So happy now that I know my nuts won't fall off

[BerndM]

Noooo....not THOSE nuts!!!!!:tennis:

I've changed out the pretty aluminum bullet prop nuts with NyLock stainless steel self locking nuts.
No worries about them loosening, EVER.

If you need any, they are 6mm X 1 thread for the DJI 2212/920 motors.

For the Graupner 10x5 props, they needed either a 6mm flat washer on top of the prop, or an 8mm washer under the prop.
Your choice.:shame:

 

[astr0b0y]

Loctite seems to work also.

 

[BerndM]

True, but multiple applications of Loctite gets real messy after a while.

 

[DucktileMedia]

nylocks are a must!

 

[NYREPS]

Where can I buy spare nuts I can't find them anywhere

 

[Bartman]

Where can I buy spare nuts I can't find them anywhere

there's probably a waiting list but then you'd also have to find a suitable donor.


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[jes1111]

Loctite seems to work also.

Many plastics are attacked by thread-locking chemicals - makes them brittle.

 

[kloner]

I use 2 nuts each and lock em down

mcmaster carr has alot of nuts, most likely have whatever you want http://www.mcmaster.com/#nuts/=i3t7wg

 

[ChrisViperM]

there's probably a waiting list but then you'd also have to find a suitable donor.


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....just stumbled across this one...great

 

[mailman35]

i get my stuff from homedepot or lowels using a single nut ive never had them come loose.

 

[Dewster]

I just received and installed some Gemfan carbon fiber slow flyer props. I wanted something more secure than the standard nuts that came with my motors so I bought some of those Nylocks. They work well, plus the give me peace of mind.

My first indoor test with the nuts that came with the motors resulted in two props flying off and hitting the ceiling. Thankfully it was just a run up test. I used plumber's tape and Scotch mounting tape to absorb vibration from the standard nuts. It worked well, but every once in awhile I would have to retighten them.

I found the 6mm Nylocks at Lowes in the metric aisle for nuts and bolts. They fit snugly, but I still use Scotch mounting tape as a second layer of insurance.

 

[mitsaras]

Great tips guys, I've bought a few M6 nyloc nuts to have in my toolbox as spares, in case a nut flies off in the fileld...:frog:

 

[Dewster]

Hexa down:

My Hexa crashed today. It wasn't due to power failure, or WKM issue. It was my brand new Gemfan carbon fiber props. One of the props snapped while in flight leaving my craft a wreck. After an hour of trekking through the woods I found my craft in pieces. Power was still applied, even though the battery was puffed and smoking hot. The Nylock did their job and didn't come off. The carbon fiber prop snapped in mid flight bringing the craft down.

I should have stuck with my APC props....

 

[Tahoe Ed]

I was flying my F550 today and had a prop fly off! I am using star lock washers. I am not sure how it happened. Recovered the prop and only broke an arm. I have replacements so no big deal it is just odd that it happened.

 

[BerndM]

Great tips guys, I've bought a few M6 nyloc nuts to have in my toolbox as spares, in case a nut flies off in the fileld...:frog:

Always a good idea to have all sorts of spares on hand HOWEVER, IF a nut came off in flight, you're probably gonna need way more than spare nuts to get it back in the air.

 

[mitsaras]

ouch, Dewster, are these the "carbon reinforced" Gemfans? I just received a set, and after reaming one prop to the right size for the DJI motors, it looked waaay too thin at the hub... Sorry for your craft, but so glad I threw my gemfans in the drawer...
I think I'l spring for some Graupners....

 

[Dewster]

Nylock works, carbon blade failed.

View attachment 4972View attachment 4971View attachment 4970View attachment 4973View attachment 4974

ouch, Dewster, are these the "carbon reinforced" Gemfans? I just received a set, and after reaming one prop to the right size for the DJI motors, it looked waaay too thin at the hub... Sorry for your craft, but so glad I threw my gemfans in the drawer...
I think I'l spring for some Graupners....

These were the full carbon blades. And you are right...they are not strong enough at the hub. While flying (very conservatively since this is my photo ship), I heard a loud snap and then watched my flat hexa spiral out of control onto the ground. Needless to say...the Nylocks did their job well. All of the hubs were still attached. It was the blades themselves that failed.

I don't see the point in having carbon filled nylon blades. That almost says: yeah...we can't do full carbon so we'll make a hybrid. The APCs flex. The ones I took off of my Hexa were still good. They needed to be balanced, but their integrity was good.

Here are some photos of the Nylocks doing their job. You can also see where the blade failed:

 

[BerndM]

Hey Dewster
Very sad about your crash. It REALLY sucks that you went to the effort to get good strong props and this happens.
I, and I'm positive, all the other lurkers here would really be interested in the response from the dealer you bought the props from.
You ARE going to be contacting them, right??
Will they stand up and help repair the heli ???????
After all, the carbon props are SUPPOSED to be virtually indestructable.
Please let us know what the outcome will be.

 

[jes1111]

To my mind there are no surprises here. The APC props are made of nylon - a fantastically tough polymer. "Carbon-filled" anything must use a more "rigid" resin (of one sort or another) to have any chance of seeing the benefit of the carbon fill - and that very rigidity means its going to be subject to stress fractures. Short of using high-tech composite sandwich construction (à la full-size helicopter blades), the best all round material (IMHO) for a prop is the original one: wood. Have we seen any reports of Xoar/JXF props spontaneously self-destructing?

 

[tstrike]

Dewster, sorry about your crash, it doesn't look like you have a washer under your locknut to distribute the compression. Also whatever that gewber is above the locknut is probably throwing your motor balance off and is unnecessary since the whole point of a locknut is to "lock".

Ed, those star washers get compressed easily and after only a couple times of compression/decompression they become thinner and need to be replaced. If dji would add just a couple more mm's of thread on their prop shafts a graupner wouldn't need any gimmicks to work on a stock motor.

8mm bolts only need 16-18lbs of torque and that's not as much as one would think.