3DR frame critique

First of all please understand that what I am posting here is my opinion through about 50 hours of using this frame. I am a quadcoptor novise, so please feel free to correct me if you think I am mistaken.I am using the 3DR frame and hope that this feedback will provide valuable input for a v2 design.1) Motor mounts:The motors mount directly to the aluminum frame, causing undesired vibration. Perhaps a simple foam mounting pad could help correct this, but the bolts would still be an issue.The most serious issue here is that a hard landing on any arm may cause the frame to bend because of the motor mount (this happened to me after a hard landing on 1 axis on grass). I want to make sure I am clear on what I am talking about here - this happens when the motor is forced towards the center of the frame because of how close the outside motor mount hole is to the edge of the frame. A possible solution here would be to provide additional internal structural support by running the motor bolts through 18mm plastic standoffs on the inside of the frame.2) Landing Gear/Leg mounts:One of the major issues that I have run into while leveling this frame was became the legs -- they will shift both forward and backwards because of the mount to the main frame. A hard landing or two (like shown in the 3DR frame stress test video) will cause the metal screws that mount the legs to the frame to force the M3 holes in the fiberglass legs to be oblong and allowing the legs to move back and forth.This may not seem like much, but when placing my 3DR frame on a 100% level slate pool table it wobbles on each axis. I solved this by placing the quad on the pool table and placing a bubble level on each axis while adjusting the legs back and forth. WHAT A PAIN!!!3) Landing Gear/Legs:The black M3 female to female 18mm hex standoffs are proprietary; the only source I have found for them is DIYDrones store. A good work around here is to use three M3 nuts and an M3 25mm bolt to create the same effect and will actually provide much better support than the OEM solution anyhow.4) Base level mount (power distribution):When stripping the 3DR frame down to the power dist level the entire frame will want to fall apart because all bolts are mounted from the bottom. A good work around here is to use plastic clamps on each arm or a dab of hot glue/etc on each of the eight bolts that mount from the bottom.That's all for now - I hope this information is helpful.

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  • I like that design, Ian.  I have been putting some thought into totally redesigning the landing gear myself, but am probably going to go the heli skid route instead of 4 individual legs.

     

    I made 1 minor change to my 3DR frame that has made a major difference for me.  Very simply I took 8 extra plastic center shaft adapters that come with the props (the ones with the small holes) and ran the motor bolts through them on the outside of the frame - this has reduced the noise and vibration dramatically.  I am also planning to test mounting the motors on top of them as well (between the frame and the motors) - I am thinking that this will further reduce dampen the sound from it.  I would recommend that anyone that has a 3DR frame swap out the metal washer that is supplied for the motor mount for one of the plastic "washers" that is supplied with your props.

     

    I have also upgraded to 12" props and it is flying like a dream.  I am sure the experts could find faults with it, but with the standard PID settings it is flying nearly tuned and responds extremely well.  Once I have the landing gear and GoPro mount worked out I will be set.

  • for the motor mounts i will be trying out 4mm nylon 42 sheet to make my mounts. my arms are carbonfiber tubes and the nylon can be heat formed with wooden molds and a heat gun to make 'U' clamps to attach the mounts to the tube. the flexible but strong nature of the nylon should do good to absorbe some of the vibration. my landing gear will be made out of the same nylon doubled up and held on by phenolic blocks with a thin rubber pad inbetween them to prevent movement. the gear will be attached with nylon bolts as well. i dont have the motor mounts designed yet but will once i get my motors in.

     

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  • That's a great idea; please post some pictures here when you get it worked out.
  • I have come up with a plausible idea for the landing gear. I have decided to mount 1 off-road shock absorber to each landing gear by connecting it to the gear on one end to the frame at the other. Basically the connection from the frame to the landing gear becomes a pivot point. This enables the frame to not to have to take as much force on hard landing. I am still in the process of working all of the mounting out.

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