550 tail exploding

[bullseye1]

I was almost finished with the build, installed the new REVCO gears and pinion that I just got today from Readyheli, installed the motor and decided to give it a little test run on the bench without the blades, few seconds into the run and the tail explodes (scared the crap out of me), it took me a while to find the pieces in my garage and it looks like one of the tail blade grips shattered and the bearing still on the spindle.
Is this ever happened to any body else or is it just my bad luck.

[Raydee]

WOW, I hope this isn't a new problem :(

[ukpaul]

Probably over reved it with not having any blades fitted, that motor looks like a bit of a beast too.

Not heard of a tail breaking like that before now. Could just be bad luck I suppose.

[tungym]

That is really weird as mine crashed dozen of times, before the tail gear box getting soft and I changed it, almost after 120 flights.
I think some other reason cause the mishap.

[Phoinix]

Running the heli without the blades is a big no-no. With no air resistance the system is running at speeds a lot higher than it would run with the blades on. Induced vibrations can disintegrate the drive train.

Did you go to full power?

[bullseye1]

I was only at half throttle, the race that hold the bearings on the right side tail grip in the photo broke off causing it to fly off and shatter the tail housing.

[tungym]

I got your meaning. So actually the tail grip flied off and the vibration causing shattering of the tail housing.
So what kv motor and gear/pinion are you using?

Even without main blades and with a reasonable headspeed, the tail grip will not shot out.