As much as I wanted the Alien 680 H4 I’ve been flying to work out, I’m not happy with it.  I’ve gone through quite a bit of work trying to get this frame to fly well but it just doesn’t.  I’ve started ripping it apart today and have a new, different 680 Alien folding frame ready to build.

Alien 680 Quadcopter

The good part about this frame is the K shape which puts the camera even with the front two motors.  That helps keep props out of the photos/video.  But because of that design, the battery needs to be put way back to counterbalance it.  That means most of the mass is NOT in the center of the bird, where in my opinion it should be.  As a result there are some funky things that happen when flying.  The bird looks almost like a teeter-totter in wind.  When stopping or slowing it is not smooth and I worry about it flipping in the air.  I’m thinking the frame and the mass distribution is the issue and surely hoping that it isn’t the MiniX flight controller.

Soon I’ll be sure.

I’m willing to try out a new, more symmetrical frame with the same hardware. That frame has already arrived and I hope to have Alien 2.0 flying soon.  Naturally I’ll post a build log.

I’ve been quite irritated with my carbon fiber landing legs I came up with for my Alien H4 680mm quadcopter.  The legs are on servo-less electric retracts which I have assigned to a channel on my transmitter.  I can put the gear up or down during flight.  That’s cool, especially with a 3-axis gimbal for the camera.  It keeps the legs out of the photos or video.

The problem I’ve had is with the 6 millimeter carbon fiber tubing I’ve used for the legs.  Those tubes wrap around the 4mm “trunnion” which comes out of the retract.  When taking off, landing, or working on my quad the legs take a beating and over time crack.  Just two days ago two legs snapped in grass as the copter shifted laterally during takeoff.

Lucky for me I have a cousin who has a machine shop.  I had him make me up some aluminum landing legs.  They have a 4mm section which replaces the trunnion, then expand to 6mm.  The “shoulder” between the 6mm and 4mm supports most of the weight, and the aluminum is MUCH stronger.

Yes what about the weight difference?  Each leg of the carbon fiber landing legs with trunnion and rubber cap was 7 grams.  The new aluminum legs with rubber cap are 15 grams.  I’m adding 28 grams to the whole bird with this upgrade.  Not terrible.

Below is a video of the old CF retracts in action.

After hours of trying to reduce vibrations in the Alien H4 680mm quadcopter drone, I’ve decided to order two new motors.  I’ll be replacing the two motors on the rear of the craft.  Despite all the attempts to balance the motors, especially motor #3 (left rear), I’m taking a guess that one or both of the motors are damaged from the crash, or even perhaps the first flip.  The vibration is practically visible on motor #3.  I can see the landing gear visibly moving.  Touching or even getting close to touching arm #3 “tickles.”  It is obnoxious and no wonder I can’t capture any decent video.

Two new motors are on the way on the slow boat from China.  I will balance them before installation, which I should have done before.  Once the new motors are installed I’ll tear apart the old ones and check to see if the bearings or the prop posts are broken or bent.  That would cause the vibration problems.  If I can fax them, then I’ll have a couple of extra motors.