1st flight destruction

[Airmotive]

Pyro... Check for a nicked prop. A small nick, especially near the tip, can make quite a bit of noise.

 

[JoeyD]

There are 2 way that self tighten prop could go off:
1: it was very loosely screwed on and you did an acceleration followed by a quick deceleration, the prop will fly off.
2: You tightened it too tight and the prop did not go into the right thread and it ended up torn apart during flight[/quote]
He said he spun tightened them and didn't use the tool to tighten so i would assume he couldn't have tightened them too tight. I don't think being 'loosely' screwed would have anything to do with it. If it was loosely screwed but still properly threaded, the centrifugal force would have tightened them to what was needed long before 30' high in the air. You mentioned that an acceleration followed by a quick deceleration would cause the prop to fly off.... this is the first I've heard this. I'm not saying it's wrong, but I'm definitely interested in this.. I would have thought that DJI would have engineered the software/hardware in such a way that would make this almost impossible.. i.e. test and identify the force required from a quick deceleration to loosen the prop and control the throttle input via software to not exceed that level of velocity. Has anyone experienced or heard of others who have lost props mid-air due to a quick deceleration?[/quote]

You can do an easy test on your p2v+: Have someone hold your p2v+ over head with loosely screwed on props, you start motor and push throttle all the way up and then quickly pull all the way down and watch how the props fly off. ( you should stay a safe distance to test this)[/quote]

How can you compare an anchored birds reaction to a maneuver of one that is floating in the air?

 

[Dirty Bird]

You can do an easy test on your p2v+: Have someone hold your p2v+ over head with loosely screwed on props, you start motor and push throttle all the way up and then quickly pull all the way down and watch how the props fly off. ( you should stay a safe distance to test this)

I just did this test...10 times! Strapped the Phantom through the gear to my kitchen table top, sat the props on the shafts and flipped them with my finger and let them spin to that degree of tightness only. Ran up the throttle for ten seconds, then pulled straight down. Up & down...up & down...ten times. The props stayed put, and they were tight enough after the test that I needed the wrench to remove them. (I usually need the wrench to remove the props after a flight)

When you pull down on the throttle, it isn't like you slammed on a brake and the motors stop. They merely reduce speed. They are still spinning in the same direction, even when you pull straight down on the left stick. Just the initial power up should set the props tightly enough for flight. If a complete prop flies off mid-air, assuming the motor shaft is still there, I would think the most likely cause would be the prop nut fractured, or had a hairline crack or seam that opened sufficiently at speed that it lost its bite on the threads and flew off. If this is the case, examination of the prop should bear evidence. That's why it is critical to find the missing prop.

 

[pyrophantom]

Pyro... Check for a nicked prop. A small nick, especially near the tip, can make quite a bit of noise.

Yes did that before I flew, I always check the props are OK and as they were a brand new set I check them for balance before I put them on they were quite good, only had to give a tweak to one which was a little side heavy. Flies lovely and quietly now so no idea what it was ! The only thing I did notice, and you guys over the pond probably suffer it more than we do due to the size of your bugs, was the props came back with spatterings of bug blood on the blades.

 

[Double-D]

I agree that it was most probably a cracked or split prop thread.
I've only had about 20+ flights so far. Props have hit the dirt twice and i regularly check the tightness but i will now make a habit of checking the threads.

 

[Tails_Up]

These are all good theories, and a mystery as to why the props came off. One more danger for all Phantom Pilots that I have found is being careless in your 'work environment'.

I have a nice service bench setup and use it to do any work on my Phantom. plus other electronic repairs. Here's where I almost messed up - flipping the Phantom upside down on anything other than a clean area can expose the motors to all kinds of small bits of metal. These motors of course have strong magnets and it's very easy to get bits of metal clinging to the motors.

So imagine, you flip it over or in some way it comes around a small metal filing that gets stuck to the motor. Not quite inside the motor, but close enough so that when under power, it vibrates into the windings.... an instant crash. And maybe there's enough stopping power to spin off a prop in the fall. No idea if that's what happened here, but I wanted to point out the potential problem to others. Afterwards, if the piece dislodged itself during the crash, you would never know what happened.

 

[yali]

You can do an easy test on your p2v+: Have someone hold your p2v+ over head with loosely screwed on props, you start motor and push throttle all the way up and then quickly pull all the way down and watch how the props fly off. ( you should stay a safe distance to test this)

I just did this test...10 times! Strapped the Phantom through the gear to my kitchen table top, sat the props on the shafts and flipped them with my finger and let them spin to that degree of tightness only. Ran up the throttle for ten seconds, then pulled straight down. Up & down...up & down...ten times. The props stayed put, and they were tight enough after the test that I needed the wrench to remove them. (I usually need the wrench to remove the props after a flight)

You did it 10 times, but you did not do it right. Because you didn't want your test to fail. OK let me put it in other words:
Do whatever you can to make the props fly off; what can you do to make them fly off? can you make them fly off using your controller ?

