How many of you had your tail rotor bolt broken???

[invertsick]

This happened to me 2 times in 4 months.
the second time was last saturday.
today a friend's 700 LE had the same issue.
And 3 weeks ago a frined of mine who flies at Appolo field had same thing happend with his 700.

Im talking about the screw which holds the tail tail blade holder to the hub.

Is any one using any kind of upgrade bolt here???

Sergio

[ualdrivr]

Sergio,

That is one of the known 700N weak link areas. You are talking about the M4 set screw, I assume, correct?

When you say it broke, what do you mean?:confused: The actual screw broke, or it came loose and the hub came off the shaft?:confused:

This screw is known to come loose on the 700, have not had this problem with mine. However, guys I know advise, clean threads of the screw with Alcohol and the threads in the hub as well. You'll be surprised how much machining oil and scum those screws have on them. If you don't clean them the LockTite is useless.;)

Some other guys put red LockTite on that screw. While we are on the topic, the other screws that tend to come loose on the heli are, the 2 M4x8 socket screws on the head, either side of the Jesus Bolt and the four M4x12 socket screws that secure the tail boom supports.

Hope this helps.

[invertsick]

No It's not the M4 screw.
I know that and I also use red locktite there.

Im talikng about the screws that hold the blade holder on the hub.
not the hub on the shaft.


sergio

[ualdrivr]

No It's not the M4 screw.
I know that and I also use red locktite there.

Im talikng about the screws that hold the blade holder on the hub.
not the hub on the shaft.


sergio

Ah yes, the screws that go through the bearings and into the hub, correct? I used the KDE upgrade for the tail blade grips and they came with longer better screws, because KDE adds on more radial bearing per grip.
http://www.kdedirect.com/TREX600700PTUV2.html
The problem with those screws is over-torquing. If you man-handle them, then you over-torque them and eventually you compromise the material and at some point they brake.

Clean them well with alcohol put them through the bearing and then apply LockTite. Screw them to the hub and use two hex tools to tighten on against the other, but don't go crazy, just let the LockTite do it's job. Make sure you clean the threads in the hub also, I poor some alcohol in there and then blow it with my compressor and let it dry.;)

[lowflyer101]

first feather shaft now the tail, watch out the sticks on your tx it could snap off anytime now :)

[ualdrivr]

first feather shaft now the tail, watch out the sticks on your tx it could snap off anytime now :)


:wow2:, I just noticed the pattern here.:roll: http://www.helifreak.com/showthread.php?t=171363 Good catch lowflyer :lol:

Sergio, what are you doing to those screws, man? Clearly you manhandling them. Your problem is over-torquing the crap out of them :shock:. Go easy dude, let the LockTite do it's job.

The biggest thing with all those machined screws is to get the oil and scum off of them and then apply LockTite. Isopropyl or Denatured Alcohol should become your best friend:YeaBaby:

[face992]

I'm done with Align. You read that much about weak screws, spindle bolds sheering of (however), boomstrikes (ask me), bad components... just no fun. My next heli will be a ElyQ Vision 90.

[invertsick]

Low fllyer : FUNNY :)
ualdvr:im not trying to attack anyone herr.
I just asked if any one is using any upgrade.
Take ur time and read my other thread to see how many ppl except me had the spindle bolt issue.
Also with the tail bolt at list I know 4 cases till now.
Just wait and you will see how many ppl also had this problem.

My friends 700 was a brand new LE.
He just Maidened it yesterday.
The tail rotor comes assembled in the box, he just mounted it on the shaft.
So what do you think?
Maybe we should write to Align and tell them they over thightening the screws.

Any way im not trying to find a solution here.
When align read this they will find the solution. (i hope)

which is also good for you guys, coz sooner or later the same will happen to ur heli.

I was just trying to find an upgrade.

Thank you

[ualdrivr]

My friends 700 was a brand new LE.
He just Maidened it yesterday.
The tail rotor comes assembled in the box, he just mounted it on the shaft.
So what do you think?
Maybe we should write to Align and tell them they over thightening the screws.

Any way im not trying to find a solution here.
When align read this they will find the solution. (i hope)

which is also good for you guys, coz sooner or later the same will happen to ur heli.

I was just trying to find an upgrade.

Thank you

Sergio,

Nothing personal buddy, just want to figure out why the thing happened...;) One thing I did notice from your post is that you did not take the grips apart, you just installed them on the heli.

I did take them apart, when I got them and to my surprise they had no grease at all on the thrust bearings and no LockTite on the screws:shock:, maybe that caused the problem. The grips had some lateral play to them, but after I greased them and LockTite them the play was completely gone.

Now with the KDE upgrade, I showed you on my previous post, they are smooth and tight.:YeaBaby:

:cheers

[Hanzuki]

Don't feel too bad. I've had it happen twice now as well. First time, stock tail, just slapped it on the heli as is out of the box. Got 120 flights and boom, the bolt breaks. Second time, 6 flights after the rebuild, boom, same thing on a brand new metal tail. This time I had taken the bolts out and cleaned and loctited them. They were not over torqued.

