Third Party Quiet Propellers Flexed/Touched Front Arms

[wingbotics]

Today, I examined the conditions of all the props. I came to realize that I have a set of quiet props from some 3th party (see attachment) and I'd used them extensively before. Apparently, they flexed quite a bit. You can see the scratched marks in the picture. I'll scrap them. Their quality is decent but flex too much. I think it has to do with the material of the props. Did you guys see this before? The OEM ones are not having the issue.

Just FYI.

Good luck and safe flying.

 

[Thomas B]

Today, I examined the conditions of all the props. I came to realize that I have a set of quiet props from some 3th party and I'd used them extensive before. Apparently, they flexed quite a bit. You can see the scratched marks in the picture. I'll scrap them. Their quality is decent but flex too much. I think it has to do with the material of the props. Did you guys see this before? The OEM ones are not having the issue.

Just FYI.

Good luck and safe flying.

Please post the brand for good answers.

Personally I stay with OEM props.

 

[RadioFlyerMan]

Today, I examined the conditions of all the props. I came to realize that I have a set of quiet props from some 3th party and I'd used them extensive before. Apparently, they flexed quite a bit. You can see the scratched marks in the picture. I'll scrap them. Their quality is decent but flex too much. I think it has to do with the material of the props. Did you guys see this before? The OEM ones are not having the issue.

Just FYI.

Good luck and safe flying.

Yes, I had some DJI props from Amazon for my MPP that were slightly more flexible than all the others I’ve had over the last two years. They would hit the arms when under high stress, like in wind or when I would descend at 22 mph in Sport mode. You can see the scratches on the bottom side of the prop. To observe it more closely, I taped the high point on the arms with electronic label maker tape. Then verified the “hit” after the flight via the black mark on the high point. I also got motor current errors when I observed the hit. I ditched the whole batch of props.

 

[eaglesurfing]

Yes, I had some DJI props from Amazon for my MPP that were slightly more flexible than all the others I’ve had over the last two years. They would hit the arms when under high stress, like in wind or when I would descend at 22 mph in Sport mode. You can see the scratches on the bottom side of the prop. To observe it more closely, I taped the high point on the arms with electronic label maker tape. Then verified the “hit” after the flight via the black mark on the high point. I also got motor current errors when I observed the hit. I ditched the whole batch of props.

View attachment 123414View attachment 123415View attachment 123416View attachment 123417

Did you throw them away?

 

[RadioFlyerMan]

Did you throw them away?

Yup. All eight of them. I saw no advantage in keeping them.

 

[wingbotics]

Please post the brand for good answers.

Personally I stay with OEM props.

I updated my original posting with an attachment to show the package of the propellers purchased from Amazon about 2+ years ago. Apparently, these props do not take stress fly too well. I'll not use them anymore. Yes I'll stick with the OEM.
Thank you.

 

[wingbotics]

Yes, I had some DJI props from Amazon for my MPP that were slightly more flexible than all the others I’ve had over the last two years. They would hit the arms when under high stress, like in wind or when I would descend at 22 mph in Sport mode. You can see the scratches on the bottom side of the prop. To observe it more closely, I taped the high point on the arms with electronic label maker tape. Then verified the “hit” after the flight via the black mark on the high point. I also got motor current errors when I observed the hit. I ditched the whole batch of props.

I like your way in checking whether the props touch the arms/body of the drone and I'll adopt this method.
It seems that your issue was with the DJI OEM quiet props, was it not? In my case, the DJI ones are perfectly fine.
Thank you for sharing.

 

[wingbotics]

... I also got motor current errors when I observed the hit. I ditched the whole batch of props.

I'd posted one complaint long time back about an overcurrent issue quoted below.
Ok, the situation was different from yours, i.e. in ascending rather than descending. Of course, I cannot be certain that I was using this set of propellers. However, I think that the degrees of flex could induce problems to the overall system behavior. For myself, aother factor of uncertainty is how long ago that these scratched marks were made. I'll keep an eye on those closely from now on.

Overcurrent Discharged

Hi, I have the latest firmware for my Mavic pro, 1.4.5. (both the RC and the aircraft). This morning, I was flying at sport mode at 37mph and ascending at 9mph then a warning, Battery: Overcurrent During Discharge, shown up briefly (6 seconds). Obviously the drone was in full throttle. I...

mavicpilots.com

 

[RadioFlyerMan]

I like your way in checking whether the props touch the arms/body of the drone and I'll adopt this method.
It seems that your issue was with the DJI OEM quiet props, was it not? In my case, the DJI ones are perfectly fine.
Thank you for sharing.

Based on the packaging, I believe they were OEM. The best I can figure, there was a bad batch manufactured on 4/2020.

 

[wingbotics]

Based on the packaging, I believe they were OEM. The best I can figure, there was a bad batch manufactured on 4/2020.

Thank you for confirming.

