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Longer flight times

Discussion in 'Phantom FC40 Discussion' started by Hawkeye 1, May 19, 2014.

  1. Hawkeye 1

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    In the search for longer flight times, I bought some of the CF battery trays that attach to the side of the Phantom and gave then a try. I found that two batteries barely gave me two extra minutes of flight time....I believe that this configuration puts the batteries out to far and the props are actually pushing down on them, creating drag that is seriously affecting the flight times. Looking for another way to do this, I realized that the two trays when joined at the middle exactly fits in the grooves between the landing gear on the Phantom and can be easily secured by zip ties. The pictures I uploaded ( I hope ) will show what it looks like. After getting things secured, I tried a flight with two MadDog 2700 batteries which yielded 21 minutes of excellent flight....very stable and it hovered like it was tethered in place. The second flight was with a Hunger 5000 battery which gave me 17 1/2 minutes of time with the flight characteristics the same as the two battery flight. The two MD batteries weigh 403 grams and the single 5000 weighed 406 ....the only other thing on the FC-40 beside the stock camera is a GPS tracker that weighs 55 grams so the weight was almost identical. I am very pleased with the times I got and the mod for the tray to hold the batteries was very simple. I hope this gives some other fliers ideas on how to improve things with little changes and share with the rest of us.
     

    Attached Files:

  2. Mandrake

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    Very clever ... will give this a try thanks .. Mandrake

    Sent from the thing that does everything.
     
  3. Gizmo3000

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    Sadly, people keep purchasing the dual-battery set-ups (often along with CF props), only to learn the hard way that the results are always disappointing.

    The single 2700-2800mah batteries seem to be the ideal sweet spot for those who crave slightly longer flight times.
     
  4. J.James

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    Nice. I also surised that the only way to not have 2 battrys were they are going to be stuck in the prop wash and cutting down on the lift would be to have then mounted some way were they are under the belly and inside the legs. Such as that or the only other place under the belly place they would or could go is on the sides of the belly at an angle with a mount that could hold them there. But for testing it out I was thinking of just using some gorilla tape. Before trying to make any sort of mount that would hold them there.
     
  5. Hawkeye 1

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    I agree, Gizmo, but in my case I think I did pretty well when I changed the placement.....17 minutes out of a single battery is pretty good and I think and 21 from the two 27's is great. I really like playing around with the thing to see what I can do from a technical aspect.......I don't think it is something I'll do on a regular basis but it only takes less than 5 minutes to set up so if there's some reason I want more time, I can put it together and go. I guarantee you, I won't be taking it apart and shaving out small pieces of plastic to save a couple of grams.
     
  6. Ohary

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    not sure how much a battery weighs, but when you think about carrying that extra load, it's going to cut down on your total flight time. While one single 2800 mah might get you 15 minutes, but two won't get you 30. (I think I'm stating the obvious.)
     
  7. Hawkeye 1

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    J. James, this is put together with zip ties and it's very solid, doesn't weigh much and keeps everything under the aircraft out of the way. You can put it together in just a few minutes...the only drawback is that you'll have to use four zip ties each time you use it unless you just leave it there.


    Ohary, you're right...the extra weight precludes you getting twice the time on a two-battery setup....that's just a matter of physics I think. But I believe you get about time and a half, all else being equal. I think I'll just be using the single 5000mah battery and settle for 17 minutes....that's a noticeable improvement since I only get 14 with a 2700. If it seriously affected the flight characteristics, I wouldn't fool with it but it flew just fine is I'll use it every now and then.
     
  8. J.James

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    Ya that a great set up considering you already had the mounts anyway and found a way to make them work at better then normal efficacy. Getting 50% extra time with 2 battery's is about the best that can be expected due to the weight and diminishing returns.

    Most dont even get that when they have the battery's mounted on the out side and blocking off almost 1/4 of the area under the props and losing lift efficiency from the props.. I would assume your set up is less apt to also have as much of a problem with fast descents as the normal way them double battery holders can also cause from the batterys blocking a lot of the props lift.