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Sep 20, 2010, 11:19 PM
Registered User
LOL!

A-main has the kit with motor and esc for $199, so I know you're wanting to get an E325 and I've kept an eye out!

If I was a little braver, I'd get it... and then the wife would kill me... hehe

Will
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Sep 20, 2010, 11:29 PM
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scottflight's Avatar
John! You got it. Chrystal. After a couple of years with 2.4, going back to 72 you forget how touchy they are. Anyway, with much testing it appears that it was loose, but also looks like it gets glitchy as it heats up. So I jammed it in there as far as it would go (receiver side is the problem), and it worked for a whole pack of hovering in the garage...

Thanks! Do you recommend getting a new chrystal....and where do you get yours....do they have to be proprietary hirobo, or will any futaba work, dual or single conversion on these guys?

Next up, I'm going try those SG blades.

S
Sep 21, 2010, 06:59 AM
Registered User
Quote:
Originally Posted by scottflight
Jl....and where do you get yours...
Augusto at yrbuy.com has them available for channel 36 (72.510). I have one spare receiver crystal (changed both of mine to same frequency) on channel 40 (72.590).

--Al Evans
Sep 21, 2010, 08:21 AM
Cranky old fart
Balr14's Avatar
I think the receiver crystal is a size that's much smaller than normal.
Sep 21, 2010, 09:26 AM
Registered User
Quote:
Originally Posted by Stenz28
LOL!

A-main has the kit with motor and esc for $199, so I know you're wanting to get an E325 and I've kept an eye out!

If I was a little braver, I'd get it... and then the wife would kill me... hehe

Will
Thanks Buddy! I'm also still waiting for a quote from Augusto on the bare bones plastic head/tail heli-only kit. Evidently, Ace Distributors (Ace Hobby) is going out of business and won't be the North American distributor of Thunder Tiger anymore - it's being picked up by Great Planes/Hobbico. It sounds like there will be a brief interruption in product availability as everything gets transferred to the Hobbico warehouses ...

Fine with me - no rush !

Quote:
Originally Posted by scottflight
John! You got it. Chrystal. After a couple of years with 2.4, going back to 72 you forget how touchy they are. Anyway, with much testing it appears that it was loose, but also looks like it gets glitchy as it heats up. So I jammed it in there as far as it would go (receiver side is the problem), and it worked for a whole pack of hovering in the garage...

Thanks! Do you recommend getting a new chrystal....and where do you get yours....do they have to be proprietary hirobo, or will any futaba work, dual or single conversion on these guys?

Next up, I'm going try those SG blades.

S
Great! I used to put a piece of tape across the one on the receiver just to make sure it stayed in and behaved. I also bent the tag over and tucked it inside to help fill in the space around the crystal and the plastic enclosure of the control unit.

It is a smaller crystal and I had trouble finding replacements - but my hobby shop did have one even smaller (I'll have to check the brand when I get home). I ended up not needing it as the problem was how I was holding the transmitter. I was never able to get any info on the crystal from Hirobo - but I would do like Al mentioned and get with Augusto - he can get you set up with what you need.
Last edited by FR4-Pilot; Sep 21, 2010 at 09:32 AM.
Sep 21, 2010, 03:44 PM
Registered User
Reading up on the thread today, I see folks are talking about the crystals. And a little light goes off in my head, THAT doesn’t happen very often!

Anyways, I have a question I hope someone might have an idea about. I’ve been struggling with the tail drifting either right or left. I know I need to adjust the trim during flight, but I can never get it to stop drift either right or left.

What I mean is, when the heli starts drifting left, (turning left), I give the trim a click, or two to the right, then it’s fine for a few seconds. Then it starts drifting to the right! There doesn’t seem to be any happy medium.

It’s especially a nuisance when I’m practicing my nose in hovering. Which I’m terrible at to begin with! Which in turn is why I practice it so much.

So my question is, could the crystal be causing this kind of problem?

Also, adjusting the gyro doesn’t seem to have much of an effect.

Even with this little issue, the Quark has still become my favorite heli to fly. The 180Z is collecting dust right now, and the Ufly is on the bench waiting for some new gears…again! I really need to stop backing into things with it.

