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DJI F550 Build

Discussion in 'Multirotor' started by GPS, Apr 14, 2012.

  1. GPS

    GPS Registered

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    The guy I spoke to at UAV Products said he thinks I should be able to get 20 minutes flight time with 4S 6000 mAh packs.  I have some 4S 5000 mAh packs from my OFNA GTP2e so I might just try them to see the difference.
  2. GPS

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    I like this guys review:

    [youtube]
    Last edited: Apr 9, 2014
  3. GPS

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    I realized I don't have many photos in my "build" thread. The kit went together with so little effort, and there are so many great DJI F550 builds on the web and YouTube that I kind of just rushed through eager to fly it.

    Here are a few photos of it first next to the GAUI 500X for a size comparison and then the F550 alone top and bottom views.
    The broken propeller is from the recent in-flight DJI brand propeller failure. I'm getting kind of paranoid about DJI propellers.

    DSCF1196-web.JPG DSCF1198-web.JPG DSCF1200-web.JPG
  4. GPBill

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    Are the props compatible between the 500X and the F550? They look very close in the photos.
  5. GPS

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    As far as blade spec the propellers are 10' 4.5 or 10' 4.7 so I think the difference in that way is minimal. However the GAUI 500X propellers are 5mm bore and the DJI propellers are 8mm bore. The DJI propellers also have two flats molded in the match two flats on the motor shaft, a nice feature but any other 8mm bore propeller would also work.

    Yesterday Rick showed me the colorful propellers he and John (Tiger) use and they seem to come with some sleeves that can reduce the molded in bore. As long as the propeller's molded in bore is at least 8mm and included some reducer sleeves to 5mm I should be able to use the same propellers on both aircraft.

    I am looking for sources for Graupner propellers and these guys seem to be the best I have found so far:

    http://www.v-eastonline.com/categories/Graupner-Prop-Shop/Graupner-E%2dProps/

    I think the 10x5 should work unless someone out there sees a problem with them.
  6. GPBill

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    I use a lot of the APC props on my airplanes and they come with sleeves for different sized motor shafts. I see they now make some for multirotor craft.
    http://www.apcprop.com/SearchResults.asp?Cat=28
    Most hobby shops, on the street and online have them.
    I've never had one break without crashing it.  ;)
  7. GPS

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    It looks like their 10' 4.7 propellers all have 6.35mm (0.250 inch) holes.  I could use the supplied sleeves to get to 5mm if there is a 5mm sleeve included in the set but that won't help with the 8mm holes needed for the DJI motor shafts.
  8. Tiger

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    I just measured the hole in one of the green props and it was 6.22mm.  That means you'd have to drill exactly .070" out of it to make it fit your 8mm motor.  That's only .035" per side.  That looks like more meat than is holding the blade on so  I think that would work just fine.

    ...Tiger
  9. GPS

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    Tiger - What model Futaba radio do you and Rick have?  Isn't it a 10 channel?  I see Futaba has a 10CG and then 12FG then 12Z before you get into silly expensive models like the 14MZ and 18MZ.  I am also not quite sure what the difference is between the 12FG and 12Z.
  10. GPBill

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    You're right.  :(   
    Eight mm is quite a large shaft for a motor that size. I had never run into that problem.  ???

    I believe the slightly larger APC props will fit up to 8mm but that doesn't do you much good.

    Edit:
    Hub inner diameter: 0.375" (9.5mm) where rings are installed. This is on an 11" prop. To big a hole without a sleeve and to small with one at 7.95mm.
    I've been little help.
    I think you have to buy the sleeves for the Graupner props.




  11. GPS

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    I'm not really comfortable drilling out the holes in propellers that should be perfectly balanced and spinning concentrically.

    The Graupner propellers have 8mm holes already and they seem to be liked by a lot of quad folks. What the Graupner USA website does not say though is if they come with sleeves that will get them down to 5mm for the GAUI.

    Graupner USA website:
    http://www.v-eastonline.com/
  12. GPS

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    I had a conversation with Pelagic Pilot this past weekend when we flew at the school on Harbeck. We wondered if one could fly to a mountain and back that is visible from the school. We speculated on what the flight time would be up to the top of that mountain and back and if we would have the battery capacity to make such a flight.

    Pelagic Pilot checked and found that it is about three miles one way as the crow, or helicopter or quad, flies.

    What is cool about this flying location is that you have a clear line of sight from the school to the towers at the top of the mountain and a nice roof shade for those hot days, which it was at the time. If there was power there I would say that spot is better than the Sunday flight place on Redwood.