 

[RadioFlyerMan]

I'd posted one complaint long time back about an overcurrent issue quoted below.
Ok, the situation was different from yours, i.e. in ascending rather than descending. Of course, I cannot be certain that I was using this set of propellers. However, I think that the degrees of flex could induce problems to the overall system behavior. For myself, aother factor of uncertainty is how long ago that these scratched marks were made. I'll keep an eye on those closely from now on.

Overcurrent Discharged

Hi, I have the latest firmware for my Mavic pro, 1.4.5. (both the RC and the aircraft). This morning, I was flying at sport mode at 37mph and ascending at 9mph then a warning, Battery: Overcurrent During Discharge, shown up briefly (6 seconds). Obviously the drone was in full throttle. I...

mavicpilots.com

I have had motor errors while ascending too, but I never had the chance to correlate them with the props hitting the arms. Also I believe there are other causes for motor current errors.

What is most surprising to me is having the blades hit while descending. You would think they would flex up, away from the arms, etc. Keep in mind that my MPP is coming down at 22 mph due to hacked flight parameters for Sport mode. That speed is not normal.

To explain this, I have a theory that the blades flex both up and down, in an oscillating fashion, perhaps caused by turbulence as the blade passes over the arm and shoulder. The amplitude of this oscillation may reach a maximum at certain frequencies (rpm) depending on flexibility, which would explain why it doesn't hit all the time.

So I believe the flex problem is batch related. I currently have a set of OEM DJI props on my MPP, and I've run it pretty fast up, down, sport mode and all without a problem. I check the bottoms of the props every so often to check for excessive flexing.

 

[wingbotics]

I have had motor errors while ascending too, but I never had the chance to correlate them with the props hitting the arms. Also I believe there are other causes for motor current errors.

What is most surprising to me is having the blades hit while descending. You would think they would flex up, away from the arms, etc. Keep in mind that my MPP is coming down at 22 mph due to hacked flight parameters for Sport mode. That speed is not normal.

To explain this, I have a theory that the blades flex both up and down, in an oscillating fashion, perhaps caused by turbulence as the blade passes over the arm and shoulder. The amplitude of this oscillation may reach a maximum at certain frequencies (rpm) depending on flexibility, which would explain why it doesn't hit all the time.

So I believe the flex problem is batch related. I currently have a set of OEM DJI props on my MPP, and I've run it pretty fast up, down, sport mode and all without a problem. I check the bottoms of the props every so often to check for excessive flexing.

Your scratched marks are deeper and more severe too than mine because yours is MPP with different motors from my M1P. Besides yours was a hacked version of variant flight parameters. Of course, on top of it is the possible bad batch of props. These might explain why I don't have problem with my OEM props.

 

[dave canada]

for seven $ I had to try them too same ones and they arn,t very quiet

 

[hiflyer201]

Maybe they meant they interfere quietly.

 

[wingbotics]

To explain this, I have a theory that the blades flex both up and down, in an oscillating fashion, perhaps caused by turbulence as the blade passes over the arm and shoulder. The amplitude of this oscillation may reach a maximum at certain frequencies (rpm) depending on flexibility, which would explain why it doesn't hit all the time.

The flapping direction should be upward if the pressure is from top upon ascending. In this case, the flex won't touch anything. In contrast, a sudden descending action, the pressure is from the bottom (the drone body) and the propellers must be working hard to push the weight downwards. Due to the air dynamic, the propellers will lean towards the arms/shoulders. The soft material of the props would give a higher degrees of bending farther enough to touch the arms/shoulders. Whether they oscillate or not in my case, I have no reason to approve or disapprove. However, I believe that the design of the first generation M1P is the key. There is about 1/3 inch of overlap of the props and the shoulders. This is a design deficiency. There is no overlap in the M2P--a better design.

 

[Harrier]

Check out Master Airscrew props. I've had the same set on for about 2 years. Still perfect. A bit quieter but so hard to tell with my 68yr old ears. Increased performance without a doubt. Not cheap though?

Masterairscrew.com

Just my 2 cents...

 

[Cookaboorra]

Yes, I had some DJI props from Amazon for my MPP that were slightly more flexible than all the others I’ve had over the last two years. They would hit the arms when under high stress, like in wind or when I would descend at 22 mph in Sport mode. You can see the scratches on the bottom side of the prop. To observe it more closely, I taped the high point on the arms with electronic label maker tape. Then verified the “hit” after the flight via the black mark on the high point. I also got motor current errors when I observed the hit. I ditched the whole batch of props.

View attachment 123414View attachment 123415View attachment 123416View attachment 123417

The same thing happened to me. They touched the body of the drone and slightly deformed themselves. I had to measure and cut accurately them to provide a safer flight. They now are not as silent as before. I keep them for emergence. BUT I bought some carbon blades unbranded. They are strong as hell, they don't flex at all ( I have a heavy modded Pro and I fly almost always over 4500 feet )
Idle hovering stays @ 4700 rpms and they are definitely quieter than stock.
I would recommend them.