Blade 400 - belt & belt gear

[stevefed]

I wish I could post a pic, but my belt completely ate my belt drive gear. I regress...

I had a minor bump and the tail rotor took one for the team. after that, I had no rudder control and the heli spun at will with no tail repsonse even though the servo/tail blades moved correctly. Almost like the gyro didn't kick in - but everything checked out ok.
except belt tension. seemed pretty loose. So, I tightened it and powered up - back to normal for a battery pack or so, and then back to unresponsiveness. slid the boom out a bit more, and better for a couple seconds and then nothing. I suspected the belt was stretching due to being ran thru a few packs, and thought maybe I was slipping gears or had a flat spot. Took the boom out, removed the belt gear shaft, and found I had no drive gear, only a flat melted looking washer with the remains of small gear teeth on the very edge. Belt is worn, too, and idle pully in the tail had chunks of belt on it.

Bad deal, indeed. I must have over tightened the belt - but all the manual states is to have the belt deflect 1/2 the way to the other side. Except, YOU CAN"T SEE THE OTHER SIDE!! :arggg:

anyone have tips to prevent this in the future?

[carlo_the_wonder_frog]

Next time adjust the belt so that you can easily spin the rotor by hand once around and it will continue to spin for 2 or more revolutions. Anytime the heli Piros( Spins, Yaws) counterclockwise that is the effect of torque. The tail rotor provides thrust opposite of the torque to keep the heli in one spot, but it has to spin fast enough to provide that thrust. If the small gear on the tail rotor shaft slipped then the tail wasn't able to achieve the right speed, causing uncommanded yawing. Hopefully thats not making it too complicated. Looks like you will need a new TR shaft with gear and a new belt.

Another trick you can try is to spray silicone lubricant inside the tail boom to get the tail somewhat lubricated, it helps alot on the T-Rex and I would assume so on the Blade 400.