Futaba 401 gyro's

Member Joined: Feb 09, 2004 Posts: 50

I wonder if anyone can shed any light on an interesting issue that I am having with both my 401 gyro's.

I have setup the gyros in both my TRex and X-Cell gasser as per the manual. The neutral was adjusted in normal mode, then the servo arm adjusted and then finally the centre was memorised. When switching to avcs mode on the TRex it is fine until I select an idle up, then it just wants to go off to the left and the gyro flashes the led twice at a second or so intervals. According to the sheet that indicates that the centre is different in the gyro to the transmitter Shocked

The gasser, when in normal mode is fine, but when avcs mode is selected, the heli very slowly wants to turn right. It doesn't make any difference whether an idle up is selected or not. The led is solid on this model.

Odd, anyone experienced this before?

Posted: Fri Feb 02, 2007 6:28 pm

Quentin, Center all rudder trims, including servo centering in the tranny. Never use any trim or centering! Adjust the servo horn until you get as near to 90 degrees as you can. Adjust the link rod until you get the tail rotor arm/crank to 90 degrees to the boom. Boot up the heli with the tranny in HH, and move the rudder stick left and right rapidy to clear the 401's memory center. Then hover the heli in non heading hold. Mechanically adjust the linkage rod until the heli hovers straight with the rudder stick at mid position. Then switch to HH mode. Fly away and whilst doing so, flick between HH and non HH 3 or 4 times counting at one second intervals.

Also fighting the tail can be caused by changes in rpm. If your tranny allows you may have to adjust the gain for different idle up modes.

Also make sure the gyro wires are not taught, or rubbing against the canopy causing vibrations to run into the gyro.

Also make sure your using the correct 401 gyro pad.

Anyway I hope this helps.

Cheers, Kev.
KRMFC

Member Joined: Feb 09, 2004 Posts: 50

Yes it does help, thank you a very detailed response Very Happy

Member Joined: Feb 09, 2004 Posts: 50

Problem solved Very Happy

It transpires that there was a sub trim still remaining in the setup on the gasser and there was one click of rudder trim on the TRex. Both had gone un noticed during the setup!