people print using rafts and pull the part off the raft when the print is finished?

High or standard print resolution should make no difference on the strength of the object, just the overall finished look of the object. I don't know about mist people but I am guessing that most print with standard resolution with no raft or support for any of the parts on this page. The thin objects like the airframe plates have very little problem with warping, the arms on the other hand can be a bit of an issue. Good luck with the print and be sure to let us know how it works out.

Regarding the arms, you recommend printing with 50% infill. Is warping still an issue with that setting? I'm printing on a Replicator 2. Thanks!

Are you printing with ABS or PLA?

Using PLA. I've successfully printed all of the parts. Now putting together my electronics order.

Loved your video so much I had to start building one right away. Cheers

Sorry for the late reply but please let us know how everything turns out when you get her done!

Can anyone provide screw sizes and length?

Hey Guys. The Mounting holes are at the wrong angle for the Hobby King KK 2.0, I used a KK Blackboard when I designed this. Sorry for the confusion. Rest assured there are many updates in the future. Arms, gear, body, mounting for KK2.0, Blackboard and APM. Also an extended body with better camera view between the arms. I think you guys will be really happy with what is coming. I just have to make it through the next week and my summer season will be over, then I can get everything posted. Three months and 400 hours of flying, I'll be glad to get some days off :)

I think I'm speaking for all your fans if I say many thanks to you. It's very cool to have an open source project which is even modular extensible and printable at home. Your work is very valuable to the community and yes we are really happy already! ;) Regarding the 45 degree rotation, I created this workaround thing http://www.thingiverse.com/thing:151821http://www.thingiverse.com/thi... people can use to mount their KK2.0 on this version of the Crossfire.

Crossfire Top-Plate for KK2.0 (orhogonally mounted board)
by leemes

Mickey, is the prepared place for the KK board at the right angle? I would like to move it 45 degrees so that it points in the correct flight direction?

I ran into the same problem. Since I already modified this design slightly to fit on 15x15 print beds I only have a further modified version of the plate. But I can go ahead and also modify the original plate for KK2.0, which might be useful not only for you since mikey suggests KK2.0 which requires an orthogonal orientation, not diagonal like his plate.

Crossfire Top-Plate for KK2.0 (orhogonally mounted board)
by leemes

This is the first multirotor I ever have tried to build and I must say that it was "more" to think of that I am used to :) Glad that I figured out that there where something wrong with the KK2 mount plate - and glad that you did that perfect print solution. I am not used with Sketchup and I dont like it, I prefer Inventor from autodesk, it is more rigid and I love the way it handles measurements!

Thanks again!

No problem! It was also my first multicopter. I also had to figure out a lot of things, like compatibility of motors, battery, ESC, radio modules, etc... What all these specifications like 3S, 750kv and so on mean. A lot of things to learn if you start from scratch. When I printed all parts (I had to shrink them as you can see in my remix since I have a small printer) I also noticed that the plate is for diagonal boards but I wasn't sure if I'm simply wrong since I am missing all the experience! But it really is for diagonal boards like others are, but KK2.0 is orthogonal. After building it, you still can't fly immediately, since you have to do some calibration. I found the videos in this series a lot helpful: https://www.youtube.com/watch?v=8NAXSBCtSLYhttps://www.youtube.com/watch?...

Good video about stabilization calibration (the "PI-editor" in the KK2.0 board menu) is this one: https://www.youtube.com/watch?v=YNzqTGEl2xQhttps://www.youtube.com/watch?... which shows how you identify what's wrong if you see the symptoms of incorrect behavior.

Thanks! I will try to get airborne tomorrow and see how it works. I will check those videos as well!


MikeyB! Can you list all the parts you are using for the FPV setup? even what goggles you are using! I want to add that as well to my quad ;)


Can you also give hint for the propellers?

It all depends on the weight but with a standard FPV setup I would go with either the Graupner 10x5 or the AWC 10x4.7. With a quadcopter without a FPV setup or a cam the Graupner 9x5 or the AWC 9x4.7 or 8x4.7 would work fine.

Mikey, you should maybe set up all this information and other within the description of this super thing! It is hard to find all information since the most can be found here in the threads.... :)

Keep it up!

How amazing! This is my first copter, so I have a few questions before I can assemble everything. I want to install these motors: http://bit.ly/16DoCByhttp://bit.ly/16DoCBy They suggest 30A ESCs, but I already bought 25A ESCs which I bought because I previously wanted to install motors with a lower max current but they are wrong and I have to return them. Will the ESCs be a problem? According to ecalc I can drive the motors at about 13A max. Here is my ecalc config, but please change the props to 9x5, these values don't seem to be encoded in the URL: http://bit.ly/16DoQZqhttp://bit.ly/16DoQZq Which part exactly determines the maximum current which goes in the motors? (With this I don't mean the max current which doesn't harm any part but with what current will the motors be driven if I trigger the throttle controller to the maximum) Do you have any further suggestions regarding my config? By the way I won't install a cam to this copter.

leemes, those motors should work fine with a 25A ESC. I am no electrical engineer and I done have much knowledge of how all the variables work into the equation. The one thing I do know is that lower Kv ratings for a given thrust with a given propeller will be more efficient than a higher kv motor.

