Over the past six months, I’ve gotten to know my 3D Robotics X8 multicopter very well. I thought I’d share some of my experiences and observations with the unique multicopter.
Last year, I started following along with the multicopter scene on some forums like DIY Drones, RC Groups, Quadcopters, FPV, and UAV/FPV. I was interested in the Arducopter platform because it seemed to allow a deeper dive into multirotors than buying something like a DJI Phantom. The Phantoms work great from what I understand, but I was more interested in tuning, upgrading, and doing autonomous missions with my UAV. I wanted a platform that would grow with me.
The X8’s defining feature is that it’s set up like a traditional quadcopter, but it features two motors on each arm. One might call it an octocopter, but it’s really more like a quadcopter with redundancy. Apparently, it can stay in flight even if you lose a motor. It is definitely extremely powerful. It’s vertical lift is amazing. Because of it’s power, it can easily carry gear, which makes it a perfect platform for expansion.
I ordered my X8 in January of this year. I ordered it just slightly before 3D Robotics announced the 2014 model, so mine is the 2013 model. The 2014 model is not incredibly different. It has an improved body, Pixhawk autopilot (2013 has APM 2.6), GPS mast, and better batteries included. The only thing I really missed out on is the Pixhawk autopilot. I will probably end up, upgrading to it someday since it’s significantly faster hardware than the APM 2.6.
The X8 took a bit longer than I wanted to arrive, but when it did, I was very pleased. It was packaged nicely and extremely easy to put together. One arm was folded up for transport. I had to cut the factory zip ties in order to get the arm into position because the ESCs were tucked too tightly against the frame and I was afraid of breaking something immediately. I replaced the zip ties with some super cool orange zip ties. My first mod.
It took about a full evening of looking through the parts and getting acclimated to everything to get the X8 all set up. There was no soldering, just screwing. One of the trickiest parts was the little rings that are included with the props. The thinner rings seemed too loose on the motor shaft and the thicker rings seem too tight. I ended up determining the thinner rings were the correct ones for the props.
The X8 is a bit bigger than you would imagine. Once you attach the props, it feels a bit intimidating. The X8 is marketed as ‘ready-to-fly’, I think that is basically a true statement for the hardware. Setting up this multicopter was very easy overall.
This was a bit trickier. There is a lot to learn before your first flight. I tested out many of the software options that are available: APM Planner, QGroundControl, DroidPlanner 2, and more. I wanted to start with my Mac laptop as my ground station and I choose APM Planner as my software. From my testing, it was the least likely to crash. It is also actively being developed and has really great features like real-time graphing and logging.
3D Robotics recommends you basically don’t mess with the software before you fly. For the most part I agree with that, but here are the main things you need to learn about your ground station before you fly:
1. Know how to install firmware on the X8
The X8 comes with the firmware installed, but it is constantly being developed and you will need to know how to do this in order to upgrade the firmware in the future. Here is an easy tutorial.
2. Connect to autopilot via USB
This is the hardwire connection you will use to do the basic calibrations. Easy to follow guide on the Ardupilot site. Here’s the biggest trick, when connecting to your ground station via USB use 115200 baud and when connecting over a radio use 57600 baud.
The X8 comes calibrated, but you still need to know how to calibrate the multicopter, because undoubtedly at some point you are going to crash and it’ll more than likely need to be recalibrated.
Frame Type. Choose your frame type.
Compass. This is how you calibrate the compass.
Accelerometer. Here is a good video that shows the process. I had to do this a few times to get it perfect. Sometimes after I would crash, this would seemingly get way off. The copter will fly terribly if this is not calibrated well.
Radio. There is also the option to calibrate your radio. Your transmitter will come pre-calibrated. I would highly recommend not doing this unless you notice something wrong. You are likely to screw this up or not set it up as nicely as 3DR has for you.
Flight Modes. Here is the best one and one you will want to investigate before your first flight, flight modes. This will change what your flap toggle on your transmitter selects as your current flight mode. I believe the default is ‘Stabilize, Loiter, Land’, but there are many other modes to choose from. Learn about them here.
