Fallen Phantom

[RodPad]

Hey guys, I need to call it a night.

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Blade Guard and String Closure

New DJI Phantom 3 4K Drone First Flight

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Rod

 

[ArgenBrewer]

I have no idea. I've never used prop guards either.

the rope prevents a branch, for example, from entering between two protectors, hit the body of the drone, on the other hand, had not had protectors placed, my ship today would not fly, because it would have stuck in an engine, instead, the protector absorbed the blow

 

[Harleydude]

It appears that the left rear propeller came off at 110.6 seconds into the flight. It's likely that you had not attached it properly. Did you tighten it or just spin it on?

View attachment 98307

I suggest this may have been a prop failure. Misinstalling Phantom series locking props is literally impossible.

This video only shows 2 attempts, but I tried literally a dozen times to misinstall the prop to no avail. It's either installed or it is not. There is no in between.

 

[sar104]

I suggest this may have been a prop failure. Misinstalling Phantom series locking props is literally impossible.

This video only shows 2 attempts, but I tried literally a dozen times to misinstall the prop to no avail. It's either installed or it is not. There is no in between.

This was a P3, and the OP stated that the props were still attached and intact, so that's not relevant. The string that was supposed to be tensioning the prop guards but was actually flapping in the breeze might have been the culprit.

And on the subject of mis-installing bayonet-style props, while I have no interest in restarting that argument with you, did your tests include trying to install a prop with a piece of grit or other foreign object preventing the spring mechanism from properly engaging the locked position?

 

[Fly Dawg]

Misinstalling Phantom series locking props is literally impossible.

This is partially true, but P3's don't have locking props.

 

[ArgenBrewer]

Discard the theme of the propellers, they are firmly placed on the engines and never left, the Drone continued flying without the slightest fault during the following days. The rope, which was fishing line, could, at some point, be the culprit, but even so, I suppose it should have appeared coiled in the engine or at least mark or damage the propeller, which also did not happen. I think this will be like another of the great mysteries of aviation!

 

[sar104]

Discard the theme of the propellers, they are firmly placed on the engines and never left, the Drone continued flying without the slightest fault during the following days. The rope, which was fishing line, could, at some point, be the culprit, but even so, I suppose it should have appeared coiled in the engine or at least mark or damage the propeller, which also did not happen. I think this will be like another of the great mysteries of aviation!: smiley:

If the string were just slack enough to catch and stop a propeller but not enough to get wound around the hub that might be the most likely explanation. I would ditch the string and the prop guards. Unless you are prone to flying into obstacles they do little except degrade the aircraft performance.

 

[Harleydude]

This was a P3, and the OP stated that the props were still attached and intact, so that's not relevant. The string that was supposed to be tensioning the prop guards but was actually flapping in the breeze might have been the culprit.

Touché. I thought the P3's used the same locking system as the P4's. I see I was wrong.

And on the subject of mis-installing bayonet-style props, while I have no interest in restarting that argument with you, did your tests include trying to install a prop with a piece of grit or other foreign object preventing the spring mechanism from properly engaging the locked position?

The spring simply pushes up against the prop. So a small piece of debris would act as a shim, creating MORE force, which would most certainly feel different from the remaining 3 installed props. Or the debris would be so large that no amount of force would allow the prop to be installed. But I'm open minded and (as you can see above) NOT above admitting when I'm wrong. If you can make a video to illustrate your point like I made a video to illustrate mine, I'll be happy to concede. Sound good?

D

 

[sar104]

Touché. I thought the P3's used the same locking system as the P4's. I see I was wrong.






The spring simply pushes up against the prop. So a small piece of debris would act as a shim, creating MORE force, which would most certainly feel different from the remaining 3 installed props. Or the debris would be so large that no amount of force would allow the prop to be installed. But I'm open minded and (as you can see above) NOT above admitting when I'm wrong. If you can make a video to illustrate your point like I made a video to illustrate mine, I'll be happy to concede. Sound good?

D

That's a fair comment, but I'm not sure that I know how to do that test on the ground.

It's not the spring force itself or friction that prevents the prop from unlocking - the spring prevents the prop from depressing and rotating out of the lock slot. If the slot is blocked by debris then it will not fully lock because the prop will remain at or near the depressed position, even though, as you mention, the spring will be pushing harder than in the locked position. In that situation there will either be less depression required to unlock or, possibly, none at all.

When the slot doesn't engage it certainly does feel different - the prop doesn't pop up properly when rotated to the locked position. I've had that happen once, with a Mavic, and I removed the prop to try again.

It's not hard to replicate that situation and leaving enough locking force so that it doesn't pop off during the motor startup blips but will rotate off by hand without really pushing down. I've done that. The difficult part is finding a way to replicate sudden motor deceleration such as happens in flight during high-speed maneuvers but with the aircraft on the ground. The throttle response is much too gentle, so I don't know how to do that. If anyone has any ideas I'm willing to test it.

 

[Roger Davis]

I don't own one of these, so I'm simply using logic. Assuming that it immediately flew again, and that the symptoms clearly showed loss of power at left rear, consider the possibility the loss of power was due to a poor connection servicing that motor, either power or control.

 

[sar104]

I don't own one of these, so I'm simply using logic. Assuming that it immediately flew again, and that the symptoms clearly showed loss of power at left rear, consider the possibility the loss of power was due to a poor connection servicing that motor, either power or control.

That's certainly possible, but usually such problems don't go away by themselves.

 

[Fly Dawg]

loss of power at left rear, consider the possibility the loss of power was due to a poor connection servicing that motor, either power or control.

Agreed, this is why I was looking at what appeared to me to me "Ground Noise"....but as I said I could not be definitive on that without a referal to those have looked at more of this particular data than I have. Not necessarily with the Phantoms, but I have seen this "Ground Noise" cause issues....and it is very difficult to locate a particular root cause. Understandably, motor noise would be seen on the data, but it should not be seen in other areas.

 

[chazzm]

It appears that the left rear propeller came off at 110.6 seconds into the flight. It's likely that you had not attached it properly. Did you tighten it or just spin it on?

View attachment 98307

Could also possibly be a weak or loose connection to the left rear motor! Seen it happen before, if the prop was properly installed then the only other thing is “something” interfered with the motor. Just my 2 cents from looking at the data provided. And I do agree with the stick positioning that a slightly loose prop could indeed spin say half way off the try to catch up give a “Pause” when trying to catch up (spinning the motor shaft tightening the prop back up) possibly!?

 

[Deleted member 109724]

Just never use prop guards and be careful when flying. I fly between trees for roof inspections all the time and never hit anything because I take it slow and keep vlos and closely monitor my iPad.