I just printed this Copter but it doensn't work: (PLA)

If I start the motors the copter is jumping up and down by itself. Like a wobble..
Seems that the arms are not stiff enough.

I used MultiWii and this setup worked for a other copter frame.

Did you guys know what I have to do?

I've been trying to get my Crossfire off the ground with the MultiWii, too. I'm having a similar problem to the one you describe. I think, but have not confirmed, that a frame flexible mode is coupling back into the rate gyros on the MW board. What I discovered, so far, (and the jury is still out on this), is that smaller props help. I was using those "bendy" 10 x 4.5 electric flight props for initial testing but discovered that the shorter 8 x 4.5 electric flight props are a bit better. Doesn't help endurance much but I think it helps quiet things down a bit. I suspect moving to large, carbon props will chase this problem away. But, I haven't finished all of my initial flight testing yet. Will update this as I go.

What % Infill did you use on the parts? Do you have any pictures? Is the quad assembled like in the picture above with the top plate on as well. It sounds like the arms have been printed to light and they are flexing. I had this problem in the beginning as well but 50% infill should be more than enough especially in PLA.

I just printed the arms with PLA and 50% infill, they are stiff as hell :) The design work on the arms looks super and I wonder what software you used when U designed this little bastard?

Thanks, glad to hear it is working for you using PLA. Also, leemes is right, I used Sketch up for the designs.

I'm pretty sure he used Sketch Up since there is such a file in the downloads ;)

Hey there.
First, I am new in RC stuff and 3D printing.
Let me tell my story before the questions:
I am 16 years old, I have a HERO3 black and a HERO2, and I want a DJI Phantom. But it costs 500$ more or less, completely out of my range, so I go DIY! I found this proyect, and I want to print the quadcopter, I downloaded the zip containing all the files, but I dont know how I need to print the skp file (containing all pieces) or copy one by one, printing individually.
2 question: I calculated that all the electronics are 150$, which is great compared to the DJI Phantom!
The skp file ONLY contains a frame for the HERO2, which its sticks into a plate, can I use the HERO2 or HERO3 black WITH the housing attached to the quadcopter via stick flat mount?
3 question: How hich can fly this thing (with gopro on board)?
This quadcopter is stable? I mean, I need to buy a gimbal or apply a stabilitation effect to the video? or is stable by its own?
Many thanks!


Hey Chernowii,
Let me try to answer all your questions.

First off the .skp file is the sketchup document. It is the cad drawing of all the components so if you wanted to edit or modify anything you would do that with sketchup

Second, the printed case only fits the Hero1 and 2. I am working on a Hero 3 case but it is on the back burner for the moment. You could however stick the Hero 3's waterproof case directly to that flat plate for the time being. It will be a little heavier but better protected from a crash.

Third, that is a touch question to answer. It all depends on your controller, how well you balance the cg and the props and motors and how well you fly it. The quad can be made to fly very stable with just a KK board but it takes a fair bit more hand flying than say a NAZA or a APM. The KK is a good inexpensive place to start though. It can fly as high as you can see or even higher if you have a fpv system on it. I have flown my quad about a mile and a half away with a UHF system on it.

Hope that helps, if you have any more questions feel free to ask.

Do you just screw through the plastic or did you use nuts? Thanks

I used nuts and bolts, you can use nylon or metal hardware. Lock nuts are always a good idea or a dab of locktight as no matter how well you balance the quad will always have some vibration.

Awesome thanks! I built one of my own quads using aluminum square arms but after some crashes I want a fully 3d printed frame. Cutting and drilling holes into the aluminum for new arms isnt very appealing lol. Thanks for this contribution!

Mikey, many thanks for the awesome quad, I have it printed and am awaiting parts from HK. Quick question, how do you attach the gopro frame to the hinge? a screw through the earplugs? Sorry if this is listed somewhere, I can't seem to find it.


Just a dab of super glue on each side of the ear plug. I used 5, one on each corner and one ear plug in the middle. Please post some pictures when you get her flying!

I was hoping to ask those that built this a few questions as I'm looking at a DJI Phantom vs DIY Quad (w/ Ultimaker printed body).

1) What is the flying weight? How much can it carry?

2) Anyone using GPS type of hold position or recovery?

3) looking to add a 120g Gimbal + 250g camera (RX100) could this build handle it?

4) Anyone have a specific recipe of electronics and motors you'd recommend?
5) I want to eventually do FPV and longer flights via GPS way points.. Is this a good platform for this??

Same questions here!

I have never flown a DJI quad but have flown many other quads, including the TBS Disco. All frames pretty much fly the same, it is a question of the electronics installed (ESCs, motors, flight controller etc.).

