phokur.com: Ardupilot FPV Quadcopter

If you read my previous post on my FPV Syma X1, you'd probably guess it was only the beginning. You would be right.

I started building a quad on a Hobbyking SK450 around Christmas last year. Initially I wanted to make a simple, cheap quad to learn to fly on. I built it with all HK parts with motors being the exception. I've learned through others that cheap, wobbly motors cause most issues with these quads. So I sprung for some CarbonBird motors from MultiwiiCopter. I slowly built it over six months or so and used a cheapo HK KKBoard clone as the flight controller.

After some software tweaking she finally flew. It was not the easiest thing to fly as almost all of my experience came from fixed wing. It made me reluctant to fly it, especially since this is my most expensive RC model. Around this time I found the Syma X1 which was the perfect trainer for me to learn on and the big quad got put on the shelf.

Between my X1 practice sessions I started helping a friend work on his Ardupilot controlled Bixler. After the maiden I knew what I wanted to do with my quad.

I decided to go with the HK Ardupilot 2.5 clone since I knew anything on a quad is not long for this world. I added a HK UBLOX GPS, HK telemetry module, HK video transmitter downlink, and eBay 808 v2 720p camera. All powered up with the video transmitter on board.

The command and control Mission Planner software with all systems running. (No GPS link since I was indoors.)

I wish I could have caught the maiden of this beauty but the microSD card ejected itself mid-flight and was never seen again. It seems MissionPlanner defaulted the flight speed to 100mph. So that first flight was kind of... intense.

The second flight went well, I hover-held over my parent's house. Got some decent shots of the Patuxent River on a gloomy, overcast day.

We had a freak warm day on Halloween this year. Knowing this would probably be the last nice day before winter, I decided to give waypoint navigation another try. I tweaked some settings and went to Saint Mary's College of Maryland (SMCM) since it's the largest publicly available field I know of. The quad flew beautifully! It navigated waypoints smoothly and held point even with the light gusts of wind. The video is worth a watch.

If you watched the video, you're probably wondering what happening. I was wondering the same thing as I numbly gathered pieces not even expecting the camera to still be filming. The last frame is my surprised face that the camera was working (its case was split apart) and then excitement that maybe the cause of the crash could be revealed.

After some "video analysis" (frame-by-frame in VLC) I found some really spectacular stills. Especially in those moments of flashes on impact. But first, I present a UFO right at the beginning of the tumble. I have no idea what it is. All wiring was accounted for and attached, so that isn't it. Maybe a bug?

Next we see what caused the unfortunate accident.

Yup, that's one of the four very important propellers branching off to try flight on its own. I assume the cause was the prop adapter loosened itself during the jerky corrections when fighting the wind 50 meters up. The trailing edge of the prop had a chip out of it. Only the leading edge should chip if it was spinning in its rightful place. The prop likely got nicked by another prop before fluttering away.

With that closure I can begin my grieving. I got some nice orbits before it hit, so that helps a little. Also, the destruction is interesting to watch. Keep in mind this is frame-by-frame at 30fps. This happened really, really quickly.

You can see the moment of impact and first bounce. The camera takes a slightly jigglyer image than usual and you can see it abandoning ship in the next image. Now for my favorite part, the quad takes a selfie!

And that was the end of the quad. A majestic flight turned horrific with a single $2 part failing. Today, the quad spends most its time in a pile on my desk.

But I will not forget the experiences it gave me in its short life. Let us remember the quad as it was, in its prime. Taking beautiful photos at a perspective I would otherwise never have seen.