Ok, so I just had my first test flight with my Iris with my new FPV system. A list of my components can be found below. I started by loading the parameters from AP Flight planner to adjust for my gimbal and go pro. Took IRIS to the park and there we went. I soon noticed IRIS was not achieving her usual altitude height. I thought this was strange but kept on. Around 9 minutes in, she just started falling, not free falling but losing altitude too fast. I tried switching out of loiter mode to manual and every other mode possible. Crash! She hit the ground. Luckily, I was only over a park field and only one gimbal leg broke. Everything else seemed fine. I still had video connection, OSD settings were on display, green light was flashing for GPS signal, so I wasn't too worried. I zip tied the leg back on and tried to take off again after a safety check. I accelerated the throttle and Iris would not get off the ground. I was going to try replacing the battery with a fresh one but rain set in. I don't think it will help but hopefully it will. Either way it doesn't give me an answer to my problem. Why did she come down so fast and without warning? This actually happened to me one time when before I even had any of my new components for the FPV system. 3DR has been no help. Does anybody have any ideas I could trouble shoot? 

3DR OSD board

3DR gopro cable

3DR video transmitter

Tarot Gimbal with go pro hero 3+

2 cell liPo battery for video transmitter

The OSD board is attached to the right of the Pixhawk (not touching any other components) 

My video transmitter is on the underside of the back right leg antenna down

2 cell battery is on the bottom of the battery door

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  • Your log is somewhat corrupted. The battery voltage reading is anyway. On the Pixhawk you have to read the logs directly from the SD card unless your are running 3.2 which is still in testing phases. If you download them via Mavlink you will see numerous anomalies.

    The first time your copter started losing altitude with full throttle out the RCOU Chan1 value was maxed out at 2000 while the other three channels are cutting back to compensate. The RCOU Chan1 values are the output magnitude from the flight computer (Pixhaw) to the speed controllers. RCOU Chan1 is the front / right motor.

    I have an Iris and it does that same exact thing with the full gimbal, legs, camera payload. It can happen at voltages as high as 11.2 volts depending on the weight/power ratio of the battery. The IRIS is extremely underpowered for what you are trying to lift. 3DR couldn't help me at all. Went through numerous troubleshooting sessions to figure it out. Funny part is they know it's underpowered and never told me but I eventually figured it out using Xcopter calc. They didn't even run the numbers before they put out the Iris.

    The second time your copter started losing altitude with full throttle out, all 4 RCOU channels were maxing out which means you voltage was way too low. something is wrong with your log not allowing the voltage to display properly but I can see continuous current draws of 30 amps. I can assure that a stock Iris will not hold up to that load. I have over 400 flights on mine. Even if you went 4S with smaller props you dealing with a very inefficient motor.


    • Great assessment! (with my 8 months of r.c. flying) lol
      Mark have you done anything to upgrade your Iris or any recommendations?
      I keep asking if 3DR has any upgrades coming for the Iris like the "PLUS" that was featured recently... and I get zip.
      I might be considered a renegade or blacklisted for openly complaining about Iris weight/ bad batteries/ moderators that omit questions or give answers to stuff they don't even own or have experience with. Anyway I digress, I value a fellow Iris owners opinions and suggestions much more.

      Thanks again.
      • I spent months try to figure out how to reliably carry the gimbal and go pro and was never successful. I installed a mast for the GPS to get rid of all the random problems caused by interference from having the GPS/Compass inside the compartment. Other than that I fly it several times per week. Right now I have about 80 consecutive flights with zero reliability issues. Once you get the Pixhawk parameters right and do preventative maintenance it can be a good bird. I spend a lot of time just flying in stabilize or sport mode. Even acro a little. with no payload it can really be a fun bird. Also do a lot of auto missions for reliability checks. I will use that exact set of electronics and configuration on the new bird I'm building. I do plan to add FPV to the Iris for testing but it will only be a chip camera. GoPro is too much weight. 

        I do mount the go pro directly without gimbal when I need to film something.

        Instead of upgrading the IRIS to 4S (still marginalI am building a bird from scratch using a Tarot 650 frame with 6S batts and high end T-Motors. I'tll be a 30 minute bird with payload but the motors and speed controllers alone will cost almost as much as the Iris.

