Tail perfect one flight, bad the next

[Nitrospazzz]

I've been having an intermidnt tail problems with my EB. First time it occured at the ORRO funfly, I got it down safely but it was very close to tipping over because the camera mount was on it. Second time I was doing a AP shoot and it went out on me over some property and expensive homes. I got it back to the road near where I took off from, it came in fast though and I set it down with too much speed. It tipped over damaging blades, flybar and possibly the spindle. I need to do a test spool up to see if I missed anything when I repaired it.

Now what happens is the heli flies fine for the first minute or two. Then the tail starts to drift left/clockwise and I keep feeding in rudder to try to correct it. Then I run out of rudder travel and have to let it spin around. It usually does half a piro so its nose in. Then I spin it and try to bring it back to me under control. It does this every 15-30 seconds though so it is difficult to fly.

When this happened at the ORRO funfly I thought it was due to low batteries because I was on my 4th tank on that charge. Running the Duralite setup with regulator. I did 2 tanks between that occurance and the most recent one. Both of those flights the tail was perfect. Didn't hunt, wag, drift, anything. I did climbouts, piros, FF all with and without the camera mount on there. So I have no idea what is causing this. All I know is I have had to turn down a job because I don't have it figured out yet and I can't afford to do that.

Thanks ahead of time for any ideas

On a side note one of the threaded holes on the tail gearbox that holds it horizontal is stripped out, should I drill it and run a larger screw or should I get a new one? I haven't looked at the price of a new tail box but I am guessing its somewhat expensive because it is so solid and heavy duty.

[cbergen]

Which gyro,servo, radio system are you using?

Are the arrow shafts drilled and pinned?

What headspeed are you running?

Driven tail/non driven tail?

What tail blades?

The gearbox can be helicoiled for 3mm or drilled and tapped for 4mm. Either way, disasemble the gear box before drilling and tapping.

[Nitrospazzz]

Running GY401/9254 combo with a 9CHPS controlling everything

Arrow shafts?

A solid 1630 in hover and a bout 1650-1675 in a full power climb

Stock tail, non driven

Running NHP 95mm tails, plan on going with bigger ASAP. I would like to go bigger, thinking 105's or bigger if that is safe on here. Have run 95's since I picked it up with no problems.

Helicoiled? Not familiar with that term.

Some extra info that may or may not be important. The engine has 3 gallons through it, just started #4 actually. Running Ozark white gas with 5 oz per gallon synthetic oil. Engine is tuned well thanks to Cody and the plug looks good. I never had this problem before the ORRO funfly.

[Gary Travis]

Check your engine needle settings, I have seen this many times, withe the engine to lean the tail servo becomes overworked and starts to drift and eventualy you will have no tail control at all. Cobine this with the 95 tail blades and it will without doubt be a problem. Richen the high needle just a hare and I suggest the 110 tail blades. This should cure the problem. As I said I have seen this problem quite a few times and have corrected it in this mannor. Also make sure the tail is set up correctly, take the gyro out of heading hold and lift the helicopter off the ground correct any drift you may have and then put it into HH
Gary

[Nitrospazzz]

Ok I'll give that a try, would be nice if it was something so simple.

Thanks

[MarkWebber]

Arrow shafts=t/r drive shafts. If the setscrews aren't properly set into the dimples when you drilled and pinned it you will lose tail control.

[MikeDD]

"Helicoiled? Not familiar with that term. "
Name brand of a device for fixing stripped out threads. You drill out, use a special tap, then a tool to insert a threaded insert into the hole.