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3D Help Needed!!!

Old 12-02-2005, 10:46 PM
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USAce777
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Default 3D Help Needed!!!

Hi
I was wondering if u could give a couple of pointers on how to setup any plane for 3D. Where CG should be located ect.


Thanks.
Old 12-02-2005, 11:05 PM
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YNOT
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Default RE: 3D Help Needed!!!

Aft CG works best.

Good place to start is fly the plane inverted and move the CG back till it flys hands off level inverted. Start there.
Old 12-02-2005, 11:13 PM
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FlooredCOBRA
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Default RE: 3D Help Needed!!!

That is kind of a hard question to answer. Everyone has different preferences on what works for them. I am sure that you will get some good ideas to start at and then fine tune from there.

As for how I set up, this is how I did my 3D planes.

CG I set up to where when I fly inverted the plane does not loose alt. If it does I keep moving CG back till it flies the same both upright and inverted. Also do lateral balance and get that set to.

Engine mounting I as right thrust to where I don't have to fight with right rudder when in hover. Add or remove as needed.

As for servo rates I use high and low rates. I first set low rates to recommended settings maybe add a hair more to get better response. Then set up expo to where it feels safe and stable to fly at. On 3D rates I set my throws to as far as it will mechanically go. Then I hold the stick in 1/4 movement position and hold, then flip high and low rates back in forth and watch the difference. I keep adding expo until where when I flip to high and then to low rates the travel does not move when i flip back in forth. This way it flies nice and tame in my normal flying position then still have extreme 3D throws at max stick movement when I need it. I do this for both ailerons and elevator. For the rudder I use very little expo.

It would be easier for me to show you than to try to put into words on here. But hope this helps you out and gets you going.
Old 12-02-2005, 11:18 PM
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somethin else
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Default RE: 3D Help Needed!!!

As with any plane you start flying with the reccomended CG. As you get comfortable with the plane you move the CG aft till you get the slow flight characteristics you like. Once you are comfortable flying the plane you can up your throws. (I set up my planes for 3d flight when putting the plane together and dialing down the throws via the radio) You want 40-60 degree throws on your surfaces and anywhere from 50-75% expo on the sticks. Each plane is different but those are the basics. To get the 45° throws with the best mechanical advantage use the biggest servo arm and control horn you need to get the job done. Don't use a standard servo arm and connect your pushrod to the lowest hole on the control horn. It may work fine on a .40 size plane but will cause lots of problems in bigger planes (flutter, stripped servo gears). You may want to start your 3d stuff way up high but that can hurt you in the long run. Start your 3ding at 50-60' high so you can see the plane and react to the plane fast enough. Too high and you will miss the small "signals" the plane gives you to correct the manuver you are trying to do.


hope this helps,

tim
Old 12-03-2005, 11:28 AM
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USAce777
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Default RE: 3D Help Needed!!!

Thanks to everyone!
Old 12-03-2005, 02:35 PM
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Default RE: 3D Help Needed!!!


ORIGINAL: FlooredCOBRA

Engine mounting I as right thrust to where I don't have to fight with right rudder when in hover. Add or remove as needed.
It is ok, after set the right thrust in hover, to mix the rudder with gas at full? So the plane go straight up. Or it's no necessary?
Old 12-03-2005, 03:15 PM
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FlooredCOBRA
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Default RE: 3D Help Needed!!!

I guess you could try it out and see how it goes. May be different for each plane.

But I found after I had mine set in hover it would still track straight at full throttle. Like I said that may be different on other planes.
Old 12-04-2005, 06:18 AM
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Red Sky
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Default RE: 3D Help Needed!!!

I didn't tried yet... but I will as soon as the weather let me. So, I don't know if it will be different at full.
What about flying normal and inverted for CG location, ''normal'' or full throttle?
Old 12-04-2005, 07:52 AM
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Default RE: 3D Help Needed!!!

If you are flying upright or inverted at full throttle, then you don't have a 3D plane (not enough motor). If you do, you won't have it for very long (too fast). 3D planes have large control surfaces and flying them at full throttle is very hard on them and can induce flutter... i.e. instant self destruction.

As far as mixing throttle to rudder, chip hyde sets his right thrust at 1/2 degree and he uses a rudder mix for the rest. For me, the jury is still out on this one. I know some guys that like, but I'm not sure if I do or not.

To get the 45° throws with the best mechanical advantage use the biggest servo arm and control horn you need to get the job done.
Read this as: Use a nromal control rod location on the control horn and use the smallest servo arm you can and still get 45 degress of throw. I think it's still generally accepted than anything past 45 degrees is just cauing drag with little, if any, additional control effectiveness. You are also losing servo power and resolution if you go with more. 45 is plenty. If it isn't, then your elevator is too small or your CG is way too far forward.

