Best way to keep props on quad?
 

I bought motors that all have standard threads on the prop adapters, which will let two of them unscrew if they ever slip at all. My first thought is to put a piece of my trusty sheetrock double sided sanding cloth on as a friction adder (been using it for years on airplanes with great results) and then put a second nut on to lock the prop nut down. Is there a more elegant solution that the multirotor crowd has come up with than that?

Just get them tight. I've never lost a prop in all the time I've been flying these things and nearly all of them have standard threads.

Well there is no texture at all to the drive area, so it will be easy for these props to slip. Maybe I'm worrying about nothing, but I think I will still go ahead and put some friction material on. On airplanes, a plastic backplate will let props slip while starting even when it's scary tight, while a piece of this stuff won't let it slip even if it's just snugged down. Thanks for the help.

Is your experience mostly with glow or gas? Electric motors are smoother so it's not as much of an issue. You do have to get the props good and snug though.

Both, and I have some electric planes and a Trex 450 helicopter as well.

One thing I really don't recommend on a quadcopter are collet style prop adapters. Lots of people use them but I prefer bolt on adapters. For quads like the Deadcat I like Emaxx 2213-935 kv motors. The prop shaft is made into the motor.

The motors I bought have bolt on prop adapters. They are Cobra 1100kv motors. I'm curious why you don't like the collet style adapters though? Do they have a habit of coming off?

Collets aren't very sturdy and can wobble

If you use the collet type then every time you hit a prop on anything you will bent your motor shaft. Not Good
It's much harder to bend the bolt on type.

My Buddy uses Team Losi Racing locknuts part # LOSA6321 and has never lost a prop since
You local hobby shop should be able to get them in or I found them on Ebay here: http://www.ebay.ca/itm/Losi-LST-Losi...item541f3d6140

The set comes with LH and RH threads.

I have started using blue loctite on my prop threads. Never come off now.
Side affect is makes them hard to undo but abit of heat from a soldering iron fixes that problem.