My interest in multicopters started last year. I read forums for months, learning everything I could. I wanted an autonomous flying robot. The first multicopter I got was a big one, a 3D Robotics X8 (which I wrote about here). Although it’s a great vehicle, I found myself interested in multicopters for a different reason than I thought. Aerial photography isn’t as personally engaging as I had hoped. Lugging around a computer and the required equipment for a big multicopter feels more like work than fun sometimes. I still really enjoy the X8, it’s just not an ‘everyday quad.’
In an effort to learn to fly better, I got into micro-quads. These are super tiny quads that are great for learning because they can take a crash. I spent a lot of time on a Turnigy Micro-H and a Walkera QR Ladybird v2 FPV. During this time, I found that I really loved flying aggressively. It reminded me a lot of the feeling of drifting a car in snow. The problem is that micro-quads are extremely susceptible to wind and it’s not really possible to capture good footage from the first person view to share exciting flying moments.
I found myself more interested in the manual flying aspect of the micro-quads than the autonomous flight capabilities of the X8. That’s when I put all of my focus on the idea of a mini-quad. I wanted to fly crazy, fast and FPV. I didn’t want to worry about crashing. It would be less of a problem with the mini-quad as the replacement parts are more affordable and the frame is proportionately more stable than a larger quad.
Some of the most popular mini-quads are the QAV250 and the Blackout Mini-H. These quads are meant for FPV stunts and racing. They can mount a GoPro or Mobius ActionCam and can carry enough battery to have reasonable flight lengths. Here’s a video which completely sold me on the way these quads fly.
Ok, if you liked that, try this.
I wanted to fly like this and the only way it was gonna happen was with a mini-quad. In order to do that I was going to have to build one.
Where to start
I think my decision between the QAV250 and the Blackout Mini-H was somewhat arbitrary. The Blackout Mini-H is cooler looking, more expensive and was seemingly less easy to obtain. I also found a great group on Facebook for the QAV250 with an active community, so that help swayed my decision.
I purchased a QAV250 ‘almost ready to fly’ kit from getfpv.com. The term ‘almost ready to fly’ is extremely misleading. What you get with the kit is merely all the parts that make up this kind of quadcopter. You will be soldering, setting up software, hiding wires, counting screws, and just about everything else. You will also feel extremely accomplished the first time it flys.
My quad was on backorder for two months. During that time, I did plenty of research about the FPV system I was going to install, as well as what kind of radio setup and autopilot I wanted.
I chose a Lumenier CS-600 Super camera with a 5.8GHz 32CH A/V 600mW (TS832) transmitter. For antennas I chose the premium IBCrazy 5.8 GHz Bluebeam Ultra Antenna Set. For an autopilot I chose the OpenPilot CC3D board. I was familiar with ArduCopter for the X8 and MultiWii for the Turnigy Micro-H, so I was up for trying something new.
These were all pretty default choices but I wasn’t feeling very risky to start, as my knowledge in the realm of mini-quads was rather limited.
The kit comes with most everything else: frame, power distribution board, ESCs, motors, LEDs, props, hardware. The only other thing you will need to decide on is batteries. I went with the recommended 1300mAh 3s 35c lipos.
For my ground station, I am using my Spektrum DX7s as well as my FPV monitor I use with my X8.
Other items you will definitely need for the build:
- soldering iron
- extra wire
- electrical tape
- outdoor quality double sided sticky tap
- lots of zip ties
- precision screwdriver kit with torx bits
It took a while, but eventually I got all my parts together and began the build.
I think it took about a week to build and test the quad. I followed this video (which is in two parts) as well as the instruction manual. I went really slow as to not make any mistakes, and for the most part I didn’t.
A few things about the build:
- Soldering to the power distribution board is about as easy as it gets. I get nervous I’m going to fry stuff, but the solder points are huge and it’s just really a matter of getting the wires to stick to them. This was a big relief.
- Hooking up the LEDs to the power distribution board is a bit tricky. The wires need to be different lengths for the front and rear. If the wires are too short they won’t reach, if they are too long, you will have trouble securing them out of the way. I held the LEDs and power distribution board up to the frame to measure them out before cutting the wires down. Still, not as accurate as I would have hoped, but it worked.
- When connecting the ESCs to the motors it really doesn’t matter which plug you plug in, you will change it later. I didn’t believe this but it’s actually true. So don’t tie down those wires until the very end because you will be more than likely changing them in order to get the motors spinning in the right direction.
- The ESCs to the power distribution board are a snug fit, I was scared the pressure would break some of my solder points but everything was fine.
- Make sure the power connector for the battery faces out to the back of the quad, I accidentally pointed mine towards the front of the craft at first and had to go back to change it. It makes sense for the battery to sit on the back of the frame, since you will likely place an FPV camera on the front.
- Hooking up the receiver is a bit tricky knowing which wire goes into which port. I would refer to this chart for help. I also happened to find this photo of my particular reciever.
After you have the quad built, you need to initialize and calibrate the autopilot. OpenPilot will guide you through the setup but there is also this really good video to help you through the process.
The cool thing about the CC3D/OpenPilot is that you can set up different PID values in your different flight modes. I used a very moderate stock setup as well as some more aggressive values recommended by Lumenier.
As soon as I finished the build I took the QAV250 out for it’s first flight. It actually flew without any problems. That felt awesome.
In my short experience flying the QAV250, the more aggressive values were too intense for the way I fly. The conservative PIDs are a little too controlled. So I will be tuning them as I develop my personal flight style.
GoPro versus Mobius ActionCam
I own a GoPro Hero 3+ and on my second flight I strapped it to my QAV250. I knew it was going to add some weight to the craft, but I immediately noticed a flight behavior difference. It felt a bit sluggish in the air. On top of that, the video had tons of jello. I was surprised by this because the QAV250 motors are not on the same deck as the camera.
I researched and purchased a Mobius ActionCam. The ActionCam weighs a lot less than the GoPro, has a lower profile on the craft, but probably isn’t as great of a camera. That being said, I got absolutely no jello with the Mobius. It shoots in 1080p and 30fps which is totally reasonable for the type of footage I want to get from the air. Most importantly, after putting the Mobius on the QAV250, I did not notice any obvious flight behavior difference.
This is definitely the quad I was looking for. It’s super easy to grab my transmitter and go fly anywhere. I basically wouldn’t change anything about the setup at this point. I can see why people add more performant motors or batteries to get more power, but until I become better at flying, I don’t see any reason to screw with the setup.
Tuning the PIDs is my biggest challenge. Trying to dial it in so I can get really comfortable with the controls. Other than that, it’s time to focus on flying.