Crossfire 2

by MikeyB, published

Crossfire 2 by MikeyB Jan 26, 2014




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The Crossfire 2 is here. Everything you loved about the original but simpler, stronger and easier to build. The original Crossfire has been out in the wild and flying for about a year now and I couldn't be more happy with the interest in this project. Special thanks are in order to all those who printed, tested, flew and remixed this thing. The open source community is incredible and I am proud to share the Crossfire 2 with you. As always please print, fly and enjoy. Feedback, makes and remixes are always appreciated. If you like my designs a small donation is greatly appreciated, it allows me to keep posting cool things!

Check out this video for some motivation. https://vimeo.com/79370836

Fpvlab.com Thread:

So what is new with the Crossfire 2? In general, a lot! It looks like the same ol' Crossfire but its not. I took a lot of feedback on improving the design and I believe I have addressed the major ones.

-The Arms: The arms landing gear on the old crossfire was weak. I designed it to be light but it ended up being too brittle. The new arms have been beefed up and strengthened in the weakest areas. It is still very light and I believe it now to be the perfect mix of strength to weight. Also the arms have been designed to have M3 lock nuts press fit in. This standardizes the hardware for the quadcopter and allows easy attachment of the arms. It also allows to top or bottom plates to be easily removed allowing access to the center of the frame.

-The frame: As mentioned above the Crossfire 2 has been standardized to M3 hardware. The frame has also been modified to receive any type of flight controller. The standard flight controllers (KK Blackboard, KK2.1) can now be mounted directly to the frame in either 45 deg. or orthogonal orientation. On top of that the Crossfire is designed to be optimized for the APM controller by mounting to the frame via vibration dampening bushings. Using this setup, without any balancing of the props whatsoever give more than adequate vibration dampening. See attached graph, vibrations are roughly half of what 3DR says are tolerances. The frame has been standardized to the vibration dampening camera mount system. Everyone is mounting cameras to their quads these days even if they are not FPV and this is definitely the best way to go to get clean video. Lastly I have added extra holes in the frame to accommodate easier wire routing depending on your setup. Also there are new standoff holes to mount the top cover.

-The Top Cover: The top cover has been modified to mount the APM 2.6's GPS/Compass module.


Update 2/23/14: I have uploaded the .SKP files for those who want to remix the design.

Update 2/13/14: I have added links in the instructions for an explanation on motor kv and a calculator to help run some numbers on motor and prop combinations. A lot of people have been asking about this, and its still a bit of a mystery to me even after building a bunch of multicopters. I hope this helps.

Update 2/1/14: I have added batter strap slots to the Bottom Plate for battery straps. If you are not planning on having a camera or vibration dampening battery tray you can now strap your battery directly to the Bottom Plate.


See the attached PDF for a build log and instructions.

At the infill settings I've published the frame weighs 400 grams with everything. Thats the 4 arms, the hardware, the Top and Bottom Plates, the Top Cover and the Battery Tray along with the vibration dampening bushings. The arms weigh 38 grams, so thats about 12 grams lighter than the DJI arms. The whole frame together weighs 400 which is 120 grams heavier than the DJI Flamewheel but they don't take into account the hardware weight to put everything together. Those numbers along with the weight of all your equipment will decide what motors, props and ESCs you go with. The one pictured weighs 1700 grams (GoPro3, gimbal, brushless motors, props, FPV equipment, APM and a 4000 may battery.

Arms: So far there are two arms uploaded.

ArmTall3H - Standard re-enforced arm with a tall leg and 3 hole mounts for the motor.

ArmTall4H - Standard re-enforced arm with a tall leg and 4 hole (16x19mm) mounts for motor.

For the Vibration Dampening Battery Trays see thing here, there are 4 different options to suit your needs. http://www.thingiverse.com/thing:239594

Here are a couple links that explain motor kv and a calculator to help with choosing the right electronics and prop combinations.

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Am I missing something, won't those press fit nuts pull right out once tightened? Or under stress? How are they secured?

Hi guys, I'm about to print this, but cannot find any info about the camera 2 or 3 axis holder, that is not in the files..any help welcome ! (even if putting a camera on it will be the latest step, of course)

WOW i really LOVE this design.
Im still printing the parts.

I was lucky ordering all required parts at Banggood Sale and got up to 11% Discount on almost every part:


Thank you soo much!

I have printed the Crossfire 2 so far it is going good. I want to thank you for sharing it MikeyB. I do have a bit of a problem though I know nothing about drones aside from a few small ones I got. Now I am to the part where I have to buy a radio and I am running in circles trying to figure out what to get. Any help or suggestions would be great. What do you have, wish you had and what are the things you can't do without when it comes to features, make or model.

Hi does anyone know the length from motor to motor, couldn't find it in the description, thanks!

I don't know if you need this or not since it has been months since you ask but I just measured mine and center line of motor shaft to center line of motor shaft is approximately 485 mm long. Tip of printed arm to tip of printed arm is approximately 530 mm.
Hope this helps.

What would this thing cost in parts, not including the gopro and the printed parts?

MikeyB, I can only do prints up to six inches. Your design seems to be one of the most popular unfortunately short of buying a new printer I have to find something smaller. Any suggestions? Thanks!

Hey is there a new build list for the electronics yet? I can't locate some of the parts.

I use a Dji naza m lite flight controller, qx 620 kv Hobbyking motors, Lumenier 30 amp esc OPTO, and a multistar 5200 mah battery.

Can I ask what Radio you are using with that setup because that is basically what I have but don't have a clue as to what radio to get.

just wondering what res I should print this at

Any resolution shout be fine. I usually print .2 layer height

thanks for the reply ! all this work is fantastic and so helpful. do you know when crossfire 3 will arrive ?

Hi MikeyB and congrats for this amazing design. First of all, I'm a newbie, so I need some help with this.... This is my first try on building a quadcopter. I know that I would start with an easier quadcopter, but I loved this one and I really want to build it!
In the past couple of weeks I've been digging around to know something about quadcopters. But, there are many different opinions... and choosing the setup for this quadcopter have been very time consuming. This is the setup that I was planning to use (please tell me if these parts will fit together... Would you change anything - for a similar price?? Will I have some troubles with this setup?? Please help!!):
Motors + ESC: http://www.hobbyking.com/hobbyking/store/__76074__MultiStar_Afro_Combo_Pack_2216_800KV_and_Matched_20A_Afro_ESC_Set_of_4_CW_CCW_EU_Warehouse_.html
Props: 10" http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=107432
Flight controller: http://www.ebay.com/itm/112134581436?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Radio transmitter and receiver: http://www.hobbyking.com/hobbyking/store/__66518__Turnigy_9X_9Ch_Transmitter_w_Module_8ch_Receiver_Mode_2_v2_Firmware_EU_Warehouse_.html
FPV camera: http://www.hobbyking.com/hobbyking/store/__80834__FatShark_700TVL_CMOS_FPV_Camera_V2_NTSC_PAL_EU_Warehouse_.html
video transmitter: http://www.hobbyking.com/hobbyking/store/__17507__ImmersionRC_5_8Ghz_Audio_Video_Transmitter_FatShark_compatible_600mw_.html
Goggles w/ receiver: http://www.hobbyking.com/hobbyking/store/__104149__Quanum_Cyclops_FPV_Goggle_w_Integrated_Monitor_and_Receiver.html
polarized antenna: http://www.ebay.com/itm/5-8GHz-Circular-Polarized-Mushroom-Antenna-SMA-Set-Tx-Rx-for-FPV-Aerial-RC-KA-/281739856195?hash=item4199010943:g:bT4AAOSw9N1VllDq
battery: http://www.hobbyking.com/hobbyking/store/__99484__Turnigy_5000mAh_4S_40C_Lipo_Pack_with_XT90.html
gimbal controller: http://www.ebay.com/itm/262184711224?_trksid=p2060353.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
gimbal motors: http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=53931
Power Distribution Board: http://www.hobbyking.com/hobbyking/store/__89569__PM_ESC_Distribution_Board.html

That should get you up in the air.