The flying weight on this quad, with a basic FPV setup is about 1400 grams. With a 4 cell battery it can lift a significant amount of weight. Definitely enough for the gimbals weight - On that note I am in the process of designing a printed gimbal for this quad, so stay tuned for that :)

As far as electronics go there are many successful combinations. I go with the turnigy type escs and have had good luck with the http://rctimer.comrctimer.com motors as a cheaper option or any of the the motors for http://getfpv.comgetfpv.com for a little higher end motor.

If you have any other questions, don't hesitate to ask!

I'm thinking in use the TURNIGY Plush 30amp ESCs with the D2830-11 1000kv Brushless motors. Do you think it'sa a good combination?
Which battery and props should I use to carry a GoPro and FPV equipment?

Thanks a lot!

The 30A Plush should do fine for you, those are the same ones I use. You can get away with using 18 or 20 amp ones as well.

As far as the motor I don't have any experience with it, but as a rule of thumb the lower the Kv the better for multicopters. I have used 1100kv motors on my tricopter, but now am running 620kv with a noted increase in efficiency.

Some good props for this are the Graupner 9x5 or 10x5 props or the APC 10x4.7. I have flown with both and both do well.

I would go with 4 cell batteries for the quad. Anywhere between 3-5000 mah. Any higher than 5000 and you will get diminishing returns on your flight times. I just got a couple 4000mah turnigy nano-techs and have really been impressed with them. Hardly any heat and bloating after a hard flight and the size and weight is significantly less than a similar battery.

Hope this helps.

Hi Mikey,
Are you using these batteries: Turnigy nano-tech 4000mah 3S 25~50C Lipo Pack ?

For the package I went with a DJI Phantom. The electronics are solid and full featured. Now I need a gimbal solution to fit my RX100 into - let me know how your GIMBAL option turns out.

How big is the quadcopter when fully built?

Hey, are you wondering what the weight would be or the total size of the quadcopter? The total weight of the quad, depending on the electronics is roughly 1400 grams.

Hi, I cant seem to find the motors for this quad. Can you help me or are there any others that fit your design?

Hey, sorry for the late reply. Any motors with the 16 x 19mm mounts (pretty much the standard motor mount dimensions) will work. A good place to start is http://GetFPV.comGetFPV.com or http://RCTimer.comRCTimer.com.

Thanks, I just placed an order for all the stuff. Looking forward to print this little beast!

Awesome! Looking forward to seeing your finished quad. Be sure to post some pics or videos when you get it flying!

Yepp, I will for sure!

So how many of these things are out in the wild and flying? I would love to see what people are doing with them.

How long is the flying time on this quadcopter? Could I use the APM 2.5 below as the electronics?

I am getting about 20 minutes out of this with a 4000mah 4 cell battery and full fpv gear. I would like to put my OSD on soon so I can get a detailed readout of voltage and amp draw while I'm flying. I don't see any reason why you couldn't use an APM on this. There is no mounting holes (yet) for the APM but it should fit no problem.

I'm not a designer otherwise I would take it on myself but a future suggestion to would be to make a DJI S800 style arm. The wires are actually integrated into the arm to make a super clean finish. So maybe an arm with a hollow cavity to feed the wiring.

Do either of you guys have any pictures that I could use to design from?

Great job! Approximately what does it cost in material (ABS?) to print one of these? I'm new to 3D printers, been flying RC toys for a while and thinking about getting one of these 3D printers to make custom parts like you did. Thanks for sharing!

In my estimates... I did 50% infill. My cost is based on $40/kg ABS.
Arm - $1.77/each x 4
Bottom plate -$1.56
Top plate - $1.23
Top - $.56
Go Pro mount - $.85

Total: $11.28

Not sure if 50% infill is required for the arms though? Top & Bottom plates probably should be solid (100%)

This includes power usage in the estimate, but does not include "machine cots", ie maintenance etc.. I'm a home user not a business so I just leave the "machine costs" out of the calculation.


Ben, thanks for the reply. How did you calculate the amount of ABS used? Is there some sort of calculator that you can plug data into or did you measure?

Another option is to simply weigh all your plastic parts. As far as I know, there's no discernible loss of plastic when you're turning filament into parts, so as long as you know what your original spool of filament cost and how much it weighed, you can figure out what your parts cost.

Using the statistic plugin. It writes a txt file with the estimates of plastic, time, etc...

compliments! great job! maybe in the next version you could try putting a smaller cam, like a sony action cam or a chinese one.

I do not own a sony action cam, but the sketchup files are posted. Feel free to design one to fit on the hinge. Thats what this project is all about. Other people modding this to their own needs :) Although I have been thinking about adding a mount in between the top cover and the top plate for a small FPV cam if people didn't want to use the GoPro for their primary flight cam.

Hey Mikey! Any way to get the SketchUp files? I'm wanting to build this but can't find a place that carries that motor model.

Yes I can post the sketchup file. The 16x19mm are pretty much the standard motor mount configuration. The only other one I've seen is the triangle configuration. Let me clean it up a bit and I'll post it up here.

Posted the Sketchup file. Enjoy!

