In a test flight preparing for videorecording the blue moon rising, the plane threw a blade. Watch the violent reaction to just 3 blades and how the P3 'lands.' I put 2 new blades on it, did a new preflight check (it passed), and sent it up to 398' for 12 minutes to video record the beautiful moonrise!



Here is the moonrise video (my flight ended 29 minutes after local sunset):

https://drive.google.com/open?id ... P3rUX2DrEiLp81IEKNM

Nice rugged P3. They can be tough.

Good job.

You mentioned Preflight Checklist. What about before the first flight.
I let my drone hover low and close for a few moments, to see if everything is ok.


Make sure your props are properly seated. ;-)



RedHotPoker

RedHotPoker Posted at 2018-2-1 12:01
Good job.

You mentioned Preflight Checklist. What about before the first flight.

"Preaching to the choir..." 3 years flying and FAA-certified. I think a blade had bad threads. They were all cinched down with the wrench... Pre-flight checklist was good.

Think you got lucky with it falling into that bush.

I wonder what kind of state it would be in, had it hit open ground.

Still, good to hear that your P+J wasn't too badly damaged.

Rigger73 Posted at 2018-2-1 12:07
Think you got lucky with it falling into that bush.

I wonder what kind of state it would be in, had it hit open ground.

NO damage! Except it came down with 2 1/2 blades, not 3!
Exactly why I buy refurbished DJIs... $1000 less loss when the WORST happens.

fans3abc17f7 Posted at 2018-2-1 12:03
"Preaching to the choir..." 3 years flying and FAA-certified. I think a blade had bad threads. They were all cinched down with the wrench... Pre-flight checklist was good.

Hand tight is right. If you are wrenching them props on, no wonder the threads were buggered up.

But you have three years experience. So why tell you...

I'm building an Align TRex 700E DFC HV helicopter kit. What a beast.
An RC friend from helifreak.com "was" living in New York, he was co-captain of their flying club, hid dad was captain. Both exceptional flyers. But on this one horrific day, while doing an inverted auto rotation dumb thumbed the RC and pushed the stick up intstead of down, to go up. That was sadly his last flight.


So saying you have experience means very little. Except that you have attitude. Go figure.

Trying to help you, but resistance is felt, so I will slowly back away. Good luck in the future.


RedHotPoker

RedHotPoker Posted at 2018-2-1 12:15
Hand tight is right. If you are wrenching them props on, no wonder the threads were buggered up.

But you have three years experience. So why tell you...

You are right, in that DJI says to hand tighten with both hands. The wrench is for removal. Of course, I know to not snug so much as to split the plastic -- not so much others. Sad about your story...

DJI-ing Since 2014 Posted at 2018-2-1 12:30
You are right, in that DJI says to hand tighten with both hands. The wrench is for removal. Of course, I know to not snug so much as to split the plastic -- not so much others. Sad about your story...

Ok, we have a glimmer of hope.

I'm not trying to be hard on you, just telling you the truth. You came on the forum and expressed concern, about something that very likely was self induced. If you horse the props on, they will get stressed. It's only plastic. Not meant to be cranked on. Haha

Anyway, now you know, and it will never happen again. Right? ;-)


They are called self tightening, for a reason.

Are you a mechanic, who relies on wrenching ...?


RedHotPoker

RedHotPoker Posted at 2018-2-1 12:43
Ok, we have a glimmer of hope.

I'm not trying to be hard on you, just telling you the truth. You came on the forum and expressec concern, about something that very likely was self induced. If you horse the props on, they will get stressed. It's only plastic. Not meant to be cranked on. Haha

Actually, I am an orthopedic surgeon and we use the term 'wrenching' when seating the patellar implant! So, I am no mechanic. I suppose the proper word should have been 'torqued'...

DJI-ing Since 2014 Posted at 2018-2-1 13:11
Actually, I am an orthopedic surgeon and we use the term 'wrenching' when seating the patellar implant! So, I am no mechanic. I suppose the proper word should have been 'torqued'...

Good for you, thanks for your health care service.

I've had nine major surgeries.

But my favorite is Brain Salad Surgery. ELP. ;-)



RedHotPoker

So to clear this up for me
You think the failure was due to the self tightening prop's threads giving out (for whatever reason) or some other reason.
You were fortunate that it crashed the way it did where it did and ended up with no damage other than the props
How often do you inspect/check your props for wear and damage?
Glad it all worked out for you!
I liked your moon rise work, obviously a surgeon nice steady hand LoL

Normally before I fly, I grab the 'barrel' of each motor and give the prop a twist and pull to make sure it's on securely.  One day I was in a rush and put a prop on loose by mistake.  I never did  a pre flight check.   Fortunately the loose prop just spun off and flew into the air before I left the ground.  

I probably wouldn't have been as lucky as you had it come off in the air

Actually not "Landed", it crashed even not hard but this is a crash/hard land

Vendex Posted at 2018-2-1 13:37
Actually not "Landed", it crashed even not hard but this is a crash/hard land

ok. "crash landed..." but it did land in the bushes.

Genghis9 Posted at 2018-2-1 13:28
So to clear this up for me
You think the failure was due to the self tightening prop's threads giving out (for whatever reason) or some other reason.
You were fortunate that it crashed the way it did where it did and ended up with no damage other than the props

I think it was a blade with defective threads... even cinched down well a very minor vibration eventually unseated it and it flew off. glad I did a test flight. the blades ARE cheap. maybe too much so...

I've never removed my blades, I bought a box carrier that can hold it with blades, because I'm worried about removal and reinstall constantly, I just give a quick bump/tug whatever you want to call it to check them before flight.  And the last flight, in awful cold, I had a vibration/wobble as it hovered about 4 ft.... I will be putting on new blades until I can stop that, your video pretty much convinced me I don't want to try 3 blade flying!

Great recovery!

DJI-ing Since 2014 Posted at 2018-2-1 13:40
I think it was a blade with defective threads... even cinched down well a very minor vibration eventually unseated it and it flew off. glad I did a test flight. the blades ARE cheap. maybe too much so...

Yup more times than not ya get what you pay for...the problem I see is after so much time goes by there becomes too many variables to nail down exactly what may have been the cause.
Fly Safe

"landed" THAT'S A CRASH!!!

I wouldn't say you "landed it", its more like "it didn't completely break apart when it crashed" :p

You are lucky to get the drone back without too much damage. To ensure the safety, it is always recommended to take a fully pre-flight checklist. BTW, thanks for sharing the video with us. It seems that the drone work well.

I only tighten my props using my index finger and thumb while holding the motor stationary using my other hand.  I don't use the official DJI tool.
Loosely placed self-tightening props should only come loose when the motor's speed slows down to about idle, and the prop still continues to spin.  A propeller doesn't spin faster than the motor itself to simply fly-off like that.  I believe your cyclic stick input was most likely abrupt causing that motor to slow down quickly (if the threads weren't already busted to begin with.
I'd be curous to see the flight log for that flight (including transmitter input).