Other notable modes are RTL (return to launch), Alt Hold (keeps you at the same altitude), and Follow Me. You will have plenty of time to explore these, but as a quick intro: Stabilize is the one you will mostly be flying in. Loiter does what you would imagine, but you can also fly in Loiter. It’s behaves like a super easy mode and won’t let you really screw up. RTL is a usually lifesaver if you get to excited, nervous, or out of control. You can also set up RTL to automatically trigger when your battery hits a certain voltage. This is extremely useful.
Once you get used to all this stuff, there is plenty more to learn about. APM Planner has incredible graphing/logging capabilities. You can analyze your flight data and learn a ton about how you are flying and what your copter is doing. And then of course, there are the autonomous capabilities of the X8 and the completely autonomous missions you can plan with waypoints and events.
You will continue to learn about the software as you progress. Don’t be intimidated by it, but also don’t take it for granted. It’s always better to understand what you are doing, rather than be surprised by unpredictable results.
Learning to Fly
Here is a recap of my first flight. I went out to a soccer field early on a Saturday morning. I set up all my equipment at a picnic table. I set the X8 up about 25 feet in front of me. Connected APM Planner to the radio. Armed the X8. Put it in Stabilize mode. Took off very slowly. Hovered for about 25 seconds. Then brought it down very slowly. It was the simplest flight ever but it was exhilarating.
The next several flights were baby steps. I controlled each individual control one by one. One flight was pitch, one flight was yaw. One flight was roll. Altitude was the hardest thing to control initially because I was always too slow to react, and consequentially I would always overcorrect. So the copter would always be going up and down and up and down.
I learned to fly the wrong way. I started with a big awesome multicopter. Everything I read online said, ‘start with a little one you don’t care about,’ but I didn’t listen.
I wasn’t learning the actual flight dynamics of the craft because I was being too cautious. I was taking things slowly and I felt like was progressing too slowly. I didn’t want to crash this beautiful flying robot. I would get nervous around obstacles like trees because I didn’t feel I could predict the results of my actions.
After a month or two of flying I invested in a micro quad. Everything everyone said is correct. The flight dynamics on a tiny quad are remarkably similar to a bigger multicopter. I practiced a lot. I learned to anticipate the unique dynamics of the multiroter. The anticipation allowed a sense of control and less erratic movements. Suddenly when I would fly the X8 I felt far more in control. I was also having far more fun.
I highly recommend starting with a small quad for anyone new to flying. Get a little one, crash it a lot. Take risks. It will make your experience with the X8 so much better.
My first upgrade was just strapping a GoPro to the X8. This was obviously awesome. It’s great to get footage from above. You will get a bit of jello from the GoPro being attached directly to the frame, but there are plenty of ways to solve that.
My second upgrade was to increase the length of the legs. 3D Robotics has some extended legs available, but not on their website. I actually don’t recommend extending the legs. I removed the leg extensions almost immediately because when landing on hard surfaces, I found I was far more likely to tip. That and the fact that the GoPro is turning out to be incredibly capable and I don’t intend on flying with a larger camera.
Next I added a GPS mast because it was super affordable and comes standard on the 2014 model. The idea here is to move the GPS and compass away from the vehicle to reduce magnetic interference.
This is where it really gets interesting. My next upgrade was to put FPV (live remote first person perspective video) on the X8. I had been flying for 4 or 5 months and I was ready to take the experience to the next level. This was one of my dream goals for the X8, to experience the flying in this particular way.
FPV is pretty overwhelming to get into. Learning to fly FPV is one thing, and I will have to write a different post about that experience. Technically though, there are a lot of options and a lot of technology to understand. I didn’t want to make mistakes and from what I could tell, the only way to find out if certain components work with other components is to test them. That seemed undesirable since I didn’t want to waste money on things that wouldn’t work together. I ended up going with 3D Robotics FPV kit because I knew I wouldn’t have much trouble getting OSD (on screen display of telemetry data) working.