Thanks for your answer. I've seen this motors at a very good price: http://www.hobbyking.com/hobbyking/store/__74760__Multistar_Elite_4114_330KV_With_Built_In_Folding_Prop_Adapter_EZO_Bearings.html

Do you think that is a good choice or it's a bit overkill? Do you recommend other motor (I can't find the motor in your manual on the internet)? One more thing, what's the max propeller size that your design can handle?

Where can i get the Solid Works files for the arm?

Hey! Can anybody tell me how many "Nylon Standoffs M3x5.6x Assorted lengths" minimum will I actually need?
There's about 6 pages of these on HobbyKing in different lengths and the assorted kits are 6mm thread instead of 5.6mm.

i think this is the best drone design but some reason C2TopPlate.stl will not print any more than 2 layers then stops not like a jam just after the layer is done it stops

How much weight can this carry

eCalc requires frame size.
I was unable to find the size of this frame.
What is it?

And what is the biggest prop size that will fit?

Hey guys, I've been kinda MIA from this site for a while. Work has been rough. I have been plugging away at the new Crossfire 3 design and was wondering what improvements you guys would like to see.

Quite hard to realize, but a foldable design would be awesome! (e.g. based on the mechanics of Firefly)

(I like climbing/hiking in the mountains and would love to take my drone with me in a backpack!)


Hey MikeyB, just found your Crossfire designs; great work! I've been a model aircraft guy for years, and I think my first foray in to outdoor quads will be printing your Crossfire. May I ask what the status is of your v3 Crossfire?

Make it so you can use these. http://www.mcmaster.com/#hex-nuts/=13bp5xw

It will make the arms alot stronger. I got 10 that are 25mm long for like $5 on amazon

I didn't like the battery being exposed, so made the arms "higher" so it fits in the space between the top- and bottom plate.

Would also prefer if the legs could screw in, maybe using long screws it could hold the motor as well?

hello, how about making a Hexacopter?

Just built this and have been flying it in small increments. Really fun project!!

hello, what have you used as electronic part?

What an awesome work, keep going !
I m currently studying in an engineering school and my team and myself are doing this kind of project.
I was wondering if there was any Opensource available of the corssfire 2.
Sorry for my bad english and thank you !

Sorry for the late reply, I just have the sketchup files that are posted here.

I have my quad almost complete! I modified the top cover for holding a round GPS, and the push button for the PX4. If anyone needs something similar, it is available at http://www.thingiverse.com/thing:1461776

Crossfire 2 Top Cover Variant

Is there an possibility to convert those files in Invenor Files or an other CAD-File format instead of STL or SKP?

Would be nice, want to make some mods for other motors etc.

The only way I have been able to convert them is to load them into AutoDesk 3DS Max and then export them into a file type that works for Inventor.

I'm sorry I don't know how. If you know of a simple way let me know and I would be happy to.

Im going to try casting this in aluminum, well see how that goes. I will probably have to machine it down in some areas because i fear it will be heavy.

what motor do you use for the 3 hole leg? i just realized there were two versions and we already printed the 3 hole legs

I'm using Sunnysky X4108S motors with 3 holes (Sunny's also have 4 holes, but they don't fit the Crossfire's spacing)

Are 6" props too small? Do you have a model for that?

So I finally got my build completed!!! I haven't flown it outdoors yet, but did manage to get it about a foot off the ground for a test. I put a post up in the "Made" section. If anyone has any questions, feel free to ask, I'll do my best to help!!

Did you use the 3 hole leg or 4 hole? I printed the 3 hole not knowing there was a difference and want to make sure I get the right motor

I used the 4-hole. I had a few motors in mind when I started the build, and they were all 4-hole. There are no 3-hole motors to suit your build? Would hate to have you re-print...

Hey Guys,
Bit of a noobie question for you, I have a Delta Printer (circle shape print bed) and it only has a printable radius of 105mm. I am not able to fit the arms on the print bed (overhang about 5mm on each side), would it be madness to remove about 10-15mm of the middle of the arms to allow this to fit? The other option would be to try and print them vertically..... but that terrifies me, I cannot imagine they will end up straight at all doing that.

Edit: I was thinking about using the V3 arm and removing that little bit in the middle that looks like its asking for a trim. This would allow the two bulkier ends of the arm to adhere together.
Thanks in advance!

I took a stab at creating a shorter version. No idea if this will work (20mm shorter) or what that means for prop selection. http://www.thingiverse.com/thing:1298247

200mm Arm for Crossfire 2

IT FLIES! Amazing thank you so much for these designs. I am running a DJI naza m lite, ax4008Q 620 kv motors, lumineir 30 amp esc's, turnigy 4s 5000 mah battery, and a spektrum ar610 recievers. Takes close to about half throttle to take off, but has tons of power leftover. Awsome!

Still working on mine after about 3 months... had crazy issues with getting ESC's/motors working, but got over that hurdle. I think I went way overboard myself, as I'm adding telemetry modules, LED lights, and even invested in a Taranis X9D Plus controller. I also had to get different motors than what was in the guide, but I think I'll be fine with them. I also have full FPV with a 600 TVL camera and ImmersionRC 600mW Tx (the same Tx I use on my Phantom 2). If I can upload a current build pic, how do I do that?

Hey guys, when i print the top plate on the makerbot replicator desktop, it always curls up and is uneven. I LEVELED the printing bed so it is not that. Wondering if any of you have any input.

Edit: I put some adhesive down so it would stick better and it worked.

I printed all of my parts on a Replicator 2, and didn't have any issues at all. Is it just that one piece that curls? What are the settings? Maybe try with a raft? That piece is pretty much flat... weird... what do you use on your print bed? We use painter's tape and it works well.

hey guys! I am kind of a amateur at programming flight controllers. I just want to program my dji naza lite to be able to fly in manuel mode, thats it. Wondering if one of you could help me. Thanks!

I've never worked with the Naza but there should be some sort of basic stabilized mode. This is as close to "manual" as you can get as these are basically fly by wire. The flight controller is mixing your input to give a desired output.

Hey just wanted to say thanks a lot for the great designs Mikey - sent you $10 as a small donation to show my appreciation (and I encourage others to drop you beer money :-)) My Crossfire 2 is almost done - may have overcooked the specs but what the heck ! Running 4s config with Mt3508 700kv quanums, 11inch props, 30a Afro ESCs, Pixhawk (OMG what an upgrade from Naze32), GoProHD, GPS, UHF TX/RX, 600MW video tx. Anyways - I like the Crossfire 2 because there is a place for everything on it (which makes inevitable maintennance easier) and there are so many options - including ones you build and the community adds to your designs - cheers !

I am about 75% done with mine, using a Pixhawk, 10 inch props, Lumenier 30A ESC's, GoPro, and pretty much everything else you mentioned... but having an issue with motors... I was able to order the motors in MikeyB's PDF instructions, but after over a month of waiting for them to come from China, they still aren't here yet, so I am lost trying to find an equivalent motor. I've read and read to try to understand how to choose, but it's way over my head... so if you, or anyone else, has an idea for replacements, I'm all ears... Was looking at SunnySky 2216 650kv...

Thanks your donation it is greatly appreciated and as you mentioned it will indeed go to beer ;) I am looking forward to seeing your completed quad, it should be a beast. Thanks again!

Running from mobile so I can't check, what sort of dimensions am I looking at here?

What would you say would be the minimum print-bed size required to print this? Would 200x200x200 cut it?

Awesome!!! I was trying to find a 3D printed quadcopter project and I'm glad I found this one! Very well explained project! Thanks in advance for taking the time to write such a great making guide!

(Any advice for a mid rnage price RC Transmitter? )

Thanks in advance for your help with this matter.


I definitely like the Frsky transmitters. They are modular and can accept many different modules such as Spektrum and EzUHF. They are also definitely the best bang for the buck in my opinion.

Thanks a lot! I was thinking in something like that too...so, I'm gonna get that one then!