I will be putting the Quk tail on this time around.

[MartinS819]

Only tail issue I've personally heard about and witnessed was the set screw on the Align thrusted tail. Those suckers back out if you don't keep an eye on them. Otherwise, just make sure you always take "pre-assembled" parts apart and see for yourself. Align makes no claims that these parts are ready to fly out of the box and instructions show you how they go together. They also include grease and threadlock in the kits, so they presumably expect you to check all your parts. It's just something that should be common practice, with any kit, not just Aligns. Sorry your tail didn't hold together Sergio, but the Quick UK tail sets are very popular. Who's your friend at Apollo? Maybe I know them!

-Martin

[UH1H]

A1 MartinS819 ! Aling manual is quite clear about taking sub-assembly : they should be taken appart, verified and upon reassembly -screw loctited. Just taking a assembled part out of the bag and bolt it on will not do it. I have absolutely no problem with my 700LE either with the grip screws or tail rotor screws. I you have a tail or main rotor strike or you crash - replace those screws. Something wrong that it all happen to you...main and now tail.. You do pre-flight and post flight inspection on your bird do you ?

[Helico-pteron]

You are tightening the screws too much. They just need to be snug with thread lock.

You don't need any special screws or mods.

[Finless]

I have ALWAYS said many times to ALWAYS take apart Align pre-assembled stuff and check / relocktite the stuff. Almost every tail I have seen has no grease and no locktite somewhere on it.

Also you have to keep an eye on the tail thrust bearings. If they go bad they lock up and can unscrew the grip retaining screw or worse yet sheer it off!

Bob

[vertol BV107II]

I have ALWAYS said many times to ALWAYS take apart Align pre-assembled stuff and check / relocktite the stuff. Almost every tail I have seen has no grease and no locktite somewhere on it.

Also you have to keep an eye on the tail thrust bearings. If they go bad they lock up and can unscrew the grip retaining screw or worse yet sheer it off!

Bob

+1 on that Bob, never assume it is put together right:thumbup:

[Finless]

I personally would like if Align did not pre-assemble anything... I know labor is cheap over there but it would increase profit or lower kit cost (doubtful) and force people to do it right. I have seen more n00bs throw parts they didn't take apart and check that I can count. Not saying invertstick is a n00b mind you ;)

BTW, the argument is that Align thinks they will sell more helis if they are pre-assembled. I don't think the few more they "might" sell especially in this heli class size, is worth the issues people have.

Bob

[terrabit]

Just wanted to add that the Quick UK tail on my Logo 600 did the same thing. I believe that what happened was I scaped the tail blades (KBDD) a couple times doing autos. Damage was minimal. I found the grip, regreased and assembled it with new bolts and it has been working great for quite a while. The point is that I believe these bolts holding the tail grips on are suseptible to the shocks associated with tail blade strikes - especially if they are excessively tightened.

[chuckk]

Just wanted to add that the Quick UK tail on my Logo 600 did the same thing. I believe that what happened was I scaped the tail blades (KBDD) a couple times doing autos. Damage was minimal. I found the grip, regreased and assembled it with new bolts and it has been working great for quite a while. The point is that I believe these bolts holding the tail grips on are suseptible to the shocks associated with tail blade strikes - especially if they are excessively tightened.

same thing happened to my quick uk tail on one of my 700's.

[Helico-pteron]

Key words

especially if they are excessively tightened.

[latchman1234]

Happened to me last Saturday. I had just upgraded from the kit plastic blade holders to the metal Align version about two weeks before that (4-5 flights since). Was flying upright at medium speed and all of a sudden I hear bad noises and see parts flying off the tail. Things started hitting the main blades just as I hit throttle hold. Things went south in a hurry, but I auto'd it down even though it was in the spin of death. Had just enough lift to land about medium force. Everything from the back of the frames forward was fine, but got the typical main blades (not badly, but enough to ruin them), torque tube, boom, tail blades, rod guide and a few other misc. parts. Several of us looked for one of the tail blade grips and whatever was left of the rotor blade, but we never found it. Must have really flown a long way in the taller grass. I checked the tail rotor hub that the screw goes into (through the bearings) on the missing blade holder side. The bolt was sheared off flush with the end of the hub shaft!! I think this was a new bolt supplied with the upgrade kit.

I upgraded to the KDE kit for the rotor assembly (extra bearing, longer screw, etc. Will see how that works. So now I am not a fan of Align's bolt supplier either. Will do my main blade grip screws when I find another option.

[Garo]

im tailes gidervaseee

[UH1H]

Consider that on a full size heli - if a tail rotor strike occurs - the tail rotor assembly - grip and all are scrapped - tail rotor gear box overhauled and tail rotor drive shafts are usually scrapped ( may vary on some type on the extend of what in required to be removed ). On our little birds..how many change damaged tail rotor blades only after a strike ? I do not advocate changing all parts as on full size heli but changing the hardware might be the fix. Full size heli have inspection and replacement of component at specified interval. Preventive maintenance..

[devious17]

Hmmm, for some reason this has never happened to me on all my helis. Thanks to Finless.