I’ve been fairly satisfied with my second frame for my Alien 680mm Quadcopter. The “Alien” frame is a foldable design, meant to be more portable and easy to transport. Unhappy with the first frame I purchased, I picked up a second one and transferred all the parts. It has been much improved.

Part of the catch with my new frame is the foldable arm mounts were weak. I ran into some issues trying to level my motors and noticed that the arms were not level with each other, and were actually sagging. There was some play in the arms, vertically and horizontally. Imagine how messed up that could be in flight with arms moving up and down and the flight controller trying to compensate. And over time that play in the arms would certainly end up in an arm failing.

Notice how much play there is around this clamp? Bad bad bad.

I took a look at the old mounts which came on my first frame, and those happened to be more solid, by a long shot. So I ripped apart the bird and replaced the weak arm mounts with the more solid ones from the old frame. The difference is remarkable. My bird is much more stable and the video quality is better. I will have to mod the folding clamps a tiny bit but that’s not a big deal.

Left: the better 16mm arm mount
Right: The weak one which was removed

It’s nice to have an entire extra frame of parts to pick from when building or tweaking a build of a multirotor copter.

Strange behavior in my Alien last night. Finally tried a test flight of the new setup with my gimbal mount forward and battery back a tiny bit. This is to attempt to get the props out of the video/photo frame.

On take off my bird would not yaw clockwise, only counter. And it would not hold position. Luckily I was able to land it without doing any damage as I had minimal control. I recalibrated the GPS/compass but still issues. A look at my motor outputs (photo below) shows the clockwise motors are at a much lower output than the other two.

Because of this event I decided to upgrade the firmware on the MiniX flight controller and will probably go through all the stick calibrations again.  More testing soon.

This weekend’s project has been to change my 680mm Alien quadcopter frame to a different one in hopes the different frame is better engineered.  I wasn’t very happy with the design of the old frame and the quad flew very poorly in my opinion because of the way the weight was distributed more toward the front and rear of the UAV.  The concept of the old one was cool, to get the camera more front, but the mass of the battery had to be put way in the back.  This made flying it in anything other than dead calm a teeter totter ride.

New Alien Quadcopter 680 Frame Flies!

The process required ripping the old Alien quad apart and moving all the components/wiring/electronics to the new frame.  That took a couple of partial days to do.  Much of the wiring was custom cut and soldered, so that had to be undone.

The new version is lighter so far.  I’ve decided that though it is cool, I’m not going to put the old retractable landing gear on the new frame.  The new frame came with some very cheap, but super light gear.  That gear also has some finger nuts which allow it to be take off and put back on very easily.  That’s part of the point of this bird, to be able to compact it down to something easy to transport in a backpack or on an airplane etc.  I will be weighing both sets of gear to make a note of the difference in grams.

Today’s maiden flight was a success! IT FLIES. Too windy to do much else other than launch it a few feet.  It was very squirrely due to being lighter and the wind conditions.  The gains are set for a heavier load.

Quadcopter test hover…

Next Steps

Now that I know it flies, I’ll be taking it into the shop again to install the camera gear.  I’ll be putting the old FPV (first person view) camera setup on it, along with a 3-Axis brushless GoPro gimbal.  Hopefully by the time I get that stuff installed the wind will have calmed and I can do more test flying later today.