Can you put a link to or a description to the Simple BGC that you used? Can't tell what specific one I need to use in the Base Cam Electronics link you provided. Any suggestions would be appreciated. Thanks


I am in the process of this build, and I managed to get 4 of the AX-4008D motors, from China, so I should get them in a few weeks.

Question: will the new arms have the right mounting holes for the 4008D? Did you change them due to that motor being out of stock? I'm not being mean in ANY way, but it'd be nice to know soon, only because I can take the 2-3 weeks to get the arms printed. I already have the plates printed, so just waiting on the arms. Thanks for being so awesome, and for having such an awesome build!! I'll try to get pictures when it's all built, probably by Christmas time...

The arms would fit all standard mounting patterns. what are the mounting dimensions on those motors?

Would it be possible to print the standoffs instead of using nylon? Also would it be possible to print the propellers or do the blades have to be perfectly smooth to work correctly?

Yeah sure it wouldn't be very hard at all to design some. As far as props I know there are some people who have tested 3d printed props and have had them in the air. However I would prefer to fly proven props on my quad especially when it had hundreds of dollars of equipment riding on it.

Any advice on selecting a GPS/compass?

Hey MikeyB, I just looked up the motors you used in the instruction PDF. At hobbyking it says AX-4008Q-620KV motors require a 70A ECS. But the ESCs you used in the pdf are rated for much less current. Do I really need 70A ESCs? This is my first quadcopter build.

Pay attention to the "Q". You have the AX-4008Q, He used the 4008D.
Yes it will work still, but the mounting holes have a different pattern than the arms provided here.
Better off just going here:

Just be careful of that site. After 3 days of trying, I FINALLY was able to order the motors from there. It kept hanging on completing the billing address. Also, I had chosen 3-5 day shipping, but when the order completed, it reverted back to free shipping with no tracking (I wasn't charged for the 3-5 day). So who knows when I'll get them...

What is the max size for the propeller? I think 12" will fit, are 13" or 14" possible, too? Thanks!

I think 13 would be possible, let me measure when I get home tonight.

Thanks a lot!

Where's the battery tray stl?

Crossfire Vibration Dampening Battery Trays
by MikeyB

Do you have the sketchup file for the new arms? I need to change the motor mount holes and want to keep the embedded nut holes.

How many amps did the turnigy battery pack have??

I use 4 cell 5000 mah battery. You can get away with 3 cells but a 4 cell has more power. I get about 12 minute flight times with the 5000s with a fair amount left over.

Just printed the tall 4 arm in Colorfabb XT, does anyone have experience of acceptable shrinkage? I cant seat an M3 nut in the arm.

Every printer and material has different shrinkage. I designed them to be a little tight. You just need to use an exacto knife to to take a little material off and tap it in with a hammer if its a little too small. Don't forget to use super glue or epoxy.

is it ok if extruder temp can only go up to 215 celsius

I need some higher skids for my gimbal. Do you have some?

Sorry I don't have taller ones at the moment. I can design some or you can remix it.

No problem. I solved it, I put spacers between the skids and the frame. Now it is okay! Thanks :)

how do you take pictures with your gopro while it is in the air?

I have a Hero 4 Black, and I set it to "Video + Photo" mode. It films in 1080p/30fps, and every 5 seconds it snaps a 12mp picture. Works great!

Just curious what the total cost of the project is. I want to build it but am not sure I have enough money right now or not. Thanks

I just priced the electronics in AUD and got around $1000.

OK, I am pretty new to all this and have access to a Dremel 3D printer. I don't see any settings for supports in their software. Are they built into the files already? The only reference I see is that if I need to add supports to use a program called Meshmixer. Which happens to crash when I click on generate supports.

I'm sorry, I don't know anything about the dremel printer. I would assume that the program would have some sort of settings for supports as this is a pretty universal function on all printers. Is there an advanced settings in the software?

There doesn't seem to be anything regarding supports in the software. The advanced settings tell me to use Meshmixer to add supports. I apologize for my ignorance but supports are just extra pieces of plastic that are removed after the piece finishes printing, correct? I can open the .STL files in Meshmixer but they are oriented all wrong (like on its side) and the supports go down like tree roots. The arms for some reason crash when I try and add supports.

OK, After I messed with the settings in Meshmixer I was able to tell it which printer I have, That fixed a few of my issues. However, all I see when I add supports are what looks like veins added the to piece, is that what I am supposed to see? I apologize for not know but we all need to start somewhere right?

No problem everyone starts somewhere. Yes supports are a lightly lattice that keeps overhangs from printing out in space. I'm not familiar with any of that software so I'm not sure what the problem is. I would just try printing without supports. All these parts have minimal overhang and they should work out just fine.

I'd bet this is an error in reporting, not plagiarism. Jaegar probably said the engineers on board printed and assembled it, and the reporter assumed that meant they designed it.

Thanks for the post. I find it interesting the the Naval Postgraduate school claims to have designed this.

Wow. I didn't even see the claims to the design. Glad to know postgraduate students think plagiarism is okay -___-

Hi! Anyone know why there are missing components in the SketchUp file? I'm using SketchUp 2015 and it looks like the arms are gone. Thanks!

Sketchup file is now posted on the Arms page: http://www.thingiverse.com/thing:662781

Crossfire Arms
by MikeyB

Geez, my bad. I didn't catch that the arms were a separate thing. Thanks MikeyB!

Sorry, I must have removed them so that I could post them in the Crossfire Arms thing. I just check though and I had not posted the sketchup of the arms on that thing. I will post that sketchup file under the arms when i get home from work tonight.

Hello, I wanted to become a quadcopter as your .... But I wanted to know if I could indicate a site where you can buy the complete kit for all electronics ??

Greetings and Thanks

Same requirement for me also but when i download the full parts there is a PDF which tells what to buy and where to buy . thank you MikeyB.

A quick word to say that I'm actually building the Crossfire 2 and I choosed Turnigy Park480 motors, 850kv. They are cheapper (20$) and with 10x5 propellers you can expect up to 82% efficiency, according to eCalc. The parts are really easy to print on my Mendel90 and really strong even with ABS 30% infill for the arms. thanks for sharing your project !

I am interested in possibly creating this build and was just wondering if anybody who has already built it could tell me around how much the entire project cost them. I am working with a limited budget as a 17 year old. Thanks :)

I Have 2 questionS
1/ this is a good choice to use
Turnigy 9X 9Ch Transmitter w/ Module & 8ch Receiver (Mode 2) (v2 Firmware)
to use quadcopter with telemetrie ?
2/ is it possible to receive the video on an iPad ?
Than you for your answer
best regards

I also choosed this one. This is a very nice cheap remote, and great with custom firmware. Please note you can't have telemetry without modifications, you need for example a FrSky module. See OscarLiang Blog, he did a great post about 9X and available hacks, including telemetry.

Sorry for the late reply. I do not have any experience with that setup or really any experience using the telemetry. I assume it should all work fine. As far as video over iPad Im not aware of how you would do that. Possibly video over wifi? If what you are going for is having a small screen attached to your radio to fly FPV from you can pick up a small monitor at a decent price and just use standard video transmitters and receivers.

Hey MikeyB, I've got mine going and I love it! One question, I have the 3DR telemetry radio and right now I've got it mounted where you have your FPV transmitter, any idea where would be a good spot to put it once I add FPV?

Sorry for the late reply, you could possibly mount it out on one of the arms. Or you could design a small mount that attaches to the top and bottom plate. It definitely will be a challenge to fit everything in such a small space. Let me know how you accomplish it as I would like to incorporate telemetry into my Crossfire 3 design that is close to completion.

When will we see the Crossfire 3?

Soon hopefully!

I had another couple of ideas I might try and implement. One would be to mount the GoPro gimbal downward off of the battery tray instead of upward. That way it's less likely to have the props in the video. This would also need a bit longer legs, but I need them anyway because my Turnigy hard case 5000mah battery is too big for the current ones anyhow.

I just used double sided tape to stick it to the bottom plate, then I zip tied the antenna to the nylon spacers. Here's a pic!


Awesome work and design! I would love to get started on making one myself. Could you list the specific electronics you used for yours?

