Tail Shaft Pin Failure

[OnTheSnap]

I had the pin in the tail shaft eject causing a tail failure at a pretty bad time. Plowed it. I had the grub nut in the tail shaft cranked down and CA filled the holes. Both counter measures failed.

What do you guys do to keep this pin in? I heard one suggestion of using shrink wrap.

[WessCo]

A lot of old Raptor folks use heat shrink. I've never had a problem with them.

[WessCo]

https://www.helifreak.com/showthread.php?t=419040

[TomC]

Originally Posted by OnTheSnap

I had the pin in the tail shaft eject causing a tail failure at a pretty bad time. Plowed it. I had the grub nut in the tail shaft cranked down and CA filled the holes. Both counter measures failed.

What do you guys do to keep this pin in? I heard one suggestion of using shrink wrap.

I just have mine ca'd in as per the manual and it seems to be holding up fine. Maybe you did not properly clean these bits before assembly? Also, you need to be careful not to let anything like triflow (if you are using this to oil your tailshaft, like many) too close to this because it may eventually act like penetrating oil and weaken this bond.

Very sorry for your loss mate.

Cheers,
TomC

[WessCo]

I just now figured out this is at TT tail......uhhh.....no idea. sorry.

[OnTheSnap]

Originally Posted by TomC

I just have mine ca'd in as per the manual and it seems to be holding up fine. Maybe you did not properly clean these bits before assembly? Also, you need to be careful not to let anything like triflow (if you are using this to oil your tailshaft, like many) too close to this because it may eventually act like penetrating oil and weaken this bond.

Very sorry for your loss mate.

Cheers,
TomC

The CA I had on there is gone. Hmmf. As the pin ejected it left some scars. Maybe I'll try some jb weld and just drill it out to swap gears.

[Bladecpnitro]

Is there room to drill a hole in the pin and install a washer and carter key in it? That should hold better than a circlip.

[zattan22]

Never have any problems with the shaft...
Do make sure the shaft is centre and the set screw are tight.

[OnTheSnap]

Thanks. It's part of my preflight now. :-)

[Ah Clem]

OTS,

This is a pretty old issue.

Several years ago, when Raptors were still very popular, there were multiple threads on this subject. As I recall, the Raptor 50 had one pin in the tail pulley. This would back out and chew up the tail case from the inside.

I used heat shrink tubing soaked in CA, on the Raptor 50 and have never had a problem.

The Raptor 90 had three or four pins (shaft drive), as I recall (it has been six or seven years since I built it).

I followed the advice of others who had the pins back out of the various gears on the Raptor 90, and cut narrow sleeves from brass tubing to fit over the gears where the pins went though and epoxied them on (knowing full well that this would be a pain if I crashed. I also put epoxy on the pins themselves. The epoxy used was JB Weld (so it is never coming off).

I never cracked either of them up (yet) and so never had to replace any of the gears/shafts).

A roll pin would actually work better in this application, as they are actually rolled, tubular springs that constantly exert pressure against the circumference of the holes in the shaft and gear. Some people do not like working with them, as they can be (and should be) hard to press in.

Sorry you had a problem, sir.

[OnTheSnap]

Thanks for the info!

Really enjoying this machine. It's flying again. I just setup up auto rotation bail out with the ikon and having a hoot. It autos really well. I managed to do 3 full rolls in an auto before a blade stop and bailout. :-D

[Ah Clem]

"I managed to do 3 full rolls in an auto before a blade stop and bailout."

Holy Cr@p!

You better be bringing that machine to the HF Fun Fly!