These are the issues I experience with my APM since setting it up as it compares to my $27 multiwii board:
It flies terrible!! I've spent an hour tuning this thing and I'm back to square one. This quad is dynamically balanced for aerial filming so vibrations are not the issue. When I takeoff, the quad pitches hard to the rear of the quad. So I thought, hmmm, lets calibrate the ESC's. Did that, same exact thing is happening, no difference. Once it gets up in the air it will level out after a few seconds and hover just fine. Multiwii board is perfectly level from takeoff to hover with 0 tuning. Everything in mission planner looks perfect.
Second: It just flies bad compared to multiwii. Feels mushy and twitchy. On forward flight it pitches hard to the rear when I try to level it out. Is the APM not capable of flying a quad that is not balanced from front to rear? It just seems like the fact my battery is in the rear of the quad that it just messes it all up. Multiwii flew rock solid, level it out mid flight and its like it skates across the air level. APM just seems incapable of this.
Anyone shed some light on this? I'm most annoyed by the fact that it seems so effected by the fact the battery is mounted in the rear of the quad (NEX N.E.O Frame). Do I have any hope of this thing taking off straight up into the air without pitching and yawing? I don't care about the APM being able to loiter and RTL if the thing can't even fly remotely like the cheapest multiwii board in existence.
Any help would be appreciated. Or response from people who have had similar issues.
Replies
I personally threw my cheap multiwii away. Heck it would do OK for a short time but then would need to be landed to reset "level". It would then fly normal again for a short period then need to be landed again. It did NOT have the newer "mems" chip. My APM 2.5 has been nothing short of amazing and IMHO even exceeds the performance of the much more expensive NAZA. I will confess that it took way more than an hour of tuning to get there, more like several weekends of hard work, but hey, it was worth it once I saw what it was capable of. The APM is not just a simple stabilization board but rather a complete "Auto Pilot" with way-point capabilities, Altitude Hold, GPS loiter, GPS Return to Launch, Auto Land and much more.
Randy (An Arducopter developer) has made a video of him flying his and it is quite impressive. A link to the video of him flying is here on DIY as are videos showing how to properly tune the APM.