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Testing the Xpro Heli Phantom gimbal

Discussion in 'Photos and Video' started by martcerv, Nov 8, 2013.

  1. martcerv

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    I recently got the XPG small gimbal, have done a bit of testing with it here is an early test using a hero3 black +

    [youtube]http://www.youtube.com/watch?v=48V1JgcdL90[/youtube]

    Main issue I see with it is the mount system and anti jello setup is too soft for the weight of this, it causes it to wobble a bit in wind and at speed.

    Here is the same video with yt software stabilization added, this has done better but reduced the IQ. Doing stabilization in premiere pro with the original 2.7k file would have given better results but I was a bit lazy and just did a quick yt stabilize test to see how it would deal with such footage.

    [youtube]http://www.youtube.com/watch?v=U0FHqbFP2cI[/youtube]

    I thought there must be a way to improve the isolation mount and so have looked into replacing it and using a DIY sorbothane isolation setup. This has worked great and below is my latest test pushing it in breezy conditions.

    [youtube]http://www.youtube.com/watch?v=QOCKxgndCM4[/youtube]

    Here it can deal with most of what I put it through quite well and also the breeze, flew in much stronger winds too with similar results earlier. There is a little vibration which I have probably removed changing the pad for the camera to a sorbothane one too so this may get rid of the last few vibrations. Quite impressed that I have yet to make the gimbal go to sleep as the zenmuse does, stabilization itself isnt quite at the DJI level with some horizon drift in yaw rotation but overall it does quite well. The one thing I didnt realize is the hardware customization options for different setups to ensure it remains balanced is only in the larger gimbal, I would almost have rather got that and then got some larger landing gear. This would get it lower and out of the props at higher pitch angles and been a little more adjustable.

    Overall I am quite happy with the setup except I am also waiting for a rear video out cable as my current cable is too short and I cant quite balance the cam the right way up with the USB sticking out. I need to open it all up again and move the cable to the other side but will soon have a rear out cable to use so am just waiting for that. I have my full setup here including FPV but no live video feed so monitor is only showing OSD info atm and I am flying purely LOS with the gimbal for now.
     
  2. martcerv

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    One more test with the gimbal and hero3 black this time in very strong winds 35kmh gusting to 50kmh so pretty much the wind limit Id fly the phantom in. Did ok here still I also tried with and without the Blurfix adapter and tiffen nd .9 filter, this was 2 consecutive flights in pretty much the same conditions but wind was very gusty and the big gusts were close to my comfortable control limit.

    [youtube]http://www.youtube.com/watch?v=Na-GOIksimE[/youtube]

    GPS struggled with the big gusts about the same as me in ATTI mode and so most of this is flown in ATTI but also some GPS. In these sorts of gusty winds GPS wont hold position very well so I found I needed to help it out a little even in GPS especially if close to trees.
     
  3. martcerv

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    Last local test as I have pretty much got the mount sorted I think. The winds just about died completly at sunset so I wanted to test it out in calmer conditions.

    [youtube]http://www.youtube.com/watch?v=9GIpURwOwzM[/youtube]
     
  4. xstatic

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    The video was too blurry to see any difference. Next time upload at 720p at least Fancy flying though! in one videoyou came really close to the tree tops, ithought. were going to shave some leaves. I almost sha$ myself!! lol vey cool. amd youmgot a lot better follong the sidewalk between the trees. Good going

    I do have a question. i am runnignthe phanton with the Arris gimbal and also an x2 phantomount. I switched to arris though in the end. I seems I have no jello at all, but there is a shakiness, almos a double maging if I fly fast. Any way to get rid of that? I have moongel. should it change to the sorbithol (sic) or however it is called <(sorbithane?). Sis you get shaking almost like a double image?
     
  5. martcerv

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    All the videos are uploaded in 1080p but yt has been weird a little lately on some browsers. Check to see if there is a 1080p option and if your on a mobile you may not always have the hd option.

    With the shaking it may be similar to the issues I had with the original mount, it still wasn't as bad as your saying it gets with yours but in the first video you will see the most shaking in these tests of mine using the stock rubber isoaltion mount. I went to sorbothane as other friends of mine have been using this for a while and its a great material at absorbing vibrations but also avoids lateral motion much better then any regular rubber.

    If your only getting real bad wobble at speed its likely due to the mount wobbling too much, you can try basic mods such as adding some foam or even foam ear plugs inside the rubber grommets to stiffen it up a little. You can also use some rubber bands pretty much anything that will reduce lateral motion but still absorb the vibrations that cause jello. What you want is to get it as stiff as possible without getting jello passed caused by vibrations, sorbothane if used properly can do a great job but you may find cheaper or easier to find materials to do the same thing.

    You also want to make sure your props are balanced as these are the main cause of vibrations and will get worse at higher rpm if very badly balanced. I recommenced getting the Dubro balancer as it works well and some other are out of balance themselves so they wont help you balance props if they aren't even balanced to start off with.
     
  6. xstatic

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    I have absolute no jello in my video. Just that vibration going from left to right as I fly forward at higher speeds. I have the Dubro and balanced 3 sets of blades, all giving the same result, even the original blades.

