HK500GT Tail Victim

Guys.. Something I think you are all missing... The screw in the tail is plenty strong enough if you have no vibration. I noticed on spooling up that the tail boom and boom supports vibrate badly at certain throttle settings . When I investigated further, I noticed that the tail shaft bearings had some play in both the bearing and also on the shaft. When I replaced the $0.50 bearings for $2 ones from my local bearing shop. All the vibration was gone and problem solved. I have noticed that a number of the original bearings on the HK500 GT are very sloppy. This magnifies any vibration due to slight imbalances many times and will cause premature failure every time, due to fatigue. This also explains why high tensile screws are failing just as frequently. Beefing up the screws to 3mm will make them last longer but that is just treating the symptom, not the root cause of the issue. Further to this, everyone seems to rely very heavily on thread lock, but if you remove the source of vibration then your screws will not come loose. I'm not suggesting you don't use thread lock, just that you should take time to critically balance each rotating part of your heli before flying it and check for vibrations after any mod or crash.

Yep my screw broke blade went flying broke housing,belt,tail gear,mixer control arms waiting for the all alloy one to come into stock now!!

I also experiment the same tail problem : M2 bolt broken... Simply buy an Align tail rotor and change all the bearings.
And now it's perfect!