Goblin clicking noise*Solved*

[Slyster]

Originally Posted by SRJay

At the request of Slyster here is a short video of how to do the mod. [/url]

Thanks much Jay!! I got it bookmarked and will do this during the winter when I can't fly.. got to tinker!

[Shogun71]

Originally Posted by Slyster

Thanks much Jay!! I got it bookmarked and will do this during the winter when I can't fly.. got to tinker!

My winter project for the fleet as well!

[Bob O]

Excellent vid!!

Sent via phone

[nivaldin]

Hey guys,

I've just assemble my Goblin 700 competition 2 weeks ago, and until now I didn't notice any clicking noise. (15 flights now).

Did you guys make a video showing this noise, or the gap?

Thanks.

[alexmit]

Originally Posted by nivaldin

Hey guys,

I've just assemble my Goblin 700 competition 2 weeks ago, and until now I didn't notice any clicking noise. (15 flights now).

Did you guys make a video showing this noise, or the gap?

Thanks.

If it isn't broken, don't fix it. Many of the kits never developed the noise.

[seefest]

Originally Posted by alexmit

If it isn't broken, don't fix it. Many of the kits never developed the noise.

+1.
My 4 Goblins I've owned have never had this noise.

[Seasick78]

I have it very loudly on my 570. Don't care though... Can't hear it in flight and she flys very well.

[DarkSyd3D]

Originally Posted by seefest

+1.
My 4 Goblins I've owned have never had this noise.

Word to the wise. Don't wait till it breaks. Fix it before

[czynot]

here is the source of the trouble. This is the screw that goes in the main tail belt pulley under the oneway.

The orginal screw has cut half way into the bolt. I thrown that out. I installed new screw and picture of the screw is new. This screw has about 5-7 flights on it. You can see the shaft already ate into the bolt already.


I removed this and installed a M3 shoulder bolt with a nut.

[seefest]

Originally Posted by DarkSyd3D

Word to the wise. Don't wait till it breaks. Fix it before

My first Goblin 700 I had over 600 flights on when I sold it. My G500 has over 750 flights on.
My G700comp and G570 have approximately 150 flights each.

It won't break because it's not loose on any of my Goblins. The clicking sound is indicative of the forward tail pulley being loose on the shaft and the Jesus bolt "banging" back and forth which WILL eventually fail......if you have the noise. I don't.

In all reality, I don't think I've ever heard of ANY forward pulley Jesus bolts failing on Goblins even pilots who have had the noise for 100's of flights. There are a metric shit ton of Goblins out there, I've heard many people complain of the noise, I haven't heard anyone having a failure.

Has anyone had this bolt fail or heard of this bolt failing? I know the early V1 Goblins(my first Goblin 700), had failures of the Jesus bolts on the main shaft and secondary shaft. It was because the bolts weren't shouldered. SAB supplied replacement shouldered bolts for free to fix this issue.

[seefest]

Originally Posted by czynot

here is the source of the trouble. This is the screw that goes in the main tail belt pulley under the oneway.

The orginal screw has cut half way into the bolt. I thrown that out. I installed new screw and picture of the screw is new. This screw has about 5-7 flights on it. You can see the shaft already ate into the bolt already.


I removed this and installed a M3 shoulder bolt with a nut.

That was the original bolt with your kit? Mine are all shouldered.

[Seasick78]

Mine has a shouldered bolt also. It may be worth mentioning, I only hear it after flying and things get warmed up. When cold on the bench, there is no clicking. I had the same exact scenario when I had a 500 previously. My 700 doesn't do it.

[Joe Bailey]

That should be a shouldered bolt rated at 12.6. The only time I've seen a bolt wear like that is on a synergy N7 Jesus bolt

[rando]

No question about it, that's gotta be resolved!

I'm fairly sure both my G570 and my G770 converted to a G700C had/have a shouldered bolt there. IIRC, my 570 had some play on that pulley though I never heard any clicking. My 770/700C doesn't have any play on the pulley. It occasionally makes a clicking sound on spool down and also if I turn the motor by hand and/or squeeze the motor belt.

I'm still eager to learn if the mod resolves the G570 growl for anyone that had it on their 570 before the mod.

[SRJay]

Even with a shouldered bolt it gets beat to shit. The shoulder on my bolts looked as if they had been installed/removed hundreds of times. To check if the mod is worth doing check the following. Remove the front tail pulley, take just the shouldered bolt and insert it through the secondary shaft. If there is any slop between the bolt shoulder and hole in the secondary shaft it's worth doing reguardless of if you hear the noise or not. All SAB kits are notorious for having too large of holes in all shafts. Its acceptable on all of the other holes because there are shoulder bolts AND clamp screws. The front tail pulley has no clamping screws to help with the oversize holes.

If a goblin doesn't make the clicking noise on spooldown or there doesn't seem to be any play when assembled it's likely because of the amount of shim used between the tail pulley and OWB pulley. On both my G630 and G700 the manual calls for .5mm axial play to be left in the OWB pulley. This means that the OWB pulley will not push down on the tail pulley allowing the slop in the tail pulley. If you shim it tight that would force the shuolder of the tail pulley bolt down against the bottom of the hole in the secondary shaft. Doing this could also prevent the noise.

[rando]

My G700C is shimmed with just a bit of play in the OWB pulley and the tail pulley does not have any play on the shaft/bolt. Shimming too tight causes other problems. I have 176 flights on my G700C. I don't see any signs of trama.

[Jascop]

SRjay,
quick question on the set screw. Once placed, how tight do you tighten it and does it leave markings on the secondary shaft? If so, would it leave metal sticking out so the OWB won't come off anymore? Maybe a bit of an exaggeration, but does something like this happen? Or is this not something to worry about?
Thanks.

[Slyster]

I found this old video I took last year.. is this the sound? I've not done the mod yet.

goblin 700 odd sound (0 min 21 sec)

[SRJay]

Yep, that's it. You only hear it on the bench or on spool down. I never heard it in flight, and didn't always hear it on the bench.

I tighten the set screw the same amount as the pinion set screw. It has not left a mark or burr on the secondary shaft and the OWB pulley slides off easily.

[rando]

Originally Posted by Slyster

I found this old video I took last year.. is this the sound? I've not done the mod yet.

Another sound! - YouTube

Thanks for that -- can say for sure I haven't had that sound.