First Video Flight - Something Went Wrong

[johna58]

Hello Everyone,

Here is my first flight I made with my GoPro Hero3 video camera attached. I wish I had my FPV in place but at least I am able to take aerial photos; that is until 6:52 minutes into the flight when I was gradually descending for a landing and then something went wrong. I do not know what caused it to fail and tumble to the ground so I am hoping someone can provide some logical explanation and direction for me to to explore and prevent it from occurring again.

Damaged: Number 3 leg broke in half, number five leg is fine but it broke at the connection at top board. LIPO was through about 5 feet from where the craft landed. Some of the outside plastic shrink-wrap tore off but the battery seemed to be fine (no swelling or gouges).

This is my setup:
A F550 with standard motors, Naza-M with GPS running on 8" DJI props powered by a Turnigy 4S 4000mAh LIPO. My radio is a Spektrum DX8 (I know I should consider a Futaba but no money).

Weather Conditions:
The air temperature in Georgia United States was 38 degrees with a 9 to 12 MPH wind and the time was about 3 PM.

 

[olof]

Were any props broken? If so where were the parts and did you find all of them.

A prop that came apart could cause this.

A bad ESC connection could also cause this.

What mode were you flying in? If the GPS antenna came loose in flight this could cause major problems if in GPS mode.

 

[tstrike]

I'm gonna guess the gps pod came loose.

 

[johna58]

No props were bent, damages or broken. I was not sure if I was in GPS or ATTI mode so I am not sure but if I was in GPS and the GPS unit came off in flight then I will have to secure it better. I know this is not proper but I've been having hard landings and other crashes so I've been hot-glue my GPS base. Maybe it came off during this long flight and the cold weather did not help. Maybe the cold could have played in a poor connection. I will make sure I do a more in-depth pre-flight from this point forward.

 

[johna58]

I hope it came loose at time of the crash and not in flight but if it did, I will have to fasten it much better.

 

[Benjamin Kenobi]

And there's nothing wrong with Spektrum my good man! Lots of people use it. I use DX7s for F550 and DX10t for S800.

Hope you fix it!

 

[kloner]

that front right motor shook pretty good towards the end.

this is usually a bullet connector from the motor side...... i've never seen a whole gps setup loose like that, i'd stick to double side tape to mount it. thank god for the tree or youda lost alot more

 

[hjls3]

Im with kloner at 6:54 you can hear a weird noise then she flips. I believe that weird noise being the ESC - motor connection. I have heard that before and flipped a similar rig. Have video somewhere, you can clearly hear the noise in my video and it sounds same as noise at 6:54. I will see if I can find it and post it here.

 

[Ttelmah]

The commonest cause of this type of thing, is I'm afraid the motor connectors.

DJI, have had an enormous 'batch' of motors, where the soldering to the leads at the bullets is faulty. It commonly works for a while, then fails. Cut the heatshrink off the outside of all of the bullets. Look at where the wire goes into the bullet. It should be a smooth curve, like the meniscus of water in the edge of a cup. If there is any visible line, or the dips as it approaches the wire, re-solder _every_ bullet (and re-cover obviously). I'd say something like 50+ percent of DJI motors I've seen in the last six months have had at least one faulty lead. I've even seen one that was much worse, where the lead hadn't been properly stripped, and the insulation went into the pool of solder.....

They are using some RoHs solder/flux, that doesn't seem to actually perform very well, with zero visual PDI. They probably do a basic resistance test, but the connections work for a while, so pass this.

One connection lost, the motor keeps sort of spinning because of inertia, but makes odd noises, and looses power. Result: plummet.

Best Wishes

 

[helloman1976]

Hello Everyone,

Here is my first flight I made with my GoPro Hero3 video camera attached. I wish I had my FPV in place but at least I am able to take aerial photos; that is until 6:52 minutes into the flight when I was gradually descending for a landing and then something went wrong. I do not know what caused it to fail and tumble to the ground so I am hoping someone can provide some logical explanation and direction for me to to explore and prevent it from occurring again.

Damaged: Number 3 leg broke in half, number five leg is fine but it broke at the connection at top board. LIPO was through about 5 feet from where the craft landed. Some of the outside plastic shrink-wrap tore off but the battery seemed to be fine (no swelling or gouges).