Here’s my review: awesome. The setup was super easy. I got OSD working immediately. I did a bunch of flights and started recording the footage with a little SD video recorder. It actually records the footage fairly well. I have to run a VLC converter on my Mac because the footage comes out as PAL in a Microsoft video format called ASF. The footage is low res, but overall it’s really neat and I like being able to watch the telemetry in real time with the video playback.
My next step for the FPV was to simplify the system and hook up the GoPro as the primary camera both recording and transmitting the video. I am currently using a GoPro frame mount directly attached to the X8 frame with this setup. One tiny mod I made was to tilt the FPV cloverleaf antenna down in the rear of the craft. This seems to keep all the antennas as far away from each other as possible. I highly recommend this setup since the FPV transmitted video is also an improvement from the security camera video.
It is at this particular point that you might realize there are a lot of batteries going up in the air constantly. There is a solution. My good friend Jeff Shafar from Hippo Bear Media was kind enough to get me an amazing HiTec 4 port multi-battery charger for my birthday. This enabled charging of multiple batteries simultaneously and greatly reduced the amount of time spent on doing so.
Some things I am looking forward to in the future are using an iPad as my ground control with the Fighting Walrus antenna. They’ve been working on some really good software for the iPad that I’ve tested. The idea of going to the field with just the iPad, RC transmitter, and X8 is super awesome.
I would also love to get a Tarot gimbal setup working. Gimbals smooth out video footage by staying level to the ground, even when the copter is tilted off axis. One minor thing keeping me from doing this is that the Tarot requires Windows to configure the gimbal.
Eventually, I would love to have some kind of goggle setup for the FPV. Right now, I’m viewing the FPV from a small monitor. Goggles give you a full immersive experience from the perspective of the craft. I haven’t done enough research to make any sort of recommendation, but Fat Shark and SkyZone seem to be the most popular brands at the moment. I’ve even seen people hook up an Oculus Rift to control the multicopter with head tilts.
I would also love to go much further with autonomous missions. I truly haven’t even begun to explore the possibilities, but that’s only because I generally have so much fun manually flying.
I haven’t had a lot of problems with the X8, but I have made a few mistakes. The most critical was when I mistaking plugged a battery into the charger incorrectly. I ended up overcharging the battery. I didn’t notice and flew the battery. It swelled up mid-flight. It was pretty terrifying. I drained the battery. Figuring out how to dispose of it properly was not exactly clear. I couldn’t find anyone to take it. So I made sure it was discharged completely, put it in a LiPo bag and disposed of it in the normal garbage. Everything I’ve read said this was the proper way to do it, but it still didn’t feel right. A completely discharged LiPo battery is apparently inert.
I’ve broken some props here and there from nasty landings. The worst accidental I had was when I had set up my battery warning and RTL to be too aggressive low. The X8 was in the middle of RTL when it fell out of the air. Minor damage overall, but it taught me to be really cautious about the battery voltage, because it can become a dangerous situation fast.
Lately I seem to have an intermittent cutout on one of the arms. The props lose power for a brief moment and the copter dips, but then it immediately regains control. I assume I might have a short of some sort, but I haven’t figured it out yet.
Overall, the X8 has given me exactly what I wanted out of the experience. It’s not the easiest thing in the world to maintain. It’s definitely not a toy. It’s a serious craft and it’s full of possibility. I still feel like I’m at the beginning of the adventure with it. I’m glad I started with a RTF multicopter, because I felt like I had some training wheels as to what the experience should be like. It was easier to learn step-by-step when things break or you want to try new features, than try to learn everything you need to know at once.
I started a Facebook group for people who are interested in the 3D Robotics X8. It’s a casual group for enthusiasts, since it’s somewhat hard to find and share information about the X8 and it’s unique characteristics. If you have an X8 or you are planning on getting one, you should get it on the discussion.