Look for the .pdfs, there is all you need

Hi, just a quick question.

would 9" props fit this quad?


How can i supply power to my radio reciver from the apm 2.6?

The best is to power the receiver from an external BEC with 5V output. But it's also possible from the apm, connect it easily.
Please read the APM Wiki, this is very useful.

Comments deleted.

I printed the arms with ABS at .2mm with 50% infill and they're amazingly strong!

WOW this looks amazing! My buddy has a Creator X printer. We are going to try to build this. I have a dx6i radio i ordered a KK2.1.5 controller and Spektrum AR610 receiver. Could you advise me on motors, esc, and rotors? That would be awesome. Thanks Wally

Hello Thingiverse! I have been trying to print this out on a replicator (5th gen) at 35% infill with 4 shells. This printed fine,but ended up way too heavy. What settings would you recommend I print at to reduce weight? Please keep in mind that it needs to be strong enough to resist fall damage but light enough to take off with all electronics. Thanks!

Im building my first quadcopter its The Crossfire 2 by Mikey B on Thingiverse. Im using DJI 2212 920KV motors and some 10 in props I thought people where using with this motor but my motor shaft is something like 5.30mm and my prop is smaller like 3mm hole. is there a adaptor or should I just buy props with a larger hole?

Comments deleted.

the original crossfire has a handy "parts list" for noobs like me...electronics specifically. Does this version have one or do we use the original list?

Hi Everyone,
I finished my printing and slowly buying my parts. This is all new to me so far I bought (4) 30A Afro ESC and 4x DJI 2212 920KV Brushless Motor for F330 F450 F550 X525 Quadcopter Multi-rotor. Can I use APM2.6 Side Pin Controller+6M GPS+915Mhz 3DR Telemetry+ XT60 Module f ArduPilot with this set-up so far?

Hello Mickey B , can i have the software list and the firmaware on may email ? Until now i have made the most parts of the prints , i prepaired the list of electronical devices , not all on hobbiking , but i will fiind a way to have them in eastern europe . My email is [email protected] . Thank you in advance .

if the crossfire is similar to the dji flamewheel, then the motors id go with would be the dji 2212 920kv (used on the flamewheel). 25 amp esc. kk2.1 or cc3d. you still need a radio rx/tx and a battery (dont forget the charger). if you want fpv, you'd have to spend more money. easy package is the fatshark teleporter v2.

Anyone have a list of the electronics? I want to get a price range before i start this.

it depends on what you want to put on. motors and esc's ~100 bucks. flight controller 20-300 (depends on what you want). cheap 8 channel radio tx/rx for 60ish. id say 250 for basic flight package.

I made really better experiences with printed arms in PLA. The arms in ABS broke very fast, the arms in PLA are hard enough!

What settings did you use for the PLA?

Has anyone worked out the maximum payload of the built crossfire 2? i.e. with it built ... i want to fit an extra camera along with the GoPro and FPV but the supplier is concerned I will at too much weight. The camera would add around 150g to the copter. Thanks!

Very nice design, but I'd like to make a suggestion (that's simple to implement). On the arms there are those recessed nut traps that require turning on support material printing. I'm okay with that, but the latest version of Slic3r insists on supporting the bottom of the landing skids as well (rather than using bridging even though "don't support bridges" is checked) thereby wasting lots of plastic. My suggestion would be instead of requiring support for the recessed part, create a single layer bridge over the hole that can easily be drilled (or punched) out. The model will have the screw hole closed off on the bottom (past the recess), but the closed part will only be one layer thick. I think you'd have much more consistent results with all different kinds of slicers that way. Just a suggestion.

Hi Guys, I searched all the comments and I cant seem to see the minimum bed size I'd need to print the arms. I'm in the process of building a prusa i3 with a bed size of 8"x8"x7". Do you know if this will fin on that bed? Great work MikeyB, this Quad looks awesome. I can wait to power my 3D Printer up.

An 8x8 bed should be just enough to print everything. You will have no problem printing out the plates and the battery tray. The arms however are about 8 3/4" long. It should be fine though if you orient the arm diagonally across the bed. You will have to print arms individually (I usually print two at a time) but hey, it might take a little longer but it all should fit. Let me know how it turns out.

Hi Mikey (and whoever else might read this) - i'm in a bit of a pickle, namely a tight budget and the question about flight controllers (it is very important that i have autopilot). Can you please give me your opinion about:

  1. http://www.hobbyking.com/hobbyking/store/__56052__HKPilot_Mega_2_7_Flight_Controller_USB_GYRO_ACC_MAG_BARO.html

I'm not even counting KK2 as an option, because this is my first build and i don't want to bite off more than i can chew.

The KK2.0 board is actually very easy to use and setup if. I am definitely a fan of the APM. It is an incredible flight controller and autopilot, that being said I have flown planes with systems that took less studying to understand than the APM. However it is fairly user friendly and very powerful. A good middle of the road controller (not an autopilot) is the Open Pilot CC3D board. Very easy to setup and tune and can be expanded into an autopilot with the addition of a gps. Personally I think whatever gets you in the air the quickest/simplest and cheapest is the right way to go for now. Quadcopters are a steep learning curve, and if you are going for an autopilot capable controller right out of the gate it is a very steep learning curve. Just my two cents.

Thank you - thank really helped. I met with local RC hobby group and i asked their opinion about 3d printed copter frame and they were all quite sceptic. I understand that it's hard to compare 3d printed plastic with aluminium, but i won't be racing my drone - it'll spend it's life flying around slowly and taking photoes so i don't think the arms will break mid flight, however they did mention that printed frames tend to vibrate more which distorts the image. They recommended using these two frames -

However i am sceptical. I don't think the image(or video) will be that much worse if there even is a difference. Especially when you take into account that your frame is a bit lighter and cheaper and it still shoots great videos. What do you think?
Also what kind of motors and gimbals are you using?

Also, if vibrations still end up being a problem, you could mount the cameras on vibration plugs. On the MHQ2 the whole layer with the flightboard, cameras, Rx, etc is mounted on 6 vibration plugs. You could make something that seperates the gimbal or camera from the body with vibe plugs.

In my experience printed frames don't vibrate any more than metal or carbon fibre frames. Vibration almost has everything to do with unbalanced props. No matter what frame you use if your props are out of balance you will get vibrations that can give your video jello and play havoc with your flight controller. Printed frames are actually quite strong, definitely won't break mid-flight even with aerobatic flying. The one huge advantage is that printed frames can be quite a bit lighter than other options and that directly correlates to flight times. Another is that you won't have to order replacement parts when you (Inevitably) crash, you just print one out. Check out my battery tray and gimbal. They are designed to dampen vibrations using rubber bushings and the video you get will be crystal clear.

I had some problems when I landed. The landing was no smooth but not very hard, but the arms were broken. I printed them with 85% Infill, I'm really wondering that the arms (the part where you land on it) broke so fast.. but okay, maybe Mikey will regard it in the Crossfire 3 ;)

Was it the arm that broke or the leg? Also printing in ABS or PLA? The legs have always been the weak spot, its a toss up between making them overly heavy or overly strong. But I think I have a good fix on the way with a newer/ modified arm.

Hi, the leg broke. I printed in ABS, Infill was 65%
Do you already have a new version? Have you uploaded it? Thanks!

Does anyone have a sketchup file of the whole design as an assembled product ... I would like to run some simulations on a computer version of the completed quad. James

I don't have one assembled, but if you take the sketchup files I published you should be able to assemble it without too much hassle.

Will the old motors fit the new design?

Old motors? The arms will fit the triangular mounting pattern of some motors and the 16x19mm that you see on most motors. If you have something other than that let me know.

This is a bit too big for my printer.
If I scale everything down by 10% will that work or would I be better to edit the arms down by 3 or 4 cm and use smaller props?

You could scale it but the mounting patterns for the motors and the mounting hole diameters for the arms and plates will be off/smaller. Have you check out the derivative for a smaller printer bed? If that doesn't work I guess you will have to use the files to redesign to fit while keeping the same mounting dimensions. Hope that helps.