Anybody printed this copter with PLA?
Is it stiff enough? Maybe with a video?



I believe JoeMattie has printed a few in PLA.

i have printed this in PLA and it flys no problems, infact my Hexa Remix is 100% PLA too

Great build. I really like your receiver slot and camera mount. very unique looking design

Hey Mike,

I have done a TON of research and I've read everything I can find on building this.. Since it's my first Quad.

I've created a post over at RCGroups. I may design my own, but I'll print yours first.. and go from there :)

It appears the best combination is a 3S (4000-6000mah). 11x4.7" APC prop and NTM 910's. Which gives hover at 53% and with a 10" prop hover at 68%. I've listed all the parts I'm going to go with...

The 3S vs 4S is where I stand right now.. I can't decide!


What is your finished weight?

A fully finished fpv build will be around 1300 to 1700 grams depending on your hardware and components. The frame I just printed using carbon arms and the motor mounts and spacers I published is about 100 grams lighter than this frame even!

You have any pics or designs of the carbon frame? I was also looking to build this with carbon arms ! Thanks a lot!

Did you try to put on 12" props? I thing i would go nicely with those 750kV motors. Well at least i am planing to do so if i manage to fix reprap and finish printing legs.

I have not tried 12 inch props. Have you done any efficiency calculations? I haven't but am interested in finding the right combination.

I'm very interested in printing this! However I've never owned a quadcopter. I have a series of eflight helis and a vintage Nexus 30 (nitro) heli. I saw your basic list of electronics. However what other parts are required?

I'm going to go with a Spectrum dx6i.. As it'll work with my blade helis.

Rotor blades? What size/pitch? I've seen a few printed blades on thingiverse, have you tried any of them?

Anything else? A charger for the battery I guess. I have a really good charger but it's only for nimh and nicad R/C packs.

Oh I have a replicator one as well :)

Hey. Go for it, you should have no trouble flying it if you can keep a nitro heli in the air :) Your dx6i will work just fine.

I would stay away from printed props. They just aren't tested. They seem ver interesting and I would love to play around with them when I have some time. I have used the apc props, the 10x4.7 work great. But I've been using graupner props now and they work even better. the 9x5 or 10x5 should do you fine depending on your weight. Just be sure to dynamically ballance the prop to the motor.

As far as chargers go there are a number that will do good. I have a Thunderpower. Just check hobbyking, anything that will charge and balance 3 or 4 cell Lipo batteries will be fine.

Hope that helps, if you have any other questions feel free to ask. And be sure to post pictures when you get it printed!

Yeah Nitro heli's are not simple... at least not the Nexus! I was quite good nose in hovering and forward flight... but I never did progress enough for fast foward flight. Things came up and I actually haven't flown it in about 5 years.. But the small Blade Heli's keep me entertained in the mean time.

Very cool. I actually found this blog post:

It's 5 parts.. It details every step! I'm still planning to print it though... as I want to do multi-colour and being able to print replacement parts is wicked. But everything else applies.

Is the motor mounting somewhat of a standard? Ie will they align with the holes in your designed arms?

I will be posting pictures !

Yes the motor mount holes are standard. And four hold mounted motors should work. I believe the dimensions are 16mm and 19mm distances. I look forward to seeing it!

Do I have to print with supports for the arm with the leg pointing in the air up from the build-plate?

No you shouldn't have any problems printing any parts of the frame, including the arms, without support. Be sure to let me know how everything works out!

Hi again. Thanx for quick reply!
I tryed to make the print in ABS, with my replicator 2x. Brand new...
The part is almost as big as the build platform, and it loosens half printed, the one end loosens, and wrap up. So the complete part looks great, it needed no support, for the "bridge" on the top of the leg....
But the motorbracket loosened from the build plate, so now the motors would face a bit outwards, and probably cause some problems...
I tried 3 times now.. Leveling the buildplatform for each time.
But the buildplatform doesent seem to be plain I think.
When I calibrate it, If I make the businesscard calibration, on all the sides, and push the BP as close to the nozzels as I can, when it goes to the center at the last calibration, its no place for the businessvard between the BP and nozzels..
So It looks like the BP is higher at center, than corners, from fabric?
Its not the calibration I think...
Tried PLA, but that I have not printed before at the Makerbot replicatpor 2X. I did not get the print in PLA at ALL..-
Just did not stick to the painters tape...
Maybe I did something wrong... I used default settings in Makerware..

But I read now that I should run the extruder for 300seconds after changing from ABS to PLA. That I did not do..
Shall try now maybe.

