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Old Feb 12, 2013, 07:21 PM
Low altitude flyboy
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Minneapolis
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Looking for Zenith 3.7 owners

I'm looking for an experienced Zenith 3.7 owner to get some set-up tips. Mine is ready to fly. I have it all programmed. But I have received conflicting advice from non-Zenith owners. I need some one who has one that can point me in the right direction in such areas as CG, Launch configuration and camber set up. Any one?

Mal
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Old Feb 12, 2013, 07:43 PM
Detail Freak
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Harbor City, CA
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I never have had one, but have heard from others that because the wing section has a lot of camber, that thermal is "in section" and cruise is slightly reflexed, and speed is more reflex.
If the statement about the camber in the wing is true, then what I have heard should be as well.

Good luck with the plane!

R,
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Old Feb 12, 2013, 10:38 PM
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Target, I have as much time on a big Zenith as anyone, and I used camber, not a lot but probably 2mm more than base. I did have two reflexes, one I called super cruise, about 2mm up, and then a full blown reflex that was about 5mm at root. If there was not much wind, I just flew in section, it got around fine, super cruise was for just getting around a bit faster. I do not remember where I had the CG at, but I had actually moved it forward from it's farthest point back and it did better, especially in really light air.

For the two reflex's, I set up the slider so I could just select which one I wanted.

For launch, about 7mm at root.

If you have any other question, ask away.

Marc
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Old Feb 12, 2013, 11:48 PM
Sherpa
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La Quinta, Ca.
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contact Joe Nave at RC Soaring. He sold then when they were available.

http://www.rcsoaring.com/

Sherpa
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Old Feb 13, 2013, 12:10 AM
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Australia, WA, Perth
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Good info here:
http://f3x.com/htdocs/jirkus/zenith.htm
http://f3x.com/htdocs/pagestuff/set%20up.htm
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Old Feb 13, 2013, 12:13 AM
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Watervliet, Mich.
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i built 4 or 5 of them. i set the c/g at 110mm for them to start at.

dave
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Old Feb 13, 2013, 12:50 AM
Low altitude flyboy
MajorMal's Avatar
Minneapolis
Joined May 2010
325 Posts
I suspect the Zenith 3.4 set up does not apply at all to the 3.7.

I was told that the cg should be set at 110 mm from the LE so that confirms it.

I was also told that there is little or no need for any camber on launch. But OVSS says 7mm? This is what confuses me. Perhaps I just need to launch it with and without and see what happens.

I think the way I have thermal camber and reflex set is all wrong. I'm going to re-work that.

Its going to be a couple months before I maiden it. Dang winter...

Would you use flaperons?

Thanks for the input guys, I'll have questions later.
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Old Feb 13, 2013, 01:09 AM
Detail Freak
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You should use flaperons on every model. Its more efficient in roll that way. The longer span the flaps, the more you mix them to the ailerons.

Happy you got info from folks that flew the plane.

R,
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Old Feb 13, 2013, 06:51 AM
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MM, you are correct, the 3.4 is a different beast tha the 3.7. The 3.7 tips have a different airfoil than the center section, and it really helped along with more span, and aspect ratio. I am not sure who told you to launch in section, but I never did, also, I added a bit more length to the towhook slot to help rotation. It launches very nicely and will rotate very well. And yes, as Target points out, aileron-flap mixing is necessary for crisp roll control.

I won the Nats UNL with mine and I wished they could make the ship with the newer mterials and technices, consider that the Vixen is about the same span and area and it weighs 1 pound less. Also, the data from the F3X site is so out of date and was based on the 3.4 ship, v-tail, and old stuff. Dave's 110mm CG will be a good place to start with, again, not sure where mine ended up cause I just kept playing with it.

Marc
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Old Feb 13, 2013, 10:50 AM
Low altitude flyboy
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Minneapolis
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Quote:
Originally Posted by target View Post
You should use flaperons on every model. Its more efficient in roll that way. The longer span the flaps, the more you mix them to the ailerons.

Happy you got info from folks that flew the plane.

R,
Target
Thanks

Would you use flaperons for all flight conditions? Or only in thermal mode?
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Old Feb 13, 2013, 10:54 AM
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Used in all exept landing mode for me.

Marc
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Old Feb 13, 2013, 11:00 AM
Detail Freak
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Every flight condition EXCEPT launch.....And landing mode too (thanks Marc!)
I have flaperon mixing shut off in launch mode because I don't want to unload the wing completely just to bank or turn a bit.

Flaperon mixing in any other mode make the wing require less total deflection to get the same roll response.

I use the same philosophy for snapflap. It on in all flight modes EXCEPT launch....(and landing mode)
For snapflap though, you want roughly the same camber position at full elevator in each flight mode, so that means more snapflap when you are in reflex, than in thermal.
Recently, I broke this general rule and have been playing with more snapflap in thermal mode...reason being that I rarely pull full up elevator when flying in thermal circles. That way, I get the snapflap I need at the stick position I use most.

R,
target
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Old Feb 13, 2013, 11:07 AM
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Agree Target, on launch I use rudder for any lateral fix anyway.

Marc
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Old Feb 13, 2013, 11:13 AM
Detail Freak
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Harbor City, CA
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What about differential and rudder mix for the Zenith, Marc?
I assume with the 3.7 you probably use more rudder mix than with lesser span,
Those settings would probably be helpful to MM.

R,
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Old Feb 13, 2013, 12:32 PM
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Well, my aileron-rudder mix is not the norm. I tend to not use as much as some. In thermal and cruise, my mix is only about a 20-25% mix, and I fly my left stick alot, especially in thermalling. In cruise, I want just enough mix for a smooth standard rate turn wile searching. In reflex, I use none.

Like I said, that may not be the norm with most, and Mal may need more to start with.

Marc
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