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Choppy descent

Discussion in 'Phantom 1 Discussion' started by Deadpilot, Mar 24, 2015.

  1. Deadpilot

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    Newbie here and although I have had to guess at a lot of things not finding easy info it's coming along pretty well I think. Only 3 days of flying so far.

    One thing though that seems to be a recurring problem is that although this thing flies great overall, when I go fairly high and then start to descend it bounces around a lot. I suspect perhaps I am descending faster than I should be for a smooth descent? Maybe that is just how they are? I sometimes start to panic slightly when it's up there because it's hard to tell if it's actually descending or not, sometimes appears to be drifting (although it hasn't really to any extent) and sometimes orientation is hard to determine.

    I am flying a Phantom 1.1 with a generic camera that doesn't fit any mounts so I had to makeshift rig it to my anti-jello mount.

    I would perhaps like to get a gimbal one of these days but don't enjoy the tinkering and it looks like a lot of them require opening up the unit, soldering, etc. I know how to do all that an am pretty mechanical (had a soldering gun when I was about 10), I just hate it and have no patience. Is there a gimbal that is easier to install? I don't even care if I can't control it from the ground, just want a smoother ride.

    I did shoot a half decent video (considering) but edited out any descents.
     
  2. Tito

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    Cheap gimbals only use a 12v+ a negative and if you want it a pitch control line. The power feeding is often from the balance plug. So, you'll only need to open up the phantom if you want the pitch control (no soldering). Everything else is plug and play. I don't know how more expensive gimbals are connected. Your viewing angle will be perfectly horizontal and only can be changed in de gimbal software settings before flight

    Choppy descent... Don't really know how to help you there. Search for Vortex ring state on youtube. I don't think its similar to your problems as the drone basically crashes. Did you do all the calibrations?
     
  3. J Dot

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    Try descending with slight ( forward, back , left or right ) movement!
    Sounds like vortex effect, where your craft is traveling through its own prop wash!
    Very turbulent descent! If you give SLIGHT forward ( or any direction )movement during descent, should
    Come down smooth! ( coming STRAIGHT down can be difficult, if your descent speed is not limited ) new update
    Has limited descent, to cure that problem!

    Do you fly prop guards? Or using aftermarket props?
    Sometime these items can make vortex effect WORSE!
    Sometimes causing the dreaded CRASH!

    Take care, Fly safe!
    J Dot
     
  4. Deadpilot

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    Yes I do have prop guards (factory) on it at the moment, what you say makes sense, I think it is fighting it's own vortex. Today I tested the RTH feature which worked fine so I'm not as leery of losing orientation or drifting a bit. I'll try that next time.

    My first video is here if anyone is interested ... I know I need to learn to fly more smoothly and get more used to the controls, that would help.
    https://youtu.be/QvyCPqGKQns

    Thanks for the advice! Still not exactly sure what to do about a gimbal.
     
  5. IflyinWY

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    Hello Deadpilot,

    Looks pretty good for a first video. Thanks for editing out the prop sound. :D

    Yep, sounds like VRS Vortex Ring State. Lots of info out there.
    The only thing I could add to what J Dot said, consider the air mass you are flying in. If the wind is blowing 10 or 15 mph, you can descend vertically. If there is no wind, you want to be traveling, in any direction as you descend.
    Some say the prop guards and VRS are related, I have yet to see definitive evidence, but am not saying they are wrong.

    Aftermarket props... blech.

    Here's a good search tool for our forum: https://cse.google.com/cse/publicurl?cx ... jku2ysgyhi
    Type in the box "below" Phantompilots.

    I can't believe you headed out over the water already. It still worries me. As much as I hate the sound of the Phantom hitting the ground, a splash would be much worse. :cry:

    Here are a couple gimbal threads you may be interested in. Your bird is basically the same as the FC40.
    viewtopic.php?f=20&t=36932
    viewtopic.php?f=20&t=36048

    Keep up the good work, looks like you are progressing quite well.
     
  6. Deadpilot

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    Thanks,

    Yeah going over the water was a bit scary, but so are trees, etc. Lots of water around here so it will be hard to avoid.

    I'll test these theories next chance I get, should have a new camera (hopefully better) today.

    Thanks for the info.
     
  7. Deadpilot

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    I did calibrate the transmitter, hooked the thing up to my computer and ran the software that was designed so nobody can really understand it ;) , also I always calibrate the compass before each flight.

