Blown one-way

[tgilton]

Had to replace the one way on my trusty Atom. What causes these to go? What is going on in the bearing when they fail?

[chopstick]

Probably the "inner" non-metal cage in which the bearings are fitted.
I had this after a severe crash. Never heard of this kind of damage otherwise.
Maybe you used a wrong lubricant for that kind of plastic.

[skunkworx]

The springs on the roller bearings can get twisted, the plastic sleeve can be come deformed, the pins themselves can get gummed up or fouled causing them not to spin freely, and the races for the pins themselves can become elongated or twisted.

One-ways work by allowing the bearing to move out and away from the applied shaft or surface when in free spin. Friction causes them to get "pinched" in between the shaft and the race going in the intended direction, thereby acting like a clutch. It's a similar operation as on a bicycle so that you don't have to constantly pedal or you can coast while keeping your feet on. OWB's can take a lot of forces because they do not usually get rotated at high rates of speed and are typically built so that the clutch effect doesn't jam the pins around a lot. If the friction becomes too great, they will slip in place and avoid damage to the entire essembly. In some cases though, the friction and impact the OWB can take is greater than the gears that are driving it and they will strip before the OWB.

When one goes out, they typically suffer from damaged races or the springs go bad and can no longer put enough friction on the needles to get them to engage. Also, being dirty can reduce the friction of the bearings or gum them up, restricting them from moving in the race properly and engaging/diengaging the shaft as desired.

[tgilton]

Thanks guys. Mine blew after a crash, but the crash was mild enough not to bend the main shaft. New one is nice and tight. I may dissect the old one to see the fail mechanism.

[skunkworx]

It's not a very common failure, but it does happen. At least it's rare and not too expensive to fix. Just catches you off-guard because how often do you stock an OWB right? lol

[tgilton]

Yes indeed, AND when it arrived, I had no idea there were two other radial bearings on either side of the one way that I needed to move from the old one to the new one. Not paying too much attention, I wondering why I couldn't get the main shaft to line up correctly... Figured it out, and popped those bearings out of the old OW and mounted them in the new one. All is good now, and my Atom is fit as a fiddle...

[skunkworx]

It always feels good to learn something new. I've always enjoyed working on my helis so it's really fun to get those "light-bulb" moments. Especially when you figure it out yourself. Makes me feel like a freakin genious! lol

[Jeff_Barrett]

I've have several go on my Atom 500 --- I've also had the starting bearing on my 3DPlus (it's the exact same one as the Atom 500) fail in the same manner with no crashes.

Alan (TheBum) suggested that he soaks his in a degreaser or some sort of checmical to remove the factory grease. I tried it on my last change out and it seems to be holding up .... hmmm ... ??