skigolfmike
05-12-2008, 01:03 PM
With all the problems I had with the TR on my 550 lately I've learned a few things and thought maybe I should pass some of it on. One of those things was how to setup the CNC Tail Rotor Grips with Thrust Bearings (http://www.readyheli.com/204650_CNC_Tail_Rotor_Grips_with_Thrust_Bearings_G _p/204650.htm).
First, I take the one of the grips off the hub and take the small set screws out of the hub. Loosen the other TR grip until the hub slides on the TR shaft. Align the bolt holding the grip on with the pocket in the TR shaft and tighten until the grip is snug and just turns on the hub. It's OK if it's binding at this point because it's coming off and getting fixed later.
Next, take the other grip and lube the thrust bearing with Tri-Flow grease or something similar. A touch of lube on the flat on the hub is not a bad idea either. Now put a drop of Loctite (242) in the bolt hole in the hub and wipe off any excess Loctite. Bolt the TR grip on the hub until it is tight. Slowly back off the bolt until the grip starts to free up. At this point it will feel a little notchy. Back the bolt off until the notchiness is just gone. If you back off too much there will be too much play in the grip, so if there is any play, tighten until it starts to feel notchy again and then back off a little until it is not. When it gets close it doesn't take much movement or the wrench to change it. More like just enough pressure to feel the wrench move, but not to see it move.
At this point, I put in the 2 set screws in the hub with loctite. Then I pull and lube the other TR grip and repeat the above.
Attach it to the slider, remembering leading edge control and to use Loctite on those bolts too.
Lastly, put the TR blades on and only tighten just enough so the blades will just stay in position.
The trick is getting just the right grip to hub pressure. There is a sweet spot, it just happens to be pretty narrow.
First, I take the one of the grips off the hub and take the small set screws out of the hub. Loosen the other TR grip until the hub slides on the TR shaft. Align the bolt holding the grip on with the pocket in the TR shaft and tighten until the grip is snug and just turns on the hub. It's OK if it's binding at this point because it's coming off and getting fixed later.
Next, take the other grip and lube the thrust bearing with Tri-Flow grease or something similar. A touch of lube on the flat on the hub is not a bad idea either. Now put a drop of Loctite (242) in the bolt hole in the hub and wipe off any excess Loctite. Bolt the TR grip on the hub until it is tight. Slowly back off the bolt until the grip starts to free up. At this point it will feel a little notchy. Back the bolt off until the notchiness is just gone. If you back off too much there will be too much play in the grip, so if there is any play, tighten until it starts to feel notchy again and then back off a little until it is not. When it gets close it doesn't take much movement or the wrench to change it. More like just enough pressure to feel the wrench move, but not to see it move.
At this point, I put in the 2 set screws in the hub with loctite. Then I pull and lube the other TR grip and repeat the above.
Attach it to the slider, remembering leading edge control and to use Loctite on those bolts too.
Lastly, put the TR blades on and only tighten just enough so the blades will just stay in position.
The trick is getting just the right grip to hub pressure. There is a sweet spot, it just happens to be pretty narrow.