        A few important things I've learned:

        1) The Iris is not a toy. The PIXhawk and all of the associated electronics are quite complex but when configured properly can provide an unlimited platform. If you wanna reliably fly with machines like this you should become a student. If you don't want to learn all that stuff you should buy a Phantom. Guys with Phantoms at the flying field don't even know what HDOP is but most of them are flying reliably. They are really impressed though when I send my Iris on a ten minute auto mission with about 20 waypoints.

        2) Use blue loctite on every bolt and check them each flying episode. Just last night I was checking mine for tightness and I found a loose motor bolt. Tried to tighten and the bolt hole in the motor stripped out. Now I gotta solder another motor on. IT's a crappy design where the set screw for the leg tightens against the motor further stressing the motor threads.

        3) FORGET BATTERY FAILSAFES - they are really useless. Use your telemetry on a droid tablet or PC and monitor your battery voltage. If you want your batteries to last and your bird to not crash, you should be on the  ground by the time you hit 10.5 volts. This applies to any quad running 3S. I have proven at least twice that running batteries at high current loads down to 3.4 volts or lower will cause battery puffing prematurely not matter what articles say. Heat is the destroyer and the lower you go with high current the more heat that gets generated.

        4) I have also proven that if you routinely don't put them at storage charge level and leave them charged for a week at a time they will also start puffing prematurely. My Zippy 5000 and my Thunderpro 3850 have both swollen enough that when they are hot I can't get them out of the Iris compartment. My bad. I know know to take better care of them. Right now I am using 5 Venom 4000's. They fit great and give about 13.5 minutes when landing at 10.5 volts. I can do 10 minutes with the go pro on the front flying aggressively. If you expect more from the Iris you will be disappointed. Bigger batteries weigh more causing the motors to work harder. When trying to fly with a full payload the Iris motors get so hot you can touch them. I have measured them as high as 150 degF right after a flight.

        5) really long flight times are expensive. Even though the Phantom does 20 to 25 minutes, the batteries are $150 a piece. 

        6) The Iris is a perfect platform for entering the open source UAV hobby as long as you don't put the legs, gimbal and camera on it. Anyone whom thinks they are going to buy a flying robot with a camera and gimbal and don't think they need to learn how to manually fly really well is in for a big disappointment not matter what brand of bird they buy.

        7) Always take off in stabilize. If you keep taking off in other modes you will eventually regret it.

        All of that being said, I bough the IRIS in January so I don't know what kind of improvements have been made for carrying the gimbal and camera but it would take an entire re-design. If you plug all of the parameters in to xcopter calc you will see that there is no way the loaded IRIS can hover at 50% throttle. Takes almost 80% at full voltage.

        Since I have given up on carrying a payload I have found the Iris to be a fun bird. I"ll still be able to use theTarot 2D on other projects.

        • Mark,

          First, thank you very much for taking the time to help me. That was some great information that I find extremely valuable.

          If you don't mind what kind of charger do you have? I am running an e4 by sky RC.

          I am going to take the same approach as you and will put my gimbal and gopro aside for a later project as well. I honestly went into this expecting the same aspects as the phantom but now I understand what I have and I can appreciate it more.

          Again, thank you so much for clearing all this up. You have put me at ease.

          • For my Iris stuff I use a HiTech X1 MF balance charger. Most important thing is to charge in balance mode. I have cutoff of10.6 vdc for 3 seconds. As long as your charger can balance charge and has a balance bridge board you should be fine. Always charge at 1C. IOW-a 3,500mah battery should be charged at 3.5 amps. My charger also has a storage charge mode which charges it up to about 11.5 volts and stops or discharges it down to that voltage if it is already charged. If you've charged up your batteries for the weekend and something comes up like weather you can still use the charger to discharge them to storage charge.

            You don't have to put your go pro aside. You can still use it mounted directly without the gimbal or legs. The latest go pros weigh 76(might be 74?) grams but I forget what the mount case weighs but together they weigh definitely over 100 grams. The gimbal alone weighs 200 grams and the long legs are equal to another go pro.

            Upgrading to 4S and smaller props can get the gimbal and legs in the air more reliably but then you have the mods to make and have to switch to 4S batteries which aren't very compatible with the Iris battery compartment. If you do this you will also need a BEC to reduce the voltage to the Tarot gimbal.

