Just finished designing my first quad. What do you think?

Discussion in 'Frame Design' started by Alyssa_fr, Jun 25, 2017.

  1. Alyssa_fr

    Alyssa_fr Member

    Dear All,


    I am aiming at building a sturdy, stable, FPV quadcopter that weight less than 800g including everything. I am not really interested in acrobatics, but rather in video quality and stability as well as in ease of flight. I can handle electronics, programming, PID setup, but I am not a gifted pilot. So I expect the FC to behave well. I have selected all the parts, but I am unsure...

    ABOUT THE FRAME
    My frame will be an aluminum and plywood that should weight 229 g for 9" propellers with 2" clearance between them (propeller tip to tip distance).
    QUESTION: Is 2" enough clearance between propellers?

    PART LIST

    WEIGHT
    All this should weight around 750 g leaving me 42 g (to 799 g) for unforseen weight (Though I took cables, connectors, etc.. into account).​

    QUESTIONS
    Based on your experience, is there any part that I should replace? Will every every part play well with the others? Will it fly? Perform as expected?​

    I have attached to this post ecalc computation results as well as a better formatted part list with additional info that also shows the pilot gear.

    Thanks for your patience and help.
    Alyssa
     

    Attached Files:

  2. mozquito1

    mozquito1 Well-Known Member

    Them esc might be OK but I would go for 20-30a those are chunky motors with them 9" props.
     
    dragger201 likes this.
  3. Alyssa_fr

    Alyssa_fr Member

    Thanks for you reply. The ESC I selected are 18 A, 30 A in bursts and ecalc tells me that I won't go over 11 A in bursts. But I have no experience. I had a very hard time finding those extra light ESC. I would replace them if I were to find some equivalents (up to 50 % heavier) for 20-30A. But I failed. Do you know some parts I could use?

    Also, I was wondering about propellers distances. Do you know which safe distance I should use so motors don't disturb each other? Because, if I could make a smaller frame, I could transfer some of the frame weignt into the ESCs.
     
  4. mozquito1

    mozquito1 Well-Known Member

    I been using pocket rocket 20a very small & capable. Been using for 7months now. No failures very reliable. I just built a quad & the props motor 1&2 there is literally millimetres in it & motor 1&3 only about 25mm . this frame is not for speed. Wrong shape but it does shift. This 210 is the smallest frame for a 5" prop.
    It flies OK even with props so close togeather. But put the same kit on a 250 frame it is faster. If I was you with that size prop try around 4-6" clearance.
    Never thought of doing anything that big but somehow those big props so close together as 2" would be more stable the more you give. You could get an octo in the same span I think would be more stable for photography. IMG_20170624_182357773-1024x575.jpg
     
  5. Jackson

    Jackson USA member at large

    Maybe make it a hair bigger so you can try some ~1045 props. Those motors can handle it and you'll probably get at least 10% more thrust while spinning at lower RPM.
     
    dragger201 likes this.
  6. Alyssa_fr

    Alyssa_fr Member

    Thank you all for your replies.

    Yes, indeed, the motors can handle the 1045 props. But that gives me a lift that is close to 3 times the weight of the copter. And I can't go over 800 g all included (law will change in my country within 12 months).

    This is the same reason why I can't go hexa or octo. Too much weight. I wasn't able to find an hexa under 800g with 15 min flight time and FPV using a frame I built myself. And I would very much like to build the frame.

    Each inch prop clearance costs me 11 g on the frame. I am moving towards 8045 props, 750g and 3.5" clearance. Thrust/weight is 2.1, estimated flight time is 15.7 min and max current 7.11 A which looks fine with 18A/30A ESC.
     
    Last edited: Jun 26, 2017
  7. Jackson

    Jackson USA member at large

    That will be one slow, flying pig. Even with the clearance you have 1045s will work. You should try some just for the hell of it, you may like the way it flys. I can't quite figure out from your drawing where the 2" clearance comes into play. There is certainly enough room between props for 1045s.

    These are the type I use, from various sources and they all seemed to be surprising well balanced. FWIW the black ones seemed more brittle. Cheap enough to experiment with.
    http://www.ebay.com/itm/2Pairs-10x4...385519&hash=item3f54022e60:g:y7AAAOSwFnFV~4fW

    Oh well, Good luck.
     
  8. Alyssa_fr

    Alyssa_fr Member

    One slow flying pig ? Oh no... I have been trying so hard to get a Trust/weight ratio of 2... The most efficient setups (the one that gave me 18 min hover time instead of 14-15 min) had 2.6-3.2 trust/weight ratio and I thought that was too much for the quad to be stable (a small change in prop speed would have a too large effect).

    So I should go for the 2.6 thrust/weight designs the?