Big picture, you want to dial up your servo travel to 150% (JR), or 140% (Futaba), or 110% (Multiplex) and, using full stick travel, just get to the 45 degrees that you need... this gives you the most power at the surface and the least likelyhood of flutter (especially if you're flying around a full throttle)
Old 12-04-2005, 12:58 PM
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Default RE: 3D Help Needed!!!


ORIGINAL: sillyness

If you are flying upright or inverted at full throttle, then you don't have a 3D plane (not enough motor).
I don't fly it at full throttle. I didn't mean to say this. Sorry, poor English...
What I wanted to say was, at minimum speed (close to stall) or at ''normal'' speed.
It is a 3D plane and it has already 2 deg right thrust. I will mix the rudder with gas if necessary - if I increase the thrust angle the cone and the cowl will not align.
Old 12-04-2005, 01:03 PM
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Default RE: 3D Help Needed!!!

Which plane are we talking about... every plane is setup differently
Old 12-04-2005, 01:14 PM
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Red Sky
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Default RE: 3D Help Needed!!!

C-arf 2,6m Extra 330L, and DA100 - if it was a question...
Old 12-04-2005, 01:43 PM
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Default RE: 3D Help Needed!!!

ABOUT THE CG, ON A LOT OF PLANE IS NEAR 30% BEHIND LEADING EDGE,,,, ON A 3D IS NEAR 40 % OR MORE.
Old 12-04-2005, 06:35 PM
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Default RE: 3D Help Needed!!!

Sorry... didn't mean to offend... I didn't notice your location. You certainly speak better English than I do your language.

Nice airplane! Take your time setting it up well, you will enjoy it a lot. A buddy has one and likes it a lot... of course my plane flies better The DA-100 will treat you very well.

I would go to the Giant Scale forum and look through the very large 2.6m thread. Here is the link:

http://www.rcuniverse.com/forum/m_1473465/tm.htm

If I were you I would explain that you don't speak English very well and ask for CG and control throw inputs from others... 92 pages looks like a lot to sort through. I speak perfect English and would not want to read it all.

Good luck!
Old 12-06-2005, 12:25 AM
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freebird1
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Default RE: 3D Help Needed!!!

OK guys (gals)

I may be mistaken, but this is my set up so far on my funtana 40. If I am wrong I sure would like to know the right way. I am new to 3D, but far from the hobby (pylon, warbirds, and pattern). I have a 40 Funtana with a Saito 72. I have Hitec 475 at 60 oz. I up-graded the control horns and added 4-40 rods with Du-bo locking clevis. I have the rods all the way out on the servo horns and all the way down on the control horns for Max travel. I have travel set at 140% on a Futaba 7 cap. Expo is set at +50% on rudder and the rest as I can keep up with. I am currently setting up CG and other for 3D. Am I wrong with the set up and long travel. I think the servos can take what the controls can take. Like I stated I am new and whould love to know myself.
Old 12-06-2005, 06:01 AM
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Default RE: 3D Help Needed!!!

You want 45 degrees of throw, and you want your servos to reach full travel at that 45 degrees of throw, all without any binding. Do that and you are good to go. More an 45 degrees of surface throw is usually wasted... doesn't add much in the way of authority and creates a lot of drag and reduced resolution.

I don't know how long your servo arms are or where the shortest location on you control horns is, so all that is meaningless.
Old 12-07-2005, 01:54 AM
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freebird1
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Default RE: 3D Help Needed!!!

Thanks for the reply sillyness. I learned something. The point I was trying to make is I thought the more control travel then the more control over the plane. I am going to reset my controls somewhat like you stated. The reason I have so much travel is I balance the plane Lat. but she will still tip to a side. It is like I run out of rudder even with all the travel. What am I doing wrong. I read and read. I even read the Mag, but still can not get her to hang with the set up I have.
Old 12-07-2005, 05:09 AM
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Default RE: 3D Help Needed!!!

Tip to the side while doing what? Torque-rolling?

If so, and it always goes to the left/right, you need to add/subtract right thrust respectively. If you don't have enough rudder authority to recover either: 1) Too nose heavy 2) Too small rudder 3) You wait too long to fix the off axis attitude. Of course, don't ruin the normal flying charactersistics by moving the CG so far that it is impossible to fly.

As for the reason that right thrust is needed... the wash comes off the prop in a spiralling slipstream... it spirals clockwise when viewed from behind. Whe it gets back toward the rudder, the bottom of the slipstream (moving from right to left) has nothing to hit. The top of the spiral (moving left to right) hits the rudder, pushing the tail right and the nose left. Right thrust helps stop this.

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