Logo 600sx threw a tail grip today. Anyone else have this happen?

[clever]

So I was having some awesome flights with my 600 today. Flew 11 flights with no incidents. Of course on my last flight of the day disaster struck. In the middle of a piro tic toc I heard a noise and lost the tail. It sounded like maybe the tail belt broke. I hit throttle hold out of instinct and the heli went in.

Upon inspecting the crash scene one of the tail grips/blades was missing and was nowhere to be found. When I looked at the tail hub I could see the tail spindle bolt had sheared off with half still threaded inside.

Anyone else have this happen? Anything that could have caused it or prevented it? Sucks to crash that way.

[rcflyerheli]

Gotta ask, is this the one you had written about earlier that had the pinging sound in the tail?

In your other thread, I saw that no one had come up with anything other than the possibility of a belt slapping the boom, correct.

I don't want to sound critical, but in hind sight, I would have made absolutely sure that the two setups were identical in every way before flying all those flights. Strange noises and pinging sounds do not seem to be a normal thing for a heli to be doing, and a heli isn't like a person with a cut that will heal itself.

I know you asked about the pinging noise, and I honestly can't come up with an answer, having not seen or heard the heli operate. There is one thing that usually is the culprit on a bolt failing, and that is overload or vibration induced fatigue.

What kind of headspeed did you have it set up for? As best as I can recall, there is a Mikado max headspeed limit of 2100 on the 600. Since Mikado has a great many of these machines in service, (one that I fly), I don't think that if you adhered to this max limit, you would have gotten an overload, so it makes me lean towards the vibration induced fatigue on the bolt. Did the bolt shear right where the end of the tail hub where the bolt goes into the hub, or was it at point where the threads end up against the head? I wish I could be of more help. If you have pix of the tail hub and bolt, if you could post them, it might help identify the culprit.

There have been reports of this kind of failure on both Align 700s and Gaui X7s. This is the first I've read or heard about this happening on Logos. I wish you luck in getting it rebuilt and back into the air.

[Johnny31297]

Was this with the old 4mm hub (black) or the new 5mm one (silver)?

[Laughingstill]

Originally Posted by Johnny31297

Was this with the old 4mm hub (black) or the new 5mm one (silver)?

The 600SX never came with a 4mm hub...

[Johnny31297]

He could have partially upgraded an old 600 3D and stuck with the old hub, which was known to frequently fail under high loads. If he's got the 5mm hub on there, we'd need to look further.

[Laughingstill]

Then it ain't a 600 SX

[clever]

Originally Posted by rcflyerheli

Gotta ask, is this the one you had written about earlier that had the pinging sound in the tail?

In your other thread, I saw that no one had come up with anything other than the possibility of a belt slapping the boom, correct.

I don't want to sound critical, but in hind sight, I would have made absolutely sure that the two setups were identical in every way before flying all those flights. Strange noises and pinging sounds do not seem to be a normal thing for a heli to be doing, and a heli isn't like a person with a cut that will heal itself.

I know you asked about the pinging noise, and I honestly can't come up with an answer, having not seen or heard the heli operate. There is one thing that usually is the culprit on a bolt failing, and that is overload or vibration induced fatigue.

What kind of headspeed did you have it set up for? As best as I can recall, there is a Mikado max headspeed limit of 2100 on the 600. Since Mikado has a great many of these machines in service, (one that I fly), I don't think that if you adhered to this max limit, you would have gotten an overload, so it makes me lean towards the vibration induced fatigue on the bolt. Did the bolt shear right where the end of the tail hub where the bolt goes into the hub, or was it at point where the threads end up against the head? I wish I could be of more help. If you have pix of the tail hub and bolt, if you could post them, it might help identify the culprit.

There have been reports of this kind of failure on both Align 700s and Gaui X7s. This is the first I've read or heard about this happening on Logos. I wish you luck in getting it rebuilt and back into the air.

Lol, yes I know a heli won't heal itself. That would be cool though. It was something I unsuccessfully attempted to diagnose and resolve. I went over both my 600s many times and they were identical in every way that I could discern. The belt tension was identical. The reason I kept flying was because others verified they had heard a similar noise and had no ill effects from it, and continued to fly.

Your assumption proved to be correct though. After viewing the logs of the last flight the entire flight suffered from extreme vibration levels. This undoubtedly compromised the bolt and the rest is history. Learning experience. I never really look at my logs unless something electrically based goes wrong. If I would have looked sooner I would have seen the vibes and wouldn't have continued to fly.

I'll have it back together tomorrow hopefully and I'll test fly on Thursday. Hopefully I can get this sorted and after the rebuild the pinging and vibes will be gone.

Thanks for the help guys! Attached is a picture of the hub.

Originally Posted by Johnny31297

Was this with the old 4mm hub (black) or the new 5mm one (silver)?

It was indeed the newer hub.


I fly @ 2200 headspeed. In doing research when I first got the 600 it seemed to be a general consensus that this was a great headspeed for 3D.

[Johnny31297]

What tail blades were you running?

[clever]

Cyclone 105s. Thinking of going back to the 95s possibly.

[Laughingstill]

105s are just fine

[Johnny31297]

Agreed, as long as you're running 105s from Fun-Key and don't exceed about 11,000rpm on the tail rotor continously, the hub shouldn't have problems staying together.

[clever]

How do you guys feel about headspeed? Is 2200rpm pushing it?

[Laughingstill]

Not at all, it is what I run...

[hilarious]

do you mean what snapped was actually the bolt that holds the grip in place? if so, it usually happens when the bolt isn't entirely screwed in. any play at that point will strain the bolt and cause it to shear. also, a bent bolt head may cause a similar problem.