Any fix for split main shaft?

[Digital Don]

I was experiencing periodic wobbling with one of my 120 SRs, I would up replacing the main shafft after discovering the 'dreaded' split. I haven't had the chance to fly it since the replacement, but it was flying good other than the slight wobbles, so I'm expecting it to be at least as good if not better.

Examining the original shaft, I'm wondering if it couldn't be repaired. My first thought would be just to dip it in thin CA while slightly opening the split so glue gets inside.

Not a big deal in any case, but I'm curious as to whether or not anyone has tried a repair on a split main shaft and if so, what were the results?

Thanks,

Don

[Liduno]

Just gluing it usually doesn't last, you can glue in a solid cf rod in the center of the hollow rod but that usually takes a bit of sanding to get the solid rod to fit.

[Digital Don]

I thought about that too. In fact, it would probably make the repair 'better' than the original. I was just curious if anyone had actually tried it. Seems like a more trouble than it's worth but if I come across a piece of carbon rod with the correct O.D., I might just give it a try and see what happens..

I flew the 120 SR with the replacement shaft today and the wobbles were gone.

Don

[airshot]

YEP...have repaired a few of them. Posted it on here a couple times. I assume you have the split at the top, if the shaft is split in two pieces then you are out of luck.
Assuming you have the typical split at the top, you need to get some CA gel, not the thin watery type. Loctite makes a very good gel and easy to find locally at most stores that carry CA glues. You will need a small screwdriver or other tool that will into the end so the split can be opened "slightly". Clean the shaft with alcohol, then put a couple drops of the gel glue into the top of the shaft. Use your tool to slightly open and close repeatedly the split until you see glue comming out of the crack. Wipe off excess glue from the outside and let dry. The gel has a little longer dry time but it
should set up in a couple miniutes. The gel will be thick enough to fill the center of the shaft, let this harden overnite. Next day get some fine sand paper and spin the shaft and sand/polish until the head piece barely slips onto the shaft, you want a snug fit here, no slop or add more glue and let dry. Once you have a good fit, you will need a small drill bit to re-drill the screw hole, remember the hole in the shaft is now filled.
After you drill, go ahead and reassemble your heli. Shaft will be stronger than a new one and there will be less chance of the screw splitting the shaft again. I have a repaired shaft in my heli now, been using it for more than 60 flights. Flys just like a new one and stronger than stock, and stronger than the aluminium shaft. Good Luck

Airshot

[Digital Don]

Thanks airshot!

Don