Cold wx behavior with HH Gyro
 

I had a chance to fly today as the winds were calm and not 25 gusting to 35 miles per hour as predicted. There was some strange behavior in the heading hold gyro and I was wondering if it was due to the cold. The helicopter was in a 70° basement and I brought it outside to 35°. As I flew, I noticed I needed to add left nose trim about every 2 minutes. At the beginning of the flight the trim was about a click to the right of center, but at the end of the flight it was between center and full left. Once I landed I added full left trim to stop the tail motor. Even at full left trim the motor would run if the helicopter was rotated nose left even slightly.
I’ve heard that the gyro can cold soak and cause drifting. Anyone here experience the same behavior? Is it always to the left? Do belt driven heli's experience the same problem?

AXE CP
G90 gyro
Outrunner tail motor and 4530 prop

RE: Cold wx behavior with HH Gyro
 

In general, its not cold but change that fools with a gyro. If its let to cool to ambient temp it shouldn't drift. Its while its cooling or heating up that causes precession (drift) in gyros.

RE: Cold wx behavior with HH Gyro
 

That's what I thought. So if I let it sit in the temperature I'm about to fly it in for about an hour before spooling up, it should act better. Now I'm concerned about the plastic getting too brittle at freezing temperatures.

I've seen some guys fly on youtube with snow on the ground. It must be quite cold and they don't complain about lots of drift. Does the Futaba S.M.M and AVCS equipped Gy240 or GY401 have the same problem with drift during cold soaking? They claim better performance than other gyros. I'm running an Eflite G90 currently, but with half the year subzero temps could consider upgrading if there's a noticeable improvement.

RE: Cold wx behavior with HH Gyro
 

Pilotlight,

I have the same drift issue with all my gyro's including a Telebee TB (on Esky Belt CP), GY240 (on the Frankenheli AxeCP V1) & GY401 (on T-rex500). If I go from the heated house to the cold outside without allowing the heli to acclimate to the temperature, in HH mode they all drift everywhere.
Leave the heli outside without it's Lipo in it (cold weather is bad for Lipo's), for 10 to 15 minutes, toss a battery in it & fly, you will have a ROCK SOLID tail.

Rick

RE: Cold wx behavior with HH Gyro
 

Thanks Shadow, you saved me the agony of swapping out gyros.

RE: Cold wx behavior with HH Gyro
 

As he said, all piezo gyros suffer from temperature change to some extent.

RE: Cold wx behavior with HH Gyro
 

how cold are we talking about here?/ i flew my helicopter today in 45 degrees. i'm using the gy401/9650 combo. i didnt let it sit or anything. i just plugged the battery and fly. no problems here.:)

RE: Cold wx behavior with HH Gyro
 

35 degrees F.

RE: Cold wx behavior with HH Gyro
 

i heard the piezo gyros have temp issues. i once flown in 40 degrees f and my gy401 didnt give me any issues. it doesnt get much colder than that most of the time here in florida.:D

RE: Cold wx behavior with HH Gyro
 

I found that the better quality gyro's are less affected by the temperature change between 30-50 degrees (Futaba, Hitec, CY, etc).

Was out flying Tuesday night, temp was in the lower 30's. The GY401 was fine out of the house into the cooler air, rock solid. My buddy uses a Curtis Youngblood gyro on his Raptor 90, he subjects his to the warm/cold shock as well without any issues. However the Telebee gyro had some HH issues when subjected to the same treatment as the GY401. Haven't flown the "FrankenAXE CPv1" in a couple months, having too much fun with the 500!

Rick