    I have no other problems with it so I tend to think it is not that sort of an issue. It's only when I am descending quickly in a straight line, it's almost as if rhythmic gusts of wind are hitting it. Seems if I slow my descent it isn't as bad if at all and haven't noticed it happening unless I am coming more or less straight down.

    I do have video of it happening (I think), but have limited bandwidth on my Internet so I need to pick and choose what I upload or download. There is no cable or DSL where I live, I have satellite Internet.
     
  8. IflyinWY

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    I'm not sure if I understood your last post completely. I think you said you don't think it's VRS.
    If that's true, I will try harder to convince you to watch your *** in those rapid vertical descents.

    In the meantime, here's a little movie for you. :D
    https://www.youtube.com/watch?v=tsd_x1i_vAA

    EDIT:
    And here's one from 9 days ago.
    viewtopic.php?f=6&t=36540
     
  9. Deadpilot

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    No I was saying I don't think it is a calibration issue, it may well be something like VRS
     
  10. Deadpilot

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    Flew a bit today and tried some of the "remedies" for this weird descent issue but I am not sure they worked. Pretty stable flight otherwise despite some light winds.

    Also put a new camera on her but now for some reason getting pretty much jello even with the anti-jello mount... other camera didn't see any, I think it weights less overall now and I wonder if that contributed to the jello. I'd stick with the old camera but it sometimes does some weird adjusting to lighting that annoys me.

    Argh... maybe I should have bought the vision or even the yuneec Q500... maybe I still will.
     
  11. J Dot

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    Did you do these steps?

    Calibrate ( tx ) radio in ( RC Assistant )
    Then
    IMU ADVANCED Calibration in ( PC Assistant )
    ( bird level, and stable, NO WOBBLING AROUND )
    Then
    Calibrate ( tx ) radio in ( PC Assistant )
    Then
    Fresh compass calibration
    Then
    Test fly?

    Calibrating tx in RC assistant, calibrates tx,
    Calibrating tx in PC assistant, calibrates tx TO phantom.

    Also try flying WITHOUT prop guards? Make sure you put SHORTER motor screws back in,
    The prop guard screws are longer ( to compensate guard thickness ) and WILL short motors
    If installed without prop guards. You have to out ORIGINAL screws ( shorter ) back in!

    Let us know
    J Dot
     
  12. Deadpilot

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    yeah pretty much did all that but don't want to remove prop guards just yet. I calibrate the compass every time. As said before it's stable except for during descent, especially if not real slow.

    I hate their software, it is much more confusing than it ought to be. I guess what do you expect, the instructions are also awful... I may remove the prop guards next time.

    Thanks
     
  13. Deadpilot

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    I don't think I have any other screws, just came with the ones that were in the quad before I installed the prop guards.
    Oh yeah I do, found them... thanks! Because of crappy weather won't be flying today, tomorrow or who knows when.

    I also am not sure what you are referencing (RC Assistant vs. PC assistant). On the DJI website I only see 2 exe program files for download both of which I have installed and run... as much as they can be understood ... "Naza-M Assistant Software v2.20" and "DJI WIN Driver Installer".

    Once again though, I don't think the issue I sometimes am having is a calibration problem, the thing flies great except for sometimes when I am descending quickly in a straight line. I have tried keeping it moving in a direction as well as rotating it while descending and it might help. I have yet to fly it without the prop guards.

    Where I live is extremely flat, close to ocean and lots of bodies of water. I think the highest point on the entire peninsula is 24 feet or something and there is almost always wind, and who knows how much once you get airborne. The video link I posted earlier shows how flat it is here... and that is called "Mount Vernon", the church at the end being on a bit of a hill is the highest point in quite a large area.

    Will try to report back next flight so maybe it would be of some help to someone else.
     
  14. J Dot

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    Hey ( DeadPilot )
    The exe. is there, here is a pic.
    [​IMG]

    You'll need that!

    The win driver, is to allow computer to talk to phantom
    The ( phantom RC Assistant ) is for radio ( update, calibrate, ect )
    The ( phantom PC Assistant ) is for the craft/radio ) craft mostly

    The RC assistant calibrates your radio, then PC Assistant calibrates radio to phantom!

    Hope this helps!
    J Dot
     
  15. Deadpilot

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    lake_flyer likes this.
  16. IflyinWY

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    Just in case you have not removed your prop guards yet. Here's another thing to check. Make sure the guards are screwed in kinda tight, no where near stripping, but tight.
    The little holes on the guards are for string and the string adds a great deal of stability to the guards if it's pulled snug. That may help with the jello. I've noticed when I do not have the string on, the guards like to vibrate quite a bit at high speed.