Leveling the build plate for the arm prints is VERY important. Just using the card will get you close but it may not be good enough. You should use a depth gauge to level perfectly. Something like this http://www.thingiverse.com/thing:23257http://www.thingiverse.com/thi... makes a huge difference. Also you need to watch that first level of the print very carefully. If the extruder is not putting out a nice "flat" bead then the build plate is too far away. If it is extruding messily or not at all the build plate is probably too close. By watching the first layer it should be easy to see that one side or one corner may be too far away. If that first layer doesn't bond well you can count on warping. One last thing to try with ABS is to dissolve some ABS plastic in some acetone and then smear it on the kapton tape on the build platform. I usually apply it with a q-tip when the platform is about 80 deg C. You will see the acetone quickly vaporize off and leave a very thing layer of ABS that the extruded ABS will bond to. When I started doing all these things my prints became 99% successful. I know these types of prints can be frustrating but I have printed many of these frames so far on my Replicator Dual and my build plate is just like yours, just a little bit higher at the center of the platform. Keep at it, and let me know how it turns out!

Replicator Bed Level Jig

Ill try that tomorrow or this weekend.
I have the depth gauge and have made all of the different types on thingiverse, but none matched my magnets or replicator 2x, so i made my own..
It is good, but still not perfect.
The acetone I try this weekend. Great!

Do I have to print with supports for the arm with the leg pointing in the air up from the build-plate?

What fpv system did you use

I'm using a 900mhz .5w tx with a 2.4g rx. But I think I might switch this one out to 5.8 and go with 2.4 on my tricopter which I use an ezUHF with.

how do you use a 900mhz tx with a 2.5ghz rx??

900 mhz video tx and a 2.4g rx for my radio. I'm using a Futaba Fasst. Thats why I don't use a 2.4g video tx with this one. By the way do you think those goggles will work out for you?

Yeah, they'll do (at least until my rift comes in :) I haven't had a chance to fly much fpv as I'm having issues with my ardupilot board. If you still have any kk blackboards that you're willing to sell could you possibly bring one next time you come to town and I'll buy it when I pay you for the goggles?

Yeah I can't wait to start plying with the rift. It just screams stereo FPV ;) Yeah I think I have a blackboard lying around. I'll bring it when I fly to FAI on monday.

cool. just gimme a call whenever you're in town

Sorry, I'm back in Colorado for a few days. I should be back in Alaska sometime next week. I did find a board for you and I'll let you know when I'll be flying to Fairbanks next. BTW has your rift showed up yet? I can't wait for mine.

not yet. I'm trying not to think about it too much. I feel like a kid on christmas eve

900 mhz video tx and a 2.4g rx for my radio. I'm using a Futaba Fasst. Thats why I don't use a 2.4g video tx with this one. By the way do you think those goggles will work out for you?

Nice work ) What is the approximate total cost of this build?
Happy Easter!

Roughly about $200 if you already have a radio and GoPro/FPV gear.

Printed your design at 65% scale as the frame for my ardupilot uav quadcopter. came out very well in pla, 3 solid layers with infill at 30% on all parts. Came out very sturdy but flexible enough I wont have to worry about the pla cracking from harsh landing.

Hey, looks great! What are your plans for the quad? Just wondering why you printed at 65%. I would like to print it out at 50% or 35% and make a mini quad. Let me know how it flies!

Hi Mike, I really like your design. Could you also share the BOM of electronics that you use on your model? Thanks!

Hey sorry for the delay. I've updated the description to contain a basic list of electric components to get people started. If there is interest in the FPV specific gear I can add that in as well.

Thanks for posting this information.
Regarding the Turnigy Plush 30A ESCs, I've read that new model has different chip and is difficult to flash with simonk firmware. I was looking at using Turnigy Multistar http://www.hobbyking.com/hobbyking/store/__25365__Turnigy_Multistar_30_Amp_Multi_rotor_Brushless_ESC_2_4S.htmlhttp://www.hobbyking.com/hobby...

But I've read that these cheap HK ESCs are good too:
Is the 750kv motor powerful enough? How much does your copter weight?

I have not tried to flash the simonk firmware to my Plush ESCs but I have a set of TBS ECSs with the firmware on another quad and honestly can't tell the difference. I have used the Turnigy Plush ESCs on a handful of quads and tricopters and they work great with no modification. I have heard good things about the HK ESCs as well.

The 750Kv motors are more than enough. My quad is right around 1600 grams with battery and the FPV setup (Vtx, GoPro etc.)

Hi MikeyB - excellent design. 1) I'm curious if you have done anything to avoid warping? I'm using a Ultimaker with PLA and on my first print the arm went banana-style. 2) Is the design viable with PLA? Alternatively maybe i'd use alu- or carbontubes like lobster.

The design works for both ABS and PLA. I have not printed with PLA but others here have had good success with it. Also I thought that PLA had less of a tendency to warp. All I can say is that bed leveling is paramount to getting a good print. If the first layer isn't bonded well to the bed it can start to warp. I will restart my print if I don't like the first layer. Better to lose a few minutes then to have the warm warp 2 hours into the print. Using something like this http://www.thingiverse.com/thing:23257http://www.thingiverse.com/thi... doest wonders for leveling the bed. As far as carbon tubes go, I haven't built a quadcopter with them yet but I have used my mounts and spacers in a tricopter build and they work great. I will post it soon.

Replicator Bed Level Jig

Curious on how you fed your servo through that hole? I can't, with the screw tabs on the servo!