 

[Dirty Bird]

You did it 10 times, but you did not do it right. Because you didn't want your test to fail. OK let me put it in other words: Do whatever you can to make the props fly off; what can you do to make them fly off? can you make them fly off using your controller ?

I didn't do it right? The OP said the aircraft had already been launched and was hovering in the air, meaning the motors had fully spun up & the props had already tightened. Once the props are tight, there is nothing you are going to do with the controller to make a complete prop fly off the aircraft. The only way the props are going to fly off is if the prop hub fails (i.e. fractures, splits, worn threads), the motor shaft breaks, or the entire top end of the motor comes off.

I'll humor you: I could make the props fly off with the controller if I reversed the polarity of the motors, then hit the throttle. :roll:

 

[Doono]

You can do an easy test on your p2v+: Have someone hold your p2v+ over head with loosely screwed on props, you start motor and push throttle all the way up and then quickly pull all the way down and watch how the props fly off. ( you should stay a safe distance to test this)

I just did this test...10 times! Strapped the Phantom through the gear to my kitchen table top, sat the props on the shafts and flipped them with my finger and let them spin to that degree of tightness only. Ran up the throttle for ten seconds, then pulled straight down. Up & down...up & down...ten times. The props stayed put, and they were tight enough after the test that I needed the wrench to remove them. (I usually need the wrench to remove the props after a flight)

You did it 10 times, but you did not do it right. Because you didn't want your test to fail. OK let me put it in other words:
Do whatever you can to make the props fly off; what can you do to make them fly off? can you make them fly off using your controller ?

Yeah DB, YOU DID IT WRONG! You noobs will never learn.

 

[rrhansen]

Since there has been dialogue regarding nicked props and other issues with them, I hope I am not hijacking this thread with the following question.
Other then vibration, noise, or minimal efficiency impacts, is flying with slightly nicked props likely to cause a catastrophic prop failure and crash? When I first started flying quads, and even to this day, I occasionally nick a prop, but at the price of them, I continue to fly with them and it does not seem to adversely affect anything. If/when they get too chipped I replace them.
Experienced pilots, can you share your wisdom please? Thanks

 

[Doono]

It's hard to say with a chipped prop, if it's minor, it shouldn't cause any major problem.

 

[Cbarberis]

Reading about your mishap makes me realize that this is something that happens more frequently than I thought as it happened to me. I own a Phantom FC40 which I have had for a little over a month and have flown it without any major mishaps for over 10 hours. I became enamored with the Phantom 2 Vision+ and I purchased one just a few days ago, I received it yesterday and spent quite a bit of time reading the manuals, updating the firmware and getting to know the machine, I also installed the DJI prop guards. I was very careful about the pre-flight checks and making sure that everything was done properly. The first flight started just fine did some maneuvers and hovering at ~ 30-40 feet and everything looked good until it suddenly threw the left rear prop, it just flew off the motor and the Phantom violently crashed into the ground without one prop and the battery coming out (the battery pack was about 9 feet away from the craft). After the crash I inspected the craft and did not see any apparent damage other than the missing prop and a few nicks on the other props and battery pack. I re-installed the the prop that flew away and re-started the motors, all three motors and props were running fine except for the motor where the prop flew away, it was basically stuttering and turning very very slow. After this incident I thought I did damage to the motor but it appears fine to the feel when you rotate it by hand. I did some research on the web as to why the motor stutters and found that this could be related to either the ESC controller or the motor itself. I took apart the shell and visually inspected the ESC board, could not see any damage or loose wiring, I also looked at the windings resistance for the three phase motor and it looked the same as the others, so obviously it does not appear to be a motor failure. However I did look at the PWM waveform using a scope for this motor and compared to the other three motors and there is a definite problem which tells me the problem is related to the ESC board. I have since ordered a spare ESC board and motor and will be installing the new ESC as soon as it arrives. I guess my biggest concern and now my biggest fear is why did the prop fly off? I hand spun the prop into place and then slightly tighten it by hand when I first installed all the props. I also looked at the prop that flew off and it does not seem to have any cross threaded damage on the threads. I am sure that whenever I get this machine back in flying operation it will always be a fear factor for me and I am not sure wether this will happen again, $1400 USD is a lot of cash to loose. Any suggestions or comments to the above will be appreciated.

 

[srandall25]

I only lightly tighten the props. On my sixth flight with no issues. But i did notice that it works better if you make sure you have at least 6 sat's and let it hover at 6 ' for a few seconds. Moving it back and forth.

Yesterday it was windy and it started going in a small circle ( i think it was tying to get back in line ) and kept getting bigger n bigger so i took over and stop brought it back to position ... then everything was great.

Finger crossed

there is no need to even lightly tighten the props.. i would say its not even recommended. Spin tight is all you need.

 

[rrhansen]

If you just purchased it a few days ago, and are having this type of obvious defect problem, might it be worth returning it as defective instead of monkeying with it and risking crashing to the point where you can't return it? It sounds like you have more than enough investigative findings to support a claim of defect with any reputable retailer, who should then process an exchange for you.
Just a thought to eliminate the constant fear factor for that quad.