Logo 500 3D - minor crash, now I got a glitch

[murp]

I had a minor crash with my Logo 500 3D. I got a little close to the top of an evergreen tree and a blade hit. I immediately stripped a gear, I cut the power and set it down pretty gently.

The only damage I could see was the main gear was completely stripped and one blade had a small nick. I replaced the main gear and did a test spool up to make sure the head didn't have any issues. Everything was right on and the blades tracked perfectly.

However, I noticed a small twitch in the tail and experienced a few ESC gltiches. Before the accident everything was working great and ran smooth. I immediately set it down and have just finished tearing the head down.

The main bearings don't appear notchy. I will say they didn't seem well captivated by the frames before I dropped them out though. The autorotation bearing appears to be in good shape. There are noticeable indentations on the main shaft where they engage but other than that they appear fine. It is still well-lubed with a light machine oil.

Can anyone suggest other areas I should have a look at? At the moment I am at a bit of a loss. Like I said before this heli was glitch free and smooth before this incident.

[Fergus]

Just off the top of my head - maybe look at the tail drive gear above the main gear for damage and that the pin is properly seated and has not damaged the plastic locating recess under the gear. Also check the motor and pinion are secure.

Regards

Fergus

[murp]

Thanks for ideas - check them and everything looks fine.

I was thinking that maybe some of the main gear that got shredded made its way into the motor (NEU). Could this cause some issues?

[Big Fil]

I'd also take the tail case apart and have a look. I wouldn't be surprised if you stripped some of the teeth off of the tail pulley.

[Mercuriell]

The Neu motor wouldn't be affected - I agree the drive train to the tail rotor likely cause - check the idler pulley's belt and tail assembly as suggested above

[murp]

I have checked the tail pulley gear and it looks fine. I will disassemble the tail case next to inspect. I'll keep you posted.

[murp]

Well, having broken down the whole drive train I decided to start disassembling everything to check it over.

I noticed that when I took the autorotation bearing collar out of the main gear that there was some hardened loctite on the face of the collar that mates with the main gear. I believe that the main gear wasn't mating properly with the collar causing it to not run true with the main shaft. This makes sense since when I was doing the mesh the first time the gear did seem to be out of round, which is unusual for Mikado parts.

I cleaned up the faces and reassembled the main gear and drive train. When I was setting the mesh this time it was much better and consistent all around the gear.

What was likely happening was the gear mesh was sloppy and "skipping" every once and a while causing a sudden drop in RPM which made the tail twitch.

Spooled it up and did a bit of test hovering for about 3 minutes with no issues.