Hoppin' drone
« on: June 24, 2019, 02:02:15 pm »
I'm mostly a fixed wing builder, but I have a quad too (450 frame, 2216 1250kv, 40A BLHeli LittleBee ESC, 1046 prop, Revolution FC, Ublox GPS/Mag, 10ch RX, 2-4x 2200 3s).
The problem I have is that when setting up, the motors spin up very easy at a low rpm.
But then, when I actually try to fly it,  any initial throttle makes it jump, rock and wobble. Motors spin in the right direction. Props are right side up.
Some times it suddenly works as it should (imho). Motors run evenly and spin up to lowest rpm and stay like that untill I throttle up. Most times however, one or two motors seem to lead their own life and run (much) faster at initial startup or they spontaneously stop running. It's not the same motors all the time, so I ruled out ESC's and motors.
I'll try higher startup revs, but in the meantime ... any suggestions are welcome.

Running LP 16.09 Next

P.S.: Mode 1= Stabilized no GPS Cruise, but I fly with GPS and Vario. Makes no difference in hopping at start up.
Aux Mag only <5% Orientation is correct (000-180-000). Cables are twisted. GPS is on a 35cm pole and at least 25cm (10") from any power source but it's own and >30cm (12") from the motors, ESC's, etc.
In flight it is stable. Pos. Hold works. RTB works. It's just a bitch to get it off the ground.
« Last Edit: June 24, 2019, 03:14:31 pm by Penthane »
If it ain't broke, don't fix it! But I can't seem to take my own advice ;)

Re: Hoppin' drone
« Reply #1 on: June 24, 2019, 10:54:10 pm »
If the main problem is that it is hard to get off the ground then I recommend these from:
Fix Instant Flip and Learn to Fly
https://forum.librepilot.org/index.php?topic=4408.msg29978#msg29978

- Stabilization->ZeroTheIntegral must be enabled.
- Do not "help it stay level" during takeoff.  Use just the throttle to "jump" up to knee high.  Do not move any other stick.
- Do not take off from the side of a slope.
- Take off quickly, as soon as you start the motors.  Do not slowly increase motor speed.  Jump up to knee high.

There good are reasons for each of these.  They are mainly related to "I term windup" is worse if you disobey them.
« Last Edit: June 24, 2019, 10:59:58 pm by TheOtherCliff »

Re: Hoppin' drone
« Reply #2 on: June 25, 2019, 12:38:49 am »
Airborne the drone is fine. It was only takeoff that gave me problems. Seems I didn't know how to fly  :o  I'll try better  ;D
If it ain't broke, don't fix it! But I can't seem to take my own advice ;)