Fallen Phantom

[ArgenBrewer]

Hello people, is that I put my Phantom standard to fly, after taken all precautions and follow all tips that in this forum are listed without notice amounts, without metal in the area, etc, etc and the minute flight, fell as fulminado on the vegetation, without suffering major damage that break projector propellers. they adjunct log to see if someone give me an idea of happened!

 

[ArgenBrewer]

DJIFlightRecord_2018-04-29_[14-29-36].txt

 

[sar104]

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?

 

[MotorCycle-Man]

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'd love to be able to see what you see here in this flight graph....please where at the 110 seconds how can you see that the prop came off.......I want to some day be like you and read these and help others here.....Thank you...and besides the prop issue what else can you see in the multi colored lines.

 

[ArgenBrewer]

Hi.
No, it did not come loose or fall off. They were tight. in fact, after the fall, I flew it again during the entire remaining battery charge without any problem. (do not touch the propellers before this second flight)

 

[sar104]

Hi.
No, it did not come loose or fall off. They were tight. in fact, after the fall, I flew it again during the entire remaining battery charge without any problem. (do not touch the propellers before this second flight)

Then I can't help you any further. I cannot see any other explanation for the behavior of the aircraft.

 

[sar104]

I'd love to be able to see what you see here in this flight graph....please where at the 110 seconds how can you see that the prop came off.......I want to some day be like you and read these and help others here.....Thank you...and besides the prop issue what else can you see in the multi colored lines.

The aircraft pitches up and rolls left, which implies loss of lift rear left. The rear left is a CCW motor, leaving two CW props balancing one CCW prop, which causes the aircraft to enter a CCW spin. The final clue, which requires having seen these events before, is the 2 Hz oscillation that is typical of a lost prop.

However - the OP states that none of the props came off, which doesn't leave much room for any likely hypothesis.

 

[ArgenBrewer]

and this, how do they interpret it?

 

[MotorCycle-Man]

and this, how do they interpret it?

I'd Love to know that also.......i have never seen that information before !

 

[Neon Euc]

The aircraft pitches up and rolls left, which implies loss of lift rear left. The rear left is a CCW motor, leaving two CW props balancing one CCW prop, which causes the aircraft to enter a CCW spin. The final clue, which requires having seen these events before, is the 2 Hz oscillation that is typical of a lost prop.

However - the OP states that none of the props came off, which doesn't leave much room for any likely hypothesis.

Sar104.... Any chance of doing a YouTube tutorial on how to read these flight data? Would love to also know how to read these. All I see is squiggly lines and would love to understand what it means if the lines go upwards or downwards [emoji4]

 

[AuldGimpy]

As Neon Euc +1.

Virtual hat raised for such a skill.

 

[sar104]

and this, how do they interpret it?

The speed error flag was set in "OSD.nonGPSCause" at 111.7 s and caused the switch to ATTI. That was 1.1 s after the aircraft lost attitude and started uncontrolled descent.

 

[sar104]

Sar104.... Any chance of doing a YouTube tutorial on how to read these flight data? Would love to also know how to read these. All I see is squiggly lines and would love to understand what it means if the lines go upwards or downwards [emoji4]

I don't know about YouTube, but for several months I've been putting together a guide to basic data analysis of log files. It's just turned into a much bigger and slower project than I expected.

 

[Fly Dawg]

Analyzing data is an art form in itself. There are instances where even the most detailed analyst will miss a clue here or there. There is a learning curve for those without some sort of previous experience in the field. A basic analysis guide would be very handy, and I salute @sar104 for taking on such a project. Personally, all my experience is from Guided Bomb and Missile Telemetry which relates somewhat in certain areas such that I can (generally speaking) understand the data from the Phantoms. This is not to say that I have it all figured out, but for the most part it is much easier to understand what the data implies. Just throwing that out for other interested future analysts.

 

[ArgenBrewer]

all very interesting, but the cause that caused my bird to fall, no one can yet determine it. It is assumed that these things should not happen if one follows the basic rules shared here.

 

[sar104]

all very interesting, but the cause that caused my bird to fall, no one can yet determine it. It is assumed that these things should not happen if one follows the basic rules shared here.

The data in the txt log suggest a specific class of event, but you have ruled it out by stating that the propellers were attached and intact and that the aircraft still flies. I'm not clear what more you expect here. The P3S DAT logs don't include motor speed, which would be the most useful additional data, but do have motor command level. If you want to post the aircraft DAT file then we can take a look at that.

 

[ArgenBrewer]

....If you want to post the aircraft DAT file then we can take a look at that.

Ok, when I return home and remove it from the drone, I share it. Thank you

 

[Fly Dawg]

The only other piece of correlation I could find would be the abrupt stop. Generally speaking, most of the time this would be where a prop loss would happen, during braking. Your speed was not that great, but it is enough to loosen an improperly tightened prop. And it correlates with @sar104 plots. The aircraft .dat may be more conclusive.

 

[ArgenBrewer]

The only other piece of correlation I could find would be the abrupt stop. Generally speaking, most of the time this would be where a prop loss would happen, during braking. Your speed was not that great, but it is enough to loosen an improperly tightened prop. And it correlates with @sar104 plots. The aircraft .dat may be more conclusive


Blades never they loosened and then, without any involvement from my part in blades, followed flying with no problems.

 

[Fly Dawg]

Blades never they loosened and then, without any involvement from my part in blades, followed flying with no problems.

Yes, I saw the response earlier. I am only going by the data we have in that aspect. Everything thus far points to that, and I am not debating your claim that the props were still in tact. I was pointing out that this correlates the above post. If you can provide the aircraft .dat file, that may be more conclusive.