How much damage is OK to have on propellors before you junk them?

[stackofpancakes]

I'm a newb and am wondering how much damage is OK to have on a propeller. I'm flying an octocopter and have CF propellers. I had a couple rocky landings and shave 1mm or so off the end of a couple props when it tipped. Am I still OK to fly with it or should I switch them. I did already try to fly and it seemed OK but perhaps I'm missing something.

Otherwise, how much do you feel is OK or too much. A 1mm chip on the end? 2 or 3 mm off the end? Where do you draw the line and fork out for a new propeller.

I realize if shooting video, unbalanced props could lead to more vibration but I'm not at that stage yet - still practicing take off and landing.

 

[flitelab]

Personally I would say none, especially with CF props. They are very stiff and ridged so you could easily have cracks at the hub or other areas if you have had prop strikes. Do you want to risk crashing your machine due to prop failure or worse yet have a prop come off in flight an injure someone?

I'd go with ABS or even wood props for practicing, bit more forgiving than CF.

 

[Shaun Stanton]

I would say that from personal experience with APC props if you just barley graze a prop because of a bad landing and you tip the copter I found that if the prop only has some micro nics I might smooth them out once. I quantify it by if the nicks and scratches are less then a tenth of of mm then it may be fine. But the more you shave down the prop you will make it less efficient than the others. Ideally if you have to really sand it down its better to be safe and replace it. APC's are fairly resilient in grass if you can cut the motors in time.

 

[Lanzar]

Even slight damage can result in failure.
In the interest off public and safety replace them.

 

[Dewster]

Props are critical. I had a carbon fiber prop snap on me during flight and it wrecked my craft, FPV equipment, battery, gimbal, motors, ESC etc. You could lose a lot if one breaks in flight. Even a small crack could cause your props to fail. APC props are more forgiving since they flex a little. You really don t want your props touching anything but air.

 

[mitsaras]

Even the expensive CF or wood props cost only a fraction of your entire rig, especially if you have a nice camera for filming and fpv gear etc., not to mention the possibility of damage to property or ...people! Better safe than sorry.

 

[stackofpancakes]

thanks for the thoughts everyone. Choosing a cheap 'practice prop' is probably a good suggestion.

I'm not flying close to anyone or anything at this stage.. the biggest danger to anything is my poor flying skills and I think that trumps a prop failure at this point... but agreed, it isn't worth risking the entire craft because of one prop.

@Dewster - did your craft coming crashing down or did the prop piece chew up the copter?

 

[Dewster]

thanks for the thoughts everyone. Choosing a cheap 'practice prop' is probably a good suggestion.

I'm not flying close to anyone or anything at this stage.. the biggest danger to anything is my poor flying skills and I think that trumps a prop failure at this point... but agreed, it isn't worth risking the entire craft because of one prop.

@Dewster - did your craft coming crashing down or did the prop piece chew up the copter?

No. The hub must have been cracked. I just bought the props and flew it less than five minutes. I heard a loud snap. My flat Hexa went crazy and then DJI's fail safe kick in (like it should) and killed all motors. My craft fell straight down like a rock.