Prop Crack

[Maxwell Jeeves]

I was doing a post flight inspection of my spark today, and I noticed a slight crack on the trailing end of the prop close to the root. See attached pic. I think this happened as a result of a minor crash I had indoors when I first bought it. I’m surprised I didn’t notice it sooner. I’m worried the reason I missed it is because it wasn’t there previously, and the crack has propagated after 4 or 5 flights. Should I switch it out? I would hate to waste a prop like that, but it’s a no brainer if I am looking at a complete failure after a few flights.

 

[maumau]

I was doing a post flight inspection of my spark today, and I noticed a slight crack on the trailing end of the prop close to the root. See attached pic. I think this happened as a result of a minor crash I had indoors when I first bought it. I’m surprised I didn’t notice it sooner. I’m worried the reason I missed it is because it wasn’t there previously, and the crack has propagated after 4 or 5 flights. Should I switch it out? I would hate to waste a prop like that, but it’s a no brainer if I am looking at a complete failure after a few flights.View attachment 5207

Yes trailing edges of props are more fragile than leading edges. And sometimes cracks are difficult to notice at once.
I had a couple of cracks like this and it's VERY easy to fix.
Just use a piece of scotch tape on the crack. Absolutely no change in behaviour and performances. I flew more than 100 times and the prop is still perfectly working.
MOST IMPORTANT: in case of slight crash undo all your props and check the small pieces that lock the prop into the motor. They are also very fragile and might break. In this case throw the prop away.

 

[Jeplane]

Couple of thoughts come to mind:

- Props are too cheap to mess around with. They are really a small price to pay to protect your investment.
- Props can turn fast. At 2500 RPM in a prop airplane, the wingtips are very close to the speed of sound. Obviously, any cracks on the prop then can have disastrous consequences. Although with the Spark being a quadcopter, we do not have to worry as it is not that fast to begin with. However, once again, cracks are not something I would mess around with, it's just not worth it losing a drone because of it...

 

[Maxwell Jeeves]

Both good points. I think I am going to trash the prop, and inspect the other 3 prop locks for damage.

 

[Spark 317]

 

[RENOV8R]

Putting anything on a prop such as tape will cause it to become unbalanced. Maybe not quite so noticeable in smaller craft but in larger birds we actually use small pieces of tape to balance props. Putting a piece on Sparks prop may not cause any noticeable change in flight characteristics, but may slightly affect your video image.

 

[John Harvey]

The root of the propellor is where all the stress , load is generated. Any crack in this area will grow and the blade will separate, resulting in a Drone crash. Blades are cheap, best to replace immediately and protect your investment.

 

[graywoulf]

Second chance box... LoL! I have to agree with all of the reasons not to continue using a cracked prop. Especially the RPM issue. I was thinking at first to use CA but CA is not stable for many plastics and certainly not any use where vibration and such is a factor. Did I learn a lesson? Yes I did.

 

[Eljay]

You definitely want to get in the habit of checking them out each time and replacing a prop if there's any hint of drama. Just carry spares and accept that you'll occasionally use them up.