HI maxi,

I think it's a bit overpowered. This motor has got 800 to 1000W . I think a motor with [email protected] Watt will be really enough for a copter like this. My copter has got 400W and 1,3kg and it's flying very well!

Thank you very much. that engine model used?

No, but a 4x1000W is definitely overpowered ;)

That engine can buy?

Which engine? I think 4x1000W are too much!

So what engine model I can buy?
The NX-4008-620kv model no stock.

Sorry, but where is the Battery Tray?THX!

The batter tray files can be found here in this thing http://www.thingiverse.com/thing:239594

Crossfire Vibration Dampening Battery Trays
by MikeyB

After a bit of searching i found this http://www.thingiverse.com/thing:168032
It's a chopped in half version of your arms.
That solves my print bed issue in that respect.
Now i just have to figure out how to modify your CrossFire 2 Plates/Covers/Mounts section to suit.
Trying to navigate my way through Sketchup to do a similar "chop"

Crossfire Quadcopter for Thing-O-Matic

I've been wanting to print this for a while now.
Just downloaded the files and realised my printer isn't big enough to print the parts.
I've got a Up! Mini 3d Printer. The print area is 120mm x 120mm x 120mm
Does that mean i'm unable to print this? I figured just scaling i down would make everything be thrown off like hole sizes etc.

Trying to find a good study printable drone for my new Go Pro Hero (the new basic entry model)

You can try printing the arms from this remix by leemes http://www.thingiverse.com/thing:142856 and using the rest of the components from this thing. As long as the top and bottom plates fit on your print bed.

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

Ah good find!
Trouble is, your top and bottom plates are about 18cm.
My bed is limited to 12cm.
I might have to try to find a way to edit everything like leemes has to fit it. Or have to get it printed in a shop if there is one near me (trying to avoid this)

Just wondering what set up you used and where you found the gimbal for the gopro. Also, I am new to these quadcopters and am wondering what kind of radio I need to buy. Thanks!

I have noticed that when I was sanding one leg, I had a fracture on the inside chamfer on the foot. Might want to beef up the foot in that area.

Dear Mike, I like your design and enthousiasm. Sp I think your Crossfire II will be my first quadcopter.
In your PDF instruction document, I found a link for instructions how to make settings for printing in PLA. Unfortunately, I could find these PLA settings instructions. Can you please tell me where exactly I can find them.

Happy skydiving in Alaska!

Did you ever print the quadcopter? What settings did you use?

I'm currently in the process of assembling all the pieces and electronics, everything's going well so far. However, I'm using the Naze32 flight controller, which happens to be smaller than even the KK2.0 board, so there are 0 mounting holes for it at the moment. I could drill or try to jury rig something, but I was wondering if anyone had any experience, or you had any other models Mikey. Thanks!

just use double sided sticky foam blocks. no need for an elaborate mounting mechanism with an autopilot that small.

Hey Mikey, first of all, thanks for that great design and lots of work you put into this (this goes to everyone else involved too of course). im currently printing it as i type, its going to be my first multicopter (although i've flown RC helis years back).

just out of curiousity, i've seen you mention somewhere else, that you are doing (or did) a hexacopter variant? any news on that?

How come you have it set to non-commercial license? I want to sell the printed parts on ebay.

Where are the parts for the camera gimbal?

Starting out the build of one of these, but wanted to make sure that I could source all the bits before diving straight into printing the parts.
The first hurdle I have come across is the motors - I don't seem to be able to find the "AX-4008D 620KV" motors specified in the build anywhere - they all appear to be out of stock (maybe something to do with this project!)
Does anyone have any recommended suppliers other than HobbyKing?

I've started printing the parts off for one of these, looks great with a lot of detail given by the uploader. On a side note though, does anyone know about the law regards flying these (specifically in the UK) as I understand it I would need a licence, but are there any extra regulations regarding flying something that is a DIY type kit?

As far as my understanding goes, you are good to go as long as you are not flying for commercial purposes; in which case you will need a licence.
"If a company or individual is operating their UAV commercially (which the Civil Aviation Authority defines as getting any kind of valuable consideration for your work) then their aircraft must be registered with the CAA and have a permit for aerial work" - http://www.quadcopters.co.uk/unmanned-aerial-photography-videography-guide-30-w.asphttp://www.quadcopters.co.uk/u...
Take that with a pinch of salt though, it's just hear-say from an enthusiast I met a while back and a bit of quick Googling.

New to the Quad world, and need assistance for motor / prop combination.
I've been able to print the airframe without any problems .... it turned out great!
Below is the estimated / actual weights of the components.
airframe 360g
Flight control 32g
radio receiver 9.8g r615x
esc 160 mass of four = 160 assumed 30A
battery 660g (Flightmax 5000mAh 4S1P 30C)
motor 352g ?
props 80g ?

my printer (xyz davinci 1.0) will convert all the files from .stl to slicer correctly besides the 3harm. Would anyone know how to troubleshoot this? When I try and convert the 3harm from .stl, the slicer result is missing part and leaves out the x like support.

Does anyone have a cheap parts list they wouldn't mind sharing?

Where is the battery tray STL file?

next iteration. the screws hole for motors that have 4 screws are a bit of a pain to get in with the leg in the way.

Thanks for the input, I think I will rotate the mounting holes 45 degrees to make it easier to access all of the screws.

I'm having a lot of of trouble getting the bottom nuts secure for the quad arms. They seem fine, I'm able to put a bit of glue in and they sit in place and hold the screws fine. But after a little bit of flying, they almost always come detached from the arms. Any recommendations for getting them to stay put? I've tried multiple kind of glue but am getting the same results each time.

Are you printing with PLA? I have heard that many glues do not work well with PLA. If you are having trouble keeping the locknuts in you might want to try just using hardware that goes all the way through.

I have had the same problem. Hard landings will pull the bottom nuts out of the bottom of the legs. I ended up zip tying around top and bottom plate at the legs for now to help hold it all together but plan to get through screws to solve it long term. Looks like 45mm M3's would work.

Nope, ABS. I've switched to using a glass plate for printing and the print has come out a lot better. I'm hoping that will make them easier to set. I've also have had better getting the nuts to stay in place by rubbing sandpaper around inside the nut housing a bit and then applying the glue. I'm hoping that and the improved print quality will make the quad sturdier. Thanks again for a great design and responding to everyone's questions.

Hi Zack
You solve your problem by using a bolt and nut lock fluid like Locktite 2700.

I'll have to try that, it's one of the only glues I haven't tried. Right now the best I have used is either JBWeld or E6000.

HI there. is the center plate's measurement same with the original flamewheel 450?

As far as the mounting hardware? No, but PM me and I will send you the files I just finishes to work with dji arms... I you are willing to test print for me?

I am fixing to print this and have a quick question. Will factory DJI Flamewheel arms work? Also I would offer up a OSD with gps for a few tweaks to the design so I could run my naza V2. I can draw in autoCAD but 3d is kicking my butt.

They do not fit on this frame although I just finished converting my top and bottom planes to work with dji arms. PM me and I will send you the files.

Any apm board tuning settings anyone could share? Just update my firmware to the lasted version and need some help getting my basic pid settings for stable and loiter.

Did you ever figure this out?

Am beginning to build this but am new to UAVs. Could someone tell me why the design includes a mount for a GoPro in addition to the FPV camera? I'm guessing the GoPro is somehow unsuitable for FPV, but then why include it at all?

Some people do not like to fly through the gopro view, one reason is if you do not power it while flying and recording the battery in it could die leaving you flying blind. There are cables that are wired up to supply power and get video all in one go. Another reason might be due to the gopro's lens, it has a strange fish eye effect that you may not like flying through. So, yes you can use either or both a gopro and separate board cam. Hope that helped.

Very helpful. Thank you!

no problem, glad to help

Mickey, why two different arm files?

