The 550pro gears don't line up

[jsbach#1]

come on mannn this is getting tiring, the 250, the 450 , and now this 550 I'm building.
All have a huge mismatch in gear mesh the mast sits too low and the gear mesh between the tail drive gears is off. You can't move the shims to the other side of the mast to lower it, that doesn't work.

And the frigin small gear that the torque tube plugs into is NEVER true, its wobbly, so the torque tube doens't run perfectly true, thats why they make the bearing suspended in a big rubber donut ?

I'm sick of this !! OCD has the best of me.

[DCflyer]

Instead of shimming the mainshaft above the main bearing block, you can add shims between the lower bearing block and main gear to try to lower the gears a bit. You may have to try a few different shims since you don't want to lower the assembly so much that you're having to force the lower jesus bolt to push through.

I have a single 0.3mm shim as stated and get 95% perfect gear mesh.

Post a picture if you can.

[FNFAL]

What DC said. Then the position of the gears on the front tail drive shaft will vary from part to part. I've bought a couple and matched up the best I could. There is also an aftermarket front gearcase that allows a little up/down shimming with wavy washer and adjusting boom insertion. And yeah, we all complain about the gear wobble, finding the black worse than the white.

http://www.rc-tek.com/store/i2rc-t55...unt-p2283.html

Then there was this thread too:

https://www.helifreak.com/showthread.php?t=497840

[Revenant759]

Ran into the same issue on my 550. Had to .5 shim the main shaft from the top but the tail drive gear and tail box gears don't line up. Even without shims moving main shaft up/down can't sit the gears at an exact level mesh. There's about 1-1.5mm of difference, but I can't remember which way it is. I think the tail drive gear sits too high/tail boom mount gear sitting too low. Might try to move the .5 shim down to above the main gears. Haven't yet really addressed (or figured out how to) that issue yet. I need a .2 or .1 shim as .5 and .3 are a bit too tight while the .5 has a tiny bit of play left.

I also had the wobbly umbrella gear. I pulled boom/TT out, pushed bearing/torque tube (with the clear tube) a bit further towards the tail(To remove any pressure from the TT onto the umbrella gear), opened the boom holder up and ensured plastic was all flush, and also swapped bearings on the umbrella gear around a bit(flipped bearings, as well as changing their positions) till it wobbled/meshed a bit less tight. Now it only binds a little bit on one tooth... those are numbers I can live with till it wears in some on my first few flights. I'm also going to put a bit of dry lube on it and hope that helps some.

[jsbach#1]

Like its so frustrating. Charge more and give me perfection, or charge less if you expect me me ot have to make a pile of changes. You can't shim from the bottom enough for it to work, the shaft diameter changes and it wont work to get it dead on.

The Talon 90 is a questionable ESC for the bird, to me thats a bunch of money thrown in the garbage with all the stuff you're getting and need to trade up or whatever. I think I'm done with these align combos.

[DCflyer]

Originally Posted by jsbach#1

Like its so frustrating. Charge more and give me perfection, or charge less if you expect me me ot have to make a pile of changes. You can't shim from the bottom enough for it to work, the shaft diameter changes and it wont work to get it dead on.

The Talon 90 is a questionable ESC for the bird, so to me thats a bunch of money thrown in the garbage with all the stuff you're getting and don't need. I think I'm done with these Super combos.

Shaft diameter doesn't change until the very bottom, where the the autorotation shaft is. If you shim between the MAIN gear and the LOWER bearing block, the shaft diam is the same. Try it and see how she looks then.

[jsbach#1]

I follow what you're saying, but it doesn't work well, when I put the shims on the bottom I can't get the bolt in the bottom to secure the gear assembly to the main shaft. I will take a pic tonight.

2 more stupid problems, the book says use third hole for tail servo horn, which it shows being 16 mm. But the 4th hole is 16 mm. So do you use the third hole or 16 mm ?

And whats with every single trex you can't adjust your pitch accurately, you have to go in full turn increments cause they want the letter A sticking out. I can't get it dead on.

[Atomic Skull]

Originally Posted by jsbach#1

2 more stupid problems, the book says use third hole for tail servo horn, which it shows being 16 mm. But the 4th hole is 16 mm. So do you use the third hole or 16 mm ?

It's an error in the manual, use 16.5mm as per the 600E Pro manual (it uses the same tail) This has been wrong since the 550E V3 came out. The new two sided tail slider needs the ball further out because the bellcrank is now longer but the manual wasn't changed to reflect this.

The Pro manual still didn't get it right with the diagram showing the 4'th hole and saying "16.5mm" but the english text still saying "13mm" while the chinese text says "16.5mm"

Inner hole on the bellcrank is the stock position, the outer hole will decrease the ratio of pitch slider movement to servo arm movement and increase tail slider resolution. So if you want to increase the tail resolution you can either move the servo ball in or move the bellcrank ball out.

Also I'd recommend putting a long aileron servo ball on the bellcrank so the rudder pushrod runs straight from the guide to the tail rather than bending up.

[Victor Kovalev]

Originally Posted by Atomic Skull

The Pro manual still didn't get it right with the diagram showing the 4'th hole and saying "16.5mm" but the english text still saying "13mm" while the chinese text says "16.5mm"

Inner hole on the bellcrank is the stock position, the outer hole will decrease the ratio of pitch slider movement to servo arm movement and increase tail slider resolution. So if you want to increase the tail resolution you can either move the servo ball in or move the bellcrank ball out.

My V3 manual English text reads the ball should be located on the tail servo horn at the third hole at 13mm from center. The manual has the bell crank ball diagram with the ball in the outer hole. I mistakenly installed the bell crank ball in the inner hole (I have the tail servo horn ball at 13mm from center).

I am using the AR7200BX.

Queston: how will my set up effect the tail? What does it mean to increase or decrease tail resolution?

[Atomic Skull]

Originally Posted by Victor Kovalev

My V3 manual English text reads the ball should be located on the tail servo horn at the third hole at 13mm from center. The manual has the bell crank ball diagram with the ball in the outer hole. I mistakenly installed the bell crank ball in the inner hole (I have the tail servo horn ball at 13mm from center).

I am using the AR7200BX.

Queston: how will my set up effect the tail? What does it mean to increase or decrease tail resolution?

It will increase resolution and decrease pitch travel range as well as increase non linearity of travel. You don't want the horn traveling much past 45 degrees to reach the end of the slider range. I'd say 50-55 degrees would be about the maximum acceptable servo horn angle to reach the end of the slider.

[Victor Kovalev]

Good to know. Thank you.

[Atomic Skull]

There's one problem with relocating the shim to the top of the maingear. Without the shim under the collar the part of the shaft that sticks out from the bottom bearing is still entirely 9mm in diameter so you will have alignment issues with the 10mm mainshaft shim on the 9mm shaft.