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  • John Maffetone 

    if take the motor MN4014-11kv330 with Prop DJI15x5 we take from one motor for 8A the thrust 1500 (with 5s battary)

    Battary 6s11Ah weight is 1235g, if we make quadrocopter then we have ~200g from each motor (1500g-1235g-149g motor) and is 800g for frame, esc, wire, reciver, naza e.t.c.

    with this thrust fo motor need 8A and time for fly is 11A/8A*60=82min.. with error ~60min, vis.asta can select more optimaly component, modify algoritms e.t.c. he spent a few years and more money. I picked up the parts for a few minutes to an hour of guaranteed flight. I think the video is true especially considering dumping batteries. If possible, I try the summer volunteered his test flights to see all by myself.

  • Two of these cells alone weigh almost two pounds... Anyone know how much power is required to lift two pounds on four motors?

  • If you do a basic calculation and assume each motor is only drawing 4 amps for a total of 16 amps that would requrire at least a 32ah battery not accounting for a peukert effect for 2 hours. Even with 2 amps you would need a 16ah battery for a two hour flight. Not even sure 2 amps per motor could lift any 16ah battery 7v that's only 56W of power. Must be some extreme battery technology. I don't think you have too much more room for improvement from the motors...not sure how much more power you can get out of a motor from a given input electrical power.

  • sorry thrust for motor is not 1170A, is 1170g :)

  • who want to check the following component for quadrocopter:

    Battary: 4 * 3s11000 (620g or 2480g for 4x)

    Motor+ESC: mt2814 -11 kv710 + ESC20A (150g or 600g for 4x)

    Reciver: Anybody ~10g


    Prop: APC15*4 (~15g)

    Controller: Naza ~80g

    4xBattary+4*(motor+ecs)+reciver+naza+frame+4xProp=~=3680g (weight)

    Thrust for 1 motor mt2814 -11 kv710 with prop APC 15x4 for I=12.7A is 1170A

    Thrust for 4 motor is ~4600g

    Battary is 4x3s11000 is 44Ah

    for this setup wi have copter weight  3680 g with thrust 4680g when I=12.7A

    Time for hovering ~44Ah/(4*12.7)*60=~50min (is with wires and additional 1kg payload)

    Сourse calculations are rounded. not taken into account in order to balance energy consumption, a little inflated these batteries and engines, the weight of wires and bolts. But even if we take the 50% error we have fly time is 25min with payload 1kg. I did not choose the most optimal motor, battery quantity, specification made ​​in 5 minutes. Cost of this components ~2000$

  • @Carl: hmm? PX4FLOW gives optical/distance based 3D position over ground, plus ground speed/direction/turn tracking which makes it perfectly viable to navigate without GPS if you know your starting point and heading. You would have to program it, but the sensor is working and very precise at what it does (I have it, still just playing around with it though). Gives a totally different meaning to Position Hold VS the pathethic precision GPS offers. 

    @Brad: I think you are discounting the antigravitational effects of the diamond coated unobtanium nanofibres used ;)

  • @Brad Hughey, thanks for your comment. i believe it should be mentioned here that on that russian forum vis.asta is constantly looking for someone how could build big (or should i say - HUGE?) props - which is perfectly supporting quotes you're bringing "bigger props -> higher efficiency"

  • I am always a bit amused when these flight time controversies arise, which they are prone to do from time to time.  The basic question must be answered: are the laws of physics obeyed by such claims?  For the answer, one must get an approximate value of total mass and the total swept rotor area.  From this, you can calculate ideal induced power at the rotor plane with basic algebra.  Assuming a perfect propeller, you'll never do better than the ideal power load.  The typical figure of merit for a properly applied prop is about .60; in other words, you need about 40% more than the ideal under real-world conditions.  The calculations in this thread are based on Newtonian momentum (actuator disk theory) and are taught to all graduate helicopter aerodynamic students.  In other words, here is your empirical hogwash detector (I'd run the numbers myself, but it's 4 AM here and I'm short on sleep):

    Given the worked example of a 4 pound quad with 11" props, the theoretically perfect power dissipation in hover would be 96 watts.  I don't care if your motor magnets are made from pure unobtanium, if you're a genius savant of propeller design, nor if you're using a photonic guidance system from the year 2211, it takes at least 96 watts to keep that copter in the air.  (maybe a couple watts less if it's cold and dry - adjusting for air density).

    Disk loading and FM, dudes.  It's all academic after that.

  • hi Guys, I follow your comments about 114 min flight show in the calcolator, There is an error.

    It's simple to find correct value and hovering time in the calcolator:

    If you use the box Model Weight ----- INCL DRIVE , you calcolate with ALL weight ON, (incluse battery pack) this is the really weight of the drone.(NON 850 gr like you with 21A pack with 1218 gr. weight)

    If you chose WiTHOUT DRIVE, you calcolate real value of the drone without battery.(500 gr - 1500 gr)

    If battery weight is calculated alone,  if you change the battery pack, your time change too, but not so like you.

    in the last right box you can see total weight ALL UP changing.battery pack, i'll show the real value.

    Hope it's useful.

    hi, Mike

  • LanMark it has been explained why he was doing it outdoors in the middle of the night. He was doing a test, not a record run. Why would he rent a stadion to make a video to show us? That makes no sense.
    I saw somewhere on the russian forum that the wight of the setup was areound a kilo and a half, not sure if he said it or another guy, but if he is usig LiSbatteries for instance, it might even be possible to achieve the flight time he gets without the custom motors and es since people have done 1hr flights wi off the shelf stuff. LiS has double the power density compared to LiPo, so a 1kg LiS would be like a 2kg LiPo but the hover amperage would be lower us giving much longer flight time.
    Eyeballing it I am guessing he is looking at 10amp or so to hover if at 6s equivalent voltage.
    I do think there is some exotic tech in this setup since he has himself said that pricewise it is not a hobby setup so it could well be including funky battery tech and some differences in how the motors are driven, not to mention handmade carbon props and motors.
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