Spark Float Gear?

Discussion in 'Spark Discussions' started by Ted Schoenfelder, Jun 8, 2018.

  1. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    I purchased the float gear in this link: Water Landing Floating Ball + Landing Gear+ Heightened Bracket Kit for DJI Spark | eBay Which adds about 65 grams to the aircraft.

    Though it is stable in flight, I've noticed these adverse performance issues: The aircraft sometimes continues to climb when the RC stick is neutral and no climb commanded. It is sluggish in response to RC inputs during climb or descent. It is reluctant to descend unless full down stick is commanded and then descends too rapidly. Max motor speed warnings occur occasionally. Has anyone else used the same gear, or similar, and had performance or handling problems?

    I've talked to Bentguy516 (see video here ) and he has not observed these symptoms, so I am wondering if I have a Spark or RC problem?

    I would love to hear from you if you have experience with float gear, positive or negative. I plan a lot of over water work and need to be able to recover the drone.
     
  2. dudez

    dudez Member

    Joined:
    May 5, 2018
    Messages:
    15
    Likes Received:
    11
    Hmmm....have u tried IMU calibration yet?
     
  3. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Yes, initially. But since you mention it, I will try another IMU calibration. However, I regularly check both compass and IMU before each flight and they consistently show green. I generally don't see IMU warning messages. Warning messages I do observe tend to refer more to some element of motor performance. Nevertheless, I will give re-calibration a try.

    I built three of my own home built float gear versions in an attempt to alleviate performance problems. Generally they reduced weight by about half, but it seems like weight is not the issue (see stats below)?

    Here is an example of one design that weighed about 30 grams in contrast to 65 grams for the ball floats (see pic below). However, it was unstable in flight and had similar performance problems.

    By the way, if curious, those are the finger guards DJI has on their web site and on the far side is my tracking device (a Marco Polo) with the antenna pointing aft, these two combined weigh an additional 20 grams:

    My Gear 1a.jpg

    My Ball Floats 2a.jpg

    My own designs, in spite of being lighter, were less stable so I went back to the foam ball version. However, the unreliable performance of the ball floats is not satisfactory. I want to be able to have confidence the aircraft will perform consistently with the float gear mounted.

    If I am not using floats, I fly the configuration below (gear weighs 50 g.) and with the finger guards and tracker is a total of 70 g. This is right between the weight of the foam balls (total of 85 g.), and my home made gear (total of 50 g.). I have no performance issues with this configuration, which puzzles me! It seems obvious my performance issues with the ball floats is not weight related. It could be an aerodynamic issue, or what I'm beginning to suspect, possibly a motor issue?

    My Reg Gear 3a.jpg

    Thanks for your suggestion! Hopefully others have experience with either the ball floats, or other variations, and can provide additional insight on a possible solution?

    TS
     
  4. Hotwire

    Hotwire Well-Known Member

    Joined:
    Jun 25, 2017
    Messages:
    101
    Likes Received:
    34
    Location:
    Australia
    Objects on the frame beneath the propellers effect airflow and create turbulence that makes flight unstable. All read to fly models have preset PIDs and rates. If you change the frame you detract from these settings.
    Apply as few of these accessories as possible.
     
  5. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Not sure what you are saying. The first sentence makes sense, but, as previously stated in the notes, stability is not an issue with the ball floats.

    What are "PID rates?" Please be more clear in your explanation. It is not very helpful information as it is written.
     
  6. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Ok, here is a follow up experiment that seems that initially seems to eliminate the ball float (and other float gear) performance issues noted above. This arrangement seems relatively stable, considering I was testing in gusty winds in my back yard.

    I used my "no float" gear setup (tot. 85 g), shown in the pic above and attached a couple of flotation tubes (pipe insulation) with Velcro to the outside of this gear. These tubes provide just adequate buoyancy for neutral flotation and adds 15 g to total weight. It will allow recovery of the aircraft from a dunk in the water. However, it does NOT facilitate landing and taking off from water due to the mount location, the A/C bottom would get wet! See pic below:

    Neutral 1a.jpg

    I did have one instance (bug) of the aircraft going into an uncommanded auto rotation around a hover point with an accompanying "max motor speed" warning, when I tried to stop the turn. I have seen this before in a couple of other gear configurations (not with floats) so I am still suspicious of an under performing motor, or some related issue, which exacerbates adverse performance symptoms. It happened once and I could not duplicate.