    By prop clearance I mean the shortest distance between propeller tips (the shortest distance between the circles). On the schematic, the propellers angle is random and the prop clearance was, I think, around 5".

    I have tried a design of a hex frame around turnigy 3020 1800KV. The thrust/weight ration is 2.6, but the estimated hover time is poor (12.4 min for 800g). I estimate the total frame to be around 717 g including everything. This leaves me a small margin for error if I plan on adding a brushless gimbal.

    hex.png Untitled 4.png
     
  9. dragger201

    dragger201 If it ain't broke, don't fix it??? You kidding?

    Hey Alyssa.................what are the dimensions on your aluminum and plywood??
     
  10. Alyssa_fr

    Alyssa_fr Member

    On the hexacopter, arms are 19.35 cm long each and 1.15 cm large (there is 2.4 cm between opposite arms in the center). Motors are located 1.5 cm from the edge. The schematic respects all proportions. The green rectangle is the 2700 mAh battery. Props are 6". The wooden discs are 6.5 cm in diameter.

    More info in the attached file.
     

    Attached Files:

  11. mozquito1

    mozquito1 Well-Known Member

    Sounds like he knows what he wants.
    I just think it would be more stable with an extra inch or two prop clearance.
     
  12. Alyssa_fr

    Alyssa_fr Member

    Actually, yes... and no...
    I want to build a FPV drone that can also be used to record nice videos (so I will eventually add a gimbal). The total weight should be less than 800 g (hard limit), expected hover time around 15 min. I do not need acrobatics but it should still be responsive (not a slow flying pig). And I wish to build my own frame (I am an electronics / computer science engineer).

    However, I have never ever used a drone. So I am new to it. But I have been researching the topic for quite some time. And I have arrived to these designs.
    Nevertheless, I do not know if they can fly. Is the hardware compatible? Can the receiver work with the FC? Can the googles work with the camera and transmitter? Will the motor or the ESCs burn?

    For instance, I have based my designs on a quad with quantum MT 2212 1000KV + 9055 props, 5" clearance and a 2.7 thrust/weight ratio. Apparently it is not a good choice since it is expected to lead to a slow flying pig. That's so unfortunate.

    I am trying to cut down the weight. But that leads to a smaller frame, so to smaller props, so to less efficiency, so to a reduced hover time (which I expect to cut by 30 % by actually flying).

    :(

    I really come to you guys because I need your experience. You know which designs work, which ones don't. You know if I should go for quad, flat hex or Y6. You know which motors I could get that are lighter than my 52 g MT 2212 1000KV.

    Bottom line : I have gone as far as I could without ever touching a drone. I am stuck and the decisions I need to take must be based on empirical facts, not on theoretical knowledge. That's my way of saying that I really need you.

    Alyssa
     
  13. mozquito1

    mozquito1 Well-Known Member

    Start small. No good getting all that gear up in the air for it to come crashing down on its & your maiden. Start small & cheap.
     
  14. mozquito1

    mozquito1 Well-Known Member

    Oh sorry did not realise you are a lady. Many pardons. You go girl.
     
  15. Alyssa_fr

    Alyssa_fr Member

    OK, lets shrink everything down. Maybe having larger props requires bigger frame and heavier motors and I am just carrying dead weight.
    Would you have a motor / prop / battery combination to set me on track ?
     
  16. mozquito1

    mozquito1 Well-Known Member

    Sunny sky 2213 1000kv bit pricey but decent motors. Doesn't have to be these but around this size. & I would say any 4series battery. 3 would get it up but be a bit sloppy. As for props I don't know which specifically would be best.
    But any 10" prop will run on them 2213 size motors. My heaviest quad is 520g my emax 2205's produce about 1kg of thrust per motor. So could easily carry a camera & gimbal. Even though it's an acro quad.
    Ten inch props is a 450 or 500mm frame. Search flame wheel.
     
    Last edited: Jun 29, 2017
  17. Alyssa_fr

    Alyssa_fr Member

    Thanks. I can find 2213 at 980 KV but not 1000. Are they still available ?
     
  18. mozquito1

    mozquito1 Well-Known Member

    Sorry that's what I meant. Aswell as around that size. I don't use that size motors but. My first set was dys be1806 & I put all sorts of props on them 4-8"
    So I can only scale up. Any 2213 does not have to be sunny sky but they are good motors.
     
  19. Alyssa_fr

    Alyssa_fr Member

    Ok. But a 1000 KV motor would require quite large props, around 8-10" depending on its power, right? So that would lead me to a "large" frame? Or am I missing something?
     
  20. mozquito1

    mozquito1 Well-Known Member

    The things I don't skimp on is motors & esc. if you want to run 9" props as originally stated then 2213 motors is the way to go. Which is about a 450-500mm frame. IMO best run on 4S batteries or bigger.
     

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