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Jan 11, 2019, 11:03 AM
What Goes Up...Must Come Down
abjets's Avatar
I just checked mine (metal) and there is no play left or right...but there is a small bit of shaft visible on the right side of the metal belt pulley.
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Jan 11, 2019, 11:06 AM
Registered User
Cyclone 7's Avatar
Afraid not, I am a torque tube enthusiast and have never done a belt drive.

I can well imagine that there needs to be certain amount of play with a belt drive though, to allow for the belt shifting left and right under the varying transmitted tension and turning forces?
Jan 11, 2019, 12:11 PM
Registered User
Quote:
Originally Posted by abjets
I just checked mine (metal) and there is no play left or right...but there is a small bit of shaft visible on the right side of the metal belt pulley.
Many thanks. Mine looks like that, I’d even say that the amount of shaft visible on the right is slightly less on mine.

But if I pull the shaft (or push the pulley) to the right then it moves to the right and that gap almost disappears. So the pulley (and shaft) can be moved slightly left and right. Note I don’t have the belt on at this point - the tension of the belt might oppose thar left/right movement.

I have just checked the extent of the movement with a feeler gauge.

Pulley over to left - gap to right = 0.35 mm
Pulley over to right - gap to right = 0.15 mm

So total amount of sideways play is 0.3 mm.

Maybe nothing to worry about, I probably wouldn’t have mentioned it apart from the shaft with the plastic pulley has zero sideways play.

Cheers,

Nigel
Jan 11, 2019, 02:35 PM
What Goes Up...Must Come Down
abjets's Avatar
Quote:
Originally Posted by nheather
Many thanks. Mine looks like that, I’d even say that the amount of shaft visible on the right is slightly less on mine.

But if I pull the shaft (or push the pulley) to the right then it moves to the right and that gap almost disappears. So the pulley (and shaft) can be moved slightly left and right. Note I don’t have the belt on at this point - the tension of the belt might oppose thar left/right movement.

I have just checked the extent of the movement with a feeler gauge.

Pulley over to left - gap to right = 0.35 mm
Pulley over to right - gap to right = 0.15 mm

So total amount of sideways play is 0.3 mm.

Maybe nothing to worry about, I probably wouldn’t have mentioned it apart from the shaft with the plastic pulley has zero sideways play.

Cheers,

Nigel

As with any helicopter...it will let you know quickly if something is wrong, lol.
Jan 14, 2019, 07:57 AM
Registered User
@Abjets - sometimes it teases you. Last I flew, I brought her up to a hover and the tail twitched, causing my heart to skip a few beats. I thought my belt was preparing to give way. It turns out that I was hovering with a quartering tail wind, and the FBL didn't quite like it. Soon as I turned into the wind - she came back into her own.
Jan 14, 2019, 08:52 AM
Turnigynarian
2Doggs's Avatar

Say no to endfloat!


There should be no endfloat in the tail rotor shaft (end-wise play as described by Nigel)

Many helis use shims in the tail gearbox to eliminate endfloat.

The tail belt is usually a tad narrower than the width between the flanges of the tail pulley to allow it to "float" between them.

0.3mm of endfloat won't cause a serious problem, but you would be better off without it, it contributes to slop in the tail linkage.
Jan 14, 2019, 01:33 PM
Registered User
Quote:
Originally Posted by 2Doggs
There should be no endfloat in the tail rotor shaft (end-wise play as described by Nigel)

Many helis use shims in the tail gearbox to eliminate endfloat.

The tail belt is usually a tad narrower than the width between the flanges of the tail pulley to allow it to "float" between them.

0.3mm of endfloat won't cause a serious problem, but you would be better off without it, it contributes to slop in the tail linkage.
Many thanks. I have been speaking to an owner on another forum who has exactly the same problem - he resolved his by filing down the facing surfaces of the tail assembly by a small amount. So to be clear this is the issue I have - see attached photo

And I'm certain it is because the shoulder area of the upgraded shaft is too short. There is no such problem with the original shaft with the plastic pulley.


So it sounds like I have three options


1) Ignore it, 0.3mm probably won't cause an issue

2) File the facing surfaces of the tail assembly to reduce the width by 0.3mm so that the upgraded shaft fits properly

3) Fit shims totalling up to 0.3mm

Ideally I would prefer to do (3) but I have no idea where to find M3 washers with a small outside diameter and thin.

Cheers,

Nigel
Last edited by nheather; Jan 14, 2019 at 02:00 PM.
Jan 14, 2019, 02:32 PM
Turnigynarian
2Doggs's Avatar
Those shims are commonly supplied with Trex 450 kits. Maybe MikeHRC or Borderlord have some in their spares boxes or know a UK source.

Mike, Jeff?
Jan 14, 2019, 02:32 PM
What Goes Up...Must Come Down
abjets's Avatar
The shafts that come with the metal pulley have the step up in diameter for the pulley itself to attach to and that 'step' fits perfect in between the bearings preventing any play on my tail. Maybe remove the pulley and see how the shaft fits in between your bearings?? Looking at the Align package that has my spare metal tail shaft and pulley...it has a sticker on it saying "longer Shaft" ??? Hmmm, maybe they put out some bad upgrades parts???
Jan 15, 2019, 01:57 PM
Registered User
plane guy here
After a few weeks of phoenix sim and 2 weeks with a xk k124 i got hooked. ordered an Trex 470LP
Jan 16, 2019, 11:41 AM
Registered User
Welcome to the club . You're gonna love the 470LP. Every time I start 'desiring' coveting' or lusting after a larger model, I take my 470 for a spin and I am reminded how awesome this hell is..

Then I'm able to take the money I save, and spend on other hobbies .. . #ItNeverEnds
Jan 16, 2019, 12:23 PM
Registered User
Yup! Then there's always that shiny new canopy, another battery, always something! I do recommend a stepping stone between a sim and a 470. It will last about four seconds otherwise. Just slow down and be ready for the next step before taking it. I usually suggest the Blade 230s v2. $200.00 and you can take it anywhere. Hate to see a new bird destroyed by hurrying. Have fun learning. When you are bored with the 230, go for it! Just think about it, ok?
Jan 16, 2019, 02:42 PM
Registered User
Thanks!
Im not really in a hurry, going to take my time specially with the sim and the xk k124 as a stepping stone

im planning to build it and fly it in the spring, but it will be nice to have the kit waiting and reminding to keep practicing
Jan 21, 2019, 01:41 PM
Great Falls, Montana
BgSkyFlyr's Avatar

Head speed efficiency


HI everyone, I have maybe an odd question. Does the Esc and motor run cooler at higher head speeds? Is it more taxing on the electronics by running a slower headspeed creating more heat? I have the HW 60A v4 and Align motor. Thanks
Jan 21, 2019, 02:13 PM
Turnigynarian
2Doggs's Avatar
As a general rule, ESC's work best at 85% throttle or more, and some don't like to run below 65%. If the ESC has an active freewheel feature, it can run at lower throttle without overheating. If using governor mode, being in the 65% - 85% range works well.


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