How bad could they be?
The Gemfan 5030 is one of the most popular props used by the mini quad/hex crowd. Their 6" sibling, not so much. I had heard mixed reviews. Some used them and liked them. Others said they will break mid air. Well, I thought they must be more durable than that and bought a few sets.
Initially they worked great. They are an efficient prop that stood up to some abuse. I never crashed them hard, but they would encouter leaves, long grass, and other bits that at 20,000rpm could damage the prop. I would use them until the tips were pretty beat up, and then replace them.
I was "just flying along"
Mountain bikers have their "JRA" stories (Just riding along) of parts that broke for no reason. "I was just riding along when my suspension fork snapped in two...can I get a warranty replacement?". Most of the time "JRA" is a nice way of saying "lie".
In this case, I assure you, I really was "just flying along". I had recently replaced the props and had not had the slightest incident with these props. I had flown them a few times, once in a big field where I did some high power punch outs and pushed it a bit harder than normal. The next time out I was doing my usual easy flying. As I came in to land, the mini hex just pitched over and flew itself into the dirt. What in the world?
Here you can see the end of the flight. I had to edit it like this so someone in the video cannot be seen. I was hovering around 8 feet high and slowly coming in to land when this happened:
I found the offending prop and it snapped off right at the hub. Apparently this is pretty common:Video not found
Don't stress them out!
Apparently these don't like too much stress. If you push them hard they will snap right at the hub. You can tell if a prop is going bad. It will develop white stress marks where the blade meets the hub. Replace the prop immediately! If you prefer to see your quad crash in glorious fashion, find a big open field with no one around and go fly. In time, the blad will no longer desire to be joined to the hub and will go for a solo flight, leaving your quad to go flailing to the ground.
I've read the grey ones are redesigned to be stronger. I don't like grey, don't trust GemFan, and don't know if these are even any better. So I'll pass and stick with HQ. Those have been much better and not one break.