Hello Everyone,

I am also writing this post because I need something, and I think its possible to do. Recently I attached the new Ronin MX, A Hyperspectral Camera, An Intel Nuc to a DJI S1000. Needless to say, the payload was around 14 - 15 pounds without the 22,000 mah batteries. Flight times ranged 3-5 minutes, and ESC, motors, batteries, wires were hot after flight. The system is not efficient. 

Is there Is there anything or has anyone built anything that is under 5,000 dollars?  I am posting this because I see a lot of bright minds on here, and I have yet to see a post that someone shows how to make a system that will most effectively lift

I am posting this because I see a lot of bright minds on here and I have yet to see a post that someone shows how to make a system that will most effectively and efficiently lift a 15-pound payload. It would also be awesome to see people's most effectively system that carry 2, 5, 10, 15, 20 pound payloads. Correct me if I am wrong, really all we need is motor size how many and what set up, preferred ESC and size, batteries needed for 20 min flight.  

Lets see what you got! We are at an interensting time where sensor technolgy is getting smaller and lighter. Hyperspectial that I put on my craft 5 years ago was 300,000 dollars and weighed 50 pounds. 


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  • If you still want to build monster here is nice small blog


    with this bird (credits go to Martin Raju,Tallin,Estonia https://www.facebook.com/martin.raju.9?fref=nf)


    3702290311?profile=originaltry to figure how much are the parts and thats not all,just bird,also this is quad not x8..also he build it himself...he knows i doubt you can,sorry...someone will charge you same amount as parts to guarantee you its safe...

    List of parts:
    *T-Motor U13 (100kV) - 4pcs 
    *T-Motor Flame 80A 6-12S ESC - 4pcs
    *T-Motor 29x9.5 3-bladed prop - 4pcs
    *T-Motor prop Quick-release for U13 - 4pcs
    *Custom 4mm thick carbon centerplates
    *Custom 3mm thick aluminium motor mounts - 4pcs 
    *Custom navigation strobo LED setup
    *Custom vibration damper
    *30/28mm Carbon tubes - 4pcs
    *3D printed parts
    *Vulcan UAV 400A PDB
    *Pixhawk FC
    *Castle Creations CC BEC (One for Pixhawk, one for retracts) - 2pcs
    *Gens Ace 16 000 mAh 6S (2S2P) - 4pcs
    *Futaba T14SG + R7008SB (+telemetry)
    *ARRIS L1000 V3 retracts

  • +1 to Emin Bu.

    I have tested KDE motors. KDE is over optimistic in specifications of their motors. they did not performed well for me either. I am using T-Motors, and I hope T-Motors U11 can do your job well.

    I have made a quad with U11 and that lifts 8kg payload without a problem.

  • I don't believe you simply because you make the point of saying "I know a thing or two about these big machines because I have built a few of them"  Too little humility too much corporate ego.

    Brian Riskas said:

    As James stated above, that setup will get you the performance you desire. However, I disagree that you can do it for $5,000. Just the motors, escs, and props will set you back more than $5,000. Factor in the cost of a frame, autopilot, batteries and chargers and a more realistic estimate is over $10,000 just in parts.

    I know a thing or two about these big machines because I have built a few of them. KDE 7215 motors, KDE 95A ESCs, Tmotor 29x9.5" props on a custom airframe with a pixhawk. Also worth noting that these large machines take a bit of effort to setup and tune. When you factor in all the time and materials it takes to get one of these larger machines built, you are probably better off buying a pre built machine (like James stated above). This machine was built for a commercial customer that is using it in invasive plant control.



  • People around here do not like DJI( i am not a great fun eather,only have Phantom 3 from them as best small setup money can buy).....the multi you are looking for is DJI m600


    you already have Ronin MX(which will only work properly and show full potential with DJI controller) and you are already familiar with DJI fly routine...for 6000$ how much it is m600 with second set of batteries,you can't go even close to the setups people suggested above...

    25kg monsters ....which are very stressful to fly,especially for 30 or more minutes...and very dangerous,in most countries you will need highest level of permission and special certification...

    It's not just multirotor you will pay...you need HD videolink (1500$)...LiPos (min. another 1000)...proper charger with power (around 500)...decent props for this big machines is min 300$ a peace...etc.etc.when u end this build you will spend more than 10 000$ bcs. with a such setup you just can't buy cheaper components (would Ferrari be the same car with cheaper brakes and tires for example?...)

    Brian's multirotor setup is great,one of best i ever seen,but ask him how much time,money and nerves he spend on that machine until he get her fly properly

    You can also achieve 15lbs payload with t-motor U7 motors(set of 8x U7 490KV i saw on fcbk group go for 600$ all together) but it wont be efficient(7-10 min with 15lbs)


    For a long time fly you will build non coaxial flat octa or hexa and i would for sure consider DJI propulsion sets wich a most efficient at the market at this moment,and maybe you can only upgrade your DJI S1000



    Also,where did u people get information that KDE is the best motors with their fake specification data,and non compatibility with other type of ESC but KDE,almost double price in some cases...check this video(lots of other specifications you are interested inside)


    I for sure vote for T-motors,greatest multirotor motor company,people outside USA are not that impressed with KDE just because is made in USA(and it is not!)

