Wagsy

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    • Rotorpix
MEGA HEXI 500 Hexacopter REVO - GPS
« on: July 11, 2016, 10:59:21 am »
Hello world.

Thought it was about time to see how building a large FPV Hexacopter would go with the REVO board and the V9 GPS.
Frame is my own custom design, alloy boom, motor mounts and stand offs.
8.5 HQprops, 1100KV Tmotors, 18amp ESC's, Crossfire micro RX, 4s 4000 Turnigy graphite lipo, Taranas.
Here is the first flight, could not tune out the wobble no matter what I did.
Since speed up the ESC in the GUI.
Seems much better now so fly tomorrow to see if I can get it locked in.
Then will try some rolls and flips in Acro+ followed by installing the GPS so I got a RTH failsafe.

Will post my settings as I go, its like flying a Airbus A380 :-)
First wonkey video from today.




Re: MEGA HEXI 500 Hexacopter REVO - GPS
« Reply #1 on: August 04, 2016, 08:16:28 am »
Did you get this fixed?  Would you call it jerky rather than a regular oscillation?

I had jerky issues and found that my FC anti-vibration mount was a major cause.  Before figuring that out, I found that increasing GyroTau (Stabilization -> Expert -> GyroSomething?) helped a lot, but also slowed reaction down and required retuning.

AutoTune is now part of next, and reducing the DerivativeFactor (maybe all the way from 1.0 to 0.0) also helps.  No need for a second tuning flight, just reboot and "re-export" your PIDs with SmoothQuick.  SmoothQuick itself is great for finding the right PIDs that you like after the AutoTune "shaking flight".  See the AutoTune wiki.

Wagsy

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    • Rotorpix
Re: MEGA HEXI 500 Hexacopter REVO - GPS
« Reply #2 on: August 04, 2016, 08:46:43 am »
Hi.
I actually gave up on this project and tore it apart to make the QUADI 400 using the 1100kv motors and props.
Figured compared to my other smaller HEXI's there was not much point.
I did try a huge range of different PIDS, just would not fix it no matter where I tried them.
Don't think it's FC vibration, the other two REVO HEXI 350's with 2000kv and 2300kv motors - 6 inch props fly great.
It might of been the 18 amp ESC's as they were different to my other HEXI powered ones
.
Anyhow built and flew it, flying time was not the best with the 4000 lipo so it's no more.
But the QUADI 400 I built with the bits fly's very nice indeed. :-)

Will have a look at the auto tune thing to see how it works. Cheers