More tail problems (Logo 500 3D / CF Tail)

[Destin]

After having problems with the stock plastic tail assembly (where the half moon plastic nubs on the inside of the assembly broke off) - I went ahead and installed the carbon fiber tail assembly upgrade.

Everything was looking good for 11 flights after the CF tail install.

Then - on flight 12 - the CF tail assembly failed. Lucky for me, I was still on the ground while spinning up for the flight. So, there was only minor damage.

While I understand that this was most likely my fault, I'm puzzled. I was meticulous when installing the CF tail upgrade. It was tightened down for sure (or at least I thought - maybe not?)

After the mishap, I inspected the tail and found that the bearing on the left side (nose away) was missing. Both bearings had worn into the carbon fiber frame, as if the entire bearing was spinning around. I'm guessing this is what caused the failure (?)

I also noticed the plastic gear that the belt wraps around was also badly worn on the left side (where the bearing was missing).

Should have I glued those bearings into the CF frame? Or used shoe goo?

Any ideas?

[itsparks]

it actually looks like the bearing locked up and spun around inside on the shaft, weird, i just installed this on my logo, hope to maiden the tail next week.

My belt pully looks like yours right now too, however im not changing it, i don't see a need to as it does nothing close to the tail..

Jase

[OICU812]

Although it does not really state it anywhere it is not a bad idea to dab a small bit of ca around the outer edge of flanged bearing to the cf, this prevents any movement. I am guessing the bearing may not have been fully seated and was indeed spinning inside the case itself.

[helicraze]

thats not good, 2 tails fail, what happened to the first one? The failure look similar. You not using to many spacers and putting to much side load on the bearings? Or is the belt too tight??

[Destin]

Ok - so my replacement parts for my tail should be arriving soon.

I am concerned that I will have the same problem, possibly in an even worse scenario...
like while I'm actually flying! (the last failure happened on the ground while spinning up)

My plan is to simply rebuild the tail paying special attention to the bearings being seated (and glued in) correctly - and more importantly making sure the belt is not too tight.

Helicraze mentioned the possibility that I may have used to many spacers or put too much side load on the bearings. How would too much side load on the bearings be caused? By tightening the tail too much? Also, I used all of the black plastic spacers that came with the CF tail - do you guys not use those? It appeared to me by the instructions I was to use all of them... ?

[helicraze]

I also just ordered the upgrade for my logo 500 after my tail turned from the half moons coming off.
Can you tell me does the stock tail fin work with the upgrade set or is everything come with it?

[Destin]

I used the stock plastic vertical fin with the carbon tail - but I had to use a dremel to cut off part of the plastic bushing that is attached to it. The fin also blocks the head of 2 bolts, but you can easily get around that by putting the nuts on the fin side of the assembly.


So yes, you can use it... unless someone here suggests a reason why it should not be done(?).

[helicraze]

Did yours get fixed yet? Can you please post a pic of your fin?? Thank you

[Destin]

I flew mine again yesterday after rebuilding the tail. It seemed to go fine, although I only got 1 flight in. Time will tell!

After thinking about it, I believe my failure was caused by me over tightening the tail assembly - which caused the bearings to bind up. I noticed during the rebuild that when over tightened, the tail shaft was increasingly harder to turn. After loosening it up a bit it turned freely again.

In the attached picture you can see the plastic bushing I cut off the vertical fin. The brass colored bushings on either side of the belt tensioner was bought separate from the kit. I lost my plastic ones that came with the kit.

[itsparks]

I flew mine again yesterday after rebuilding the tail. It seemed to go fine, although I only got 1 flight in. Time will tell!

After thinking about it, I believe my failure was caused by me over tightening the tail assembly - which caused the bearings to bind up. I noticed during the rebuild that when over tightened, the tail shaft was increasingly harder to turn. After loosening it up a bit it turned freely again.

In the attached picture you can see the plastic bushing I cut off the vertical fin. The brass colored bushings on either side of the belt tensioner was bought separate from the kit. I lost my plastic ones that came with the kit.

If i were you i would take that main tail shaft out, and clean it then put new oil on it, its looking kinda grimy, keeping that shaft smooth and clean will keep that tail working properly.

Jase

[Destin]

It does look dirty! Oddly, it is a brand new tail shaft that I just installed. I put a few drops of oil on it, flew it once... and now look at it. Wow!

[helicraze]

Thanks for the pic, the back set of screws need to be tight and with loctite, the idle roller should be made sure its not too tight.

Are the idle bearings (tail belt pulley/guide) standard for the Upgrade?

[Mercuriell]

Helicraze mentioned the possibility that I may have used to many spacers or put too much side load on the bearings. How would too much side load on the bearings be caused? By tightening the tail too much? Also, I used all of the black plastic spacers that came with the CF tail - do you guys not use those? It appeared to me by the instructions I was to use all of them... ?

I found on the CF tail of my 6003D that the black spacers were too long and the CF side wouldn't sit flush on the spacers - I cut them down with a razor saw till it all fitted nicely. Bob always uses Shoe Goop on his bearings - I like to use builders adhesive as it packs up any slack in the bearing recess a bit more. Obviously any bearing spinning mismatch like outer race in mounting or shaft in inner race will quickly lead to a local demolition derby !