Loiter dangerous behavior

Hi you all.
I’m new to arducopter drones, and drones at all…

I’ve built a Quad, using APM 2.8 Board (non-3DR), M8N Gps, 470kv 24p motors, 15x5,5 CF props, and tarot 650 CF frame, all running on 4s 10.000mah and turnigy 30A Plush ESC.

In the beggining all worked fine, i’m started to learn how to pilot the Quad, using stabilize and loiter. obviously loiter resulted more attractive because was hard to me maintain altitude when making horizontal displacement in stabilize…
some day the quad started to toiletbowl and i got scared and did everything wrong and crashed at high speed to a 25 meters tree, cutted off some branches, and fall down. Result: 1 broken arm, 2 wasted props, and complete landing gear destruction. apm and gps was scratched too.

recently i fixed the aircraft, and this time I DID COMPASSMOT (not done before!), to avoid toiletbowling. I mounted APM with 4 3M slow response foam earplugs in a double plate, and sticked to APM and frame with double-doublesided foam tape.
In stabilize is rock solid, but alt hold and loiter works weird…

in loiter, when you let the quad hovering, it twitches the throttle, like an angry bee, i don’t know how to explain. it’s like the quad stops and re-run motors for a fraction of a second, and looses about 2 or 3 inches of altitude and go up again. its like a glitch. I tried to fly loiter anyway, was making squares about 2 meters above ground to practice, and suddenly… quad rocketed up in the sky… this time i was ready, and switched to stabilize. the quad started to fall, and with a throttle punch it leveled again, but at an altitude i never used it… so i decided to switch to LAND mode, and the quad suicided itself drifting away and descending too quick. this time: 2 more props wasted, and a crack in the lower main plate. gps stand was destroyed as usual…

i spended much money to start my aerial filming project, and i do not trust this aircraft to hang a professional camera on it. i thought it will be like a phantom, but bigger, nicer and stronger, capable of carrying a full dslr camera. But it is only a big and dangerous machine, and i’m hating it so hard.

i will leave you the last flight logs. if somebody with experience and expertise give me a hand and analyzes my logs, i will thank you very much.

i can only think i have a vibration issue, so i ordered a moongel pad to reinforce damping.
The big problem is i’m in Argentina, and any replacement part or upgrade takes a month to arrive, and a ton of paperwork to claim it in customs…

looking forward to fix this, and sorry for my neanderthal english.


i found this. Looks like throttle out is getting crazy when i switch to loiter.

Log shows you were flying in loiter, then dropped the throttle to 0%.
Very quickly after that you change mode to Land, RTL and back to Land. The throttle output goes up in response to the RTL command.

You raise throttle to 35% and swith modes to Loiter then Stabilise and then raise throttle to 80%
The barometer says the altitude didn’t go up until the RTL was engaged though.