I've been practicing hovering for the last few days. I've noticed a strange thing happening. I'll have all the controls set up so the helicopter hovers with the tail not swinging around, but then after stopping it an refueling it, the tail is all over the place. What gives? How come it's set up correctly while I'm flying it, but after I land it, shut it off and refuel it, and start it back up, the trim for the tail seems to be off?

Today I took back off and the tail started swinging around, so I had to quickly set it down. The landing was hard and the rotor hit the grass, ripping the shrink wrap on the blades. Luckily the heli was still flyable, and I continued to hover it after I checked it out.

I just want to know why the tail trim seems to get messed up on its own. The gyro is set up properly, since it works right most of the time. (just not after shutting it off and refueling)




I'd appreciate any help.

Hi.

Check all of the control rods. Especially the tail rotor's control rod.
Alot of time it slap and hit a nut or bolts under vibration since it is
the longest rod in the helicopter. Also check the percents of gains
on your gyro. Set it around 45 to 50 percent for start. Good luck.

Another thing to check is the mounting tape for the gyro. Make sure the gyro is not loose.

what type of gyro is it?if it's a csm 180 or similar rate gyro then it's normal for it to pirrouette slightly because the rotor speed changes slightly between full and empty tanks due to it changing the mixture setting.this means that the revo mixing would be either over compensating or not compensating enough due to the rotor speed being to low or high.this doesn't happen with a heading lock gyro because no revo mixing is used and the gyro is far superior at holding the tail so it can compensate even when the rotor speed is too low .this is a possible soloution to your problem,it took me ages to figure out why my heli was pirouetting in this manner

did you bump the heli when you turned it on thereby, mess up the gyro initiallization???

The other day, the tail of my JRZ230 heli started to twitch and hunt around on its second flight of the day. Upon checking EVERYTHING (tail servo, gyro, etc.) it turned out that the receiver battery was going bad and the voltage had dropped dangeroulsly low! Apparently the tail servo could not keep up (lower voltage = slower reaction).

The tail works perfectly well with a freshly charged battery.

It's an Ikarus Profi gyro. It has heading hold. Right now it's disabled so I can make sure the heli is setup properly before I enable HH.

ok try the heli with the heading hold function switched on,if you still have this problem with the heading hold on then i'm at a loss as to what is causing your problem

I don't see any mystery. Piezo-gyros are sensitive to temperature.
I always have to re-trim my gyro's heading hold between flights
before I leave the ground. I know and expect this, so I have no
problems in the air. Does your gyro sensor happen to be near to
where your engine could heat it?

I mounted my gyro up front where the receiver is, so I don't think it gets too warm up there. But you might be on to something about the temperature outside causing the gyro to drift, since the helicopter is going from my warm house and my warm car to the cold New Jersey November air.

I had the same problem with mine, I had to trim the tail by adjusting the linkage, If I tried to trim it by the radio it would act just as you explained. Another thing to note is the rudder ATV's need to be set at there max, its a balancing act really.

Good luck

could be onto something with the temperature change. I read in the manual for my Futaba gyro that you are supposed to let it acclimate to the outside air temp difference for 10 minutes before you use it.

Also weak battery theory could be it. Maybe it's only good for one flight if it's getting weak.