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!HELP! Serious balancing issues

Old 04-13-2006, 02:54 PM
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CitatioN10
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Default !HELP! Serious balancing issues

I got the modeltech formula 3d used from a guy and I got it going good , although in my manual it says "4 1/2" to start with


As you can see I have done this and its EXTREMELY tail heavy , I have 6 sockets on the nose and that brings it to the balance point ...

Whats going on here ????

I added a few more pictures.
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Old 04-13-2006, 03:30 PM
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bubbagates
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Default RE: !HELP! Serious balancing issues

If the rudder servo is all the way in the rear, change it to a pull pull. That plane l;ooks like it has a 3 to 1 tail moment so 2 ounces in the tail equals 6 ounces in the nose. You could also go to a heavier prop such as the APC, or a heavier prop nut, or a heavy spinner. It also looks like there may be wheel pants that go with it. If you look at the main gear there appears to be holes near the bend down by the wheels. If you have wheels pants, put them on. It will help also

The may be other things but I'm not familiar with that plane
Old 04-13-2006, 03:33 PM
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CitatioN10
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Default RE: !HELP! Serious balancing issues

Rudder servo is in the middle of the plane . I do have 2 servo's in the real for the evevator.
Here is a FULL REVIEW of the plane .

http://www.rcuniverse.com/magazine/a...article_id=579
Old 04-13-2006, 09:06 PM
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CitatioN10
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Default RE: !HELP! Serious balancing issues

I guess i'll just have to add a TON of weight to the nose of this plane and go from there .


Old 04-13-2006, 11:52 PM
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jetmech05
 
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Default RE: !HELP! Serious balancing issues

move your battery and recvr as far forward as possible you'll be surprised how much a diff that'll make
Old 04-14-2006, 12:57 AM
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broke_n_bummin
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Default RE: !HELP! Serious balancing issues

Hmmmm ... if the range is between 4 1/2" and 5 1/2", I would only expect it to ballance perfectly at or very near 5 1/2". If you put enough weight on it to ballance it perfectly at 4 1/2", it will track like an arrow ... kinda like training mode. It's going to be real sluggish, and the elevator won't have much authority. As you start shedding weight, it will move the CG back and give the elevator more authority. I would imagine they recommend you do this to break YOU into the plane
Check your CG around 5 1/4"- 5 1/2". If it's really close, add some weight till it ballances at 4 1/2" or so and see how she handles. 3D is a completely different type of flying than scale and sport. Sport flying relies mostly on speed to carry it through the maneuver, letting the wings do all the lifting. 3D takes it to the next level, letting the prop do the lifting, making your control surfaces more like thrust deflectors. I got a used Katana GS 70 and had to find out the hard way. I'm just now to the point where I can fly it around at just a little faster than a walk, but it takes alot of getting used to ...
Anyways, that's the reason for the range in CG, and why it won't ballance right at 4 1/2"
Best of luck
Also, I don't know what prop you're using, but I have an FS 70 surpass on mine, and an MAS 14x6 worked the best for me
Old 04-14-2006, 08:04 AM
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da Rock
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Default RE: !HELP! Serious balancing issues

It should really be fairly simple and easy to move the two elevator servos forward. And that'd probably be enough weight movement to solve the problem. Of course, moving the battery as far forward as possible would be a no-brainer.

Adding weight, dead weight, sucks.

An hour's worth of effort in the shop could turn that mediocre model into a jewel.
Old 04-14-2006, 08:05 AM
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CitatioN10
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Default RE: !HELP! Serious balancing issues

Thanks for the replay I will try adding some weight today , I did move the battery back and reciver under my fuel tank in the front and it helped a little but not as much as I need... I would need at least 5 more battery packs to get it even close LOL .
Old 04-14-2006, 08:08 AM
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da Rock
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Default RE: !HELP! Serious balancing issues

CitatioN10,
I gotta hand it to you, you've got just about the most HEAVY DUTY balancing rig I ever saw!!

You could make your fortune selling them mail order except I'm afraid the shipping charges would break you.
Old 04-14-2006, 08:10 AM
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CitatioN10
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Default RE: !HELP! Serious balancing issues

LOL well thats what I get for letting a friend borrow my balance machine . I didnt have anyone here to help me either.
Old 04-14-2006, 08:19 AM
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Campy
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Default RE: !HELP! Serious balancing issues

Another item to consider is the DuBro Crankshaft weight. They come in 1 oz and 2 oz sizes and are used in place of the washer under the prop nut. These weights will fit under MOST spinners also.
Old 04-14-2006, 08:20 AM
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Default RE: !HELP! Serious balancing issues

Hi!
Don't add weight!
As Daroc said ...move the servos from the rear and use pull-pull wires to control the elevator and siderudder.

Regards!
JanK
Sweden
Old 04-14-2006, 08:32 AM
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CitatioN10
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Default RE: !HELP! Serious balancing issues

I understand what your saying but I can't belive this plane is so out of wack !!
Old 04-14-2006, 08:51 AM
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bubbagates
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Default RE: !HELP! Serious balancing issues

I just responded to your elevator flutter issue

You guys may want to look at this.

http://www.rcuniverse.com/forum/fb.asp?m=4164103

I'm now starting to think that he has a wrecked plane that has been repaired and that is why it is so tail heavy
Old 04-14-2006, 01:33 PM
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Stew99
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Default RE: !HELP! Serious balancing issues

I agree with broke n bummin. You need to find out where it balances with no additional weight in the nose. If it is within the design range you are in good shape. Before doing any drastic surgery I would just add the weight needed to move the cg forward and as you get more comfortable with the plane you can start taking it out. Also, 6 sockets look like a lot but sockets are not very dense; how many ounces are actually needed to get the cg to 4 1/2"?

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