Trex 450 DFC head slop

[Helibelly]

Hi, I was wondering if there should be any in out, or up and down movement on the blade
grips in the 450 DFC head?
The head is assembled correctly, no missing parts. I had to grind down the feathering shaft a very small amount at a time, to take up the play to the point where the blade grip inboard radial bearing was just starting to become notchy, to eliminate the play.
Surely having play in the head like this is not a good thing.
Why not provide shims for adjustment , or machine the feathering shaft more accurately.

Eric.

[Civerad]

It's been a while since I've owned a 450 so I don't remember if I've ever needed a shim, but Align does have a set of main shaft spacers available (H45189). Alternatively the T-REX 250-500 Hardware Bag (H45168) also has it. I prefer buying the hardware bag as it gives me all the screws I'll ever need for my kits.

[Helibelly]

Hi, thanks for the reply. Yeah the main shaft spacers are 5x9x0.1mm and 5x9x0.2mm, so would need to be ground down to 5x8mm.
I have actually ordered some of the correct size shims for future reference ( 4x8x0.1mm and 4x8x0.2mm ).
What I would really like to know is should there be any slop there to begin with, i.e. is it there for a reason?
Eric.

[Civerad]

Sorry, I just realized you're talking about the blade grips and not the main shaft slop. There shouldn't be any slop on the main grips. Double check if you installed the spacer that goes between the head and the main grip. Also double check that your bearings are correctly seated.

Looking at the parts finder, there are also two feathering shafts for the 450. H45021A is for the pro/sport 450 and it has flanges at the end to fit the thrust bearing. Maybe what you need is H45H005XX.

[Helibelly]

Hi, yes the spacer that goes between the head and the main grip is present and correct. Also all of the bearings and spacers are present and installed in the correct order as per the manual. I have checked this multiple times.

The feathering shaft I am using is part number H45H005XX, without the step down at the end. But being an upgraded version of the H45021A, the lengths should be the same.

This is far from my first heli build, but the first one to have this problem.
Eric.

[helislope]

Originally Posted by Helibelly

Hi, yes the spacer that goes between the head and the main grip is present and correct. Also all of the bearings and spacers are present and installed in the correct order as per the manual. I have checked this multiple times.

The feathering shaft I am using is part number H45H005XX, without the step down at the end. But being an upgraded version of the H45021A, the lengths should be the same.

This is far from my first heli build, but the first one to have this problem.
Eric.

It is possible for you to take video. Upload video to dropbox or google drive. This will help us see the amount of moment. You can send link to alignsupport@enterprisehobby.com or aligntech@enterprisehobby.com

Thanks

[Helibelly]

Hi, actually as mentioned I have ground down the feathering shaft a small amount, and the play is now gone. I went a little too far so had to also take a very small amount off the damper.
I wasn't totally happy with this so bought and fitted new feathering shaft and dampers, and now there is no play without having to modify them!
One or both of these new parts are obviously different dimensions than the first set.
I cant compare them with each other as I have modified the first ones, but suspect the dampers as the new ones are a tighter fit in the head.
Just one more question though, the new dampers have a rough finish on one end ( all four of them ), does this rough end fit next to the aluminum shim or the head block?
Thanks,
Eric.

[Steve Joblin]

Originally Posted by Helibelly

Hi, actually as mentioned I have ground down the feathering shaft a small amount, and the play is now gone. I went a little too far so had to also take a very small amount off the damper.
I wasn't totally happy with this so bought and fitted new feathering shaft and dampers, and now there is no play without having to modify them!
One or both of these new parts are obviously different dimensions than the first set.
I cant compare them with each other as I have modified the first ones, but suspect the dampers as the new ones are a tighter fit in the head.
Just one more question though, the new dampers have a rough finish on one end ( all four of them ), does this rough end fit next to the aluminum shim or the head block?
Thanks,
Eric.

Rough end goes in the head... The smooth (slightly curved end) should face out.

[Helibelly]

Hi, I have assembled it the other way around! I wish the manual would have clarified this. Never mind, thanks for the info.

Eric.