First Flight - First Crash - Some Questions! - Discussions

Hi All,

Took my maiden (outdoors) flight this morning. It ended in a pretty spectacular crash!

Three propellers broken, two arms bent and an engine mount broken. What seemed to happen was that either a propeller failed (snapped) or the propeller was thrown from the engine. Most probably the latter. The copter was drifting away in the wind and developed an instability that wasn't apparent in pre-flight checks. I put it into RTL mode and things went badly and the prop failed etc etc.

I have a few related questions that I was hoping some of the more experienced may be able to help with:

a) Just before the crash, the hexa developed an instability/oscillation. Almost like a plate spinning on a table? This happened periodically. What causes this?

b) I seem have a "chirping" sound coming from either a motor or an ESC intermittently. I cannot identify the suspect. Is this something to be concerned about?

Regrds,

Paul

Paul,

a) I think it means your stabilize p values are just a tiny bit too high, but I am assuming that this happens after you provide input to the hover, by moving the copter - perhaps with a slightly deeper angle - or that wind and movement push it enough such that the movement does not settle but rather increases with each iteration. I would try to lower stabilize (roll and pitch) P by .001 or .002 at a time until you don't see this behavior begin to build after fast/aggressive movements.

b) only a guess, but if the chirping does not sound electronic (a beep) then I'd guess it might be bearings going bad. Noises like this often can be heard in videos just prior to a crash in a quad but then again I also gather that a lot of guys fly without any issues with all sorts of noises coming from their motors. I had a motor making infrequent twitchy sounds on my 3DR quad, I replaced it. But in describing it on another post, other members say they fly with this sound without issue. In other words, I'm no help here (either, if you find its not stabilize p)

Replies

Moderator

Michael Pursifull November 20, 2011 at 5:12am

Paul,

a) I think it means your stabilize p values are just a tiny bit too high, but I am assuming that this happens after you provide input to the hover, by moving the copter - perhaps with a slightly deeper angle - or that wind and movement push it enough such that the movement does not settle but rather increases with each iteration. I would try to lower stabilize (roll and pitch) P by .001 or .002 at a time until you don't see this behavior begin to build after fast/aggressive movements.

b) only a guess, but if the chirping does not sound electronic (a beep) then I'd guess it might be bearings going bad. Noises like this often can be heard in videos just prior to a crash in a quad but then again I also gather that a lot of guys fly without any issues with all sorts of noises coming from their motors. I had a motor making infrequent twitchy sounds on my 3DR quad, I replaced it. But in describing it on another post, other members say they fly with this sound without issue. In other words, I'm no help here (either, if you find its not stabilize p)

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