Mike
Sep 21, 2010, 04:13 PM
Registered User
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.

-John
Last edited by FR4-Pilot; Sep 21, 2010 at 04:18 PM.
Sep 21, 2010, 04:29 PM
Registered User
Quote:
Originally Posted by FR4-Pilot
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.

-John
Thanks for the reply, John.

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

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

Mike
Sep 21, 2010, 05:21 PM
Registered User
nwjhawk's Avatar
Quote:
Originally Posted by scottflight
John! You got it. Chrystal. After a couple of years with 2.4, going back to 72 you forget how touchy they are. Anyway, with much testing it appears that it was loose, but also looks like it gets glitchy as it heats up. So I jammed it in there as far as it would go (receiver side is the problem), and it worked for a whole pack of hovering in the garage...

Thanks! Do you recommend getting a new chrystal....and where do you get yours....do they have to be proprietary hirobo, or will any futaba work, dual or single conversion on these guys?

Next up, I'm going try those SG blades.

S
I'd try to contact MRC and see if they would swap out the crystal set or just send you a new receiver crystal. From what I hear MRC has been pretty accommodating for the most part.

I think I read in a post way back that the Berg micro crystals will work. http://www3.towerhobbies.com/cgi-bin...1p?&I=LXMAH4**
Sep 21, 2010, 07:46 PM
AMA# SIMAGES
simages's Avatar
You are correct Berg Rx crystals "which can replace" those Hirobo crystals work fine. In fact I had problems with mine and used them.
Quote:
Originally Posted by nwjhawk
I'd try to contact MRC and see if they would swap out the crystal set or just send you a new receiver crystal. From what I hear MRC has been pretty accommodating for the most part.

I think I read in a post way back that the Berg micro crystals will work. http://www3.towerhobbies.com/cgi-bin...1p?&I=LXMAH4**
Sep 21, 2010, 09:28 PM
Registered User
My quark seems to be one of the "tail drifters". It will tend to rotate CW during a flight and I have to compensate with trim.

Since I had experience with this on my Blade 400, what I do is this:

Turn on the receiver.
Put the tail trim slider all the way to the left.
Turn on the Heli.

This way I have lots of right adjustment. I tried restarting the Heli part way through the flight but it didn't help.

Would be nice if I could fix the Quark the same way I fixed my Blade... With a GY401!

Ciao
Sep 21, 2010, 10:06 PM
Registered User
Since no amount of trimming will correct the issue with the tail drifting from side to side, I’m considering swapping out the control unit for a Spektrum setup. I have most of what I would need, including a spare AR6100e Rx. I have a tiny HH gyro, it’s about half the size of a Telebee GR302-AD. In other words, it’s about half inch square. Can’t remember the name of it.

My problem is, I don’t know how to set up the tail motor. I know how to slave it to the main motor, but that does little good unless the tail is a variable pitch setup. And I’m not about to start messing around with that on the Quark! That’s baby!!!

I’m pretty sure someone else here as done it, but I haven’t been able to find the thread.

Not really sure I would do it, unless I was sure I could revert back to the original setup.

Just thinking out loud…

Mike
Sep 21, 2010, 10:35 PM
Cranky old fart
Balr14's Avatar
here you go, starz:

https://www.rcgroups.com/forums/show...&postcount=430
Sep 21, 2010, 11:13 PM
Registered User
Quote:
Originally Posted by Balr14
Wow, thanks a heap, Balr14!
(Bookmarked)
It’s greatly appreciated.

It looks like I’ll need to order a few parts, but I already have the most expensive components. So cost should be minimal.

Hmm, I may give this a try.

Thanks again.
Mike
Sep 22, 2010, 04:26 PM
Registered User
DMala's Avatar
Quote:
Originally Posted by starz
Wow, thanks a heap, Balr14!
(Bookmarked)
It’s greatly appreciated.

It looks like I’ll need to order a few parts, but I already have the most expensive components. So cost should be minimal.

Hmm, I may give this a try.Thanks again. Mike
Apologies if the question is stupid, but how was the mixing between the ESCs for the main motor and tail motor accomplished? Besides the gyro, don't you need a mixer when you have a separate tail motor?


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