    You might get tired of hearing this, but make sure you use the proper screw. Touch the motor winding and it's over.
     
  17. 750r

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    Can you get some vid of what your talking about ?
    Prop guards can cause problems with flight . Can you fly without them once to see if thats a problem . What props are you running ? Have you balanced them ?
    Since you have water around you might want to get a getterback
    http://www.ebay.com/itm/like/221695314319?lpid=82&chn=ps
     
  18. IflyinWY

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    750r has a couple good points. How about editing those descents back in while you're waiting for your getterback to arrive. ;)
     
  19. lake_flyer

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    If you still use the original props (8") that came with your P1 you probably don't have to fear a crash because of VRS, although it will wobble like mad coming down fast. The prop guards however do spoil some of the lift and make wobbling worse.

    make sure you never pull the left stick more than half down and keep a forward, backward or sideward motion. Circling is OK as long as the circles are not too tight. When descending don't descend with the wind direction or the spoiled air will just stay under your quad. Descend against the wind. If there's a strong breeze you can descend straight down. But again, always not more than half down throttle.

    If you already have other props, specially the 9" P2 props, like the 9345 or the 9450, you CAN and MUST NEVER descend with more than 2m/s. You get into VRS over 3m/s for sure, unless you are experienced enough to counter it, the moment you notice it happening. Without FPV and OSD (telemetry display) you can't really tell what's happening until you are well into VRS and it's clearly visible from where you're standing.

    If you encounter really heavy wobbling you are getting into a VRS state. The way to get out is to just let go of both sticks immediately and wait for it to settle. In any case DON't try to counter it with extra throttle or pitch. Because the air pressure below the quad at that point is insufficient to carry your bird. It will descend another 10 feet or so but eventually it will hover again (takes a second, maybe two). If you happen to be too low already you just crash.

    A Walkera gimbal is very easy to install. The white G-2D is cheap and very light. I have only used 1 standard servo female-female cable from the F2 port on the Naza controller to the pitch port on the gimbal. This way both the gimbal as well as the pitch control is powered. You only have to open the shell for this.

    Don't worry, it's easy, just 4 screws in each motor arm, flip off the top shell and plug in the servo cable, let in run trough one of the holes in the legs or make a hole in the side. You will be opening the shell lots of times, mine has been opened maybe 15 times or so. It gets routine :)
    You probably don't even have to adjust the gimbal. Normally they come perfectly balanced as they are. You probably only have to set the pitch travel in the Naza software.

    One tip while opening and closing the shell: remove the little philips screws in the tips first. When reassembling again, screw them in last. That way those tiny heads will survive.
     
  20. lake_flyer

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    And don't worry about the vision guys here. They have all the possible factory installed options on their model and (only some) automatically think any other Phantom is the same. Just like the guys always driving the most expensive version of a car. "I'm sure it's because your electric heated seats with memory and butt vibration are causing interference with your auto distance control and auto parking". Well, you don't have a butt vibration, electric seats, auto parking etc., and you park yourself, since you're driving the base model. Same engine, just as fast, only less bells and whistles. And a lot more freedom to choose and build your final configuration. With eventually real 5.8Ghz FPV/OSD (if you want) and not a phone app that cut's out after a couple of hundred yards. And a cheap gimbal that works great and doesn't set you back for 600$ after a minor crash.

    The P1/FC40 is still a wonderful bird (only difference is the control freq). You will understand what I mean once you get your second quad and you think you want a P2, or worse, a P2V+ (whatever version). The Vision software is actually highjacking your quad. DJI decides where you can fly or not. DJI decides that your gimbal is no longer supported (but they also decided that you just can't downgrade anymore), DJI decides you can't descend with more than 2m/s even in an emergency, DJI decides your battery gets new firmware, making the battery think it's depleted while still on 70%, the list goes on and on.....Not saying a P2 or V2+ isn't cool and great, they are, but DJI is messing way too much with the software, limiting newbie pilots as well as aces in every way they can, just to play it safe for them, with regards to claims and whatnot.

    Good morning y'all, I think I'm awake now......was a bit grumpy getting out of bed seeing I just lost one hour of my life (daylight saving started last night) hence my tone, sorry.