Can I mount batteries under the wings ?

Hello There,

I have 2 quick question, I got a predator on his way 74" from Hking in which I ve planned to set up 2 x 5000mAh batteries that weight around 500gr each.
( Google says 500 grams = 17.636981 ounces )

Do you think that this is something doable ? Do you thing that it would be too heavy for the wings ?

My other question concern the Antenna, I d like to have one antenna 8dbi, my question is about the location :
- located on the top of the frame, near CG around the middle ( so the antenna is looking up)
- or on the same level but on bottom frame, so looking down ( between the wheels more or less )

Could any of these location bother the flight in a manner or another ?

Thanxs to all for your great knowledge !!!!

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  • If your wing load still allow for additional weight depending on what wing load you have and what is already on it it's possible , just make a small profile compartment as aerodynamic as possible and find the CG of you plane as it is, balance your batteries in the compartment as well as you cant and fix it under your wing as centre to you CG as possible and it should work good, don’t forget that the scale of a model plane is not submit to the exact same fluid dynamic then big one so be careful to keep the CG at the same place with or without the compartment


    So fin out your wing aerie in inches / load in oz you can fin info for that every wear on the net, weight your plane without the extra battery and with it as long as you do not exceed that load it’s all good

  • I ve received an email from Hobbyking there wont be no predator for the next 6 weeks ....

    Ok then, I guess that was not the one I needed ..... But damn that's the one I wanted lol

    Anyway, I m so going for the MAJA

    Just to let you know !

  • Hello There,


    Just to make my point and avoid all the usual " Predator blablabla, get yourself an easystar " that can be found in all post regarding this airframe ( I believed you made your point with this ) 


    However, I do have an easystar that I m using to learn RC basics and IT IS NOT MY PROJECT to set it up for UAVing.
    If I had to crash my Predator 10 times before I sucess then just accept it and help if you feel like, is not because someone say this and this that I wont get my chance to play with it and moreover try to sucess where others fail, that is call a challenge and that a big part of my motivation.


    Plus a part of Chris in which I saw the predator ( I loved the paint of the grey one ) who actually did  built & flew their own Predator ? I guess you guys are saying this based on others people experience so you are evaluating all aspect of my project ( Bad airframe, low skills, budget ) when I am only looking for help not judgement.


    So if anyone could help me with the Antenna question and the formula to calculate the Watt / Weight that would be really appreciated !!! 


    We know you guys are ( almost ) all pro in this topic so you dont need to comes up with these stuff to show out. I say almost because I ve read post of some of you that though ducted fan had equivalent flying time has brushless for same batteries, so getting the easystar stuff from that kind of members I consider it has trolling lol


    Thanks to all of you guys, especially to these who gave me usefull answers !! 


    Shekou !

  • Hi Chris,


    Thanks a lot for your answer that's gold to me really, 

    In front I ll have:

    - The APM
    - A Larson scanner ( ) [ Yeah I know that's so geek but I believe that would look awesome with the predator paint in black ]
    - An IR Camera for FPV I m not sure which of these 2 models below I will choose yet it depend of how much load the Predator can take.
    First one is near 500Grammes ( 17.6 ounce ) [ ]  
    Second one is around 200Grammes  ( 7 ounce ) [ ] 


    In any case I will need to counter-weight so I can permit some extra weight in front, if anyone is interested in the cam above, I used to work in my previous job with the first model and the quality by night is quiet awesome  and they are not as big as they seems on the pictures. 

    I have the tech specs somewhere if someone want them just drop me a line.


    Since I m here anyone could orientate me on the kind of brushless I should use to send this 4kg bird into the sky ?
    I ve seen a rule of 150w / Kilo but I m not sure if it was kilo and neither how to calculate this.


    Thanks a lot !!


  • You might be better to put one in the nose and one between the landing gear. Under the wings may give you longitudinal stability problems (roll) as well as pitch problems with all that added weight. From other people's reported experience this plane is already difficult to fly without doubling the weight and messing with the CG.
  • 3D Robotics
    Sure, you can mount the batteries under the wing. But I think you'll have trouble getting the CG right. What will you use for weight in the nose?
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Aug 25