Feathering Shaft Loosening...

[bigdawg86]

As per the title, my feathering shaft keeps loosening up. The first time I noticed I was 2-3 threads away from ejecting my brand new blades. I disassembled, did a acetone wash/soak on the shaft/bolts, let it dry, and reassembled with blue liquid locktite. Figured that would be the end of it, but after 5 flights today it loosened again. I am using genuine align feathering shaft/bolts and I was wondering if anyone has had the same problem? Their is no binding in the blade grips that I am aware of so I am lost as to why this is happening. I have liquid and gel loctite maybe I should try gel but I am wanting this fixed...any help is appreciated.

[edhall]

Feathering shaft threads oily?

Old loctight?

[bigdawg86]

I know they aren't oily... but I tried again and have 4 flights without issue. I changed my blade grips and the thrust bearings seem to operate more smoothly. I also wire brushed everything with a dremel because I think there was a minute amount of threadlock that was causing one thrust bearing to not spin so whenever I was pitch pumping instead of the bearing spinning it was backing out the screw. I guess I didn't need to post about it since I figured it out lol

[helidude71]

Once after a repair i had the same.
I think in a new shaft is some left over drilling oil.
You can also see this when they are still in the package.
The headspeed pushes the oil against the locktite and weakens it.

After some flights i always remove blades and check if screws are tight.

[bigdawg86]

Ya I did a lacquer thinner bath... definitely no oil present. I think it was the one binding bearing due to some excess threadlock making its way into the thrust bearing.

[CoolKD]

I had the same thing hapening to me for the first time. Just 4 turns left of threads before disaster. Found out that one of the bladegrip bearing was rubbing on the damper shim, and was unscrewing the bolt. Replased the bearing and all is ok now after 16 packs.
When using thredlock, have it sit over night to cure.
And like ewery body ses " sheck that theres no oil or grease on the threads where threadlock is used" it will not work propely.

[ckirschman]

My buddy started doing crack maneuvers and had the same thing happened. He noticed it was loose and tightened, but a few flights later his blades got ejected. Good thing about those crashes is that the blades don't get damaged. I ejected the blades pulling out of a tail slide. The screw in the feathering shaft snapped.

[snjbird]

I have had this issue since I started fly Align 3 years now, I had it happen with the 250-600It is very frustrating, because you use loctic and think your good, then bam blade ejection two times It had bite me in the ass on the pro now... I have caught it half a dozen times, but once I heard a strange sound, a flapping sound, and before I could get to the ground POP, then I'm buying parts. the second time I saw the blades had loosened, got distracted, flew again and POP, buying more parts It make one hell of sound when it comes apart, both crashes took out servo gears, the dam heli falls fast when the blades are gone

This is happening more now, must be effected by harder flying because I am flying harded now than ever...

[CoolKD]

OOOK.. It almost happend again. Was just out flying and ewerything was great until the 4th pack. Half way in something was not sounding right. "Is that untracked blades I hear" I tought to myself. So I went in for a quick landing. As the hali came closer I coult clearly see that the blade tracking was WAAAY off. Took a closer look, and the grips was on its way out
Lucky I landed when I did. Not crashed this baby so far, after 94 flights. The screw that was loose was the same one that came loose the last time, and the threads on the bolt are fine. So there must be a problem with the treads inside the featheringshaft I use blue LOCTITE(243) threadlock as I have always done, and I have never had anything come loose until this bird. Going to pot on a new shaft and hope thistime it will stay in its plase.
Cleaned screews and shaft with alcahol this time, so the treads are 100% clen.

UPDATE: Ok, got this sorted. It is no doubt that the screws are coming loose coz of oil from the factory when they make the threads. Just clean bolt and shaft thorough and it's not coming undone. Have about 100+ flights now and still going strong.

[600rex]

I tried everything to stop the feathering shaft bolts from coming loose.
New bolts and shaft making sure to remove any oil from bolts and the shaft
threads and still two to three flights and one bolt would be loose.
I'm now on my 12 flight and all is still tight. I used loctite 263.

[maarset]

I had this issue atleast 3 times. I got in the habit of checking the grips pre flight.

I ended up using rubbing alcohol and q-tips to clean out the feathering shaft.

I ended up using the green loctite on the FS bolt. The same stuff you put on a pinion. No issues after that.

[RcGuga]

same problem for me...i was flying the thirth batery when i notice that my heli has a little shake problem when i took off and in the air too, them i sow two plates that's what it makes me land it..once in the floor i give it a little throttle and the blades suddently ejected i got luck it was on the floor...what do you suggest me to do? chanche the feathering shaft? put or not to put threat look? for now i just re arm it with some threat look and with the same fheathering shaft..no problems untill four flight for now

[magbarn]

I use some rc car nitro spray into the feathering shafts when I assemble my heads. I then give it a nice blast of compressed air to get the rest of the machining junk out. I then finally loctite the bolts in.

[AverageJoe]

When assembling, you need to apply the threadlocker to the bolt AND to the threads in the feathering shaft.

From the Henkel website:

Q: What is the proper way to apply threadlockers for both thru and blind hole applications? A: For thru hole applications, such as a nut and bolt combination, threadlocker is applied just to the bolt, coating 3 or 4 threads, going all the way around the diameter, and then assemble. On the other hand, it's critical to apply the threadlocker to both male and female threads for blind hole applications such as a bolt going into a closed housing. If it's applied just to the male threads and torqued down, air pressure will force most of the product back out as you assemble. This will result in incomplete coverage and partial cure only, leading to premature failures.

[trexpro]

Originally Posted by bigdawg86

As per the title, my feathering shaft keeps loosening up. The first time I noticed I was 2-3 threads away from ejecting my brand new blades. I disassembled, did a acetone wash/soak on the shaft/bolts, let it dry, and reassembled with blue liquid locktite. Figured that would be the end of it, but after 5 flights today it loosened again. I am using genuine align feathering shaft/bolts and I was wondering if anyone has had the same problem? Their is no binding in the blade grips that I am aware of so I am lost as to why this is happening. I have liquid and gel loctite maybe I should try gel but I am wanting this fixed...any help is appreciated.

I've had this problem once, wash/soak on the shafts/bolts and making sure to remove any oil! and it came loose again!
I took a new feathering shaft/bolts that was the end of my problem, maybe the threads of the feathering shaft was too wide or something? Now I check after every flight if there is play on the bladgribs. Better safe than sorry

[lcc014]

Originally Posted by trexpro

I've had this problem once, wash/soak on the shafts/bolts and making sure to remove any oil! and it came loose again!
I took a new feathering shaft/bolts that was the end of my problem, maybe the threads of the feathering shaft was too wide or something? Now I check after every flight if there is play on the bladgribs. Better safe than sorry

How do you check any play on the blade grips ? By wiggling them or else ?

Thanks,