This is my setup:
A F550 with standard motors, Naza-M with GPS running on 8" DJI props powered by a Turnigy 4S 4000mAh LIPO. My radio is a Spektrum DX8 (I know I should consider a Futaba but no money).

Weather Conditions:
The air temperature in Georgia United States was 38 degrees with a 9 to 12 MPH wind and the time was about 3 PM.

You can hear in the video where an odd sound comes into play and you can see the shaking on the multicopter on the right engine. It sounds as if something is grossly out of balance and you can see it's on the right hand side or that front right motor itself. Make sure your props are balanced, I do not see any signs of a motor failure myself. Check that all your motor spin freely and also that there is no grinding.

Do you have black tape on the sides of your Naza flight controller?
Do you have failsafe enabled and a radio that supports it? Have you tested it?
Do all the motors spin freely assuming they weren't damaged in the fall?
What ESC firmware are you running, custom?

 

[johna58]

I am sure part of the problem that might have led to an ESC connector becoming disconnected is the weather coupled with the [inherent] vibration of the craft. I went through and balance the props as best as possible along with the motors. I do have black electrical tape on the sides of the Naza FC, the DX8 does support failsafe (I did successfully test it in the flight before this by turning off the transmitter), the motors do spin freely (before and after the crash) and I am using the latest version of firmware on the DJI 30 amp ESC (no custom here).

When I rebuild the craft, I will replace and balance the props, check the motors and balance as needed. I am also thinking of rapping electrical tape around all six ESC connectors and anchor my GPS more securely.

On another topic, I have seen where many have used foam ear plugs as a vibration dampening material. When I mounted my GoPro to the top PCB, I cut, to size, a piece of Mr. Clean Magic Eraser Original (no cleaning solutions in the material) than put the cut piece between the frame and the bottom of the camera then secured everything down and in place with one Velcro strap running vertically around the camera, sponge and top frame. I know it sounds strange but it seemed to work for me.

 

[hjls3]

John you could go ahead and solder the ESC and motors.

 

[SleepyC]

I think a prop broke in flight. Were you using the stock DJI props?
If you listen it shakes, and then a motor spins up really quick as it's tipping over.
When I had a F550, I threw out the props before ever using them.

 

[hjls3]

he had previously mentioned no damage to props.

I think a prop broke in flight. Were you using the stock DJI props?
If you listen it shakes, and then a motor spins up really quick as it's tipping over.
When I had a F550, I threw out the props before ever using them.

 

[SleepyC]

Sorry missed that. Could one have come loose at least? I can hear that one motor spool up.

 

[kloner]

the only problem i see with a majig eraser is it might decompose on ya faster than something else. the key that happens with earplugs is your able to record at crazy high res and with zero jello even out of tune on the multi rotor and a big part of that is minimal contact on something firm enough but within the right durometer rating to absorb the vibes right. ideal on a 900 kv motor 450-550 kinda rig, your looking for durometer 7 ish..... earplugs have a really wide ratting cause there soft but firm. that eraser is kinda like that.

there is a commercial silicone product that uses the same general engineering by using minimal surface touching the cam. most people that don't make earplugs work is from not using a light rubber band and over compressing the cam down. Theres a point where too loose makes the camera shake, to where it works perfect to too tight and makes jello. Hovering isn't a real test, this is how you go from 0-60 and it stays nice and jello free along the way

 

[tstrike]

+100 on the earplugs, cheapest vibe dampener you'll find (save for used kitchen products).
I still think it was the pod coming loose and falling to the left, the sound you hear is it getting nicked by the back left prop. The base plate looked pretty clean and hot glue holds for crap on cold metal to metal action.
that's my crackpot theory and I'm stickin with it...

 

[kloner]

i agree, the stick shoulda broke, not popped off like that.... i'd still watch them bullets on the side that fell first.

 

[johna58]

It was cold and the wind was howling. I would not rule out that a connector from one of the ESCs came off. I will consider soldering them. At least when I rebuild it again (and I know will), I don't have to worry about which directions the motor is turning.

 

[johna58]

I agree that the hot glue failed due to the cold climate. In warmer climates it serves as the weakest point of failure for the entire housing and it is easy to put back on but I will have to do some reinforcement especially if I intend to attempt cold-weather flying in the future.