Never mind, figured it out, one has 3 holes, the other 4 holes

Started to build a quad like yours, going to be using the new pixhawk, only problem, its a bit bigger than the APM2.6 and doesnt fit between the top cover and the top plate. Was looking to implement http://www.thingiverse.com/thing:163472http://www.thingiverse.com/thi... and maybe still use the same vibration dampeners as the rest of the quad. Any clever ideas, i dont want to tweak the native files too much so that everything still works(like the bolts that hold on the arms) but i want to update it to hold the pixhawk as the next gen of people to make quads will likely be using that hardware. take a peak.

Omnimac 3DR Pixhawk Anti Vibration Mount

Hmm maybe just remove some of the standoffs on the side? If you can send me the dimensions of the pixhawk I can add it into my next revision.

I am going to likely use this mount(below) so that one doesn't have to have more than one kind of vibration dampeners. Ill post it once im done.

Omnimac APM Mount v1.2

Updated it in sketchup but there seems to be a hole messing everything up. Theres a photo on my MADE page(http://www.thingiverse.com/make:72235)http://www.thingiverse.com/mak.... You may have better luck

Crossfire 2

I get a page not found for that link. I would like to see what you have done though and figure out that hole problem. Can you e-mail me your sketchup file?

Hey Mikey,
I'm working on getting mine together and everything has been great so far. My question is about the battery tray. From what I can tell, it's just the shock absorbers that are holding the tray and gopro mount to the rest of the frame. Is that right? Just seems like that won't be enough to hold the weight. Is there something I am missing?

That is correct. Just the 6 rubber dampeners. It is more than enough to hold it even through serious yanking and banking.

Appreciate it, thanks. It's looking good. One more question, where can i find the full assembly for the GoPro mount? All I can seem to find is the holder for the camera.

Are you talking about the gimbal mount or just to mount the go pro statically to the vibration mount? The different vibration battery trays can be found here http://www.thingiverse.com/thing:239594http://www.thingiverse.com/thi... and the gimbal assembly can be found here http://www.thingiverse.com/thing:140126http://www.thingiverse.com/thi....

Crossfire Vibration Dampening Battery Trays
by MikeyB
Brushless Gimbal
by MikeyB

the afro esc from hobby king come flashed with the simonK stuff so you dont really need a programmer unless you want to fiddle with stuff. If you get a 11 inch prop you might be able to get a bit more air time as well depending on the weight of you copter. http://www.ecalc.ch/http://www.ecalc.ch/

That list looks pretty good, haven't used the motors before or heard much about them but I have heard that the Afro Escs are good. I'm using 10 x 4.7 props on mine. You will just have to see what weight you come out with and what prop works the best for you.

Hi Mikey, I don't see the arms in the skp file. Are they the same as in Crossfire 1?

Hey markaw,
The arms aren't part of the crossfire 2 sketchup file. Both arms will work but I prefer the C2 Arms, they can be downloaded from this thing. I've been saying that I will be publishing a new line of arms that are interchangeable and mod-able for a while. As always life gets in the way. But everything is finished now and as soon as I get off the road and back home to AK I will publish those. If you would like me to send you that .skp PM with you email. It's not a cleaned up file but all the components are good to print.

Hey mike what size battery are you using and what kind of flight times are you getting?

I'm using turnigy nano-tech 4000 mah 4 cells. I fly for about 15 minutes before I change a battery out. I think that I could easily do 18-20 but I don't have an osd so I can't see my current draw when I'm flying.

Thanks for the awesome design! Got a quick question for you-- you mentioned in the instructions that the arms by themselves weigh 38g. Was that for the 4-hole tall arms?

I just printed them out but in PLA using a Replicator 2 and Makerware: 0.20mm layer thickness, 2 shells, 40% infill. After removing the print support, mine come in at 52g each for just the plastic. No hardware or anything else. 40% infill in PLA definitely feels sturdy with no flex. I'm wondering if I should decrease the infill for the weight advantage/reduction. Doesn't seem like much, but my arms are 36.8% heavier than yours!

Hey Tim,
I haven't printed anything out in PLA. It seems like PLA may be a little bit heavier? 52 grams is still pretty light, what you are aiming for is that the arms have as little flex as possible. If you can get away with less infill and still get good rigidity then you are golden. If the arm has too much flex the flight controller will have a hard time compensating and the quad will become very unstable. Hope that helps.

Hi, PLA it is little heavier (more density material), but also more rigid, i printed out arms at 35% infill and it is flying very well. Tested with APM2.6 and KK2.1 boards

Do you have a complete parts listing for people that are brand new to the hobby? I have downloaded the pdf but it seems like there are some things missing? Great Build thanks for your time!

What parts are you wondering about?

Thanks for the reply i did a little more reading and figured out most of my question. What kind of flight time did you get with your setup from your instructions? Thanks again!

It flies for 15 minutes with a 4 cell 4000 mah battery. It could go longer but without being able to see the voltage in real time I usually just time my flights. I'm going to put an osd on soon and then I can get a max flight time.

hey mike, im just about done with my build but was wondering it you were going to upload the skp files like with the cfrossfire 1 i need to make a few changes to the top plate?

Hey Stefan, .skp file is now up.

Thanks for getting back to me Mikey.

Sadly, I don't have any calipers handy to test the dimensions. I suspect that you're correct, and that the issue is PLA vs ABS when things are as tightly designed as they are here.

I really chiseled away at another arm I'd printed, and I finally worked the lock nuts in there. One more to go, which I'm impatiently printing now.

Appreciate the consideration - future PLA printers will surely appreciate a little extra space.



I had success using some channel locks to push them into the holes after shaving a little off of the inside edges with an X-Acto knife. The super-glue is key. I've seen a number of people mentioning that they have had issues with the lock-nuts spinning. That will happen if you don't glue the lock-nuts. I thought about heating them up as mentioned by JoeGargery, but I didn't know how much heat the nylon in the locknuts could tolerate. Glad to hear that method works.

Heat the nuts up and melt them into the pla, press fitted. That's what I did and then added super glue and they work just fine. No need to chisel anything.

Hey Joe,
I'm sorry you're having trouble with the arms and the lock nuts. Do you have a pair of calipers? Can you give me the dimensions of your lock nuts? I haven't had any trouble with my ABS arms splitting, sounds like this could be and issue with PLA. I am putting together a Thing file for all the arms, from the original to some new variations, all the arms will be there. You can expect that in a day or so, the tolerances should be right on all the arms and the sketch up files will be posted there as well. Thanks for pointing out this problem, hopefully I'll have it fixed soon.

Hi Mikey,

First of all, thank you for this great design. It's been my inspiration to put together my first quad.

I'm having some trouble with the tolerances on the hex nuts when printing in PLA. Even after digging the holes out with an exacto, I've split 3/5 arms that I've printed while seating the inside nuts.

I see that you were going to expand those holes a bit. Do you have any files available with slightly larger tolerances, or source files that I could try to modify?

Thanks again,


Have you figured out what the issue was? I am interested to know.

I was away on business so I didn't have a chance to try again until last night. I attempted PLA this time because the electronics came and I want to assemble. I'm still having some issues so it makes me think it could be the slice or the hardware. I re-sliced using Cura which didn't help. I'm noticing some stringing with the PLA (image below) which I noticed before but thought it was the ABS. This stringing could be what was causing the layer adhesion issues. I think there might be a blockage in my extruder.


It could be a blockage in your extruder, but it doesn't look like that to me. Every time i get stringiness its because my bed is just a little too far away. The lower arm in the picture (the one being printed) really makes me think that you need to bring the bed up a little bit. Can you level the bed while you are printing? Just keep raising it until you have a nice flat bead and you can see any of the bed after the first layer is filled in.

The first lay comes out exactly that way, nice and flat with full coverage. I like to keep the bed close for the first layer for proper adhesion. This is making me think it could be a setting in Cura. I modified the printer head sizes to 0 so I could print both arms on one platform. I'll try doing another test print when I get back later.

does anyone know if theses parts are all i need to build a quadcopter? if not, tell me what i am missing please. Not for this model in particular. i want one as a introduction before i goo big.

To the designer: I like this a lot! i intend to print this after i build my intro

Yes, I think those electronics should do fine for either frame. The 360 is a smaller frame at 360mm, while this one is about 450mm but I don't think it will make too much of a difference. Let me know how it works out.

