This is why you don't stand over or in front of a prop while testing.. this was on my Thunderbolt after some maintenance, and the high speed needle got misadjusted. Found the prop nut eventually, about 100 feet to the front, and just about 10 feet to the left. It was the weighted Higley spinner nut. I had just commented to the cameraman that you didn't want to be too close..

http://www.rcuvideos.com/video/Prop-spin-off-MPG

I have one of those higley hubs as well but decided to go with the Tru-Turn hub for my Jug
http://www.truturn.com/cgi-bin/store...exact_match=on

with the adaptor it is a double jamb nuted, and its also right in the scale size range, not too expensive as well, looking at the dammage on RCKen's hand having the double nut makes me feel bettter about having the prop not flying off, I have only had one do that on my 4st engines, after starting it backfired and I didn't have the nut tightened enough it didn't fly off like yours did though, your lucky to find it

hmmmmmm...........

Actually, nobody should be anywhere in front, cameraman or not.

This is the Beginners Forum isn't it?

Well, beginners, the rule most often quoted is to stay behind the prop or move behind as soon as possible. And as you see, it's a rule applies even after you've got a couple of years of flying behind you.

Exactly my point. The prop was double nutted, didn't matter that I used a 12 in. crescent wrench to tighten them with, either. If you look at the video right about 26 seconds, you can step through the prop nut and lock nut coming off, and the prop striking the ground and flying off to the left. It went about 30 feet.