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Old Sep 21, 2010, 04:29 PM
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Originally Posted by FR4-Pilot View Post
It's funny - both the Quark and Blade 400 use piezoelectric elements (crystals) in their gyros (as opposed to the newer MEMS technology) and many of them act the way you describe. There are a few that don't do the drifting as much or at all, but many do and it seems no matter how much adjusting you can't get them to stay still for very long. Probably the quality of the crystals and their temperature coefficients (stability over temperature changes) used in the gyro circuitry are to blame - which are not the same as the crystals used to tune the transmitter and receiver frequencies.

I used to work at a place that made crystal oscillators. Those designs that needed to be "accurate" had to have a "heater element" included in the design in order to keep the temperature constant - a real PITA. They were large and easy to spot - and they draw a lot of current. Since there's no temperature controls or compensation in the Quark's control unit or the B400's gyro I'm not surprised they drift the way they do. Frequency "drift" is an actual term used to describe how the crystal oscillator's output frequency would change over temperature conditions. Seems fitting the term also applies to the heli's tail behavior.

Sorry for the ramble - in short, the crystal that you can change on the Quark won't affect the gyro.

Thanks for the reply, John.

Thatís pretty much what I thought. That would be to easy. (The last part you said).

Oh well, itís really only noticeable when Iím hovering. When Iím out in the backyard, flying around, it seems to fly quite well. So I guess Iíll just learn to live with it.

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