Pinion gear on motor

[MrBrink]

Hey guys,
So a while back I was flying my Trex 250 when I lost it coming in for a landing. I noticed that the motor was still going and as a matter of fact it was high pitched but the blades weren't moving. Come to find out the pinion gear had broken loose from the motor spindle. I had used Gorilla glue (epoxy) the last time I glued it and was surprised that it had let go. I had let it cure for a few days in a room of the house that tends to run a little warm.

How long should this epoxy last? I was a little surprised that it lasted only about a dozen flights before breaking loose. Any suggestions as to how to get this to last a little longer or maybe a different epoxy?

Thanks.

[gimbleguy]

Which type of pinion do you have? Does it have a grub screw?

With pinions that has no grub screw I use green threadlock on the motor shaft, let it cure for a couple of days(curing time depends on the quality of your threadlocker).

If you have a pinion with a grub screw, you'd have to make an indent on the motor shaft. I use red threadlock on the grub screw and the motor shaft

[myxiplx]

Epoxy is the wrong stuff for a pinion, it will always break loose. You should be using a retaining compound, green loctite 609 I believe.

It's very liquid stuff, and takes around 24hrs to set, but once on you will need heat to remove it. My pinion hasn't been touched in over 300 flights now, with nothing but retaining compound holding it in place.

[nflanagin]

It's a 2.5m shaft and years ago scorpion had a three pack with a 14t, 15t, 16t. The DFC uses a 15t in the kit. Hobbyking has one:
http://www.hobbyking.com/hobbyking/s..._Gear_15T.html

In the three pack I had, I used the 16t for slightly higher head speed. Maybe you can still find that product.

[MrBrink]

It's not the kind with a grub screw unfortunately. I don't know why I was thinking I had to used epoxy. Thanks for the heads up on the loctite.

Have a Merry Christmas!!!