    Anyway, it got me thinking about flight times again. I read on another forum recently where a few DJI F550 owners felt that their hexacopter was more stable with more weight. This theory is supported by a video DJI themselves made:



    At about 1:34 you can see in the video above they load the hexa up with 1 KG worth of batteries.

    I want to try and get 30 minutes of flight time and so I am going to make a parallel adapter and try flying two 3S 6400 mAh batteries which are 500 grams (17.6 OZ) each. I am getting a solid 18 minutes of flight time with one of these batteries so I am curious how much flight time I will get with two in parallel.

    Anybody care to guess what the flight time will be?

    I will be mounting the batteries for my test to the top of the hexacopter which could be a disadvantage compared to the DJI folks test mounting the batteries to the legs down low.

    Since I don't yet have anything but the DJI propellers to try this test with I will probably stay at a low hover since I have lost all confidence in these propellers.

    What could go wrong? ;)
  13. Tiger

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    I'll be interested to hear how this comes out.  I know some other guys that did battery tests and decided that 4000mah was the sweet spot for them.  Seems like at some point adding more batteries provides diminishing returns.  Not that you don't get any more time, but the little you get isn't worth it.  I'm getting about 15 minutes of real flying on my 3300's right now on the DJI frame.  It's interesting that you're only getting 3 minutes more with about twice the battery.  Hope you make the test twice under identical flying conditions using one and then two batteries.  If your 18 minutes represents real flying, then your two battery test just hovering is going to be a little distorted. 

    ...Tiger
  14. GPS

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    I get over ten minutes flying with 2250 mAh batteries on the GAUI 500X.  I should get some of those 3300 mAh you use to see what the run times on the GAUI are.  I tried the 6400 500 gram batteries and the GAUI 500X does not like them, they are just too heavy.

    Don't forget the DJI F550 has 50% more motors than the F450.  I think they are the same Kv rating.
  15. Tiger

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    Yes you have two more motors, but they shouldn't be working very hard.  That is until you stick some big mother anchor of a battery on there.  Why don't you just try my 3300 on yours some time.  I'm using EC3 connectors, but I have adapters to most other things.  What connector are you using?

    ...Tiger
  16. GPS

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    bump

    I have EC3 on the GAUI and Traxxas connectors on the DJI F550.

    EDIT:  Found a couple Traxxas parallel adapters from my Traxxas eRevo 1/16 scale truck.  Now I just need to replace the broken F550 prop and get some long battery straps.
  17. GPS

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    Well the DJI F550 can lift the two 6400 mAh batteries, with ease I would even say. Unfortunately I had my THIRD in-flight DJI propeller failure only about two minutes into the flight time duration test. This time the propeller failure caused more than just a broken propeller or two.

    EDIT: I ordered ten Graupner propellers last night.

    DSCF1202-web.JPG
    Last edited: Apr 9, 2014
  18. w00d

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    Sorry Yoda, but I'm going to say it anyway being the gruff OLD man I am...
    ... Why not give Tiger the benefit of doubt, I would also guess the larger batterys might be causing your blade failure !?!

    Try your old blades and/or the entire bird with less weight and if the dieting solves the issue you will at least know this is causing your problems

    Then if you still want to use the larger Batts ...
    ... If after 'testing' your SURE this is the problem it's now the time to go shopping for better and probably more expensive blades

    Shopping blind is expensive !!!

    Ps: Do this testing on the repaired arm ...
    ... DIY, the arm repair and keep the new arm (and since you've already ordered the blades) and presumably newer better blades in your inventory until your sure your not going to have any more blade failures ;)

      [​IMG] [size=1.2em][shadow=gray,left]w00d[/shadow][/size]


    [hr]
  19. Tiger

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    GPS - I have a couple extra white arms on order.  They are scheduled to arrive tomorrow according to tracking info I just got.  I should be able to bring you one at the indoor fly or meet you in town when I pick it up at the PO tomorrow.  You can borrow it until your order arrives.

    wOOd - Good thinking!  I totally agree on the weight being an issue.

    ...Tiger
  20. Pelagic Pilot

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    Even though I am not a DJI owner (yet), I have been following the blade issue and I am beginning to be convinced that DJI blades are bad. Far too many youtube and forum posts of this happening. When you take two pieces of these blades and tap them together they sound like glass. I would expect some kind of factory recall or something in the future.

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