    I will send you after I upload it so you can see what I am talking about.
    I am on a tablet so I will switch to my pc to see your video in hd

    Thanks again for your help
    In the meantime you can see my better video in no wind and low speed here. let me know what u think

    http://vimeo.com/75280932
     
  7. martcerv

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    I still think its just the motion of the mount that is giving your side to side motion at speed, all rubber grommet isolation mounts do get this if the rubber is too soft for the weight being suspended off it. Even the DJI H3 2D has these issues if people use the wrong grommet softness or if flown at high speed. I tend to like to fly hard and fast but also like the slow cinematic type of flying so I wanted a gimbal that can take the loads and g forces applied which my first few tests have shown me it can do. But this also showed me the mount issues as I have had in the past with VGE and other type of anti jello mounts before I used a gopro. I used a very similar mount to the one the comes with the XPG with near identical rubber grommets, this was great with a single h3 black but then trying 3D with 2x h3d black I got vibrations and also more jello until I modded that mount.

    What I meant to say above but probably didnt come across properly is that the rubber ball isolation mounts generally work very well at stopping jello. They are normally very soft and so vibrations dont get transferred through this, the problem is that also being too soft can have the negative side effect of swinging the entire mount in wind or at speed especially if more weight is hanging off this type of mount. This is the tricky thing as you want to get the mount as stiff as possible to avoid the swinging motion but at the same time as soft as possible to avoid vibrations being transferred and turned into jello.

    This is quite a balancing act as you need to find a place in the middle between stiffness and softness which is why I went for sorbothane as it takes much more load but also absorbs vibrations well. If you stiffen your mount up simply adding foam or rubber bands its likely you will completely eliminate the shaking motion but then you may also start to see more jello as the mount may no longer be absorbing as much vibrations and passing these on to the camera.

    I use ND filters not just for Jello reduction but mostly to control shutter speeds as I prefer some motion blur over very high shutter speed video that has that strobey type look to it and not fluid motion. The correct ND filter for the light your in will give you slower shutter speeds and better motion, also smooth out tiny bits of jello that may still be there while at the same time also help protect your camera lens if you happen to have an unplanned landing AKA crash. :lol:

    To show how its possible to pretty much eliminate the swinging actions of this type of mount and also have no jello here is an earlier flight of mine before the gimbal. This is pushing real hard with speeds of over 100kmh going by my OSD at times and regular no wind forward speed around 85kmh using my setup. This was actually with 2 gopro's onboard and modded anti jello mount total weight not much less then my setup with the gimbal only about 50g less here with no gimbal.

    [youtube]http://www.youtube.com/watch?v=FQHY5zXXk5E[/youtube]

    Compare that to this my first test flight with a phantom and VGE mount all stock getting real bad shakes which shows pretty much the same wobbles issue from the mount. No real jello just very bad swaying of the mount and as I came in to land I actually saw it swinging side to side pretty badly in the wind and thats when I started experimenting with these jello mounts. If you watch the last couple of minutes of this video you will see the mount wobbles the worst I ever got and once I saw that footage I knew I needed to do something to deal with that issue before the mount fails and camera falls off.

    [youtube]http://www.youtube.com/watch?v=aI1WSvOLKYo[/youtube]
     
  8. xstatic

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    Thank you for that in depth reply. I much appreciate the time you put into it. I do have the neutral density filter which cut out all the jello, but I will work on the vibration that I am getting. I guess the sorbithane would be my next move. I am using the moongel right now but I dont't think it is really doing anything as my video before and after don't look any different. The biggest difference was the neutral density at 60 fps. I am on my ipad now so I will compare your videos later as they are not coming in high def. But i did have a quick peek and wow, you sure fly fast! Very cool. I assume you are using fpv as. I dont't see how you can keep the copter in sight at those distances. Specially the low dlying, it is much easier to judge with fpv. I see you had mentioned that you were fly at about 85 km, so I am asuming that was not with a phantom. What copter wee you using?

    Where did you get your sorbithane? I guess the best place is Ebay unless you now some other tricks.

    Right now the weather is just dipping under freezing, but if I get the sorbithane soon I will brave the cold and test it out
    I am in Montreal so the flying season is nit as long as in the states, lathough you can fly all year, I dread the snow and the moisture
    I already plunged my copter under water for several minutes so that was enough drama this season. A blow dryer fixed everything, even the gopro came back. to life.

    I also see that the sorbothane come in many size. Did you use the half ball type or regular flat whixh comes in several thicknesses. What thickness worked for you?

    Happy flying.
     
  9. martcerv

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    I think your better off trying some cheaper solutions first, using extra foam or earplugs and this will give you an idea of how that will work. You may find you stiffen the mount and still have no jello so youd be all good but you may find it fixes the wobble but adds jello so you may need to look into sorbothane. I found a local stockist of the stuff its not cheap but they had all different types so I went had a look and bought what I though would work best. Not sure if I have perfected it yet need some more testing but its rained non stop all week or blown way over 50kmh so ive kept it grounded as my windy tests are at the limit I will fly wind wise. I have used some 30duro sheet not sure of thickness maybe 1cm and some 30 duro grommets though there wasnt enough space to use these as they should be and its quite a diy hack job lol.

    I do use fpv but not yet with my gimbak setup as my video cable is too short and not ideal so I am making a rear video out setup just waiting for a part. Speeds are with a phantom in atti or manual mode my cruising speed is around 23m/s and with a bit of wind I have got it up to 130kmh but thats pretty sketchy in that sort of wind lol. Fpv and osd makes things much easier and one of the mai reasons I got the dji osd is so I can seee attitude lines on screen making it easier to fly fpy with a gimbal.

    Because I like to fly a bit harder then some I wanted a gimbal that can handle this and also the reason I have spent a bit extra on the mount to give better resuots in sfronger winds or higher speeds.