    I decided to test the above configuration based on comments on the official DJI Forum related to possible conflicts with the visual system by objects hanging under the aircraft, like float gear. This type of conflict could fool the aircraft into sensing ground, or an object, is too near and forcing an initial uncommanded climb or vice versa on descent, resisting the descent until forced. I'm not sure if this test proves anything, but it certainly seemed to make a difference by having the flotation placed outside the vision system's sensing arc and outside the prop wash. Weight did not seem to be a factor, except it will obviously reduce flight times.
     
  7. Hotwire

    Hotwire Well-Known Member

    Joined:
    Jun 25, 2017
    Messages:
    101
    Likes Received:
    34
    Location:
    Australia
    All ready to fly multirotors have a preset tune and that tune is only for the default frame setup. If you change the aircraft too much it will become unpredictable.
     
  8. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Thanks for your response but your answer still does not explain what the initials "PID" stand for. I understood the general concept you were trying to explain in your first note, but you used an acronym without giving the full name of the term. Please provide the full description of the acronym. Thanks!
     
  9. IanSR

    IanSR Active Member

    Joined:
    Jun 1, 2018
    Messages:
    25
    Likes Received:
    7
    The reason it was climbing is probably because the downward censor was seeing the floats and mistaking them for the ground, you need to turn them off, Ive done it to mine because of where we live, I have the info written down somewhere if you want me to get it for you?

    PID is a betafloght/cleanflight option that can be changed to alter the beahvour of a quad in the air, it's generally something you'd change on a homebrew one, the term is uselessness or A Di products as you cannot change them in sparky.
     
  10. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
     
  11. IanSR

    IanSR Active Member

    Joined:
    Jun 1, 2018
    Messages:
    25
    Likes Received:
    7
    PID stands for Proportional, Integral, Derivative.

    To disable the downward sensors, change g_config_misc_ofg_vps_func_en to 0 from 1. I am assuming you know how to change the Spark's operational parameters here with DJI Assistant 2.12, if you don't, then don't attempt this - you do this at your own risk and should be aware self landing no longer sees the ground so landings are bumpy, best to grab the quad while it's hovering instead and tip it 90 degrees instead of using the autolanding feature. This will also allow you to decend through cloud.
     
    #11 IanSR, Jun 12, 2018
    Last edited: Jun 12, 2018
  12. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Thanks for the explanation of the acronym. I finally did what I should have done in the first place and Googled it! Below is a link to a detailed explanation for those who may want more info on what PID is:



    As for the other part of your comment, I did come to the conclusion the downward sensors were the problem, thus the latest flotation mod shown above.

    But how do you shut these downward sensors off and how does this affect the aircraft with regard to the note on Page 12 of the manual that states:

    "The aircraft will switch from P Mode to ATTI Mode automatically if neither GPS or Vision System are available."


    Perhaps turning off the sensors has a different outcome than a failure of these sensors? I would appreciate it if you could pass on the instructions for turning off the downward sensors. I would like to try the ball float configuration again with sensors turned off. Thanks!
     
  13. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    You were too quick with your response! I was writing a response to your first comment and ended up sending mine after you had already made the explanation of how to disable the sensors.

    And, no I don't know how to make the parameter changes in DJI Assistant and will probably not go there! I am relatively new at the game and don't want to get too carried away with big changes. Thanks again for your helpful comments!
     
  14. IanSR

    IanSR Active Member

    Joined:
    Jun 1, 2018
    Messages:
    25
    Likes Received:
    7
    haha I'm probably as new as you, only got Sparky last week, I just like to twiddle, one step at a time mind you. It was only luck the OP's subject was relevant to what I was doing at the time, I wanted to disable the sensor to stop the Sparky from refusing to descend in fog, which was a scare I had the other day.

    I must admit I was very nervous about turning off the bottom sensors, and nearly chopped my hand off tonight trying to catch Sparky who was insisting on landing somewhere he shouldn't have (my mistake), so I was so relieved when it worked.
     
