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HelicopterFlybarless Rotor Head SystemsFutaba CGY › CGY sensor not impervious to vibes
08-04-2013 12:41 AM  4 years agoPost 1
unclejane

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santa fe, NM, USA

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Just FYI, there's a limit to even the CGY 750 sensor's resistance to vibes. My Whippy nitro came down with a drift problem shortly after the first flight, it was subtle and I could see how it might even have gone unnoticed. But I debugged it as a vibration issue, the sensor now sits on a slab of Zeal gel and that seems to have fixed it.

So just in case you have it hard mounted and seem to be chasing strange drifts, it could be vibes. Sounds strange I know because of how resistant the sensor really is, but it can happen.

The 750/1.31 is THE gyro for nitros...

LS

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08-05-2013 12:03 AM  4 years agoPost 2
devin120

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Canada

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hmmm

What head speed? Ive had drift at 80% avcs at low hs and a slightly bent TT. Mines hard mounted, Bobby Watts Hard mounts his to EVERYTHING. I would hate to mount a 270 dollar gyro on a gel pad.

I dunno, maybe checkity check your setup for a balance issue and your mechanical tail setup? Im a huge futaba fan. So biased I am. I could be completely F((*(&*( wrong. My two cents.

DC

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08-05-2013 12:31 AM  4 years agoPost 3
unclejane

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santa fe, NM, USA

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This was just an FYI post to say that hard mounting isn't always the right thing to do, even with a nearly bullet proof sensor like the one on the 750.

Just saying that, because the 750's sensor is so stout and vibe resistant, you might think you're getting away with hard mounting even tho you're actually having a subtle problem. It just won't go bonkers like other gyros that are more sensitive to vibes. It might even be flying ok and you don't notice it unless you're really looking for it in the hover, moving the governor around, etc.

There's nothing wrong with a $270 gyro sensor on a Zeal pad. It's a perfectly good solution.

In other words, don't be afraid to change the tape if you've done everything else but are still having a drift problem....

LS

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08-05-2013 02:35 AM  4 years agoPost 4
Dr.Ben

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Richmond, VA, USA

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It's OK on the Zeal as long as it is parallel to with a degree or so AND stays that way under flight g forces. If it moves in the slightest in flight, the system will cross control corrections.

I would have been inclined to try a 3mm 502 gyro pad first. If that did not work, I would use a 2 mm pad, 502 metal plate, and then another 2mm gyro pad. Only as a last resort would I use the Zeal because of the ongoing risk of having the sensor move even the slightest bit off alignment under flight loads.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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08-05-2013 02:38 AM  4 years agoPost 5
devin120

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Canada

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Ok cool

Dr. Ben knows his ****, you learn something new everyday. Happy flying.

DC

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08-05-2013 02:56 AM  4 years agoPost 6
unclejane

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santa fe, NM, USA

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I prefer Zeal gel to any kind of foam these days. The secret to Zeal is a thin layer of low-stretch plastic on the surfaces, which double as the sticky material. This tends to make any rocking motion of an item stuck to it force it into an "S", providing additional resistance to rocking (reminiscent of some engine mount brace designs in full scale, it's a similar concept). Same with turning, which it resists more than the general smooshiness of the gel itself would allow. But you still get the full vibration absorption of the gel, without as much of the wiggy, twisty tendency of traditional foam.

Zeal gel is another one of those sleeper products like the Reactor X2 reg. from Scott Gray - one of the best things ever invented for R/C.

That said, foam pads with metal plates can work as well and I've had success with it on my Beasts in the past. The Zeal is just better, ironically because it resists turning and rocking better than a foam pad even tho it's smooshier overall.

No problems so far on a buzzy nitro with the sensor moving that I can tell. Maybe a good pilot could tell in a hard manuever, but that's not me .

BTW, did I mention that the 750 is Da Bomb for a nitro FBL unit... you just can't do better...

LS

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08-06-2013 12:11 AM  4 years agoPost 7
Dr.Ben

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Richmond, VA, USA

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The trick is having the gyro sensor lead restrained enough to not move around in flight and pi$$ off the gyro BUT still have it loose enough to not pull the sensor out of perfect alignment. The softer the mounting, the more delicate this balance.

Ben Minor

Team Synergy Team Futaba Team Kontronik USA
Progressive RC

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08-06-2013 02:24 AM  4 years agoPost 8
unclejane

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santa fe, NM, USA

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Agreed. In fact, this is one of the advantages of gyros like the 750 with the separate sensor over fully integrated units like the Beast that I think a lot of guys may not realize. Don't get me wrong I love my Beasts, but there's a bunch of leads coming out of there once hooked up that all together make a very good vibration transmitter. Right into the unit lol.

I used to tie those wires up nice and neat with velcro straps all wrapped around them, but not anymore....

On my Beasts, a significant portion of the installation is monkeying with those wires to prevent this. If you hard mount that helps, but then you have the potential of direct vibe transmission through the gyro mount.

This is a big advantage with the 750. You only have that one wire to deal with. I've found on my installations that leaving a good 3" of the wire just loose with a gentle curve in it seems to work the best on a soft mount....

LS

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HelicopterFlybarless Rotor Head SystemsFutaba CGY › CGY sensor not impervious to vibes
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