Could you design one that use 8mm carbontubes instead of the printed arms?
I am thinking about it making some motor mounts, but i cant get it just right..

Hey lobster. I am designing motor mounts and arm attachments for both a 9/16 OD carbon tube and an 11mm OD carbon tube as we speak. Are you sure that 8mm would be strong enough? The 11mm seems kinda small to me. I should have these up and printed in the next couple days, should be pretty easy to make them fit any size arm you like.

from what i hear the carbon tubes are pretty tough. but on second thought, i can source 10mm tubes.
Im printing a new frame atm, because i liked it so mutch.
A carbon tube setup could prove very helpfull in cutting materials and time used.

Lobster, they are very tough! Are your 8mm OD or ID? An 8mm ID wouldn't be bad, I am holding an 11mm OD arm and the ID is about 9.5mm and I think it would work fine. If the 8mm arm was OD though it just looks really small. Let me know and I can easily post a design to your specs. As far as saving printing time, that was my thought exactly, I'm pretty sure it will also be lighter and stronger. I think I may try and figure out how to use thingiverse's customizer so that people can print out whatever diameter mounts and spacers that they need. I have found that CF tubes tend to vary a lot between manufacturers.

My 10mm OD is 8,5mm ID. if you just make spaces, to put the tubes inside, that would be very nice, then its just a matter if openscading them parametric, then your golden.

My knowledge of openscad is nonexistent :) Do you know anything about it? I have the motor mounts all drafted up in sketchup. I'll post them as soon as they are printed and I can confirm that the tolerances are right.

I mostly do my modelling in openscad, il be happy to try and make them for you.. the customizer looks like a challange :D

As in you make them as you want em, i print em and try to remodel them in openscad. or you can send me the .skb files, then i try

I got those motor mounts up. They are for 9/16th OD tube. Let me see if I can export a .skb from sketchup.

thanks for all that info. i'm going to print it soon. what kind of remote control would you recommend?

I use a Futaba 7C. It's 2.4 ghz so if you're planning on setting it up for fpv you want to choose a different freq. for the video. 5.8/1.3/900 etc. The Spectrum radios are also very popular. A little less expensive than the Futaba and with one less channel but still very good. I would go with the DX6i. Either way you can't go wrong. One of the cool things with Spectrums is that there are a lot of bind and fly models out there that will bind to the radio right out of the box.

Thanks for the help! the frame came out really nice on my printer, I've got a uPrint that I picked up cheap on ebay. the fit of the pieces is good.

Awesome! Do you have any pictures? I'd like to see them as there are only a few of these out in the wild :)

Yep, just posted a picture. Not assembled yet

Looking good! Let me know how it flies and if you have any more questions. Multi-rotors are like a disease that can't be cured...You've been warned

Hey have you found any other geometry problems with any of my other files? I think I found all of them and re-uplaoded good files. Most of them didn't cause any problems printing but when I re-desiged the arm for some reason that error did. I have heard of netfab but haven't used them yet, maybe I should give it a try.

I printed my arms out at 50% with ABS and they feel very rigid but maybe a little heavy. I have slapped it into the concrete in the hangar a few times and haven't broken them, but no crashes yet... I'm going to try a few more sets at lower infils to see if I can find a happy medium between strength and weight.

I'm glad to hear that yours is flying well, so is mine. I'm back flying the scheduled flights and will be up in FAI mon/wed/fri if you want to meet up. I also have an old pair of video goggles I can sell you cheap if you're interested. We gotta get you into FPV :)

Totally! I sent you an email with my phone number and the address of my shop. Did you get it?

Hey Joe. No I didn't get that e-mail. Did you sen it through thingiverse or my personal e-mail? Plans have changed for me, we are training a new pilot so I'm sitting on call for medevac. Not sure when I will be back flying scheduled flights but send me your number again and I'll let you know next time I get to Fairbanks.

Phone number is (907) 750-5174

I've had really good luck printing the arms solid with 25% infill (see new new derivative I posted), and the added bonus is that they take less time to print due to having fewer perimeters.


I'm printing this thing out as we speak, it's going to be my first quad, I was wondering if you can post what size motors you used and that sort of thing. thanks.

Yeah, 10,000 views. Thanks for the support everyone!

The one with the gear integrated into the arm? I had wondered about that. I've only printed in ABS, I hear PLA is a little bit brittle? Also did you have any problems printing the arm? I had a weird error printing one with some runnoff lines. I found some internal geometry and deleted it. Going to try it again tomorrow. Now that I am back in AK I can concentrate on finishing this project. Thanks as always for beta testing :)

Got around to printing V3, this time out of PLA. Works perfectly, I have to say, although the landing gears break off after the first hard crash.

Link was good for me!! Yes a bit wobbly coming back down.
The GoPro needs some sort of dampening to stop the jello effect.

Been working on that problem. I believe that I have come up with a simple fix. I will post it soon.

