Blades not spinning...

[Cralis]

Right,

I decided to try fly my T-Rex 450SE without training gear for the first time.

Started up fine, and just got it light on the skids.. but chicked out each time.

Then got it up for a few seconds (story of my life) and landed again, as I was drifting.

I then spun it uf a few times again, but chickened out.. Then, on the last attempt, I pulled the throttle back to 0%, and the blades started slowing, then suddenly stopped. That is, it never took ages to slow down. They just jarred stopped.

I never tried to spin up again. I hit the lock button, and went to see..

I've removed the battery, and have found that I am unable to spin the blades ! They seem to be jammed. That is, backwards OR forwards.

I can spin the top (big) gear (looking from the top, tail pointing at me) anti clockwise, but it's very sticky.

But I can't spin it forwards. That is, clockwise. And I can't see whats stopping it.

I never crashed. It was just spinning down when it happened.

Please tell me there's a simple answer and fix...

[Cralis]

I've noticed I can't spin the tail rotor either....

[ChrisB]

The one way hub could be locked up,located in the main gear

[Cralis]

Possible problem. Attached photos are of the tail. I think the belt seems not right.. It seems off to the left... And because of that, it's not sitting properly on the rollers in the tail.

Does this seem wrong?

If so, how do I fix it, and what SHOULD it look like?

I guess this could have come off the right track because something else locked, but it does seem a bit wrong to me.

[Cralis]

Now, the main gear WAS removed to replace the main shaft before this flight... Could the guy have replaced it incorrectly or something? Is there a way I can check it?

[ChrisB]

The belt should be dead centre on the rear pulley,thats the cause of the problem,,i suggest you take the tail gearbox apart and see if anything is amiss

The rear pulley has quite big guides on the edges so its odd the belt is like that,is the belt loose?

[Cralis]

Belt seems extremely tight to me - but that may be due to the jam...

[Cralis]

I have managed to get the belt back on the rail, and it's spinning freely now. I need to work out what has caused this. Could have been pretty bad if I was off the ground...

[ChrisB]

How tight is the belt now its back on the pulley correctly,it may be too loose


Chris

[Cralis]

Very loose.. needs tightening. How do you tighten it?

[ChrisB]

Ok thats your problem then,its too loose and was able to ride over the side of the pulley

Loosen the 3 screws at the rear of the top frame where the boom passes thru and loosen the horizontal fin clamp,this will allow you to gently pull the boom out from the frames to tighten the belt

A good tension would be when you look at the front pulley and push on the belt towards its other run and it should move about halfway,if it touches itself then its too loose...


Chris

[Cossie]

I love it when the solutions come to like this. These forums are brilliant for advice and help.

All manufactures manuals should have links to forums like this in them

[Cralis]

Right, tightened, and it seems better. Got a hover! For about 20 seconds. Then, things seemed to go wrong again. Harder to hover.. drifting more... So landed... and noticed the blades spun down pretty quickly again. Not as fast as last time.

Checked the belt was still in place and tight like Chris said, and it was, but again, the blades seem pretty stiff to spin.

Something not right... I'm sure I used to be able to spin them freely clockwise?

[Cralis]

Noticed something.

If I spin the gears clockwise, and watch the small gear turning the small gear that seems to drive the tail, it turns OK.. but seems stiff. If I then turn the main gear anti clockwise, and watch the tail gear, it seems to stay still, like it's not meshing properly.

This is unlike the main gear that touches the engine. That connects both backwards and forwards..

Does this seem wrong?

[Cralis]

I'm wrong! When I spin it anti clickwise, the lower gear doesn't move. Sorry. Red herring for me.

Still just seems too tight to spin the blades...