R50v2 Tail Failure - That was not fun!

[chilipepper]

Talk about scare the crap out of a guy! I was just starting out for the day after being out of town for a week. I fired it up and everything was going just fine took off and pulled into a hover nose into the wind. I was about 8 feet up and whack! Started spinning like crazy and luckily I was able to just set it straight down and kill the engine.

Since i'm only on my second gallon with this heli but it was used, what could have caused this? I did go over the tail after I received it and check bearings, tail shaft, etc. but I would like a little insight into what to do differently or check to try and keep this from happening again! Thanks!

[nitro burner]

I never seen this before :shock: It's almost looks as if one of the tail blades cut the tail off. Sorry i coundn't not help. Great save by the way :thumbsup2:

[Sar]

Where's the screw that holds the tail grip on?

[LuckyLandings]

I have had the tail grip screw break off at the hub before on an R50 I had. I think it was because it was tightened down to tight by the previous owner. I have had better luck with flapping hing type set up. Screw just snug and allow the thrust bearings to take the load.. Good luck with your findings.. James G.

[chilipepper]

Thanks for the replies! The tail grip screw is sheared off in the hub and the rest is gone. 2 of the six bolts holding the tail case together are also left as a project for a metal detector and some patience! :^)

I've heard of the overtightening problem with tail grips but would it affect the case as well. I think that is where my problem stemmed from. It looks like it broke off right at the back of the tail boom. This would explain some of the other carnage there...

[LuckyLandings]

You got a picture of the rest of the heli.? Did it come down hard? My guess would be you just slung a tail blade from the bolt breaking off. And if it came down hard it could have made an existing hairline crack from some where open up and break the housing.
Although that wouldn't explain why your belt is cut also. Hummm
I see you have the pins on the tail pitch slider Y-arms that dont have the little e-clips to hold it in place. You could have lost the tail blade holder connection to the pitch slider causing it to go out of balance and strike the housing? :dontknow
I have slung tail-blades, but never cut a housing in half.. Thats is a strange one! :?
I bet if you pull that loose tail blade from the holder you will find the other end of your bolt still in the bearings. :wink: If your careful with a dremel and heat up your hub you can get the broken bolt out pretty easy and save your hub. I replaced mine with Boca thrust bearings and good hardened cap-screws from micro fasteners when that happened. Have not had had that problem again..(knock on wood!)Good luck!

[mplourde]

This look like you have tight too much hard your screw!!! My friend who's have a Raptor 50 had this problem 3 times!!! It's was because he tight too mush his screw in the midle. :arggg:

Put some locktite on the midle screw and don't tight too much the screw. It is that he done and now, all is ok. Any problem with that afther!!!

Good luck!!! :thumbup:

[Hercules]

Do the bearings still turn when you try to spin the tail rotor shaft? How about the guide pulleys? May sound stupid, but, I've seen automobile engines sieze up from bad bearings in the pulley assembly. Actually, I've seen it happen three times with the bearings in an alternator, guide pulley, and tensioner. So it's not out of the realm of possibility that one may have bound up momentarily causing the tail to be torqued apart.

[chilipepper]

I very much appreciate all of the great input... in this particular case upon the autopsy I realized there was a very small crack in the tail case that let go under the stress of possibly a tail belt that was a bit too tight. It let loose right at the connecting point of the tail boom. I believe when this broke free it allowed the tail to drop and bound the tail belt up and basically rip it from torque or actually flipping the blade up and cutting it. Or else the tail blade grip broke free upon impact with the ground. (I did come down a bit fast) :shock: It all happened pretty fast!! Thanks again!

[WillJames]

Good thing you did not damage the heli or yourself. That could have been a lot worse. Good save!!

[johndale]

:cool: Here is what you need HARDENED TAIL ROTOR HUB

$ 7.99
Part# TTRPV0499

This is not uncommond problem. Some of you have been lucky of this not happen to you yet. www.Onlyraptors.com has this part and the problem goes away. :glasses2:

[R-4-L]

I have had this problem, but did not reach disaster state, as I noticed the gearbox having a little play and strange sounds are coming out of it when idling, changed the case and bearings (and ofcourse the belt), did the job!.. good save man!

[Shortman]

I am sorry to see that you had a failure. I just went out and bought the part John said to buy after hearing about these failures. It seems much sturdier and made out of steel instead of aluminum. Hopefully this does the trick.

[R-4-L]

heliproz have new items from mavrikk like the metal tail case..

could consider it

http://www4.mailordercentral.com/heliproz/prodinfo.asp?number=805503

[Janek]

There are two modes of failure on Raptor tail hubs (R50, R60 & R90).

1) If the hub is intact, and it's the set screw that has sheared off, at the point that the nut butts up to the hub, then the cause is over tightening of the set screw and/or nut.

2) If the hub had failed, where it steps down to the bearing seat, then the failure cause (I believe), is that the inner bearing (closest to the shaft) has been rotating on the hub. I've started to loctite my blade grip bearing to the hub specifically to stop this :wink:

The gearbox has broken up simply because it cannot withstand the excessive forces placed upon it when the tail rotor is so massively out of balance after the blade and grip have departed.

Oh, and if you have the constant drive gear fitted (white), and you loose a tail blade, it is VERY difficult to execute an auto, because the massive out of balance situation robs all the energy out of the system.

And how do I know all this ?. . . . . . . . . been there, done that, too many times to remember :roll:

[mplourde]

That's right Janek!!!

I have seen the same thing than you on a Raptor 50 V2!!!


1) If the hub is intact, and it's the set screw that has sheared off, at the point that the nut butts up to the hub, then the cause is over tightening of the set screw and/or nut.



I said:


This look like you have tight too much hard your screw!!! My friend who's have a Raptor 50 had this problem 3 times!!! It's was because he tight too mush his screw in the midle.

Put some locktite on the midle screw and don't tight too much the screw. It is that he done and now, all is ok. Any problem with that afther!!!


good luck!!!

[HelicopterJohn]

Hi Chilipepper,

If you are looking for a bullet proof all aluminum CNC tail rotor gear box you may want to contact "cforcht" here on the forum. It will not keep the blades from flying off but I would think the tail rotor gearbox would not explode.

Just send him a PM or e-mail for the details.

Something you might want to consider.

:)

[WillJames]

As Janek said, overtightening is the #1, #2 and #3 cause of raptors loosing tail blades grip and all. You do not need to make them more than a little tight or you will over stress the set screw that holds the grips to the hub. I have seen at least 10 times over the past 3 years where people who overtightened lost tail blades/grips. Ask Steve Dixon about how close one came to him...

Use locktite and DO NOT TIGHTEN them more than hand tight, a loose hand tight. They will not depart unless overtightened.

[rcmike]

I agree, you threw the blade and it caused the other damage. I threw one once on a V1 Raptor and almost everything from the frames back was bent, broken, or otherwise destroyed.