I got it in the AIR today!!!!

its quite stable in hover, it wobbles alot when decending (probably due to bad tuning).
It flyes very nice.
The problems i had, i chalk down to "i want to fly NOW!!"
I redoed the tutorials calm and rested. it flyes good.
i got a clip going up to youtube unedited. its should be up in 2 hours or so. (http://youtu.be/_-ytf8BMtsk)http://youtu.be/_-ytf8BMtsk)

The Link looks good now. It does look like it is flying very well indeed. The props need to be balanced a little but otherwise it seems pretty well tuned. The wobbly descent happens when the quad gets into its own downwash. Pretty common on all rotorcraft and can result in "settling with power" as it known with helicopters. The is where no matter how much power you add the craft continues to sink through the turbulent air it is creating. Try descending with forward speed to keep the turbulent air behind you.

Ooh, that made perfect sence. il keep that in mind.. thanks :D
if you look at my youtube, you can find another upload, its done in a little windy conditions.

Hey, it seems that your link is broken. I would love to see that thing in the air :)

Hey the link looks wrong and doesn't seem to work. I'd love to see it flying :)

It took longer than anticipated to upload.
Btw i have a protection dome i made that fits the frame.
I had an unfortunate mishap today, when at great height, i wanted a rapid decend, turned motors very low, it inverted, could not recover, head/rear down first, smashed to bits. electronics intact, dome broken.
Il upload the dome as a remix, it saved my electronics today.

Hi Mike,

Got the quad wired up and am happy to report that it works perfectly with my fix. Haven't tried printing your updated parts yet though.

Hey Joe,
Thats great news. Hopefully mine will work as well. Got any pictures of the fix you can upload? I would like to see how you set it all up.

I just uploaded two photos to the thing for the fix.

I did notice that the GoPro mount was a bit sloppy so I added a couple of washers to fill the gap.
Would like some small lugs for the GoPro mount to sit in as you can tighten up the bolt and it still
Seems to move, Had this problem before with tricopter when you bump the ground a little hard the
GoPro would tilt down.

Yeah, I've noticed that too. Have to get the tolerances and the shrinkage down. The first set i printed was way too tight. But I figured I'd come back to that once the rest of the quad was sorted out. Also I need to add a hole for the servo arm to attach to the gopro mount. Ultimately I would like to have the option of a roll mount, a tilt mount and a roll and tilt mount, but thats a ways off.

Just waiting for some servo leads and mine will be ready for test flight, printed in PLA and seems ok.

Hey Mike,

I fixed the wobbly arm problem: http://www.thingiverse.com/thing:41895http://www.thingiverse.com/thi...


Wobbly Arm Fix for MikeyB's FPV Quadcopter

Awesome! Simple and elegant fix. Have you printed and or flown with it yet? Also do mind if I run with this idea as when I do the Arms V3.0? I really appreciate all the time you have spent on this project. I'm in Colorado now but heading back to Tok in a week. Where is your shop in FAI? Hear it has been pretty damn warm up there recently :)

I've printed and assembled it. I have an hour of wiring to do before it's ready to fly, so I should have it tested by early next week. I'm pretty much positive that it will work, based on how much more rigid it feels. Feel free to incorporate the mod in your next revision. All I really did was rotate your existing arm 90 degrees and chop off half of it anyway.

My shop is on Birch Lane, about a mile from UAF. It has been warm here for the last few weeks, although I missed most of it due to being in Hawaii for my honeymoon. The weather was nice there too :P

Cool, I know exactly where that is. Congrats about your honeymoon, perfect time to get out of Alaska as well. I got a message from another guy who has designed a 3D printed quad who is also in Fairbanks. We may need to have a 3D printing summit in Fairbanks sometime.

Sounds good to me. We can have it at my shop if you'd like

Just got mine printed, and the mounting for the gopro on the bottom did not print at all, its due to my printer being angry..

And i have a slight curling of the prints so the quad looks sad.

Im going to mount the electronics and test it.
Printed with 30% infill overall. Using a CC3D fc, and cheap china motors and esc.

I tryed to fly it, but i encountered either error in the FC or quite the resonance during take off.
I could not get it up at all, it wants to flip over.
So im guessing i got somthing wrong with the hw.
Im off to work tomorrow, and wont be able to test for another 2 weeks

Lobster, I have been having the same problem. The arms still seem to be too flexible even at %50 infil. I went nuts balancing my props, best balance job I have ever done in my humble opinion. And things got way better. I got it in the air and flyable but there is still some resonance and the whole quad will twitch randomly. So its back to the drawing board to beef the arms up a bit more. Compared to the first design the second gen arms work much better but there is still a was to go hopefully arms 3.0 will be the ticket. Also I am going to release parts to use a carbon fibre tube instead of the 3D printed arms if people would rather do that.

Check out http://www.thingiverse.com/thing:42633 for an idea on the arms, those are very rigid loadwise, but a little twisty - did not cause any problems for my KK. (arctic tern quadcopter) also, who'd of thought, I'm in Fairbanks too... perhaps the printable quad community should get together and chat sometime! We're working on a drone for forestry...

