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Old May 25, 2012, 10:11 AM
Chess club geek with wings
blunight's Avatar
United States, FL, Cape Coral
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Zone 2 flight mode setup

I've got a question that I cant seem to find the complete answer for - I'm sure its been asked a million times but I'm not finding it. I've read G_T's sticky and will read it again but....

Flight modes for the Zone 2 airfoil -

I've read that this airfoil requires camber changes to take advantage of its wide speed range.

Whats the best way to set my radio (DX8) up for this foil???

I'm considering the following, please let me know what you think:

Lauch on a momentary switch (up elevator)
3 position switch for:
Speed (both ailierons up)
Cruse (ailerons centered)
Float (ailerons slightly down)

Flaps on the throttle stick with elevator mixed in - this would let me adjust the flaps while in a thermal and go to full flaps for landing.

Anyone have any thoughts? If you have links to articles I should read, please give em' to me
Trent

PS. Can someone explain to me what setting up a "snap flap" is for and how it's used?!
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Old May 25, 2012, 10:29 AM
Team Hong Kong F3K
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Hong Kong
Joined Sep 2010
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Trent,

Take a look at the first post of the Neos thread for the throws and setup as a starting point.

I have launch on a momentary
3 flight modes on a 3-pos switch on left shoulder
triple-rates on a 3-pos switch
flaps on throttle stick

not sure what you mean by a snap switch, do you mean snap flaps?
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Old May 25, 2012, 10:34 AM
Chess club geek with wings
blunight's Avatar
United States, FL, Cape Coral
Joined Aug 2008
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Thomas,
Sorry - yes, snap flaps! Your post in the Neos build log concerning it caused me to wonder what it was and how it was used.

Also, could you explain your triple rates on the 3 pos switch - or is this your speed, cruise and float?

And as long as I have your attention - do you have any up aileron mixed in with up elevator for your launch mode?

Thanks for your time
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Old May 25, 2012, 10:53 AM
Team Hong Kong F3K
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Hong Kong
Joined Sep 2010
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Trent,

Snap flaps is really simply flaperon to elevator mixing. Pulling up on the elevator will result in the flaperons moving down slightly, and pushing down will result in the flaperons coming up slightly. This is to increase efficiency.

I have actually only started using dual/triple rates recently, I mainly stay at the 2 lower rates depending on conditions (calmer = lower rate).

I have about 2 mm DOWN flaperon mixed in to my launch to get it to turn up while losing a bit less energy than pure elevator (in theory anyway, I haven't noticed much difference, haha!)

Take a look again at my setup regarding the camber for the 3 flight modes, the wings are cut in the speed condition.

Thomas
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Old May 25, 2012, 01:26 PM
G_T
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Hello everyone,

Blunight, I do not know which Zone-V2 winged plane you have. If it is the Fr3aK, then your camber settings sound like they could be in the ballpark. But for others, probably not.

The camber setting of the Zone-V2 foils in their native camber is for speed mode and for launch. Here is a picture of what the root foil should look like for speed mode:

http://www.rcgroups.com/forums/attac...mentid=3635310

If you can imagine putting a straightedge on the bottom side of the airfoil then you would find that the back two thirds of the airfoil is not all that far from being flat. For (at least nearly) all modern DLG foils, this test should yeild a position that is reasonably suited to speed mode.

For the Zone-V2, one is unlikely to find improvements in launch height when using reflex beyond this position. That is due to the Zone-V2 being designed to have minimal drag down to zero lift at this camber position. This is in contrast to the Edge for instance, which can benefit from additional reflex for launch. In any event, if one is not a 70M thrower, then one might as well just use the default speed mode for launch mode.

There is no need to use extra down camber for launch rotation either, with the Zone-V2.

Feel free to test of course, but in all likelyhood you won't get much if any improvement; almost certainly not enough to tell without altimeter that is accurate, consistent, and a very consistent throw in consistent conditions.

Cruise camber would likely be on the order of 2mm down from this speed position. If you are coming from a background of slow, floaty planes, then likely this will seem fast.

Float camber probably starts at around 4mm down from the speed position. Again, if used to flying floaty planes, you may be more comfortable, at least initially, using float camber as if it were cruise camber.

There have been reports of Zone-V2 planes being able to use up to about 1cm of camber for float. I have not flown one set up like this so I cannot directly comment. But I have flown other planes which can use this much camber. However, in my experience the sink rate is higher than if one uses lesser camber. High camber may give a friendly feel in thermals, but having a little less and letting the plane be a bit more lively will likely result in a higher climb rate.

The reason is that in general, the more flaperon camber a wing carries, the narrower the optimal speed range.

Not all foil families can utilize high camber. Edge for instance would punish one for trying. Zone-V1 can use high camber.

Planes with foil families that I've designed tend to be slippery. This means that one need pay a little bit of attention to airspeed to keep the plane flying optimally. They can easily overspeed if you let them. They can also easily be flown too slowly. If the plane starts to feel mushy then likely it is being flown a little bit too slowly. But in any event, it is up to the pilot's skill to keep a DLG flying efficiently. That requires the pilot to be familiar with the plane, regardless of which plane it is or what foil family it uses.

