Align Trex600n feathering shaft sleeve set (HN6061)

Reviewer: Rob Turnbull
Review Date: 14th April 2008
Supplier 50-tuning.com
Manufacturer: Align
Unit Cost: £2.70

Introduction

The dampers that come with the Trex600n kit only go up to a hardness of 80 durometer. These are fine for general flying about and should last some time. However, if you fly 3D you will probably find that they don't last anywhere near as long as you would like!

Luckily, the replacement dampers cost very little, so you could just keep changing them. Alternatively, you can install some harder dampers that should last quite a lot longer!

Align realised that the combination of the headblock, feathering spindle and standard dampers was giving pilots issues with longevity, so they released this feathering shaft sleeve set. The sleeve sits inside the headblock and gives less room for the feathering spindle to rock inside it, while the 90 durometer dampers help to keep things nice and tight for many 3D flights.

Here's a picture of the packet, containing the plastic sleeve and four 90 durometer dampers (two for each side of the head block).

  • The feathering shaft sleeve setThe feathering shaft sleeve set

Removing the existing dampers

The first step is to remove a blade grip. Use two M4 hex drivers, one in each bolt at either end of the feathering spindle and turn them against each other to undo one of the bolts. Remove the bolt that comes undone and the blade grip can then be taken off the feathering spindle. Be careful not to lose the thrust races out of the grip when removing it. You might find it easier to unclip the short double link from the blade grip before removing it.

With one blade grip removed, the other blade grip will now pull out of the head block and take with it the feathering spindle, leaving just the headblock and dampers. Be careful to not lose the spacers that sit between the blade grips and the headblock.

  • Remove one of the feathering spindle boltsRemove one of the feathering spindle bolts
  • Remove a blade gripRemove a blade grip
  • Remove the feathering spindleRemove the feathering spindle
  • Headblock with dampers removedHeadblock with dampers removed

I use a small hex driver to help remove the dampers from the headblock.

Fitting the feathering shaft sleeve and new dampers

First, apply some grease to the dampers and to the inside of one end of the sleeve (to help with sliding the feathering spindle through it).

  • Grease the dampersGrease the dampers
  • Grease the inside of one end of the sleeveGrease the inside of one end of the sleeve

To fit the dampers and sleeve set to the head, take the blade grip with the feathering spindle attached to it and fit one of the spacers and then two of the dampers onto the feathering spindle.

Next, fit the sleeve to the feathering spindle. This will take a small amount of force to push the spindle through as there is a lip halfway down the inside of the sleeve. Push the sleeve up against the dampers that are already fitted.

  • Fit a spacer and two of the dampersFit a spacer and two of the dampers
  • Fit the sleeveFit the sleeve

Push the feathering spindle through the headblock until the dampers are snugly fitted into the head. Next, fit the dampers to the other side of the head.

Once the second set of dampers are fitted, take this opportunity to clean any grease out of the end of the feathering spindle as grease inside the threads will prevent the threadlock from doing it's job when the bolt is fitted.

  • Fit to the headblockFit to the headblock
  • Fit dampers to the other side (push them in!)Fit dampers to the other side (push them in!)

Next, fit the second spacer and then the blade grip.

If the thrust races came out of the blade grip, or were removed intentionally, fit them into the grip and onto the end of the feathering spindle, ensuring the races are the correct way around and the shim that sits between the radial bearing and the inner thrust race is fitted. The thrust races are marked as In and Out, with In going nearest the headblock (In has a larger inner diameter than Out). Finally, add threadlock to the bolt and tighten it into the feathering spindle.

  • Fit the spacer and the bladegripFit the spacer and the bladegrip
  • Fit the feathering spindle bolt using threadlockFit the feathering spindle bolt using threadlock

Make sure the bolts are tight in the ends of the feathering spindle, and thats the job done. You can refit the main rotor blades and go fly.

  • Blade grips refitted and everything tightened upBlade grips refitted and everything tightened up
  • Blades refitted ready for flightBlades refitted ready for flight

Flight review

This Feathering shaft sleeve set was fitted to replace a set of Carbon eXtreme dampers which I had fitted when I originally built this helicopter. I could tell in flight that the dampers were worn due to the helicopter veering off course and generally being a handful to fly around manoeuvres such as hurricanes etc, which the helicopter normally sits in very nicely without much work required.

I would estimate the Carbon eXtreme dampers had around 200 flights on them before they needed replacing.

Having fitted these new dampers, the difference (from damaged old dampers) was significant, as is to be expected. The helicopter instantly felt locked in again and went where it was told without deviation.

The damping effect of the sleeve and 90 durometer dampers is very good as it stiffens up the response from the helicopter. Combined with decent carbon blades, 3D flight is crisp and accurate.

Pros and Cons

Pros
The sleeve reduces the amount of teetering space the feathering spindle has in the head
Harder durometer dampers last longer when flying 3D
Stiffens up the responsiveness of the head
Very cheap
Cons
Fractionally more fiddly to fit than standard dampers

Conclusion

I found the dampers to be significantly longer lasting than the stock 80 durometer dampers and in fact only changed them to begin reviewing some other alternative dampers rather than being forced to change them through wear and tear.

I have put at least 50 flights on this set of sleeve and dampers and they may be good for many more. I would estimate somewhere between 80 and 100 flights before they need changing. This would depend a lot on the flying style of course as stick banging or aggressive 3D tends to eat dampers much faster than smooth 3D does. They could also last much longer than I am thinking they will if they are not abused.

Perhaps I've become too accustomed to paying very high prices for dampers, but the ultra low cost of this set makes them an obvious choice to use. They work well and are extremely cheap. Changing them is not difficult or time consuming and they work brilliantly. Until something better (and perhaps even as cost effective) comes along, I would suggest using these.