            The best advice I can give you is:

            Take your naked Iris (no gimbal/gopro) to an open field and learn to fly oval race track patterns and figure eights. Learn how to fly. You will find it very rewarding as you progress. You could start in alt hold mode and then progress to stabilize mode. Once you master manual flight you will have much more appreciation for how the dynamics of the bird change as you add weight. You will be able to sense if the bird is underpowered or if some tuning needs to be modified.

            Learn the modes well.

            Use loiter to get you out of a bind when you lose visual orientation of yaw.

            I use Mission Planner on my MacBook Air to give me a verbal warning through a bluetooth earpiece when the battery voltage reaches 10.7 volts and then I make haste to get the bird back to my planned landing spot to make sure I don't get into low battery situations. 

            Trust me, your friends will be more impressed by watching you bank your Iris into a hi g turn than hovering with a camera and crashing:)

            One other thing - If you haven't already, go buy an Estes ProtoX or a Hubsan X40 and fly the crap out of it in your house and yard. It's all the same except smaller scale.

            It's fun stuff and it's and excuse to go in the garage and drink beer when you need to charge batteries:)

            • What a great thread and some great, thoughtful replies!  Such a shame this is in the "Unassigned" category, as I usually only view the main page and the IRIS section.  I wonder if this can be moved to the IRIS discussion area?

              I got my IRIS (with gimbal) back in April.  It's my third Quad after a Blade 180QX w/camera, and a Blade nanoQX (fantastic for indoor learning!).  As Mark mentioned, the basics of quad flight transfer at nearly 100% to a larger quad like the IRIS in stability mode.

              I've had a busy summer, so have only had the IRIS out flying on 6 difference occasions, with all but one just in my backyard.  I'm going slow, and haven't yet attempted to attach the long legs and gimbal and GoPro.  I'm very glad to be readying this additional information about being at the performance limits in that configuration.  I'm curious, Mark, if you ran the DJI Phantom 2 Visio+ through the XCopter Calc how it would compare to the IRIS with gimbal, long legs and GoPro.


              Pixhawk and the Ground Control software are pretty amazing, but amazingly complex.  I have to remind myself it is OK (and probably saving me $$) to take baby steps.



              • Since I don't have a Phantom I don't have enough data. you need weight, dimensions, prop size, motor size, ,etc. etc. For my new project I'm having to look each component up and  see what the weight is to total them in a spreadsheet.

                Concerning the gimbal and camera. Every once in a while I find people on this site that are having zero issues with their Iris carrying the extra weight like this one but most are having similar issues with power and flight times. Here is another thread where several of us discovered the issues back in March.

                Here is a link where Christian Elsen took the time and patience to get the Iris to stay in the air more reliably. I decided to avoid those mods and build another one. His Cloudsurfer site link provides more details.

                • Great stuff.  Thanks very much for taking the time to summarize and post.  Now that the Iris+ has been announced, including an upgrade kit (supposedly for $200) it'll be interesting to see what happens next.


      • Armen,

        This is a pretty good thread.


        I think 3DR is more interested in attracting investors like Richard Branson and going on trips to the Caribbean than fixing their flawed product:


        I have been very disappointed with their service department. I have found a lot more help on this website than from them. I am thinking about selling my Iris for parts and investing in a DJI, they seem to have it going on and know how to treat their customers.

        • The funny thing is that I've heard dji has good products but horrible support.
          But just checking in on Rcgroups phantom vision 2 threads/forums whatever they're called. Lol, all the support comes from often very knowledgeable, cool owners kinda like whats been happening here.

          I would compare 3drs support like politicians selling a broken healthcare plan to everyone. They know its crap but if they can fill their pockets while venturing to bigger deals than hey who are we? I too was soo excited about purchasing an Iris. I was bragging about it for months until they finally were ready. I for some crazy reason thought that 3DRobotics was gonna be the best being that they place their logo on everything related to apm/px4 etc. Chris Anderson plasters his name on anything "DRONE"...

          He likes taking credit for other peoples work...
          Google it. You'll find that in college ................?

          So having a community with his name on every page kinda tricks you into thinking you're getting the best.

          This is just a place to take credit for other peoples work and no real 3dr support.

          Oh boy this may piss off the brass; that is if they are not out playing with better toys than they sell.
This reply was deleted.


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