Metal tail upgrade "explodes" during test

[psindrup]

I had a minor crash, and broke one of the links in the tail, and decided to do the metal tail upgrade that had been lying in my drawer for a while.

The installation went without a "glitch" and everything was locktite'ed as per the installation instructions.

I wanted to see how the tail was balanced, so I spooled it up on the living room floor, without the main blades installed, just to see how the tail was behaving.

After 10 - 20 seconds of "tail exercise" (left and right rudder) the heli starts to vibrate violently.

I took the heli to the kitchen table, and each and every screw in the tail has gone loose and one had already fallen off/out, and the tail "side plates" was bend.

I have no clue whatsoever what went wrong, but I am very disappointed/sad, because the metal tail upgrade looked so "cool" (high quality) compared to the stock tail.

Peter

[rotorhead58d]

too many rpm's ? wow, that sucks.

[knucklesdragon]

Peter,

Did you give the loctite time to set-up? I've heard you should wait at least an hour after applying loctite before you fly.

[Gr4yb3ard]

Pete,

That's got to be vibration from somewhere. I think we're starting to see a common thread on wear in the tail.

Since most of it centers around the bearing mounts, or recently the bearings, maybe we should start balancing the tail rotor and lubing/replacing tail bearings every so often. Just a thought.

Checking mine when I get back...

Gr4yb3ard
"...no tagline on this one, crashes are one thing, but 'tis not funny when stuff starts blowing up unexpectedly, and I know <exactly> what you guys were anticipating.."

[psindrup]

Peter,

Did you give the loctite time to set-up? I've heard you should wait at least an hour after applying loctite before you fly.

No, I did not. :thumbdown:

Good point - That must be the reason. :thumbup:

Thanks

Peter

[psindrup]

Pete,

That's got to be vibration from somewhere. I think we're starting to see a common thread on wear in the tail.

Yes, combined with not letting the locktite "dry".

But no wear in this case - the metal tail was brand new.

Peter

[rotorhead58d]

i used red loctite, and never had a screw come loose. they are not that hard to take apart. you just have to spend a little time cleaning them after you remove the screws. worked for me.:thumbup:

[Gr4yb3ard]

I doubt that letting the locktite set had anything to do with this...

It's meant to be there for the long term, a few sessions of left and right movement don't account for your problem from that standpoint.

Can you check the tailshaft and tail rotor for balance and straightness with what you've got left? You know what I mean, from the belt to the blades.... That's my particular suspicion right now...

If the tailshaft (tail rotor shaft) got bent, then the entire thing went to heck in a handbasket in short order as a result, from the tailshaft on back down the chain... (my theory)....

Gr4yb3ard
"...theories are like *rseholes, everybodies got at least one..."

[psindrup]

I think you nailed it Gary.

My boom is bend, but not more than I thought I could still use it.

I suspect that it is bent "enough" for the "teeth" on the belt to touch each other, causing vibration, causing the tail to shake apart.

Peter

[J-Heli]

Never of that problem happening before, but glad you found the problem. :cheers

[stoatnchips]

...Not related to Tail explosions but i was sorting out some parts and found that the EP100 Metal Balls Pack 883500 are exact replacements for the brass pitch slider ball on the MH tail.. they look better machined than the MH ones as well.

[BenHeli]

I was told that without the main blades, all forces/torques are now concentrated on the tail & tail blades which consequently caused the tail to explode.

[Gr4yb3ard]

Pete,

You back up and running yet?

I forgot to mention, if you're putting in a new tailboom, weigh the old aluminum one, and let me compare with my carbon spare.

I've no doubt that you'll go carbon if you can get it, it <should> be lighter, and definately prevent this from recurring (it will spring back to shape or break outright).

Thanks too, for a bit of Danish on another thread, way cool!

Petah, To he tsu?

(Peter, how have 'ya been doing?, in Tsalagi)

Gr4yb3ard
"...anyone feel free to jump in and correct my Cherokee, I don't speak much..."
" The correct name is 'Tsalagi. <Cherokee> is a Creek word for (people that don't speak Creek!)"

[psindrup]

Hi Gary

No, I am still waiting for a new (and straight) tail boom.
I don't want to "experiment" no more. :)

The Danish greetings between me and Bjørn was:

Tak for sidst - means "thanks for last time spend together"
(A special Danish/Scandinavian greeting that can not be translated)

Tak i lige måde - means: "Thanks, the same to you"

How on earth do you speak an old Cherokee language? :thinking

Peter

[Gr4yb3ard]

Pete,

I've spent lots of years meeting, working with people from all over.
I enjoy learning about cultures and lanquages, tends to make one more humble and understanding, I like that.

One of the many reasons I hang out up here. lotsa cool folk from many places...

