Hey, this morning when I was learning on my T-Rex 450, one of my learner landing balls snapped off and caused my chopper to lunge forwards. Luckily, I only bend my main shaft, minor damage to my blades, and destroyed my SF mixing arm.

However, my question is should I order a metal or plastic SF mixing arm? Say I do get metal, would this break or bend just as easily as the plastic?

My other question is (for someone who has built a T-Rex 450): What holds on the tail boom? My belt was tight, and after my small crash (nothing even touched the tail) my belt was extremely loose? What holds on the tail boom, because all I can see are 4 non linking screws that bolt into 2 pieces of plastic - This can't possible be holding it ...

thanks,
Matt.

The SF mixing levers break very easily , in my experience. So does the plastic flybar see-saw. I woulk say go for the aluminium.
The boom is kept in place by friction. Mine slides in a little and the belt gets loose every time i touch down too hard. loosen the 4 screws, pull the boom out again and re-tighten the screws. Not too tight, eventually the srew holes strip their thread.

Tolla's got the experience with those plastic parts. I would disregard what I told you in the other thread and get these two items in metal. I do run the plastic grips and really flew them hard last night. No problems. But everything else on mine are metal, so I didn't know which ones would be weak.

Tolla: If you will wrap the end of the boom with ONE SINGLE layer of scotch tape, it won't slide in any more. Works really well...

I've been doing this for a while now, and find that it really locks the boom in there good...

Ct40,
I prefer it to slide in. It lets the energy go someplace in a crash. It holds fine normally, but with any ground contact it's able to slide forward. The pin that stops the boom rotating within the tail boom block (plastic version) has also long broken. Better so, I say, it lets the boom twist with ground contact as well. That way crash energy is absorbed and not transferred elsewhere.

Ct40,
I prefer it to slide in. It lets the energy go someplace in a crash. It holds fine normally, but with any ground contact it's able to slide forward. The pin that stops the boom rotating within the tail boom block (plastic version) has also long broken. Better so, I say, it lets the boom twist with ground contact as well. That way crash energy is absorbed and not transferred elsewhere.