Replacing main rotor blade holders

rdsvark

Hi,
I have just upgraded to a metal main rotor blade holder on my Trex 450 Plus. Need some advice on tightening up the screws into the feathering shaft. I take it you need two 1.5 hex drivers on either side and then screw tight?
How tight do you screw them in? Do you have to center anything? At the moment I have only one Hex driver so one side is tight and the other floppy>

When you tighten the screw does it compress the blade holder?

Thanks

Burgess · Extreme 3D Joined: 27 Mar 2012 Posts: 1103 Location: Wales

Hello rdsvark,

You need to download a pdf manual it will show the correct order of assembly for bearings, shims, and spacers.
M2x6mm machine screws either end of feathering shaft, so yes you will need two hex drives.

The feathering shaft will self centre in the rotor housing.
First do a dry-fit and check there is neither lateral free-play, or compression on the bearings. The blade holders should pivot freely on the shaft.
If you need shims go to Align.co.uk.
Disassemble apply grease, reassemble and apply small amount of BLUE thread-lock to first few threads on both M2 screws Align T43 or similar. Hand tight and nip-up.

By "When you tighten the screw does it compress the blade holder?" I take it you refereeing to blade-holder screws, then yes, you will need a 5.5mm socket or ring spanner to hold the nut.

Burgess

Dumb Thumbs · Posted: Sun Dec 09, 2012 9:22 am Post subject:

You'll need two drivers to tighten the bolts that hold the blade grips onto the feathering shaft, tighten them all the way.
Exclamation

Be sure to clean any oil off bolts and shaft bolt holes with denatured alcohol before applying Blue Locktite, otherwise it may not hold properly.

Having a blade eject while hovering @ eye level can really ruin your whole day!

rdsvark · Posted: Sun Dec 09, 2012 3:58 pm Post subject:

Thanks for that, will wait for my second hex driver.
I havent replaced the feathering shat, just the blade holders. When you tighten the screw into the feathering shaft through the blade holder, does it compress the end of the blade holder? As stated I have only managed to tighten one side as I only have one hex driver and one of the blades is really tight in the blade holder, doesnt move freely even with now screw in place.

Wasnt sure if the blade holder is defective or if i have compressed it by tightening the screw into the bearing shaft..

rdsvark · Posted: Sun Dec 09, 2012 5:55 pm Post subject:

Last question.

With both hex drivers in place, do you tighten them together or one a time?

Burgess · Extreme 3D Joined: 27 Mar 2012 Posts: 1103 Location: Wales

First:
That screw you've fitted with only one driver, will not be tightened up enough, even if you've applied blue thread lock because it's a space filler rather than a cement or glue.
If you try flying like that, the blade will be ejected, both the feathering and the main shafts will bend, the main bearings will also suffer damage, and may-be the motor shaft too.
So, when you've got the other driver, disassemble the rotor housing, that is, take off both blade holders and clean-off all old thread-lock from internal and external threads.

Compression:
The only things that may compress are the Damper rubbers in the rotor housing.
As I've said, do a dry assembly, blade holders and spacers, washer and M2 screw in one end, while applying steady pressure to that end observe the other within the blade holder. The outer face of the bearing should be flush with the end of the feathering shaft.

If the bearing is proud of the shaft adjust the spacers, if the shaft is proud fit shims.

Tightness of blades in blade holders:
Thickness of blade roots, should be 4.7mm.

Measure the width of the opening in both blade holders.
If the slot in one does taper, contact your supplier.

Or you could use a pair of hardwood wedges to ease it open, but they need to be made with precision. Place one wide-end in against the inner end of the blade holder, then using a G cramp slowly and gently, press and release, press and release the other wedge in, this will gradually ease open the blade holder till it matches the other one.

*******************Edit******************
To answer your last question,
Use both drivers and work one against the other.

****************************************

Burgess