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401 gyro drift

Old 05-13-2010, 03:09 PM
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Default 401 gyro drift

Hello All,
Lately I've been really trying to get my heli dialed in so I can really try to develop my skills as a heli pilot. This past year all I have done is hover and some forward flight. The engine tuning and curves was fine for this type of flying, but lately I decided to upgrade blades and get things a little more up to speed. One thing I have always noticed is that my gyro gain had to be set really high to keep any kind of lock. around 97% if I remember correctly. If it wasn't this hi the heli would slowly yaw the nose to the left. Another guy I fly with has his gain alot lower and his tail is solid. I pawned it off as different headspeeds and left it alone. Well with the carbon fiber blades I just put on, the engine required some tuning to spool up properly and I noticed that no amount of gain will stop the drift now. That is in both normal mode and Idle up. This is a futaba 401 gyro and I am expecting this baby to lock in.
I'm curious as to what things I may look for to fix this.

Some things to know about my setup:
ATV are 100%
No sub trim
no rudder trim
Limit on the gyro is 110
Delay 0
Using the digital servo that game with the gyro (forget the number...92..something)
the rudder has pretty close to equal throw on both sides (though I did Not perfectly trim the rudder in Rate mode, and I don't think this is the problem but who knows)

My ENGINE TUNING IS STILL NOT DIALED IN- This is what I think the problem is.
I discovered last night that my high speed needle was less than 1 turn out!!!! I think I was just running a rich low speed needle to compensate and since my throttle never went more than 40 percent it seemed to run "ok".

How much effect will the engine have on gyro performance? and do you think this is probably the cause of my problems?
Any advice you guys can come up with would be great!
Old 05-14-2010, 08:16 AM
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Default RE: 401 gyro drift

Lets look at engine tuning and gyro interaction.

The gyro's job is to counter torque produced by the engine and main rotor system.

If the power output of the engine is inconsistent then the torque will constantly change. So yes, poor engine tuning will drive a gyro batty.

As you say, 97 percent gain is way too much, you should be in mid 60's.

Get the motor tuned correctly first. Then look at gyro mounting, how and where is it mounted, do you have a strap across it? Are the wires arranged so that there is pressre on the wires against the sensor or is there slack?

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