what happens when a propeller break in the air?

tyor

Member
I am asking because I have some strange behaviour yesterday. I was flying my f450, 10" dji props and 4s lipo. suddenly the quad tiltet bak and to the right and flew in to woods. I heard a big crash and thought everything was lost. but when i found it the only dammage was a broken prop. the one back on the right side. it was broken in the middle of the hub.

Tried it with 8" props when I got home and everything seems normal.

I wonder if the prop break in the air and was the reason to the strange behavior. Here is a pic of the rest of the prop that was left on the motor.

View attachment 5821
 

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Fransvh

Member
Hi Tyor. There are many report about braking DJI props.
Looks like you over-tided the the prop-bolt and that results in little cracks in the hub. Rotating with a few thousand RPM the hub brake.
You shouldn't use the DJI's anymore.

Without payload you can use APC
With payload like cam's etc, use Graupners
 
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Warlock

Member
I'm confused, and or stupid I guess. A bit ago I took off the 10" DJI props which were working great, and replaced them with a set of 10" Graupners. Took it out and it had zero lift! I had marked the prop nuts "R" and "L" prior to removing the DJI's. As well the DJI props have an "R" after the numbers "1045", the the left turning ones do not. I didnt notice at first that the counter clockwise Graupners have an "L" after E-PROP written on top of the props. On the back of the card each Graupner prop comes in, its says "Clockwise" or "Counterclockwise". My idea of clockwise is turning right and vise versa. I came back inside and switched each one . This time, it wanted to turn over to the right looking at it from behind but I did not let it. A couple props were blowing upwards...not good. The others didnt blow up or down. I carefully put my hand under and over each prop one at a time.

I also checked the pitch of the graupner clockwise prop against the DJI "R" and there opposite. Same thing with the counterclockwise. I know I'm kinda old, and not the brightest bulb on the Christmas tree, those excuses aside. Im lost. Oh I put the DJI's back on and they work great. If this problem is only too obvious to you all, dont worry about hurting my feelings, somebody straighten me out please.
 




hjls3

Member
Warlock - when your motors spin, the leading edge is the highest edge. Hope that makes sense. Graup props logo should face the sky.
 


Dewster

Member
Say bye-bye. That's what happened to me. Flat Hexa dropped like a rock after one prop snapped. I'm building a Y6 now...hoping that if another prop break occurs that I will be able to do a controlled landing vs. experiencing Newton's Law.
 


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