First Flight - Recalibrate? Replace Props? Battery charger.

Hi Iris+ people,

  • Before my first flight I updated the firmware, and recalibrated the ESC, Compass, and Accelerometer.Followed the 3DR Youtube vids.

So my first flight went well, but I called it quits as I thought the wind was too strong.  It was gusting at around 15mph.  Just seen a YouTube vid where some guys fly in +- 30mph winds! 

I figured the wind was too strong, as the Iris could not hold a steady position in Loiter, although it did seem to try.  However, there was no gimbal or camera attached. The Iris also flipped during a take off, but maybe I just need to be quicker taking off as the wind seemed to upend it and the feet would catch on the grass.
One of the props was slightly bent during the flip.  Very slight bend, but I can feel it.  Should this prop be scrapped?  I'm guessing yes, but it never hurts to check!

Any thoughts, comments about flying in the wind?  Things get pretty gusty up in South Dakota.

Lastly, the long wait for batteries to charge!  I've been looking at some options for a better charger.  Would anyone care to recommend something? Preferably less than $100.  Would it be possible to charge more than one battery at a time, for this price?

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Replies to This Discussion

Hi There,

scrap the bent prop pronto! :)

choose a less windy day for your initial flights to avoid damage to the IRIS.. its NOT very powerful especially WITH the gimbal and camera and stock props..

especially watch out for the high hover throttle when fully loaded  on stock IRIS+ 9"  props(especially in wind).. somewhere between 68-73% according to xcoptercalc

The IRIS/IRIS+ comes calibrated and RTF.. nothing needed to be done...

          enjoy your new IRIS.. they are loads of fun!!


I don't consider myself and expert, but here are some quick thoughts:

  1. Bent prop.  I would replace it.  You won't get steady flight out of your Iris+ with a bent prop.
    When filming I use only pristine condition props.  I do keep around some scratched up props as backup, but never a bent one.

  2. Take off.  Try card board, a plastic sheet, a dirt patch.  Grass can catch your legs.  Pavement is perfect.  A lot of guys take off from their plastic hard case. If its windy, once you are ready to take off, go for it.  Full throttle.  You can back off quickly and just hover at a few feet above ground, but don't mess around trying for a slow gentle takeoff in the wind.

  3. Flying in the wind.  I feel totally comfortable up to 15mph winds but I have flown in much stronger wind and been just fine.  Since I'm mostly shooting video, I try to avoid strong wind as it leads to vibration.  I suggest you avoid song winds, at least until you are really comfortable with all the features and quirks of your Iris - especially the fail safes and how to override them (you don't want your Iris darting off in an unexpected direction because of a fail safe and not know how to regain control).  Take some time to really study what happens when you breach your geo fence and how RTL is supposed to work.  You may want to tweak the parameters associated with those.

  4. Fast chargers. There are chargers out there that will charge your lipo faster, but they also shorten the overall life of the battery.  Some guys actually deliberately "trickle" charge their lipos - slow but longer life.  I would think about investing in more batteries.  If you do, just try to keep track of how many charge cycles each battery has been through.
+1 for everything Erik said, with a couple of comments:

1. Bent props. I have successfully straitened SLIGHTLY bent props with the help of a hair dryer with no noticeable increase in vibration, but I would just use them for back up in an emergency.

4. Fast Chargers. I use one of these:

I have had it for a month and am very happy with it. Most recommendations I have seen are that you not exceed 1C charge rate. For a 5100 mAh battery that is 5.1 amps. I set my charger for 5.1 Amps max and it never actually exceeds 4.5 Amps. It takes about 1.5 hour to fully charge a battery, including balancing, that has been run all the way to the "Low Battery - Land" fail safe, about 10.4 volts. It does not heat the battery noticeably.

I actually did straighten the bent prop out, and it flew just fine!  Still, it is now relegated to emergency duty.

Thank-you for the charger recommendation! I would rather have to buy batteries more frequently than have to wait as long as the stock charger takes.

Now if I could just get the telemetry to go a bit further.

Hi Global,

    I wound up breaking all rubberducks I had to see what was inside.. only in the case of genuine 3DR rubber ducks did they contain attenae elements appropriate to the frequency stated.

All of the antennas for 433 and 915  from other suppliers I had were really 2.4 ghz rubber ducks instead.

(I was only getting about 1/2 k away before telemetry went down)

I wound up using coil loaded 915 whips from range video aboard and a HG908P(8db patch) on the GCS end and get solid telemetry to the distance I have been flying(about 1-2 kilometers from launch.)

I suspect the system will  operate at far greater ranges given one end is airborne but dont have  access  to a large test area immediately and in craft rebuild since fridays crash.

      hope the above helps




What caused your crash?


See issues 1951 and 1952

I would NOT follow  recommendations of a backup RCTX powered on and in the stick switch settings it needs to be for arming from the tower app STAB mode with throttle = 0.

at that point ANY RCRX error will cause the RCTX switch settings to be newly noticed by APM(which in this case are STAB with throttle 0 and the craft will come sailing out of the sky at no power :(

its been suggested that FS_THR will keep this from happening but it comes out of FS and seeing the backup RCTX with the CRASHME setting(STAB THR=0)  and does exactly as commanded given APM is not locking off RCTX xmissions for disastrous mode changes when the Tower app is in control(or ANY GCS actually)

For now the ONLY way to avoid this is to fly with the GCS app or the RCTX but NOT both... or to remove stab mode from the RCTX switch config(and with no throttle kill NOT advisable at this point)..

Also with GCS only again NO throttle kill at present.. so really tablet/GCS mode unsafe at this point unless RCTX switches are manually reset after arming and that again will be seen by APM and perform an inappropriate mode switch, hopefully on the ground.. sigh.. just cant win some days

the flight if you want to play it back is on

basically we need an analogy of file locking semantics so that only the GCS in control can command a disastrous mode change and a STOP button needs to be provided in the Tower app for engine kill for Tower only flight... and then the backup RCTX can be used safely...


ps the core developers may or may not agree with the above :)

WOW. I have tested taking control away from Droidplanner with the TX to STAB mode but I always put the throttle stick to center first.

Thanx for the info. 

Sorry for hijacking the thread guys. When a guy like Hotel has a bad crash there is usually something to learn.


My first thought on hearing the RCTX beep was.. I wonder if they have flight console locking  semantics of any sort on RC RF errors when I heard the motors go to zero...

and of course the RCTX was NOT in hand and only the GCS tablet was ,10-20 meters didnt leave any time to grab the RCTX and bring up to hover throttle..



Would this work with such a charger? 

Parallel Charging Board:

That will work but will increase the charge time for each battery added.  Two batteries would double the charge time unless you increase the amps.

In this configuration the batteries will try to even out so that all of them have the same charge.  So plugging in a fully charged battery will charge the other battery to somewhere in the middle without the charger plugged in.


Hi Global

Quote: "Would this work with such a charger?"

Not really, the charger in question is only rated to 6 amps, so you might be able to charge two batteries but it would take as much time as the OEM charger. To charge 6 batteries at 5.1 amps each would require a charger rated at at least 30 amps. You are talking a lot more money for that one.


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