Tail failure today :(

[freddyferris]

WTF happened?!

this gear failed today: 0866-5

The heli has about 5,5-6 galons thru...ist there any metod or so to prevent this happening again?

The only thig i could imagin what could have caused this premature failur are my inverted autos... they arnt always quite perfect and somtime i touche the ground a bit with the tail, but as my tail blades are very loose, they take most of the energy´...

Ciao

Fred

[Peter]

it only needs a touch ... been there , done that..... :( :(

[DavidH]

As Peter said it only needs to touch some times to shear the teeth.
When you install a new one. Set the mesh as tight as you can and the gear still turn smoothly. Also make sure the pinion is fully seated on the crown gear. The edge of the pinion should at the least be flush with the edge of the crown gear.

If you still have the brass spacer and shim on your main shaft. I would take them out and just set the mesh without them. Those parts are not in the kits anymore.

David

[freddyferris]

ok too bad.. gonna buy me a stock of crown gears then.. ^^

Fred

[freddyferris]

how do you actually set the gear mesh of the tail pigno on the crown gear?

Fred

[EricLarson]

Fred,

Just like David said, remove the shim and brass spacer. Once everything is assembled just hold the model by the rotor head and let the weight of the model hold the crown gear against the pinion. Set the bottom collar. Check the mesh. It should have no backlash and maybe just slight resistance in a couple places until it all is run in. The mesh should not be tight, but just as little backlash as possible.

The other thing is to make sure the pinion is positioned correctly on the crown gear. Look very closely and make sure you are set right forward and aft so you get max gear contact.

The crown gear should not wear out. You can take it out by dragging the tail, but they are fairly strong. I would think the mesh may have been a bit loose or the pinion was not in the right spot.

[freddyferris]

Just took the fury appart and foud that brace thing and the spacer, gonna tae them out, and yes the mesh wase to loose as i took care to position the pignon correctly! hope getting the crowngear friday, thanks alot for everything!

Cant wait to fly again, Mini Air Realy rocks :P

Fred

[EricLarson]

Cool sounds good Fred. Glad you had the pinion right. Just keep that mesh nice and close and the gear will hold up very well. later,

[BiRD_of_PrAy]

Hi,

@Eric and David

i´m not sure what Spacer to remove - think it is the Partnumber #122-15 including the optional shim´s on my Tempest FAI right? Think i have this part still in it.
Should i remove or only if i get trouble with it?

thx
Thorsten

[DavidH]

Thorsten
What Eric and I are referring to is the brass tube that is or use to be on the mainshaft right above the main gear. The brass tube will slide up inside the lower bearing block. And sometimes it had a shim washer also on the main shaft right above the main gear. Those pieces are no longer included in the kit.
If you have those pieces on your heli. There is no reason to take them out unless your having problems with crown gear mesh.

David

[angelob]

Set the mesh as tight as you can and the gear still turn smoothly

David, Eric,

Do you set this at the high point on the crown gear (tightest) or at the low point on the gear? I have been setting it at the high point on the gear (I've had no issues) but I'm wondering if I'm doing it correctly.

Angelo

[EricLarson]

Sounds like you are doing it right :) As long as you are not having issues your mesh is probably good. You should not have much backlash, but it should also not be tight.... It is really not that hard or super critical, it is just something that is hard to explain when you are not in person.

[ManuelCJr1]

I bought my Fury extreme in April of 05 and it had the brass spacer and the shim. Is it wise to take it off? It has about 1/8 in. backlash in the crown gear and pinion. (measred from the movement of the tip of the crown gear from left to right.) and the pinion is right in the middle of the crown gear.

If so, just so

1. I inderstand take them off and assemble the head leaving the collars loose.
2. Make sure the pinion is in the middle of the crown gear so it is fully seated.
3. Hold the heli up so the crown gear is hitting the pinion. ( the pinion will be
holding the wieght of the heli against the crown gear.)
4. Tighten up the bottm collar.
5. Check the mesh. If correct tighten up the upper collar and make sure that
there is absolutly no up and down play on the main shaft, because that would
mess with the mesh

Is this correct.

[EricLarson]

You can use them, but per the instructions you adjust the size of the shim to get the right mesh.

Or just remove the spacer and shim and do it by hand.

Your choice.

[ManuelCJr1]

Is 1/8 in. good or should I try to use a smaller spacer to get rid of the slight backlash.

By hand you mean lifting the rotor head I assume. Do you lift the heli completly or just so it is hitting the crown gear.

[DavidH]

1/8 inch of back lash is quiet a bit in my opinion. Especially if your talking about the back lash measured between the pinion and the crown gear.

What we are referring to is the following. This is without the brass spacer and shim being on the mainshaft between the constant drive unit and the lower bearing block.

Loosen bolt of the collars that hold the main shaft in position.
Now lift the heli up by the rotor head completely off the table. Give it a downward jerk to make sure everything is seated and meshed. Now while still supporting the heli by holding the rotor head. Push the lower collet down against the lower bearing block and tighten the collar. Now rotate the rotor head and check how smoothly it rotates at the crown gear and pinion. If it rotates smoothly now take the upper collar and slide it up against the upper bearing block. Tighten the collar.
Then should allow everything to rotate smoothly and the mesh between the crown gear and front pinion will be good.

If you want to leave the brass spacer on the main shaft. You will have to keep trying different thickness shims till you get the mesh correct. If you have too much back lash now, you need to take the shim out and just try it with the spacer only.

David

[ManuelCJr1]

I'm just a little scared about setting it because i set the pinion to the top of the crown gear(most tight) to get rid of backlash and it stripped in flight. It was my first ever flight on the heli and i had not set the hold switch because i was excited to fly. ( boy did i learn an important lesson)
I have about 16 flights on it the way it is set now but i have not done any hard piros yet. But i always like setting my helis up really good so getting rid of back lash is what i need to do.
And no one at my feild has a Fury Extreme, so no one can help me with that.

[EricLarson]

Read this section of the Stratus manual ----- Read around pages 67 -68 in the assembly manual here http://www.miniatureaircraftusa.com/Support/Instructions/Stratus%20Assembly%20Manual%20Standard%20Head%20R1 .3.pdf

The process is the same. It is not anything complicated. It is just like setting most any other gear mesh. Set the pinion in the crown gear so it is centered front to back (that is covered in the stratus manual). Then adjust the up and down of the main shaft until you have the least amount of backlash in the crown gear and pinion without the mesh being tight. You may feel a bit of a high spot in 1 or two places but it should otherwise rotate fairly smoothly.

If you are using a 601 or 611 max gain should be 38-40%.

I have not stripped a crown gear in probably 4 years except in crashes. I also have not used the collar or shim in about 3 years now. I don't spend much time setting the mesh, I just get it close by feel so the backlash is minimum and go fly. Just make sure the pinion is centered on the crown gear from to rear.... I have seen a few way off and that will cause a problem.

Look over the Stratus manual, it will probably answer a lot of questions for you.

Hope that helps some!

[ManuelCJr1]

Thanks so much.