Are the motor mounts universal (the screw holes)? Sorry I'm a newb when it comes to quads

Do your motors have 4 holes or 3 holes? Pretty much all motors fall into these two mounting patterns, with the 4 hole version (16x19mm) being the most common. I have both arms published here, so just choose which arm to print out according to what motor pattern you have.

they have four. it says that i can't upload your file and i need you permission ill re-download it and try. I think your pattern will work. Thank you

Just print out the 4 hole arms, your motors should have the required hardware to mount to the arms.

Thanks for replying so quickly. I will follow, maybe we could collaborate on something sometime.

Hi MikeyB, that is a good thing to make. Thanks. I have one question about electronics. In the "Crossfire 2" pictures you show a electronic board at the above of the APM 2.5 Flight Controller. My question is, What is the function of that electronic board?

The board above the APM controls the gimbal.

Thanks for your reply, Im searching a motor and I find this NX-4008-620kv from Hobby King. What do you think about this motor? is that good option?

Yes, those are nearly the same motors I have. It seems the ones I am using have been discontinued and these are their replacements? Those should work great for you.

Hi All!
Im almost done printing all my parts and I do have a few questions regarding all the components (flight controller, motors. etc ). I am interested in being able to lift a GoPro and was wondering what KV range should I be looking for when picking motors. I know there are many choices but Im really perplexed by the shear number of options.

I plan on doing some 3D photogrametry with my Crossfire 2. One of the features that would be great to havie is the ability to preprogram a multi waypoint flight to do some auto surveying. Is there a flight controller that can do that?

Any help would be much appreciated.


I just added some links in the instructions that should help with choosing electronics and explaining things better than I can. As far as the flight controller goes the APM can do exactly what you are wanting. It can overlay waypoints and make a grid for aerial mapping. You can choose how much overlap on each photo you want as well as have the APM control the shutter. I haven't experimented with this but I know that it has been recently added to the software.

I am trying to put M3 lock nuts into the arms and not having much luck. They are undersized a good bit. The sockets are 4.67mm and my lock nuts are 5.4mm.

i had some issues with a few of the nuts spinning when the bolt would hit the nylon insert in the nut. after messing with it for an hour or so, i just wound up using some longer bolts that went all the way through the whole assembly. It's not quite as slick, but it should be even stronger. I had visions of the nuts pulling out that made me nervous, although it probably would have been ok.

Hey just saw the make you just posted, it looks great! Did you super glue the nuts into the arm or just leave them free? I had one nut turn on me on an earlier version of the arm, but when I added a drop or two into the hole before tapping the nut in they bonded and are unmovable. I also added a very thin bead of glue on top of the perimeter of the nut. I'm pretty sure even cross threading the nut couldn't move them. Either way though, a through bolt works just as well. Thanks for posting your print, what electronics are you using?

I did superglue all mine. And as to crossthreading I did happen to cross thread one and it still did not spin the nut in the socket. I am using KK 2.1 controller and turnigy 25 Amp plush ESC's. With turnigy 750kv motors.

yea... I saw your instruction to add glue to the nuts, but I was worried about getting some in the threads, so I didn't... I feel safer using bolts all the way through anyway, even though the arms that were working seemed pretty secure.

Right now I just have an old FY-90Q quad controller on there and the radio is a dragon link. Its just left over stuff from a few years ago. The motors and ESCs are from a stock GAUI 330x.

I am printing a camera mount as we speak and will wire up a video transmitter today. I also ordered a 3DR Pixhawk, so that will get installed when it arrives. That will be my first autopilot, so it should be good.

The airframe seems nice an solid. Now I just need to improve my heli piloting skills! :)

They will be a little bit tight, you will have to "flare" them out a bit with an exacto. The tapered side of the locknuts need to be facing into the center of the arms on the outside holes (if that makes sense) and they will need to be tapped in with a hammer. Mine went in with one swift tap. It's the nuts towards the inside of the frame that are a bit tricky because they go in with the flat side facing the top of the arm. Where did you get your locknuts from? I got mine from Hobbyking, I will go check the dimensions of mine when I get home.

After carving them out a bit I got them all to go in. Got a bit of splitting on a couple but seems to have worked ok. I don't see them coming out easily =)

Awesome, just saw your make. It looks great! I'm going to take off 1/256 off each edge of the perimeter, hopefully that will make them a little easier to get in. I still want to keep a fairly tight fit though. Thanks for being the first to make!

Thanks! Yeah I think just a little bit would help on the fit.

Would I be able to print the frame and legs in PLA plastic? If so what would be your recommended temps and infill? (I have a replicator 2)

I run 20% for the body parts and 25% for the legs. The trick I found doing this, leaning and crashing a lot, was print the legs using Makerbot white PLA. Because? Amazing crash damage can be quickly fixed using Acetone as an adhesive. Their white PLA takes to acetone like crazy glue to skin. Other brands and colors, not so well.

Really? I never knew that. I always fixed my broken legs with super glue.

Yeah, being in a boat shop that was the first thing we grabbed off the shelf. At first we thought we had the silver bullet. Then we tried to fix a red leg printed with another vendor's PLA. No luck at all. Who know's what the deal is besides, all PLA is not created equal. But for the white Makerbot stuff, its the ticket.

i think your PLA is really ABS. Acetone should not react with PLA at all, but reacts a LOT with ABS.

Yes, many people have printed in PLA, although I couldn't give you a solid recommendation on where to start. Maybe 50% infill on the arms? The frame parts should be fine at 20%. Let me know how it works out.

Thanks for the great info! I probably won't be able to print it out for a little while because I just ran out of filament but I'll let you know when I try!

I printed 2 out of 4 of my arms in PLA with no problems. I have a crossfire 1 I built with the same setup and I've broken the abs arms twice on the legs, but never the pla yet.

I'm attempting to print the arms in ABS but I'm having layer adhesion issues. The areas not part of the core are coming out very brittle. I tried increasing the flow and turning off the fans, which helped but its still not strong enough. Do you have any suggestions?

Weak areas -> http://imgur.com/86PTTYlhttp://imgur.com/86PTTYl

What slicing program are you using? I had similar issues with another print when I was using Slic3r. I switched to Cura and my problems went away. Also, I saw some issues like this when I was using poor quality ABS.

I'm already using Cura. Who do you recommend as a good source of ABS? I'm in the US.

I have had good luck with IC3D abs, and its reasonably priced...

What do you mean by layer adhesion? The layers are not bonding?

Yes they are not bonding fully on the Z. There are also issues on the the X and Y axis drawing. A criss cross pattern occurs to the point where from the top layers appear see-through.

This project is my first attempt at printing with ABS so the question is likely more suited for another forum. I was just wondering if you faced any similar issues or have any tips.

Hmm, my first two guesses are either bed level or temp. What temps and extruder speed are you using with ABS? Im guessing your temp is probably too low.

260C printhead 90C bed
I'll definitely try calibrating my bed.
I think it may be speed I'm doing 50m/s

I'm guessing thats the problem, 260 seems way too high. I print at 220-230C on the extruder and 110 on the platform. Do you hear popping? Is the ABS kinda bubbly?

It didn't pop or bubble. I tried 240C, 110C, slower print speed, and a temporary enclosure. It didn't improve. As you can see from the picture below the main body was fine but the extremities are having issues.


Wow, that is very strange indeed. I've never seen anything like that. The strangest part is that as far as I can tell the main part of the arms look fine. The layers all look really good. But when it starts climbing the leg it goes all fucko. It looks as though the flow may not be consistent, but I don't know why it would show there and not everywhere else. Is there a possibility that vibrations from your printer are causing the print bed to back off, because the only thing that I can think of is that it looks like your nozzle is too far away from the print as it gets into the legs? Do you have any other colors of ABS to try? Could it be bad plastic? Honestly I'm stumped but I am really curious to know what the problem is.

How did you go about choosing the different motors? Every time I start looking at available options for equipment on these, I'm just swamped!