  15. spark29

    spark29 Member

    Joined:
    Apr 29, 2018
    Messages:
    20
    Likes Received:
    1
    Is that a gps device i spot on picture 2? And if it is where can i get one of those?
     
  16. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Yes, I just got started back in February and have made a lot of flights since then, I'm located in Minnesota so I started early with snow on the ground. However, I'm planning a two week trip in the Temagami Region of NE Ontario in the fall.

    This is a planned solo houseboat trip with Temagami Houseboats ( see link: TemagamiHouseboats ). This area of Ontario is similar to our Minnesota Boundary Waters so I will take my kayak and plan to do a lot of over water video.

    Being able to locate a lost drone on land in this remote wooded area with lots of water around is critical, and there is no cell service, thus the Marco Polo tracking device. Recovery in the event of an unintentional dunking (likely) is also essential. I have DJI Refresh, but without the carcass, there may be no refresh!

    I would also like to fly from my kayak, but that may not be possible unless I can get a float configuration that performs consistently. I think I now have a means of recovery with my latest mod. Previously, my only on the water landings were with the ball floats and I don't have complete confidence in consistent flight performance of that rig. There is an alternative ball float design built in Canada, but I'm not real confident it will perform differently from the cheaper China built ball float rig. The Canadian builder claims his rig will perform just fine but it is a more expensive alternative and I need more positive evidence it will perform better than the China ball float rig before I spend the bucks on another alternative.

    It would be nice to get more comments from current users of both ball float systems. My performance issues seem different compared to the little feedback I've received from other users of the ball float systems. Evidently, there are very few flyers using any type of float system for over water flight. Thanks for your comments!
     
    IanSR likes this.
  17. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    I suspect you are referring to the Marco Polo I mentioned in my comments of #3.

    No it is not a GPS unit, it uses an RF signal that can be tracked for up to 2 miles in the open, I find it is pretty consistent up to a 1/2 mile in areas with obstructions like houses or trees.

    Below is the Amazon link, though you may find it cheaper if you shop around:

    https://www.amazon.com/dp/B01N9592RQ/ref=asc_df_B01N9592RQ5508433/?tag=hyprod-20&creative=394997&creativeASIN=B01N9592RQ&linkCode=df0&hvadid=218413592118&hvpos=1o1&hvnetw=g&hvrand=10912431127383446837&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9019543&hvtargid=pla-418834116677
     
  18. IanSR

    IanSR Active Member

    Joined:
    Jun 1, 2018
    Messages:
    25
    Likes Received:
    7
    I record the screen of my phone so if it goes down I have a rough idea of where it went, and if it hit something it shouldn't, I can decide if it's worth trying to track it down.

    I live opposite a school so my flying time is limited to evenings and weekends, there's no actual law to say I can't fly during the day, it's just less hassle, there only two of us with drones capable of long distance flight in the town, so it wouldn't take long for some super paranoid parent to find out who whizzed over the school during the day and call the police.
     
  19. spark29

    spark29 Member

    Joined:
    Apr 29, 2018
    Messages:
    20
    Likes Received:
    1
    Hi. Okay some kind of tracking device never the less:) Thank’s , Ted i’ll check the link later.
    I’m a little jealous on you upcoming trip to the wild nature even if i live in a nice area with fields and forrest.

    IanSR, what do you use as screen recorder? And i know the feeling of somebody reporting you for flying over buildings/ football area or other puplic places:) Annoying
    i would consider my self respecting the laws of drones in general bit there are quite a few drones haters ot there.
     
  20. Ted Schoenfelder

    Ted Schoenfelder Active Member

    Joined:
    Feb 20, 2018
    Messages:
    31
    Likes Received:
    3
    Since the DJI Go 4 App records the data, back up video, and also has the "find my drone" feature, what are your reasons for doing an additional screen video backup?

    I've watched several videos where Spark flew away and out of range of the RC where video stopped recording. Locating a lost drone in those cases could be extremely difficult particularly in a wilderness area without additional tracking ability over and above the app. That is one reason I have the Marco Polo tracker. Don't want to lose it!