Quick Gyro Queston

[retiredflyer]

  I know this has probably been answered somewhere but I have a quick question.  Regarding the hook-up of gyros and initialization.  I have several planes that have the battery tray/receiver location on the underside of the planes.  The gyros are also mounted underneath.  My question is you read to quickly hook-up your battery and step away until the gyro initializes, then go and fiddle with the wires and putting the battery in it's final resting spot.  If the plane is upside down while I'm hooking up my battery, then it is not in good position I would think for initialization.  I mean the plane might be sitting at a weird angle in the back of my van when I change out the battery.  You see pilot Mike hooking up a bunch of batteries of planes upright, sitting on the ground, removes his hands and lets the gyro beep, then puts on the canopy, etc.  You can't do that when the plane is upside down.
Is this an issue....or it just doesn't matter as long as you have the gyro physically mounted correctly in the first place. P.S. I usually use the Eagle A3-L gyros.

[OV10]

RE: Quick Gyro Queston

Hello RF,
The physical orientation of the airframe is not a factor with regard to gyro initialization. As you asked, the correct physical mounted orientation of the gyro is the important factor. The reason for 'no touch' during power up of the gyro is so that the gyro rotor has an opportunity to come up to speed and the gimbals to align. The beep is just an audible that the engineers made for human interaction letting us know that the gyro has achieved it's alignments and knows it's orientation whether that be right side up/down. The 2-3 sec alignment process of these modern model gyro's makes me smile when I think back to the days of aligning the inertial platforms(gyro) on real A6 Intruders and how long that took........ many minutes. But then again the airframe was moving around because of the pitching/rolling motion of the USS Nimitz.
Best regards,

[WintrSol]

RE: Quick Gyro Queston

There are no rotors in gyros currently used in small model aircraft, so it's not a question of letting the gimbals align. But, you do need to let the MEMS gyros set up while not moving. As far as plane orientation, that depends on the gyro type. For rate gyros, it almost certainly doesn't matter, but for some position-sensitive gyros, like those used to put the aircraft in an upright and wings-level position, you have to read the manual. The ones I use can be in any position, as long as the initial settings are done correctly; I don't know about the other brands.