bent prop H

Good time Charlie · May 25, 2019

Sarah said:
Pilot is not online, because he definitely thinks the prop bent and drone fell, his ego doesn't allow him to consider any other solution, pilot's pride....

Therein lies problem number 1.

DoomMeister · May 25, 2019

Looking at the graph showing pitch, roll, and yaw of the craft it was not stationary when the trouble started. There was close to a full forward pitch command for around 3 seconds at the 45:00 mark then a full reverse pitch command for about 2 seconds at 45:04. A full left yaw command started just past 45:06 and that is when things went bad. The aircraft continued to spin left and pitched violently forward then back and oscillated lifted and right by 150 degrees as it fell from about 60 meters.

My take is that there was a mid air collision with something. The prop did not just bend like that in flight and cause the crash. I also find it hard to believe it bent without cracking. That looks more like the result of heat applied to the plastic after the fact.

Grumpy · May 25, 2019

I'm going to call this pilot error. Don't see any telemetry on the battery voltage. For the sake of argument, if the prop did fold, it would have gone into five motor mode where the pilot could have landed it. How experienced is this guy?

Sarah · May 25, 2019

Grumpy said:
I'm going to call this pilot error. Don't see any telemetry on the battery voltage. For the sake of argument, if the prop did fold, it would have gone into five motor mode where the pilot could have landed it. How experienced is this guy?

Pilot says to be experienced in flying.
Voltage is shown in altitude's graph, no shortage.

Sarah · May 25, 2019

DoomMeister said:
Looking at the graph showing pitch, roll, and yaw of the craft it was not stationary when the trouble started. There was close to a full forward pitch command for around 3 seconds at the 45:00 mark then a full reverse pitch command for about 2 seconds at 45:04. A full left yaw command started just past 45:06 and that is when things went bad. The aircraft continued to spin left and pitched violently forward then back and oscillated lifted and right by 150 degrees as it fell from about 60 meters.

My take is that there was a mid air collision with something. The prop did not just bend like that in flight and cause the crash. I also find it hard to believe it bent without cracking. That looks more like the result of heat applied to the plastic after the fact.

yes I've noted pitch +20/-20 seconds before fall. (and altitude log stopping at 8 meters) do not understand how this pitch change could bend a prop

AH-1G · May 25, 2019

We can assume all day or until we're blue in the face. If the owner doesn't want o come aboard and give us his side of the story, This is all mute!

DoomMeister · May 25, 2019

Sarah said:
yes I've noted pitch +20/-20 seconds before fall. (and altitude log stopping at 8 meters) do not understand how this pitch change could bend a prop

The pitch change didn’t. The only thing I’ve seen cause that type of telemetry is a bird strike or similar. It didn’t necessarily have to take out the prop. It could have broken an arm or such.

But the pitch changes also debunk the claim that it was hovering.

arruntus · May 25, 2019

Data is missing, because telemetry says something, but damage to the aircraft can also give you clues. The problem is that we only see one engine and that damage can perfectly be caused by the fall, 60 m are many meters and what seems to have broken is the plastic support, and the carbon fiber tube ... how is it? And the rest of the arms?

I don't know, the H pro also has the ability to fly with 5 engines? It is a functionality that is added with software.

Sarah · May 26, 2019

AH-1G · May 26, 2019

Are those OEM blades? A blade at that angle would have shattered. This looks like a very cheap plastic from another manufacture?
I a bit confused, one picture shows the bird yellow the rest orange?

Sarah · May 26, 2019

AH-1G said:
Are those OEM blades? A blade at that angle would have shattered. This looks like a very cheap plastic from another manufacture?
I a bit confused, one picture shows the bird yellow the rest orange?

Blades are not from Yuneec,
Orange-yellow, must be a white balance auto setting

arruntus · May 26, 2019

It's scary to see the state it's been in, and sadness

With this photos, we can see the propeller bent in another angle, not only in vertical, another propeller is also turned on its axis and another one has split in the axis, it is curious, that plastic as it has preserved the deformation.

Looking at the log, from minute 45, for 6 seconds the drone retreats and advances suddenly, tilts backwards to 20 degrees and then forward almost 20 degrees, a sudden maneuver, then there is an imbalance in all axes. It doesn't seem to be in stationary, or can it be the beginning of a propeller that has bent itself? or with the help of a bird? How difficult it is to say something......

