Jetranger Question...

[Guest CHEVY II]

I'm wondering if any of you have encountered "stiffness" when walking the main rotor on a 206 backwards?

It seems to take more effort than it did before :shock:

[transientorque2]

I'm wondering if any of you have encountered "stiffness" when walking the main rotor on a 206 backwards?

It seems to take more effort than it did before :shock:

 

 

Had that happen to me once. It turned out that it was a collapsed seal in the turbine. if you can't turn it at all you have carbon build up. Back up the blades about 15 to 30 minutes after shut down. Its called N2 lockup. But this is just coming from a pilot, not an engineer. it could also be something else too.

Edited November 21, 2005 by transientorque2

[Guest CHEVY II]

Definitely not "lock up" but the collapsed seal theory sounds interesting...care to elaborate?

[treetopflyer]

It's been a while since I worked a 206 but I recall that you should turn the blades backwards after shutdown to break up any carbon at the 6 and 7 bearings. This will prevent N1 & N2 lock-up.

 

What did your engineer tell you?

 

ttf

[transientorque2]

Definitely not "lock up" but the collapsed seal theory sounds interesting...care to elaborate?

 

 

I don't really know what they did but I heard that it was some sort of seal that might have been improperly instaled or something. That was the outcome. The symptoms grew worse with time. When the engine was hot no problem, but when it cooled down you couldn't turn the rotor at all either way. You will have to talk to an engine expert on that one.

[Guest CHEVY II]

It's been a while since I worked a 206 but I recall that you should turn the blades backwards after shutdown to break up any carbon at the 6 and 7 bearings. This will prevent N1 & N2 lock-up.

 

What did your engineer tell you?

 

ttf

 

TTF, thanks for that advice but lock up is not the issue here. We've always used mobil jet II and with proper cool downs have "never" had N2 lock up using that oil.

 

Engineer had a good look around. So far it's still a mystery although it is a new turbine with approx. 200 hrs. on it now.

[Mac-Ex-wafu]

TTF, thanks for that advice but lock up is not the issue here. We've always used mobil jet II and with proper cool downs have "never" had N2 lock up using that oil.

 

Engineer had a good look around. So far it's still a mystery although it is a new turbine with approx. 200 hrs. on it now.

 

What happens when you manually turn the engine turbine blades at the back end?

 

Are there any binding or scraping sounds?

 

Don't know too much about the 206 myself,but,,, is there a freewheel unit in the transmission line?

 

If so, and the engine rotates freely in both directions without binding/scraping, it suggests that the stiffness encountered from turning the main blades is maybe somewhere between the freewheel and the head, (pump cavitation/suction maybe)

[transientorque2]

TTF, thanks for that advice but lock up is not the issue here. We've always used mobil jet II and with proper cool downs have "never" had N2 lock up using that oil.

 

Engineer had a good look around. So far it's still a mystery although it is a new turbine with approx. 200 hrs. on it now.

 

 

Talk to the guys who did the engine. I think thats its a warranty issue.

[lamanated]

I'd say get ahold of the engine guys also.We had the same thing and they said send her back........

[treetopflyer]

Hey ChevyII,

 

If memory serves me right I've had it on more than one machine using Mobil Jet II and I know I was doing a 2 minute cool down and can only assume everyone else was.

 

Let us know what it is when you get it figured out.

 

ttf