Haha thats a slippery slope. There are many different combinations that work. Basically the more expensive the motor the better. The windings, number of poles, kv rating etc. I really don't have a great understanding of how it all ties in but basically the lower kv motors the more efficient they are. They are also lower power so finding the correct prop combination is key. The bigger the props the longer it takes them to "spool" up and down. A slow turning, big prop is more efficient than a small prop spinning fast but the flight controller has a hard time controlling props that lag a long time behind the inputs. I guess what I'm saying is that this is all a bit of black magic (its not, I'm sure and aeronautical engineer can explain it better) but there is always a little experimentation involved. An motor listed on Hobby King or websites like http://GetFPV.comGetFPV.com under multi-rotors will all work. They should have a listing for what prop size and what size airframe they will be best on. Also forums on multi-copters have LONG threads on combinations, it might be more reading than you are interested in but you might find some good info. Good luck! Let me know what you end up going with.

Hey! Thanks for this design... I'm printing as I type this. I just wanted to make mention of your comment about a lower KV motor being less power... In actuality, the lower the KV the more torque the motor has. So to swing a big prop and not have the lag you mentioned you would actually want a lower KV motor. KV = RPM per Volt. So, how many times will the motor spin after it consumes one volt of electricity. On my current hex setup, I'm using some 530 KV pancake motors in combination with APC slow fly 14 x 4.8 props. This is a large setup and it easily carries a full size DSLR camera. This is a pretty good explanation: http://www.flyelectric.com/ans.kv.htmlhttp://www.flyelectric.com/ans... . Also, someone mentioned eCalc, in case you didn't know, here is a link to xcopterCalc: http://www.ecalc.ch/xcoptercalc.htm?ecalc&lang=enhttp://www.ecalc.ch/xcoptercal... which is a version of eCalc specifically for multicopters.

Hey, thanks for that, it really clears some stuff up for me. I'm going to add links to these two pages in the instructions.

Also struggling with picking out motors. One important factor that seems to be missing from the conversation is approximate weight. How much does the quadcopter in your pictures weigh with all of the devices, batteries, etc. That seems like it would be helpful information in determining motor to purchase. Thanks!

This is what I used to come up with my original setup. Would have been lost without it.


Good luck!

-jim lee

Going out to get a scale now, it's definitely something I should have. I'll get you a gross weight soon!

Ok, so the quadcopter, how I have it setup (FPV gear, gimbal, APM, and 4000mah 4 cell battery) is 1700 grams. The frame alone, with hardware, is 400 grams. Obviously different prints and different infill will yield different results but those should be good rough numbers.

You mention a battery tray in the instructions, but I do not see one in the thing files. Also does the C2ControllerMount work with a KK 2.1?

dcowan, thanks. I have just added a link to this thing: http://www.thingiverse.com/thing:239594http://www.thingiverse.com/thi... in the instructions. It is the collection of the 4 different battery trays depending on how you want to set your quad up. As far as the "C2ControllerMount" file goes, that one is to mount a second controller above the APM vibration mount. It will fit any 50x50mm board so the kk 2.1 will fit on it. The Top Plate also has 50x50mm patterns to mount those boards. If you want to isolate your board from vibrations you can attach the C2ControllerMount to the APMmount and that would work. Would you like me to modify the APMmount to with 50x50mm patterns as well?

Crossfire Vibration Dampening Battery Trays
by MikeyB

I'm not really seeing how the battery try mounts. I couldn't tell from any of the pictures here or in the instructions. Are screws used or just zipties?

I will try out the current mount first. I had no problems with Crossfire 1 mounting directly to the top plate so I don't expect any issues with this. Thanks

The battery tray mounts to the bottom plate via vibration dampening rubber balls. You can find them on Hobby King. They are definitely the way to go if you ever plan on mounting a Gopro to your quad.

Any chance of uploading the native (SketchUp?) drawings like you did with the original CrossFire? Makes it easier for remixing! Also had a problem printing one of the gimbal parts through Simplify3D so would be easier to fix with a native drawing.
Great work by the way.

Zebble, yes I plan on uploading the native SketchUp files soon. I just want to clean them up a bit as they get messy when I work through a design.

Great work! We were just about to print v1, and now this! But am I blind, or is the battery tray STL missing? Also, do I understand correctly that I could build with either APMmount+TopCoverAPM or only TopCoverPlain? Thanks

Bror, sorry for the confusion, the battery tray is either in the Brushless Gimbal thing: http://www.thingiverse.com/thing:140126http://www.thingiverse.com/thi.... or the Vibration Dampening Mount: http://www.thingiverse.com/thing:124868http://www.thingiverse.com/thi.... I am going to consolidate all of these battery tray into one thing with a link to this page. Or would you just like a Bottom Plate with holes for velcro? Because I have been thinking about adding that if its something people would like. The APMmount is only the vibration dampening plate for the flight controller. The compass/gps module will fit fine on the TopCoverPlain there is just no mount for a ccd camera. Hope that clears things up. If you have any more questions feel free to ask.

Brushless Gimbal
by MikeyB

Aha, I think that clears it up. Well, we're building without cameras first, just to make sure all components come together (it's our first..). Probably a bottom plate with space for velcro would be good, but we'll just duct tape and cable tie things down for now. Will get back when we have more (parts are printing, but HobbyKing package stuck in customs atm). Thanks!

What is your electronics list? Are you building for the APM or other controller?

No, the KK2 controller (perhaps we ordered both 2 and 3, I forgot now, anyhow not APM). Electronics list is very similar to a make of Crossfire 1: http://www.thingiverse.com/make:43514http://www.thingiverse.com/mak...

We are aiming to mark down the first dozen crashes with cheap parts ;) Then we could start thinking about vibration damped cameras and whatnot ..

that controller should do you very well for a while. It is not nearly as stable as the APM, but thats not a bad thing. It will teach you some solid stick and runner skills and if you do end up upgrading you will really see the difference. Keep me posted on how it all works out.

Thanks, will do!

Bror, I have added slots for velcro straps to the Bottom Plate so now you can strap your battery directly to that if you don't want to print out a battery tray. Thanks for the suggestion.

The two standard arms, a 3 hole and a 4 hole (16x19mm) for motor mounts are up. More to follow soon, but theres are the arms that I printed the Crossfire 2 with.

mikeyb i was about to start printing the parts on monday and and came across this today. the only question i have is the arms did you up load the stl or do we use the one from the crossfire 1?

Crap I didn't upload the arms. I have a bunch of different arms now I think I will post another arms section this morning. Anyway don't print the arms from the original. While they would fit, the new new are better. Ill have these up soon.

Well - I've already printed 2 arms from Crossfire1 when I ran across this new #2!
I shouldl be able to continue with all 4 #1 arms and then print everything else from #2 version - rght?

Sherry, yes the Crossfire 1 arms will work with the Crossfire 2 frame. The only difference is the through holes are bigger. Might I suggest printing out the last two arms in the new version. You will be able to see the improvements and decide which you like better. You can still attach the arms with "through" hardware if you don't have any M3 locknuts. The slight difference in weight should't make any difference.

Thanks and about that gopro3 on the gimbal you have pictured is that also going to be uploaded. Again love how professional this looks

Thank you, yes I am uploading and updating the gimbal as we speak. Should be ready to go soon. Thanks for all the interest.

Absolutely LOVE our instructions! I'v been meaning to write something like that for mine but I've been too lazy. You've done a great and very complete job!

Thanks, I spent a while getting through it. Love the legs on your quad by the way, very cool!. How strong are those hollow arms?

On the hollow arms, besides the landing loops, I've not broken one. That's why I finally gave up on the loops and tried the legs. I now have a lot of arms with broken loops. I've not tested the legs yet. (fingers crossed)

Designing the legs hurt my brain. Ive been using this project to teach myself 3D CAD.

P.S. You do realize you didn't post your arm design?

I can't see any reason why your legs wouldn't work, they seem very stout. Yes thanks, I forgot to post the arms. They are up now. I only posted the two standard ones but I've got a few more iterations I'm working on. One kinda similar to yours. Hollow arms and different types of landing gears.