I've also got a massive ancestory problem ;-) I don't really have enough bandwidth to learn all the stuff I'd like, but I'm getting to grips with English, and dabble in "Cherokee", just a few words...

But, I realize, just now, that I can also order dinner in "Redneck"! ;-)

Yes, I'm afraid it's not a truly "living" lanquage, but it's also not dead yet. There's some fine folks trying hard to keep it alive, that and others. Sad to say, worldwide, we're losing a lanquage every few years.... And just for the record, this is not the only Native American lanquage, there's a bunch, varied and unique unto themselves...

Here 'ya go laddie! http://www.wehali.com/tsalagi/index.cfm?event=showHome

Mange tak, Go li gi

(That should mean: "Thanks, my friend" in bad Danish/Tsalagi....;-)

Gr4yb3ard
"...But enough 'o this, let's talk heli's, or at least go murder an Englishman!.."

[psindrup]

Mange tak - actually means "many thanks" :-)

And now you have to explain the logic behind " Gr4yb3ard" - I guess it is "written sounds" :)

Peter

[Gr4yb3ard]

Yes! Mange Tak! (so very similar to <many thanks> do you see the patterns?)

Also "Tak for sidst", I think I've got some understanding here, basically, it means "thanks for being patient, or thanks for understanding, thanks for waiting for me.", no? I don't think that's untranslatable, sounds like a friendly appallative to me...

Well now, far off topic in un-charted waters, Just my cup-o-tea!

Pete, PM me when you get a chance. Good talking with you, as always...

[MonsterMaxx]

First off, you have to give loctite time to setup.
Secondly, without the main blades placing a load on the system it will totally overrev. You are lucky you didn't blow the motor up and even the oneway clutch. Way too much RPM for full throttle w/o the main blades.

If you are going to spin up w/o main blades you must be very careful how much throttle you feed it.

[psindrup]

First off, you have to give loctite time to setup.

I did not, and that, I believe was the problem.

Did reassemble and let the Locktite set, and have had no problems since.

Secondly, without the main blades placing a load on the system it will totally overrev. You are lucky you didn't blow the motor up and even the oneway clutch. Way too much RPM for full throttle w/o the main blades.

If you are going to spin up w/o main blades you must be very careful how much throttle you feed it.


I never said I gave it full throttle. :YeaBaby:


Peter

[GeneP]

I am about to install an MH tail box and CF boom - any "must know" stuff before I start, well besides the obvious Loctite & wait 24 hrs. to rev up to 10,000 rpm:bs

Whats that about the EP100 balls fitting the MH slider? Why do I have the urge to order some before I even start??:shock:

[Buzzkill]

I have two of the MH tails and haven't had a problem. The only concern I can think of that's not MH specific is the tail binding. With the MH tail and the stock tail too much left rudder will cause the slider to bind. Be very careful setting the tail up in regards to the limits. The MH tail will not be as forgiving as the stock plastic slider.

[psindrup]

I am about to install an MH tail box and CF boom - any "must know" stuff before I start, well besides the obvious Loctite & wait 24 hrs. to rev up to 10,000 rpm:bs


Yeps - and I would recommend read Locktite on those tiny little screws on the tail, and green Locitite (from a T-rex kit) to secure the bearings in the side "frames"

And yes, wait 24 hrs. to let the Locitite "dry" (or whatever that is called in English).

Peter

[GeneP]

Thanks, Paul, that is good to know. That nose kick to the left after releasing left rudder I PMed you about is still there. I noticed that even after right rudder is released it kicks left. I re-set limits on the slider, servo rate, and basically sniffed around for anything and still have it. I keep wondering if it is the 2100t itself.

This is a basic, stupid question, but are the blade grips on the tail supposed to slide back and forth on the shaft? One of mine was sliding and not the other. So, I either fixed it or broke it worse. Now they both slide.

[GeneP]

Yeps - and I would recommend read Locktite on those tiny little screws on the tail, and green Locitite (from a T-rex kit) to secure the bearings in the side "frames"

And yes, wait 24 hrs. to let the Locitite "dry" (or whatever that is called in English).

Peter

Can I just dip the tail in a jar of locktite? :roll:

I have red and blue locktite -- what is different about the green? I guess I could rob some green out of my Trex kit that I am sitting on till I get somewhat more skilled at crashing.:Bang

[psindrup]

Can I just dip the tail in a jar of locktite? :roll:

I have red and blue locktite -- what is different about the green? I guess I could rob some green out of my Trex kit that I am sitting on till I get somewhat more skilled at crashing.:Bang

The green is "bearing lock" of whatever it is called.
It is used to prevent a bearings outer racer to rotate in its seating.

Peter