Monday, March 17, 2014

Tunning our new DJI phantom with 9.4 inch props

We have added another toy to the inventory that seems to be a basic phantom without the camera but a newer version of the phantom with the bigger 9.4 inch advanced props that now come with the new phantom 2. But this one still uses the original battery type so it's some kind of hybrid of half phantom 1 and half phantom 2 I guess.

My first test flights from the balcony of my condo, I noticed a bit of instability and some 3 Hz wobble oscillation that didn't seem normal to me. I did some research on gain settings to see what was needed to correct the small problem. When I hooked up the unit to the assistant software I noticed it was running the newest versions of Naza M V2:
phantom s/n 4
hardware firmware
main controller 4.02

I also noted some differences from our other 3 phantoms that must be the older models that use ppm instead of what this new one uses D-Bus on the receiver settings. Also I don't recall seeing the receiver firmware settings in the older units but maybe that's part of the new naza M assistant software that is now version 2.20 that I used to view and change settings with on this aircraft. I was running naza M assistant software version 2.18 on our older units. Also our older Phantoms have the stock 8 inch props installed.

All test seen here are run indoors in my apartment off my bed.
in atti mode unless specified other
these tests were run on phantom s/n 4 with the new V2 9.4" props
I used this link as a reference
in making any attempted changes from what effects were seen.

All gain values bellow are in order as seen in assistant software as
basic: pitch roll yaw vertical
attitude: pitch roll

original settings when we got this aircraft from the shop
125 125 100 125
125 125
with the original settings I noted oscillation when flown on the balcony from wind turbulence without any stick input that at times become a bit scary
, with as much as 2cm roll and pitch osc without any stick input from just outside wind turbulance effects

Today first tried with these values
140 140 100 125
140 140
with this we still have high speed oscillation but tolerable with very fast pitch roll movement when flown indoors.
not sure how stable this would be in windy turbulent conditions or in rapid descent, but I might give it a try
outside later.

140 140 100 125
90 90
OK no osc but slow handling

170 170 100 125
90 90
OK no osc but still slow handling pitch roll

190 190 100 125
90 90
still the same slot pitch roll and also note that slow to go back to center
as I'm sure was same above but
didn't notice till this try.

120 120 100 125
200 200
in this setting I get very fast return to center and still controllable indoors (a bit scary fast for indoors)
I also note that when I give quick pulse of roll or pitch that I see oscillation of 3 cycles of overshoot but only about 1cm or less before it dampens
so I would assume that means that attitude at this setting is a bit too high?
But this is also what I was told is the default settings from the factory in Phantom V2. But the V2 have bigger battery and must be a bit heavier so need more gain to compensate I would think.

200 200 100 125
95 95
has some improvement in response but I still note some overshot in quick pulse of roll pitch that dampens in about 2 cycles
and is very small over shoot of less than 1cm at the aircraft lifting tips.

200 200 100 125
90 90
same as above still over shot with dampening at 2 cycles

tried this outside on the balcony on the 12th floor
180 180 100 125
90 90
flies OK stable without any noticeable oscillation
even with rapid decent from 20meter above launch had only expected roll pitch wobble of about 2cm at tips probably from prop wash
. it doesn't seem quite as responsive in roll pitch as the other phantoms in our inventory with slow to break on center stick when flying at high speed
also seems to hold position in both altitude and lateral outside in gps mode very well. stayed within 1 foot in most cases
I'm ready to give this a try at the beach. but I might also try the 140 gain at some point outdoors also
I'm guessing that with this slower response time will also act in favor of longer battery life without high speed feedback in motor pulses
also probably a better setting for camera applications (better than fast mode) for smoother movments.

Last try outside today
120 120 100 125
190 190
I flew this outside on the 12th floor balcony and find it not as stable in many ways
I think there was a bit more wind on this flight so maybe not a good compare.
But on rapid decent it had big wobble oscillation that got very scary to a point that I had to decreased my rate and in fact I would only take small steps as I took the aircraft down.

I've now returned the settings to my present favorite for these conditions
180 180 100 125
90 90
These settings will now be tested at the beach to see how that goes.

Update May 1, 2014
We have continued to have intermitent problems with this aircraft and are now trying another set of gain settings in hopes to partly correct some of the problems:
Pitch Roll Yaw Vertical
180 180 100 125 Basic Gain
90 90 Attitude gain

changed to:
Picth Roll Yaw Vertical
120 120 80 115 Basic Gain
95 95 Attitude Gain

As some of the problems seem to happen when we do radical quick stick movements I'm hoping that the reduction in basic gains might prevent this from happening. Also a slight increase in attitude gain might improve correction times. Without high Basic gains the small increase in Attitude gain should balance out and hopefully still not cause oscilation problems. I've also had problems with one crash from a quick decent that put the aircraft into an unrecoverable spiral so I'm hoping the reduced vertical gain might lesson that happening again.


  1. Hello!
    Thank you for your article.
    Tell me, please, what the final results?
    Did you find the perfect performance?

  2. hello

    Super info.
    Only I want to know also the final result of the gain settings..
    Greets from the Netherlands