    With all mentioned above,and also as an ex-owner of relativly cheap and big multi

    Foxtech D130 U8 https://www.foxtechfpv.com/d130-x8-v2-a2-6s.html 

    which i sold bcs it was annoying and too big,and to expensive(once i break 3 props and it was almost a 1000$ to replace them) i strongly suggest you go for m600!

  • Tom-

    That is pretty much the setup you would need to get the payload/ flight time that you want. I have some (very poor) video of the machine flying around, but getting better videos are on my agenda. The machine has so much thrust that it flies effortlessly with a 20lb payload. I actually wound up limiting the lean angle of the copter and reducing the rcfeel parameter to get a fairly tame flying copter.

    As for the X8 vs flat octo, the X8 layout is more efficient when you are limited by mass. This machine was designed to stay under the 55lb FAA limit, and the X8 frame layout is much lighter and can fit larger props than a flat octocopter of the same weight.

    I have not had a motor failure with this large X8, but I have had a failure with a flat octo that we used to develop the tank system. The machine flew well even with one motor out, and was a huge reason to go for the X8 when we developed the larger machine. I see no reason that the X8 couldn't offer the redundancy at the payloads that we are flying (approx. 16lbs). This machine hovers at ~48% throttle with an AUW of 55lbs, so there is plenty of thrust overhead in case we were to lose a single motor.



  • Thanks everyone for your input. So far it sounds like 120 - 100kv motors, around 30" props, and matching ESCs is the way to go.  I have a feeling it is easier said than done. 

    Brian, your multi-rotor looks awesome, and I appreciate your input! I would love to see some video of it flying and what would be even more impressive is to see it fly with a 20lb payload. I am very curious of its responsiveness and its attitude when flying under load. I like the graph of payload and flight time on your website. We will be in touch. 

    As far as the X8 goes is that the best approach, what makes it better than an octocopter set up? Would the X8 design respond similar to the octocopter in a situation with ESC or motor failure? 

    Does anyone have any videos of one of the 30' prop multi-rotors flying? 

    Lets keep this big copter thread going! Who else has input? Does Brian have the only compleated and documented design?


    -Tom H

  • Hugues-

    The idea behind the design was to have a modular frame assembly that would support a variety of layouts, from a quad to flat octo to an X8. For example, a version with 16" props would use the same electronics housing (the 'big money' part) and would use the same airfoil shaped booms, just shortened. Based on the interest in this thread I will put together my own blog post in the next couple of days.


    Our main motivation for going with the airfoil shaped booms was actually vibration reduction. We ran a few CFD simulations while we were still in the early phases of the design, and the pressure drop across a 30mm boom is substantial, even at the lower air velocity from the larger props. Factor in the larger mass of air impinging on the boom, and you have a recipe  for large vibrations.

    In our testing, we have not noticed any strange behavior compared to any other X8 (ie no weird vibrations, uncontrolled movement, etc). I agree that the asynchronous phases of the props are very difficult (if not impossible) to model, but so far in our testing it seems to be a non issue.

    The machine climbs and descends very well, and is extremely stable, even in the wind. We intentionally flew with no payload on a windy day (15mph, gusting to 20mph) and the machine seems to be pretty much unaffected.  I personally believe that the airfoil boom acts like a stator in a jet engine, and helps to align the flow from the upper prop to the lower prop, increasing the efficiency of the lower prop (although I have no scientific proof of this either way).

    As for your comment on helicopters, I am in total agreement. Once you scale to larger sizes, a swashplate will always have a better response than a large fixed pitch prop. A variable pitch multirotor is a solution looking for a question, and has all of the negatives of both a single rotor helicopter and a multicopter (although I would still like to build one someday just for the challenge of the gearbox design).

    Thank you for your compliments, our intentions were to develop the best heavy lift multirotor platform, bar none.  I will post some better pictures and technical information in the next few days.



  • Hi Brian,

    Of course the improvement in efficiency is obvious.

    But I can also certainly understand, how especially with the big slow props and high mass and periodic pressure waves from them on the spar, that broad low to medium frequency high amplitude periodic asynchronous vibration could be a serious problem and be hugely reduced by the aerodynamic shape.

    I am wondering if you still don't run into some negative effects simply because of the out of phase coaxial blade interference especially when maneuvering or climbing or descending.

    With those big slow props I would think that might still get a little choppy sometimes.

    Just a question relating to my own impressions, wondering at the real life importance of the issue.

    You seem to have been one of the first to put together a really well designed serious large multicopter.

    From what I know now, I think your large X8 copter probably represents the reasonable upper limit of multicopters.

    For practical purposes, larger hovering UAVs are probably generally going to be better as helicopters.

    You are at the top upper diameter fixed pitch propeller wise that will work effectively and provide an acceptable response rate for a hovering vehicle.

    I suppose you could make a Coaxial 10, 12 or even 16 using the same components, but I think a properly designed heli would have the edge, both handling better and being more efficient.

    In any case, hats off, you have set the bar.

    Best Regards,


  • MR60

    Thx Brian for explaining your frame design. will you produce a smaller version for 16" props? would be interested.

  • Nice Brian we wait your post :)

This reply was deleted.


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