3DR Hexacopter - maiden flight to wipeout in 4 days

Costly and frustrating start to my foray into hexacopters....  a heap of parts for a 3DR Hexacopter arrived last Friday, including APM 2.5, 5000mah 4s lipo, sonar sensor, 3DR telemetry link, uBlox GPS and the kit 850Kv motors and 10" props.  Asembled and working for Sat morning, with a couple of test flights in the garden Sat evening.  All good at this stage, but a couple of the prop nuts span off causing some crashes into the hedges.  No damage, but did need a metal detector to find the missing bits.

As of Sunday, I switched all the prop nuts for nylocks and went for some higher altitude tests, tested RTL and loiter functions.

Stabilise test:

https://www.youtube.com/watch?v=f-9JV8qvOsQ&feature=g-upl

RTL test:

https://www.youtube.com/watch?v=mtlYYcI2dn4&feature=g-upl

Fast climb test:

https://i3.ytimg.com/vi/njhNUfK-BZE/mqdefault.jpg

Today the weather improved, and managed to nip out to a local abandoned airfield to test the telemetry link and the auto waypoint navigation.  All went well for about 30 sec, taking off smoothly to hover at 20m, then ascending to 50m for the next waypoint......  then disaster struck as I watched a prop flutter off into the distance, and the copter go into a terminal tumbling dive, crashing at high speed into a shallow bog! 

Suffice to say, it did not fair well - two motors sheared off the alu struts, four props shattered and the electronics stack shredded along with its protective foam cover....  not a pretty site.  Plus it was sat in about 5 inches of muddy water, covered in grass.  Dragged it out, removed the lipo and then trudged back to the car with my expensive armful of wreckage :(

So - the lesson - make sure your prop nuts are tight, very tight, and loctite'd and perhaps even lock-nutted!  Fortunately it didn't hit anyone on the way down, but there were some spectators nearby who almost cheered at the splash it made and then watched fascinated as I fished bitsout the bog.

Now to order some more bits....  hopefully mk2 will last longer than 4 days!

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  • people see my video's but go into shock when i drop stuff like I have broken over 500 props getting this good. Welcome to the hobby crashing is part of the game. Clearly oscillating while acceding not a good sign you should have taken her down and checked everything.

  • Developer

    Hi Damian,

    I had similar problems at my first steps except that I had no big crash with my quadcopter. I have destroyed some planes and thus brought me into danger while learning to fly.

    My Quad wobbled like your and I lost a propeller once fortunately directly after landing.

    if you can manage to get access to rc simulator, try to fly in the simulator with the same wind conditions you expect on the testday.

    should avoid some crashs.

    Regards,
    Linus

  • I had a few props break up mid air......until I started using the Gemfam Carbon Reinforced that is. Try em out, I was amazed that when I tipped my quad over the blades didnt break (I broke a bunch doing that in the beginning)

    So what do you think is easier to fly...Quad or Hex?
  • ok .... 20 meters then :)

    And for propellers dont use the ebay black ones! They have bit me several times, so I have a bunch lying in the drawer, Switched std grey APC ones 12*3.8 , they withstand a crash into dirt - most of the times, not tonight though :)

  • I have been in the Arducopter scene for more than a year, only recently I started getting serious flying time with FPV 3DR radio and a good PID config. Tonight the quad went straight into the dirt due to a loosened hex lock screw on the motor collar. This is a very complex flying platform, and the code is not yet "bullet proof" either so expect a lot more crashes! And I second the others here : be very careful with people nearby. Any humans within 50 meters and  I land!

  • I found a new source for gemfam carbon blades....AMAZON! you have to buy the cwand ccw separate, though....oh and free shipping.

    comes out to just under $2  a pair!

  • Sounds like they are not very good prop adapters if the nuts won't remain on. I must have several thousand flights with props on electric motors and never had one come loose (never used threadlock either). Never seen any come loose on aircraft belonging to other club members either.

    Some general advice from another newbie to multicopters. Take it slow. I've had 15 flights on my hexa now without incident but I've taken it slow and steady; if something didn't seem right I stopped. Took me until flight 13 to even try anything other than stabilise with the odd loiter.

  • I am with Phill C on this. No props failing or coming off during flights... so far (nearly 20 - only one broken prop).

    Because it is a collet type 'bite', I hold the prop center rather than the motor while tightening. Holding the motor (on an outrunner type) would do nothing but allow the entire collect to slip while tightening the nut.

    This works the same way as the R8 collet on my mini-mill. Rather than clamping a cutting tool, we clamp on the motor shaft. The taper is drawn into the conical section, toward the nut, and then 'bites' the shaft.

    I agree that reverse thread type would be cheap insurance for a 'fly away' prop.

    -=Doug

  • @Randy - I've thought about reverse prop nuts and wondered if there were any available. I too wish they catch on. It only makes sense. Reverse threads are used on bicycle pedals and table saw blades for example. I hope you can encourage some supplier to offer them. 

    I've not experienced any props that have come off except during a crash... yet, but I would feel better if I had collets with the "right" threads. 

  • I had a blade break on my first flight, with a carbon fiber frame. talk about disintegrating quad! Look For the Gemfam Carbon  reinforced props. There only a dollar more then normal props,  and they are so strong its crazy. i crashed 3 times yesterday without breaking a prop! And please stick  to open areas without anyone around.

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