FWIW, just because a plane uses a particular foil family, one cannot infer everything about how it will fly. Wing loading matters a lot. The progression of foils chosen by the designer matters a lot. Wing shape matters a lot. Each change alters the flying characteristics. The foil family chosen sets potential, but the rest of the design and production process are what determine how the plane will actually fly. Different Zone-V2s launch differently, and turn differently. These are the places where differences are most likely to show up.

Thermal mode - is the float mode. It is also the cruise mode. Thermal mode is whichever mode gives you the best climb or best hang for the conditions you are dealing with.

You want what is being called snap flap. Really what the DLG crowd calls snap flap isn't snap flap, but is instead elevator->camber mix. Just set it up as a linear mix. Have it set so that half up elevator stick gives about 2mm down, and half down elevator stick gives perhaps 2mm up.

If you set this up for different modes, then for speed you might want only perhaps 1mm up, and for float you might want only 1mm down, at the half stick positions.

YMMV, these are tuning parameters. The numbers I gave you here are guaranteed not to be optimal. But they should be safe numbers. They will give you a feel for what "snap flap" does.

Gerald

PS - In general I recommend avoiding dual and triple rate switching setups, at least if the person is not an expert pilot. Experts can pick their own poison to drink. Multiple rates just adds one more thing to get wrong for one without the experience, and one more control to pay attention to. If one really wants an aerobatic setup, then just make a separate program. Multiple model memory is a good thing. 0.02c.
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Old May 25, 2012, 01:43 PM
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With the JR/Spectrum radio's you can easily set throw rates to flight modes. I run 4 modes and the control throws are set per the mode so I don't have to worry about other switches. My thermal mode has reduced elevator and ailerons and my cruise mode does not. The amount of difference is minimal and the expo settings makes all the modes feel similar around the center 15% of stick motion.
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Old May 25, 2012, 03:02 PM
Aurora Builder
United States, MD, Lusby
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I run mostly what Gerald outlined in his lengthy post, with a few differences:

1) My cruise mode is 3mm of camber. I can move around and thermal fast moving lift in this mode.

2) My thermal mode is 6mm of camber. I pop into this when I've mostly cored the thermal and/or when the lift is super light.

Gerald's point about foil progression in the different Zone v2 wing designs is certainly valid, however I'd argue that in the real-world differences in how the plane is built matter more. Accuracy in building is not trivial, but I will argue that the 4 major Zone v2 planes on the market are all within a few points of each other on the build quality. The key difference I see is how the planes are a built. A hollow molded wing generally has much lower roll inertia than a solid cored wing. This makes general flight more lively and air ready easier. The trade off is wing durability.

-Sam
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Old May 25, 2012, 04:33 PM
G_T
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Sam, I think the reverse on roll inertia. A hollow molded wing's mass is primarily a function of the core mass plus inner and outer skins. The mass of the wing as a whole scales relatively as surface area. The mass is also distributed similarly.

A solid core wing has a core weight that ends up being a function greater than the square of the chord. Greater, due to the thinning of the wing, percentage-wise, as one approaches the tips. It would be square if the airfoil were constant. So core weight distribution is substantially different. Solid core wing's core mass is concentrated closer to the root.

Skin requirements are similar, as are spar requirements and tip reinforcing.

So, net result is that for same weight wings, solid core should have a little lower roll and yaw inertia.

Gerald
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Old May 25, 2012, 08:23 PM
Aurora Builder
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Hmmm, can't argue much with that logic. Perhaps my dihedral angles are different but I don't think so. My molded wings just feel lighter but the 10g in weight savings over my lightest solid core wings, combined with the cleanliness of hollow molded makes the bigger difference.
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Old May 26, 2012, 09:37 AM
Chess club geek with wings
blunight's Avatar
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Gerald,
Now I know the “why” behind Thomas’s flight mode suggestions - Thanks!
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Old Jun 01, 2012, 10:31 AM
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Joined Dec 2007
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Hi,

Small question, Whats the CG you all fly with the Zone V2. Mine is at this moment on 72 mm but i think its to nose heavy. It flyes great (better than the Edge, but thats mine opinion)

I'am currieus at wich CG point you guys fly it



Lyckele
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Old Jun 01, 2012, 10:55 AM
Will fly for food
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Nice looking ship. Both of my Z2 wings are good near 74 to 76
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Old Jun 01, 2012, 10:59 AM
G_T
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CG depends more on tailboom length and horizontal tail than most other things. Unless someone has an identical plane, the numbers you get just won't matter for your plane.

Perhaps this post will help: http://www.rcgroups.com/forums/showt...2#post21491125

Gerald
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Old Jun 01, 2012, 11:11 AM
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Gerald, In general would a longer boom moment support a more rearward CG?
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Old Jun 01, 2012, 11:13 AM
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The Netherlands, ZH, Alphen aan den Rijn
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Thanks Gerald for the link. And thanks David

In one hour i go to the field, an try it out.

Lyckele
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