These are the fully 3D printed T4 (quadcopter), Mini T4 (quadcopter), and T6 (coaxial hexacopter) designs I've posted on Thingiverse.com (aside: "T" is for Tubular). The comments section on Thingiverse doesn't provide a great place for discussing designs so I've created this topic here instead.
These designs are based on a tubular arm with a vertical "I" beam running down the centre. This design seems to be very strong and rigid and all of these designs are very stable in flight.
Other common features include:
- motor wiring is routed through the arms and down into an enclosed (ventilated) power and ESC tray.
- batteries are located in the centre of rotation (T6 is designed for dual batteries).
- bevelled cable "tunnels" provide a way to route cables between the power tray and top plate.
- Top plate is designed for Pixhawk or APM flight controllers with elevated GPS.
- Bottom tray has mounting points for a Tarot Gimbal.
- Optional long and short legs include "springy" feet. The legs are designed so the 3D printed threads "wrap around" the arms which makes them quite strong for their length.
- Sketchup files are included so folks can modify both designs to suit their needs.
I figure I've put hundreds of hours into these designs with prototypes and drawing time. I'd love to get feedback from anyone who makes one. Together we can improve these designs for everyone's benefit.
Replies
Hi Terry. Great to hear you are working on one of these.
Regarding connectors you'll need a hefty connector to connect the battery to the ESC (eg XT60 or Deans). The ESC and the motors should just plug together (3.5mm bullet connectors) but you'll probably have WAY too much cable (3DR motors and QBrain all have really long leads) so you'll probably want to to shorten them. Did you get a 3DR power module? - if so that just goes in between the battery and ESC (also a longer 6-wire DF13 cable can be handy to reach from the power module in the power tray to the Pixhawk). It's worth getting a couple of spare 6-wire and 4-wire DF13 cables from 3DR (the standard GPS to Pixhawk cable is okay but could be longer).
The T-2D controller board should just be listed as a spare part. If you've ordered the full T-2D gimbal then you should get everything you need the arms, motors, controller board, and even USB cable for connecting to your computer. The only connection you may want to make between the gimbal and the Pixhawk would be to pass through a signal from your RC transmitter (eg one of the knobs) so you can control the tilt of the gimbal from the ground. For FPV you'll need to add a camera, video transmitter and a cable to connect the two - plus receiver and googles (or monitor) on the ground.
I got most of my batteries from HobbyKing (I'm in New Zealand) or my local hobby shop. Yes you can buy all sort of battery chargers (2 dock and 4 dock). Be aware that many of them require a pretty grunty power supply in addition to the charger. A 6000mah battery requires about 6 amps (@12 volts) if you want to recharge it in one hour. Twice that (12 amps) to do it in half an hour.
I haven't played with my new Taranis yet but that would be the one I would buy right now if starting out. Stocks are still pretty limited though I believe.
Good luck with the build. Please let me know how it goes and/or post photos!
Brendan,
I printed all the parts. They turned out quite good. The only issue that I have is the four loops on the top plate for zip ties (I think) were week and easily snapped off. I suspect you must have quite a bit of experience designing things as the parts are quite elegant and very well thought out. This can't be your "first rodeo" ;?)
Did you glue the GPS post into the top plat and GPS receiver plate? At the base of the GPS post, there is a vertical plate with a hole. What is this for?
I added a third thru hole with internal post to the arms in case I want to install the screws in the legs.
I am still waiting on the QBrain module and the batteries. Also am on a waiting list for Taranis. If this gets to be too long, I may just purchase a cheap radio to get it in the air. I think I am going to wait a bit on ordering video stuff until I have a better feel for what I want. I am trying to locate some people in my area (Houston, TX, USA) that are into multirotor to ramp up my knowledge.
From looking at your thingiverse photos, I think I have most of the component location sorted. I am using Pixhawk and the other electronics are from 3Drobotics except the QBrain.
I am still missing a bit on the concept. I was thinking that the small radio shown in the photo is for telemetry data that gets displayed on the LCD of the hand held radio (or maybe something else) I assume there is still an airborne receiver that receives commands from the hand held radio and communicates these commands to the Pixhawk. In the photos, I only see the Pixhawk, QBrain, power module, radio, and GPS. There is another photo with electronics, but they are on the top plate so I was thinking maybe this was a different generation of electronics.
Do you balance your props?
Thanks for all your help and a really neat design.
Brendan,
I have pretty much printed all the parts. They turned out quite good. The only issue that I have is the four loops on the top plate for zip ties (I think) were week and easily snapped off. I suspect you must have quite a bit of experience designing things as the parts are quite elegant and very well thought out. This can't be your "first rodeo" ;?)
Did you glue the GPS post into the top plat and GPS receiver plate? At the base of the GPS post, there is a vertical plate with a hole. What is this for?
I added a third thru hole with internal post to the arms in case I want to install the screws in the legs.
I have attached a photo of where I am.
I am still waiting on the QBrain module and the batteries. Also am on a waiting list for Taranis. If this gets to be too long, I may just purchase a cheap radio to get it in the air. I think I am going to wait a bit on ordering video stuff until I have a better feel for what I want. I am trying to locate some people in my area (Houston, TX, USA) that are into multirotor to ramp up my knowledge.
From looking at your thingiverse photos, I think I have most of the component location sorted. I am using Pixhawk and the other electronics are from 3Drobotics except the QBrain.