Sarah · May 26, 2019

Pilot reports to have seen an arm break just before fall. He explains the arm broke due to heavy vibrations from bent blade. (which I doubt)

arruntus · May 26, 2019

Sarah said:
Pilot reports to have seen an arm break just before fall. He explains the arm broke due to heavy vibrations from bent blade. (which I doubt)

To break a carbon fiber arm by vibrations only means that they have been brutal. In that case it is clear that it has been one of the propellers.

With the original propellers, they recommend to change them every 20 flights, that would be only 7 hours. I find it too conservative when a colleague here has reported that with a Tethered Power System 24h of continuous operation.

It would be interesting to know, those propellers how many hours they had flown. Anyway a manufacturing error can always be found.

The fact to change the propellers, to put of another brand, to that it was due? I say this because those of the H520 are not cheap, but neither excessively expensive, considering that it is a fundamental element. They gave more performance?

AH-1G · May 26, 2019

Sarah said:
View attachment 16717

I would say this is a very defective blade.
I'm going out on a limb here.
Looking where the motor and housing sheered off, bent blade side.
The non sheered side of the housing (straighten blade side) still had lift , while the bent blade lost lift, thus causing sever instability
and immediate twisting of the housing. I would say it sheered off left to right?
Can you take on original OEM blade and the current non OEM blade, bend both as seen here, what will happen?
Which was more difficult to bend? I'm looking for flexibility.

AH-1G · May 26, 2019

arruntus said:
To break a carbon fiber arm by vibrations only means that they have been brutal. In that case it is clear that it has been one of the propellers.

With the original propellers, they recommend to change them every 20 flights, that would be only 7 hours. I find it too conservative when a colleague here has reported that with a Tethered Power System 24h of continuous operation.

It would be interesting to know, those propellers how many hours they had flown. Anyway a manufacturing error can always be found.

The fact to change the propellers, to put of another brand, to that it was due? I say this because those of the H520 are not cheap, but neither excessively expensive, considering that it is a fundamental element. They gave more performance?

I've only replaced 4 of my original OEM blades with a new set of OEM's, many moons ago.
I have over 85 hours.

NorWiscPilot · May 26, 2019

arruntus said:
With the original propellers, they recommend to change them every 20 flights, that would be only 7 hours. I find it too conservative when a colleague here has reported that with a Tethered Power System 24h of continuous operation.

Reminder: per @Sarah post #13, this is an H480 tricked out to look like an H520. Why this thread is in the H520 section is a mystery.

Anyone reading the telemetry see differently?

Jeff

Eagle's Eye Video · May 26, 2019

Grumpy said:
I'm going to call this pilot error. Don't see any telemetry on the battery voltage. For the sake of argument, if the prop did fold, it would have gone into five motor mode where the pilot could have landed it. How experienced is this guy?

WHY anything about this claimed incident is given any validity I do not understand... this entire thread is, (like another recent thread) is 3rd party hearsay... so once again, if the actual pilot of the aircraft does not come on to this board to give accurate information, this thread will be locked by the end of day.

Sarah, it is not standard for pilots to share their telemetry with others to post on a forum. What exactly is your relationship to this pilot?

Steve Carr · May 26, 2019

1. A motor did not make a clean break because of a bent prop. The flight controller would have detected a high load on the motor and would have shut down the motor. The fact that the wires are also severed is a clue.
2. Using aftermarket props is foolish. They are known to fail in-flight.
3. Upload the logs please, not just a screenshot.
4. This scenario is more likely to be a result of something like the video below.

arruntus · May 26, 2019

Steve Carr said:
1. A motor did not make a clean break because of a bent prop. The flight controller would have detected a high load on the motor and would have shut down the motor. The fact that the wires are also severed is a clue.
2. Using aftermarket props is foolish. They are known to fail in-flight.
3. Upload the logs please, not just a screenshot.
4. This scenario is more likely to be a result of something like the video below.

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Good video, in this case breaks only 1 motor bracket and not the arm but the way the FC control it handles the situation is outstanding.

Now, if instead of only one engine, it affects two contiguous engines, the disaster is assured, you have a stone 60m high. The bad thing is to discern the damage caused by the failure or collision with bird, with those caused by the fall.

These types of accidents, or other incidents, put us on alert and we stop thinking that it can't happen to us. Unfortunately, the best way to learn is by taking blows ?