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Synergy R/C Synergy N9 > Tail blade grip and main gear slop
 
 
Leebert
Heliman
Location: Surrey - UK

Hi,

I've taken the plunge and got myself a Synergy. I have gone over the heli and all seems okay except for two things...

1. With the tail blades out I can move the tip side to side by about 1/4 inch. The slop seems to be between the hub and the grip. Is this normal? I have stripped it and all seems okay (bearings good etc.).

2. The main gear can be moved up and down on the main shaft by about 1/16 to 1/8 inch. Is this also normal or do I need to invest in some shims?

Thanks for your help.

Cheers
Lee
06-09-2008 09:38 PM
 
 
pariah
Senior Heliman
Location: West Valley City, UT - United States of America

Quote 
1. With the tail blades out I can move the tip side to side by about 1/4 inch. The slop seems to be between the hub and the grip. Is this normal? I have stripped it and all seems okay (bearings good etc.).

My understanding is that it's normal for the synergy. I bought mine & built it with the SE tail, so I'm not positive. I do know it's what happens on the Hirobo Sceadu tail, and it seems to work fine.

This play is one reason why there's a number of upgrades to the tail hub from Kasama, HyperPerformancerc, and Synergy itself.

Quote 
2. The main gear can be moved up and down on the main shaft by about 1/16 to 1/8 inch. Is this also normal or do I need to invest in some shims?

This shouldn't be happening - or at least it isn't happening on mine. Is the whole shaft moving, or just the main gear?

If it's the whole shaft, you need to loosen the collar above the main gear, and move it upwards until there is no play, then re-tighten.


--
Helicopters & Women: The last thing I want is one whose head has a few loose screws.
06-09-2008 10:24 PM
HOMEPAGE  
 
 
HiroboFreak
Senior Heliman
Location: Central Coast, NSW, Australia

1. The "slop" in the tail is normal due to a single radial bearing & a single thrust bearing.

There is a new long tail hub "upgrade" which I recommend you get as there have been reports of the tail grip bolt failing due to radial load.

2. Is it just the main gear moving up & down or the entire mast??

If it the main gear & hub, the small bolts in the bottom of the sprag hub may be loose (tighten them slowly & evenly), or the 4mm bolts holding the hub assembly to the mast may be loose.
If you find these loose, they may have been loose for some time check for wear around the bolt holes & threads.

If it's the entire shaft, loosen the 4 grubscrews in the collar (through the hole in the side frame) push down on the mast & up on the collar & tighten the grubscrews evenly (apply Loctite).

Cheers.

Synergy N9 | T600n Pro
06-09-2008 10:31 PM
HOMEPAGE  
 
 
HiroboFreak
Senior Heliman
Location: Central Coast, NSW, Australia

heh.

Too slow.

"Snap" pariah

Synergy N9 | T600n Pro
06-09-2008 10:31 PM
HOMEPAGE  
 
 
Leebert
Heliman
Location: Surrey - UK

Hi and thanks for the replies.

That's put my mind at rest about the tail. That's the second time someone has mentioned the hub upgrade. I'll be ordering that today

The main gear moves up and down by itself. The main shaft has no play in it at all.
I have been told that I may need to shim the crown gear as the mesh is a touch loose which will raise the entire shaft but not by as much as the main gear moves.
I will check the 4 bolts on the hub for looseness and wear/damage
06-10-2008 07:38 AM
 
 
HiroboFreak
Senior Heliman
Location: Central Coast, NSW, Australia

I've never seen a problem with using the crown gear shim suggested by the manual.

Check that the pinion gear is flush with both sides of the crown gear before changing the shim.

Seems as though something is not right.

Synergy N9 | T600n Pro
06-10-2008 08:26 AM
HOMEPAGE  
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

The main gear and sprag hub housing will have a little up and down play so this is normal. 1/16 to 1/8 inch play is normal. As long as the main gear doesn't contact the side frames the play is ok.

If the crown gear is new then you want the shim so the bevel gear mesh is tight. The bevel gear will wear in the crown a little after a number of flights.

Charles

Please stand by for faster service!
06-10-2008 01:02 PM
 
 
Leebert
Heliman
Location: Surrey - UK

I just measured the movement in the main gear. It moves and down on what looks like the inner sprag race just a nats under 1/16 so that's okay.
For info, the tails (105 SABs) are moving 3/16 from left to right fully extended. I have now got the longer hub with extra radial bearings so I hope that should reduce the play there.

Does anyone have a good crown gear photo showing a good 'tight' mesh please? My Synergy is secondhand and I don't want to add shims if they are not required.
Many thanks,
Lee

EDIT: Just downloaded your build tip doc Chuckie. Great stuff in there - Thanks!
06-10-2008 08:52 PM
 
 
pariah
Senior Heliman
Location: West Valley City, UT - United States of America

I don't think a picture would do you much good - a picture won't really show you the difference between a "loose" and a "tight" mesh. It's probably like a picture showing the difference between 'touching' and 'pushing'.

The only thing I can think of that can is something like not being able to fit a strip of paper of a given thickness through the gears...

I'm in the same boat in that regard - I have no clue whether my mesh is what is considered "tight" Maybe it is, maybe it's loose - I just don't know.


--
Helicopters & Women: The last thing I want is one whose head has a few loose screws.
06-11-2008 12:02 AM
HOMEPAGE  
 
 
Chuckie
Key Veteran
Location: Crofton Maryland, MHA member

Regarding crown gear mesh, yes it’s hard to describe but I do have a way to check. I'm glad you like the building tips. In addition to what I'm posting here check out page A26.

I have the blades removed and with one hand rotate grip the center of the head and rotate it back and forth. You should feel a good amount of friction and when you quickly spin the head it will only turn a few times before stopping. Once the crown gear has worn in there will be a lot less friction and the head will spin 10 times or more. With the blades on it will be harder to spin the head as fast but if you do it will rotate more times.

If I ever remove the boom and reset the well used crown gear mesh I'll adjust the boom position slightly forward (with the front trans fully seated in the boom) to get only a little tension on the crown gear. In this situation I'll hold the head and with my small finger I'll move just the bevel gear back and forth slightly to feel for how much back lash is present. There shouldn't be much free play at all and I will rotate the head to feel if other parts of the crown gear have the same back lash. You may find one part of the crown is a little snug and another has a little loose back lash. Just make sure the position that is a little loose is not too loose. In this situation its ok to have a little back lash and what I'm saying above is that with a new crown gear run it tight.

When you feel a big amount of play in the bevel gear and the boom/bevel gear are moved forward a good amount then its time to start adding /checking for shims under the crown gear.

Regards,

Charles

Please stand by for faster service!
06-11-2008 12:14 PM
 
 
Leebert
Heliman
Location: Surrey - UK

Thanks for the info Charles.
I think I understand what you are saying.
The only thing I am unsure of is how many flights the crown gear has done.
After the first couple of flights, there were tiny "hairs" of what looked like gear material on the outer edge of the crown gear - as if it was bedding in.
The bevel gear appears in the correct position in the crown gear and there appears to be only a tiny bit of play / no play between the two gears (depending where you are on the crown gear).

I think I'll go through all the checks in your guide and see how I get on. I maybe concerned over nothing and should just get on with flying!!
Thanks for your help Guys.
06-12-2008 12:32 PM
 
 
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Synergy R/C Synergy N9 > Tail blade grip and main gear slop
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