I am still missing a bit on the concept. I was thinking that the small radio shown in the photo is for telemetry data that gets displayed on the LCD of the hand held radio (or maybe something else) I assume there is still an airborne receiver that receives commands from the hand held radio and communicates these commands to the Pixhawk. In the photos, I only see the Pixhawk, QBrain, power module, radio, and GPS. There is another photo with electronics, but they are on the top plate so I was thinking maybe this was a different generation of electronics.
Do you balance your props?
Thanks for all your help and a really neat design.
T4 Parts.JPG
Brendan,
I have pretty much printed all the parts. They turned out quite good. The only issue that I have is the four loops on the top plate for zip ties (I think) were week and easily snapped off. I suspect you must have quite a bit of experience designing things as the parts are quite elegant and very well thought out. This can't be your "first rodeo" ;?)
Did you glue the GPS post into the top plat and GPS receiver plate? At the base of the GPS post, there is a vertical plate with a hole. What is this for?
I added a third thru hole with internal post to the arms in case I want to install the screws in the legs.
I have attached a photo of where I am.
I am still waiting on the QBrain module and the batteries. Also am on a waiting list for Taranis. If this gets to be too long, I may just purchase a cheap radio to get it in the air. I think I am going to wait a bit on ordering video stuff until I have a better feel for what I want. I am trying to locate some people in my area (Houston, TX, USA) that are into multirotor to ramp up my knowledge.
From looking at your thingiverse photos, I think I have most of the component location sorted. I am using Pixhawk and the other electronics are from 3Drobotics except the QBrain.
I am still missing a bit on the concept. I was thinking that the small radio shown in the photo is for telemetry data that gets displayed on the LCD of the hand held radio (or maybe something else) I assume there is still an airborne receiver that receives commands from the hand held radio and communicates these commands to the Pixhawk. In the photos, I only see the Pixhawk, QBrain, power module, radio, and GPS. There is another photo with electronics, but they are on the top plate so I was thinking maybe this was a different generation of electronics.
Do you balance your props?
Thanks for all your help and a really neat design.
T4 Parts.JPG
Hi Terry.. great so see your progress with this - nice prints!
Sorry about the zip tie posts. I haven't had that issue. Thinking about it I probably have a habit of using my thumbnail to pull the zip tie "head" against rather than pulling entirely on the mount.
I haven't bothered to glue my GPS posts as, for me, they were quite a firm fit and I don't fly inverted for too long :-) but you could use CA or even hot glue if you liked.
The hole next to the GPS post mount is for a safety push switch that comes with the Pixhawk flight controller.
In my main T4 photo there is a small Spektrum satellite radio control receiver zip tied half way up the GPS post. You are correct ...the big fat aerial in the far back corner is one end of a 3DR telemetry radio link back to a similar radio on the ground which is connected to either a notebook PC or Android tablet running one of the Ground Control Station applications. I use Andropilot (tablet) or Mission Planner (PC).
I do check/balance my props ...but all of the latest APC 10x4.7 ones I've been getting from 3DR haven't needed any adjustments. I've never bothered to dynamically balance my motors/props.
Good luck bringing everything together.
Hey Terry,
I am a little ahead of you in the build, I have mine assembled but haven't had a successful flight yet, can't get the Qbrain calibration to stick.
To answer some of your questions.
The small upright with the hole by the GPS tower is for the Pixhawk safety button.
I think Brendan has his Receiver for the Rc radio on the gps tower, Either elastic or zip tied on.
I have placed mine on the bottom at the rear with a piece of velcro.
Hope this helps.
Craig
Hi Craig. That calibration sounds like it is being a real pain. I'll see if I can run through the process again myself tonight and let you know if I come up with any suggestions.
Thanks Jin. I hate adding up costs like that :-)
If you were starting from nothing I think you could sneak in at about $300 with the following recipe:
- KK2 flight controller
- QBrain 4-in-1 ESC
- 3DR 850KV motors
- 2 sets of 10x4.7 propellers
- a 3000mah 3S battery
- a basic Lipo battery charger
- a basic transmitter like the Turnigy 9X with 8 channel receiver
- a few plugs and cables (eg male-to-male servo cables to connect KK2 to the radio receiver, XT60 or Deans connectors for connecting QBrain to battery)
If you use separate ESCs then you'll need some way to distribute power from the single battery connector to each of them (either homemade or 3DR and Hobby-king sell boards). The QBrain really makes it easier AND cheaper!
Flight controllers like the KK2 are great value if you just want basic stabilisation. The APM and newer Pixhawk add the option for GPS and programming flight missions using a PC or tablet, return to launch if RC link fails, auto land if battery gets low, etc... The current Ardupilot software will probably be the last for the APM hardware as the developers have now reached the limit of what it can handle. Development will continue rapidly with the Pixhawk.
For RC gear I started out with the Turnigy 9X mentioned about and then moved to a Spektrum DX8 and have just received a new Taranis.
Regarding the prints, with one springy leg I had to run a blade along the plunger slot to help break it free (and then give it a reasonably hard push down onto the bench). Once moving you can try lubricating with a bit of olive oil or similar.
If it helps, with PLA I use budget hairspray on the glass with the heated base plate set to 55 deg C. For me higher baseplate temps increase the chance of warping. With this combination I haven't had any issues and normally have to put the prints in the freezer for a couple of minutes to get them to pop off the glass (after they're down to room temp).
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