Discussions

I've spent the last few weeks building my first multicopter.  I've ended up with a fairly stock arducopter setup.  I had intended to load the ardupirates code but coincidentally my build was wrapping up just as the new ACM code was becoming available.  I have done all my first flights on ACM 2.0.x.

My setup:

Arducopter quad frame in + mode

KD A22-20L motors

HK 30A Blue ESCs

Turnigy 2650mAh 3s 30C lipo

Turnigy 9x tx/rx

EPP 12x47

Last weekend I had my first real flight time and I collected some notes that may or may not be useful to others.

Take Off / Flight:  

• I spent a lot of time trying to stabilize my quad at knee level.  18-24" is just not high enough to get out of ground effect consistently.  As soon as I got up to about 36" I was able to stabilize much more effectively.
• "STABILIZE" mode seems to be something of a misnomer.  I hate to admit the naivety but I really expected to be able to apply some throttle and have a stationary quad hovering in front of me.  I had to apply quite a bit of roll and pitch adjustments during and after takeoff for a level quad and to maintain position.  The level of control required varied and highlighted the level of skill I had previously seen in every $%&@ flight video on youtube.
• None of manuals or wikis seems to go into trim adjustment.  Being new to R/C as well as multicopters this was a foreign topic to me but some R/C types clued me in and I seem to be making progress.  
• The turnigy 9x has a digital trim that appears to be an overly coarse adjustment.  I could go from very gentle clockwise yaw click the trim once and be in a gentle counter clockwise yaw.  I suspect this is configurable sensitivity to be explored this week.
• Bullet connectors really are bad.  I built with a large number of bullet connectors.  I have high confidence in my solder connections but I've seen these bullets connections fail several times.  They have to be rechecked before every flight.  I'm going to remove them and go to full soldered connections asap.

Crashing:

• I've crashed enumerable times in widely varying configurations.
• The arducopter frame has proven remarkable resilient.  I was very skeptical of the polycarbonate frame pieces.  I have crashed upside down, spinning yaw, etc and have yet to damage any of the expensive components.  
• The frame pieces most likely to break, in my experience, are the upper motor mounts.  In an upside-down crash I crack these at the point they overlap the aluminum.  The long metal screws that go through both motor mount plates and the arm bend in this scenario as well.
• I had previously purchase a spare frame set using the ponoko site and full frame design.  These parts have worked wonderfully but are different than what you buy in the kit from diydrones or jdrones stores.  The parts are acrylic rather than polycarbonate so slightly more brittle but very usable.  Also note that while 3mm is the right size for most parts the upper motor mount in the 'official' kit is 5mm.  The 3mm seems to be acceptable replacements.
• The nylon screws and nuts that attach the dome to the legs are very susceptible to vibrations.  I've bent a couple and just lost a bunch.  Jani's assembly videos emphasize hand tightening as sufficient here but I think some locktite may be necessary.  

Code:

• I am running on beta ACM 2.0.x code using the latest mission planner.  Very good progress but still noticably 'beta'.  
• I can pretty routinely crash the mission planner under windows XP.  It uploads the latest code to the arduino board without issue.
• In many open source projects I've worked with they advertise a 'stable' beta version and a 'bleeding edge' alpha version.  At my level of expertise there is no reason I should be on the bleeding edge as I'm not going to reliably recognize the source of an error be it in the code, hardware, or sticks.  I would like to recommend the team publicize a stable beta version and allow the mission planner to track that version as well as the true latest alpha.

Safety:

• Pulling it all together - after one spectacular crash with broken motor mount I went to lift the copter and bumped the throttle.  WHOOSH.  I had neglected to disarm the motors.  Nice prop gashes up my right arm.  I think I won't forget that again any time soon.....

Maybe one or two of the above will help somebody else out!