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Old 02-14-2013, 05:06 PM
  #1  
essyou35
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Default CG Machine

So I bought the Great Planes CG Machine, thinking it would work for my jet since it says up to 40 LBS.

I would not even use this machine for a foamy, what a piece of junk. The little pad slip off the rods and mess up the jet finish. Got some nice scraches on the bottom of my wings. Also the box, and the directions both show the little rulers sitting nice and parallel in the air. BULL _ CARP. They hand all caddy whompus at an angle and the rulers fall forward.

I have no one to help me except my wife and that is usually a frustrating process trying to use my fingers and hers, though that is how I've done it on 2 jets so far.



So, any tips on measuring CG?

Old 02-14-2013, 05:22 PM
  #2  
felker14
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Default RE: CG Machine

http://www.ezbalancer.com/

Dreamworks is dealer.
Old 02-14-2013, 05:34 PM
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luv2flyrc
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Default RE: CG Machine


ORIGINAL: felker14

http://www.ezbalancer.com/

Dreamworks is dealer.

+1

Excellent unit, allows you to move componants around while balancing as it won't let the plane fall Worth the money, makes a job that used to be a PITA, a piece of cake now!

Mike

Old 02-14-2013, 05:40 PM
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invertmast
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Default RE: CG Machine

An excel spreadsheet (pm your email address and ill provide it free) and a digital shipping scale good to 25lbs. No balancing by the fingers or fancy (over priced IMO) machines necessary.
Old 02-14-2013, 06:15 PM
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Bob_B
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Default RE: CG Machine

Actually the cg machine will work. You can drill two small hole at the cg point at the outer edge of the fuse then place masking tape over the hole and around the area to protect the finish.
Place the model on the cg machine using just the ball at the end of rod.
Old 02-14-2013, 06:32 PM
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Edgar Perez
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Default RE: CG Machine

a good chair will do.
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Old 02-14-2013, 07:14 PM
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afterburner
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Default RE: CG Machine

I've had the c.g. machine for about ten years and used it on my Reaction and a Carf Hawk. The Hawk required the assistance of my 12 year old to supprt one end while I got it in position but I would have needed help no matter what I was using. For the Hawk I had to use music wire instead of the supplied rods to have the haves go wider and clear the fuse. Take the rulers out and use painters tape to mark the CG range and protect the wing. Once you get it on where it's balanced, you can put the rulers back in and get them parallel. It is doable. I looked at the EZ balancer II but thought it was way too much money for a couple pieces of aluminum, foam and hardware.

Marty
Old 02-14-2013, 08:26 PM
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afterburner chuck
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Default RE: CG Machine

Daddy long legs
Old 02-14-2013, 09:22 PM
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Default RE: CG Machine


ORIGINAL: luv2flyrc


ORIGINAL: felker14

http://www.ezbalancer.com/

Dreamworks is dealer.

+1

Excellent unit, allows you to move componants around while balancing as it won't let the plane fall Worth the money, makes a job that used to be a PITA, a piece of cake now!

Mike

+2 One of the best tools I've purchased for this hobby.
Old 02-14-2013, 10:03 PM
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Default RE: CG Machine

I built one of these:

http://www.rcuniverse.com/forum/m_11...m.htm#11309392

Simple, cheap, safe, easy to use.

It may not be technical enough or expensive enough to impress the guys at the field though . - John.
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Old 02-14-2013, 11:46 PM
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Yann
 
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Default RE: CG Machine

Edgar, I love your chair trick... I'll sure use it.
Thanks.
Old 02-15-2013, 07:54 AM
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Art ARRO
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Default RE: CG Machine

Actually, the Great Plains CGMachine works well if modified with the addition of vertical dowel rods from the pivot points to the base of the machine. The mod forms a triangle which is very rigid. Ichose fibreglass driveway markers (1/4" diameter) but any stiff rod material, such as arrow shafts or metal rods, could be used. The reinforcing rods are secured to the top of the existing rods with CF or kevlar tow and thru drilled holes in the machine's plastic base. All this was described in an RCJIarticle by Oliver Nicholas (Olinco) on prepping jets for their maiden flight. Unfortunately, I don't have the RCJIissue handy or a digital photo to post here. Ollie uses this modded CGMachine to balance large jets, weighing up to 60 lbs,and it works well forme on my jets-up to 25 lbs.

Art ARRO
Old 02-15-2013, 09:37 AM
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Default RE: CG Machine

I've used both the EZbalancer and the one suggested by Boomerang1, the easiest to use has been Boomerangs suggestion (and the most cost effective). I have checked the balance with both units and they both give the same results. The picture shows my T-33 being balanced. Very easy to use and components can be moved around to get the proper CG location.
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Old 02-15-2013, 09:59 AM
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Default RE: CG Machine

Great suggestion Art.
Old 02-15-2013, 11:06 AM
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Default RE: CG Machine

ORIGINAL: Edgar Perez

a good chair will do.

Edgar i like chair idea and save a ton of$$$$ in alumminun balancer, please to freaking spencer
Old 02-15-2013, 11:42 AM
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Default RE: CG Machine

wait till i get to the field ill show them how smart iam what a way to balance
Old 02-15-2013, 12:57 PM
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mario tavarez14
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Default RE: CG Machine


ORIGINAL: [email protected]

wait till i get to the field ill show them how smart iam what a way to balance

show us some pictures how you doing came on
Old 02-15-2013, 01:08 PM
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Default RE: CG Machine

EZ Balancer, got mine from Dons Hobby Shop worth every penny!
Old 02-15-2013, 01:58 PM
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Default RE: CG Machine

ill do like youngguy use a chair
Old 02-15-2013, 02:01 PM
  #20  
rcand
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Default RE: CG Machine


ORIGINAL: essyou35

So I bought the Great Planes CG Machine, thinking it would work for my jet since it says up to 40 LBS.

I would not even use this machine for a foamy, what a piece of junk. The little pad slip off the rods and mess up the jet finish. Got some nice scraches on the bottom of my wings. Also the box, and the directions both show the little rulers sitting nice and parallel in the air. BULL _ CARP. They hand all caddy whompus at an angle and the rulers fall forward.

I have no one to help me except my wife and that is usually a frustrating process trying to use my fingers and hers, though that is how I've done it on 2 jets so far.



So, any tips on measuring CG?

Sorry yo hear you don't think this works. I have had this same one for many years and I have balanced TAMs super hornet, BVM bandits, CARF Ultra flash, gee, the list keeps on going.
Old 02-15-2013, 03:51 PM
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Default RE: CG Machine

ORIGINAL: Edgar Perez

a good chair will do.
YES!!!!!

Several Thumbs UP!!!!!!!!!!!
Old 02-16-2013, 01:04 PM
  #22  
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Default RE: CG Machine

Hi

Regarding this method, how do you calculate the cord lenght for leading and trailing edge?

regards

Nuno
Old 02-17-2013, 09:52 AM
  #23  
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Default RE: CG Machine

EZ Balancer all the way. No comparison.

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