Accident Investigation

[Danny_K75]

I had a bit of a mishap with my blade 400 today.

I had just taken off and was hovering at about a foot then the whole tail section fell off!

I bought this heli off ebay and as you can see from the pics it has an ‘upgraded’ tail section. Now this heli had actually been my better blade 400 (I have two) and I had flown it a couple of hours earlier for a few mins but had to land as it had started to rain.

So any ideas why the tail might have failed like this?
I had tightened the pivot arm earlier that day* as I’d noticed it was loose and checked the rest of the screws and they were fine.
One theory I have is that there was a hairline fracture that I missed when checking the tail earlier.



*The pivot arm is fully in tact and working correctly.

[callum]

Hmmm,

I have an idea,

Probably because its not an official upgrade, probably one of those really cheap chinese upgrades you can get, but the quality is very terrible, and can actually affect flight performance,

Ive heard of cheap tail upgrades, and the tail shaft and bearing fly out!

Regards
Callum

[jamiem]

metal fatigue, the tailbox on my old 450se v2 did the same - replaced it with a beam tailbox (before then replacing the whole heli with a beam!)

[Boggy]

metal fatigue caused by vibration.
i had a boom shear straight through like it had been cut with a knife. (i had ignored a tail vibe for a while and it bit me )

[Holst]

It look like a bad design as well.

The bolts look very close to the point of fracture.

Cheap materials + poor design = faliure

[Danny_K75]

Cheers for the replies guys. The thought of it just being cheap parts did cross my mind, but I thought surely they can't be that bad!

Luckily I also got the standard head* and tail sections and I guess I'll just put those back on.

*This model also has a similar aftermarket alloy head which I'm now questioning the quality of!

[Sqwidge]

why bother with cnc parts? yes they look good but they add weight, why would you want to do that?
If I were to fit cnc to my blade it would only be the blade holders front and rear and the pitch slide, this would cure slop but not add much weight, but I would also buy from a respected dealer to make sure it wasnt cheapy chong sh*t