New User X8 3DR RTF on a harsh learning curve.

First is anybody else flying the X8?  

I bought mine RTF to do Aerial vids with a Hero 3D rig.  I bought an brushless RCTIMER ASP 2-Axis Nex-GH5 .  It was fairly easy to get a sound install and finally figure out how to power up the gimbal and it's seems to be working fine.  I had to add landing pads to the base of the X8 landing gear to give the Gimbal and camera space for landing.

I have begun flight testing the rig and found the simply to adjust the COB on the x* I hang two batteries as far aft as I could.  they were two 3s 4200 mah. My early flights were short and damaging.  As I have now learned to view the flash logs and T logs I could see that I had a serious power deficiency and he throttle mid point was way low.  I have to run the throttle hover mid point at 600 to get loiter stable.  Is that too high? I found I was running routinely at 70-80 amps with the 3s batteries that came with the machine. Flight time was barely 4-5 minutes was precipitous drop at the end.

I decided to try a 4s battery 4000mah and have noticed some improvement in throttle levels and stable fllght times. I think I am on track with the larger 4s for the added weight but I'd love to hear other ideas.  One thing I have found out is it's easy to kill a good battery if you run the voltage below levels and I've done it to three already when I try to get the maximum flight time.

I still have no confidence in this rig for a mission.  I have been hover around the backyard. Trying to get it stable and get predictable flight times.  When the juice runs out this thing drops like a stone and unlike my Phantom there is no real warning time.

I can only conclude I need more and larger batteries to get my flight times up.  I am running the stock rig shipped by 3D Robotics.

Is there a mentor out there that would tolerate my incessant question while I try and master this very hard to fly rig?

I attach an image of the present set up with my ears open for better ideas.

Jamie

IMG_1138.JPG

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Replies

  • To reiterate in my case everything was as it should be, props installed correctly. Based on the newer specs for the X8 from 3DR I can see that my suspicions about the batteries and the IMU were correct. They have both been upgraded.  Too bad I am stuck with the older version.

  • Man Oh Man! I think I found my problem too!! LOL!  My bottom props were upside down too!  Thanks Dan and Mikael.

     I was having problems with battery duration too.  

    • Ahmed,

      what is the flight time now / payload weight ? 

  • I'm owing to do something I hoped I'd never have to and admit I was an idiot. I have had power issues, stability issues and battery issues with the X8 and now it seems I have found the reason. As an excuse, I am not a wizz att aeronautics so i didn't notice straight off that the lower props where mounted UPSIDE DOWN.
    All though rotating the right way and providing some lift they caused more havoc, battery drain and power loss than if I had removed them and gone with just four props.
    Heavy rain stops me from flying today but indoor pull tests were a LOT better.
    • Mikael: How did you find out about the props?  Thanks a lot for posting your mistake which was mine too. Thanks again!

    • YUP!  I was just going to post this, as that is exactly what was happening to me...  put the props on and instinctively put them on with the text 'up' in relation to the motor.  I was getting like 5 minutes on the 4S...  was freaking out internally, until I figured out the bottom props were on incorrectly.

      W

      • HI Warren, 

        what is your payload weight and the flight time now with the props in the right way? 

        Thanks! 

        Tom

        • Hey Tom,

          It's been quite some time since I've flown it (time to repair from a major crash, then in the field with my fixed-wing for a month, and now cooooold winter weather...).  At any rate, I believe I was getting about 10min or so until the battery/voltage FS was kicking.  Maybe a bit longer, but not much...

          Warren

  • Here you go, from our stock X8

    3drX8.param

  • I just got my RTF X8 up and running this weekend and took it out for it's first test flight lastnight.

    * I haven't balanced the props (yet)

    * 3DR Telemetry and FPV video kit are the only payload beyond battery

    * I followed the quick-start guide, so radio calibration was done, but not compass or anything else.

    On takeoff there is a slight roll to the left, but it quickly evens out as soon as it lifts off.  In still air (no wind at all) it is very easy to hover in stabilize mode, and doesn't drift.  Loiter mode is sort creepy - it just sits there like the alien spacehip in District9.

    Eventually I'm going to be adding an NEX-5 payload, but I'm working on getting familiar with it first.  I'm also not planning on doing video, so I'll be going for a very lightweight (non-motorized) mount for the camera.

    A couple of things I noticed...  You can set the Failsafe for battery levels so it will RTL when the battery gets low.  You can also get a Piezo and attach it to the APM module to get a buzzer for battery levels (as well as arm/disarm).  I'm planning on ordering the piezo shortly, and will be testing out the failsafe afterwards.

    -Tash

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