I have been flying a custom-framed aluminum Arducopter on the Ardupirates code. I took a break for a couple of months and then recently started up again. I decided to switch to the AC2 path, so I updated the firmware with the most recent version of the code using the Mission Planner. I then went through the setup and test procedure described in the wiki, setup the motors, setup the radio, turned on and tested the sonar, and so on. I setup my mode switch to start in "Simple" mode. Thus far in the setup and testing, everything seemed OK.
But when I attempt to take off, the quad is extremely unstable. As I increase the power on the throttle, even before it gets off the ground, I see it rocking rapidly, with small amplitude but high frequency. When I juice the power to take off, it goes up a few inches or feet depending on how much power I give it, but is extremely unstable, rapidly whipping and tilting back and forth in increasingly large motions, as if it's desperately trying to get control but loosing it, and then flips and crashes. This same behavior happened consistently three times before I decided I had a definite problem and I needed to diagnose it.
I've seen various bad flight conditions (backward props, lose motor connections, broken props, etc.), but I've never seen this rapid oscillation and wild instability before.
Does anyone have any suggestions?
1) Sorry. I should have provided more info. I'm flying a + configuration.
2) I thought I selected + during the configuration, but I'll double check that again.
3) I will run the motors test again.
4) I will try this test also.
On #4, I just did a test holding the quad above my head while a friend handled the controls. The quad responded to throttle with lots of wind power and upward thrust. When we moved the roll stick left/right, it responded appropriately, but when we applied pitch forward and back, the quad rolled rather than pitched. Also, when we tried to yaw, the quad tilted quite a bit (where I would expect yaw to be a flat rotational movement, not a tilt).
Did you load the right firmware (quad)?
Have you run the motors test in the CLI?
Shown settings in the CLI to confirm that you're in "+" mode?
It's a setup problem of one sort or another.
Chris, you were right. It was number 2 on your list. I had it configured for x instead of +. Once I changed that in the CLI, it flies very, very stable. Excellent. I'm flying again! :)
Thank you for your excellent advice. I'm sorry I made such a dumb mistake. I'm appreciative of you pointing me in the right direction to find it.