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!

Views: 3895

Comment by Rob_Lefebvre on October 30, 2012 at 11:53am

Sorry to hear that.  Did the props come off even with locknuts?!  That's really weird.

The first video, you have some serious Rate P term wobbles going on, and please, watch out for that kid!!!


Developer
Comment by Jason Short on October 30, 2012 at 12:38pm

My first quad lasted 10 minutes. Which is way better than my first plane which lasted 30 seconds...

I would concentrate on tuning that guy before moving on to AP modes. It has gains for a quad on it and the rate terms need to be lowered.

Jason

Comment by HoverX on October 30, 2012 at 12:55pm

Wow! Holly Crap, how can you fly next to a small child?

Comment by Luke Olson on October 30, 2012 at 1:33pm

I had problems with prop nuts coming off before I got too far along and started flying higher. The blue Loctite with standard prop nuts fixed the issue for me. Hopefully things go better next time around!

Comment by Tony Heaton on October 30, 2012 at 1:46pm

You realize you're not flying a toy right?  The child could have been severely injured or even killed.

Comment by Alexsey Novik on October 30, 2012 at 2:17pm

Sorry to hear... I also got my Hexa on Friday and doing my first flights with it... but there are already snow in my city, so i planned to fly later...

3DR really need to replace those bad quality prop adaptors in their kit to something that screw directly to motors.

Like this one: http://www.hobbyking.com/hobbyking/store/__14501__NTM_Prop_Drive_35...

I also have two crashes because of stock prop. adaptors... They just flew away no matter how tight you fasten your props.

And i'm second to warn you about flying near child.

Comment by Luke Olson on October 30, 2012 at 2:23pm

Alexsey, that won't solve the problem. In fact those are the exact prop adapters that I use which came off several times with my NTM 35-36A 910Kv motors. The design of either is fine when used properly, you just have to use thread locking fluid (like Loctite). You can tighten then as much as you want but without thread locking fluid they will inevitably come off.

Comment by Alexsey Novik on October 30, 2012 at 2:24pm

Luke, i'm not sure locktite is suitable on collet type adaptors. It is good to fix the thread, but will it lock plain shaft with collet?

Comment by Luke Olson on October 30, 2012 at 2:28pm

Also about the kid, or any living thing for that matter. There are several posts on this site with bloddy emergency room photos from props coming into contact with flesh. Case in point, so please be more cautious in the future. We'd all hate to see a headline "Four year old blinded and disfigured by drone" and would ever more hate to see a child injured.

Comment by Alexsey Novik on October 30, 2012 at 2:35pm

By the way, will this adaptors fit 880kv 3DR motors? Or maybe anybody know where to get suitable ones? http://www.hobbyking.com/hobbyking/store/__16719__NTM_Prop_Drive_28...

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