Warp Tail vibes. reasons and fixes...

[Swinto]

The tail pulley..........

I've been trying to eliminate vibes for ages (continually fracturing booms) - fitted new brass bush, new tail hub, balanced tail rotor assembly with kbdd blades, then did some bench testing - with little improvement. I decided to blow the dust off the warp today to check over the tail assembly and found my kit has a dodgy tail pulley!
Don't have a dial gauge handy, but looks to have about 1 mm of wobble when manually driving the tail by hand. Plan to change this out with the tail shaft bearings as this has to be the source of the vibe issues now that my not-so-wobbly motor can is loctited in place.

Hopefully test this soon and report back.

[Chris Nifty]

I've yet to find one of those that doesn't wobble.

[SandorV]

Originally Posted by A VIKING

GREAT!! If the rest of your ball links in the tail control system are absolutely free, than I can say with almost certainty that what you discribed above is your issue. I had the same issue.
To smooth out the binding in those two links I actually swapped their positions on the slider. Manufacturing tollerances may work in your favor (right now they are not) in getting the freedom you need with the two pitch liks. I found that helped somewhat but it came down to disconnecting one link and moving the tail through full motion, then re-connecting it and disconnecting the opposite link and running it through. From that I could tell which had the most resistance (which equals ball link to grip ball out of alignment with both ball links hooked up) and that's the link I picked on to do MORE resizing on. That did the trick! I did end up with more play in one tail pitch ball link than the other but the ship fly's perfectly with no hint of wag or loose tail in flight...all from working with the ball links, nothing else. You could split the differance and resize both ball links equally but I just picked on one.
You do have choises, you could move the tail grip ball out to meet the position of the ball link with a small shim or washer under the ball ( I didn't do that because I didn't want to loose thread engagement with the grip) or you could remove some plastic from the pin side of the ball ink to slider attachment ( I didn't do that for worry of further alignment issues) or simply resize the tightest of the two ball links (safest and easiest), of course resizing the ball links to much and you run the risk of it coming loose in flight...that will have to be your call.
Loosen those ball links up and your problem will vanish.
Also I had to take one step futher in moving the tail rocker cup for the slider ball down to move the ball out of the cup, they were to tight also causing binding. You can see in the photo how far I went, the silver shim above the rocker is what I installed to do the job, actually it is a spacer from another ship but any shim will do, just make sure the shim only catches the inner race of the rocker bearing when installed or you'll be right back to binding again. Last install a longer rocker mounting screw with shims added so it's attached securely.
Let me know, my fingers are crossed for you and I am knocking on wood for good measure.

Viking

I'm going to order some parts today, i'm going to try this out for sure, what bolt and shim is that, from which helicopter? Thanks

[A VIKING]

Originally Posted by SandorV

I'm going to order some parts today, i'm going to try this out for sure, what bolt and shim is that, from which helicopter? Thanks

The shim I used between the rocker and it's mount in the photo is actually an aluminum gromet used on some servo mounts. The hole in the metal gromet matches the rocker mounting screw at M2,5 and flange side of the gromet matches the diameter of the rocker mount itself. I had this metal gromet in my spares bag from a ship long gone and it was just luck it fit perfectly. You wouldn't have to move the rocker cup that far away from the ball to get the result your looking for. Anything you can find for a shim or washer will work. Make sure what ever washer or shim you use that it has a small outside diameter and that it will only contact the inner race of the rocker bearing when you tighten the screw or you'll end up binding the bearing and won't have free travel. Whatever you use as a shim will determine the screw grip length. The metal gromet I used called for a M2,5X16 screw to be used to get full thread engagement in the rocker mount. Goblin 700 has many M2,5 diameter screws so I just ordered some M2,5X18 screws and cut them to length.

Side bennefit from installing that shim, it also provides better clearance between the control rod side of the rocker and tail boom so you won't scratch the bottom of the boom with the threaded end of the ball link screw sticking out of the rocker.

Viking

[SandorV]

Just to let you guys know, I changed some parts, well actually the entire tail from boom towards the back and the tails holds just GREAT. Still a wobble sometimes due to the headgain, but atleast now I can start finetuning it without the worries of the tail.

Plus i'm getting insane flighttimes, 1200mah gens ace batteries, some normal hovering and flight and after 4 minutes I still got 22 volts left according to the telemetry?