Arctic Tern Quadrotor

Awesome are you part of UAF?

I think it would work. I have a alu quad with fiberglass. and that flyes awesomely.
Id look into it, though your design is a very good looking one.
I did seperate the sig from the esc cables, so its only the sig who is streched out to the FC.
I am going to mount up the old quad again, to see if the problems persist. if they do, then i need to shield the signal wire to the esc.

Everything was zip tied into place, not including the motors, they where mounted correctly.

I'm going to go out on a limb and guess that its not RF noise thats the problem. Most likely it is the vibration. I wonder if printing out at 100% infil on the arms will solve that problem. Maybe you can give it a try? I am home in colorado at the moment and wont be going back to Alaska (where my printer is) for a week. A month vacation was very nice but I miss working on my projects :)

Hey Joe, you were right.  The arms are too flexible.  I got everything put together on mine and when I went to fly it I just could not get it to fly right.  What is happening is that as the arms flex upward they are in a sense creating dihedral.  When a motor adds power to counteract a dipping arm that arms flexes up even more.  As the dihedral increases that prop becomes less efficient and loses lift.  This flexing, or "coning" is almost completely counteracting the thrust from a motor as it tries to stabilize the platform.  Thanks for being the first to point out this problem.  I will try more infill on the arms, say 25-50 percent and see how that goes.  If that doesn't work I will try adding additional bracing to make them more rigid.  Hope you are staying warm out in Fairbanks.  This morning in Tok we were down to 47 below :(

That makes sense.  We've got it a bit better, it was -41 at my house this morning.  

Could you provide a seperate stl file for just the legs, and remove them from the arm.stl

I am looking for a nice fpv frame, and i think il give this a try.

Sure I'll post a .stl for just the arm and the leg separately. 

Btw, i print with PLA on a Ultimaker

The separate Arm, Leg and Pad files are up!

Joe, just out curiosity were you testing this frame outside?  I know that my tricopter is nearly un-flyable in temperatures below -10 F.  I have to let the flight controller sit outside and coldsoak and then reset the throttle endpoints at temperature.  I don't know if this is an issue with Wii boards but I would guess so because gyros have a monster drift when they are cooled.  After I reset my flight controllers my coldest flight was 50 below zero.  Also did you print at 10% infill?  I would expect that printing with a higher infill, even in ABS would result in a more rigid arm?  I don't have any experience printing in PLA.  I also wonder how either plastic will stand up to the extreme temps that we have in our area :)

Heh, no I was testing it indoors.  I ended up rolling my own towel-rack based version which I've taken outside down to -40 so far.  Problem with those temps is that I keep breaking props and zipties with my rough landings.

Too much flex in the arms, exactly.  The airframe  is plenty strong enough otherwise.  I tried it with the following electronics: arduino mega + WMP/NK sensors running aeroquad firmware, then with multiwii firmware, then with baronPilot firmware.  Then I tried it with a teensy++ 2.0 running multiWii, same IMU.  Then tried with a KK2 LCD flight controller from hobbyking.  While I did manage to get the copter in the air a few times, it proved impossible to get the PID control tuned to the point where it was able to keep it stable.

I'm pretty certain that it would have been fine if I had printed it from PLA...

Hey Joe.  What was the nature of the problems?  To much flex in the arms?  Airframe failure?  What kind of flight controller are you using?  

Hey Mikey, having printed one of these and failed to get it to fly correctly, I would advise printing it out of PLA instead of ABS. I used ABS and I believe the airframe is not rigid enough with that material.

Havn't made and decisions yet on electronics.  Probably KK board or APM.  As for ESCs I'd like to get my hands on some Turnigy Plush's But haven't really thought about the motors yet.  Any suggestions?

Awesome design, I've just printed one. Quick question, what do you use to hold it all together?


I went for "Turnigy 2217 20turn 860kv 22A Outrunner" because they were cheap and seriously powerful. I know I struggled with what to buy, so I just went for the same setup I saw on someone's blog.

Have you made any decisions for electronics yet?

That's really cool, I do wonder if the arms should be stronger in the vertical direction than horizontally - there's not much force sideways. I 've got a CF + reprapped quadcopter (http://www.thingiverse.com/thing:32112)http://www.thingiverse.com/thi... and I've crashed it a few times and snapped the CF rods where they meet the body, so if I were you I'd thicken the arms there and where they attach. Alternatively it may even be worth printing a weak coupler to join the arms to the body, that sacrificially breaks on impact, so you can have a load of spares printed without using too much plastic. As it is, i'd be a little worried about the point of failure being the top panel bending/snapping, which could break any electronics mounted to it. For my build, I used small m3 nylon bolts to secure the electronics, in the hope they'd fail before the pcb. Just some thoughts, I look forward to this progressing :)

reprapped + carbon fibre quadcopter

You link is a little messed up lol i ran into Thingiverse's awesome 404 page, there was a ')' at the end of the link


reprapped + carbon fibre quadcopter