Is there a DIY version of a CG checker that I can make? Are there any plans? Is it easy to build from home depot parts?

fingers

Yea, it's called fingertips.

Dr.1

I do most CG stuff with the fingers as well.

However, if you want an easy "machine" it's very simple. I have a bit of scrap wood that I drilled a few holes in. I put a wood dowl in the hole, and one of those penncil eraser caps on the top of the dowel. For heavy planes, I clamp the board to the work bench first. The only problem with this approach is that very heavy planes might damage themselves by sitting on the eraser ends, too much weight on such a small area, but I've used it on planes up to 14lbs with out issue.

Fingers rarely fail.

At one point I made REALLY fancy ones with two #2 pencils with big add-on erasers and paper clips bent into "L" shapes. I adjust the "L" in the eraser so I have the distance specified from the leading edge and add weights until it balances.

Normally masking tape on the desired balance points and fingertips. No matter WHAT the plans say I fly it to determine where the COG needs to be. The initial balance is just so it survives the maiden and first few trim flights.

One of the older members at my club screws a small eyehook into the centerline of the wing at the recommended CG.
Seems like a good idea and any time he makes a change he can quickly check.

Well said Charlie!!

A machine for balancing is about as necessary as a plastic rubber band puller (Yes, you can buy one of those)

The "Recommended CG" is just a "Ball Park" starting point. Balance it with your fingers, then fly it and determine if and where you want to adjust it to.

the rubber band puller is a mandatory gift at the Christmas party!

Unless your balancing heavy planes your fingers will do just fine. I used my fingers up untill I got into gassers. Then I use the hanging method (linked below).

http://www.rcuniverse.com/forum/m_708060/tm.htm

Austin

Here's mine, and in action. (I know you are supposed to balance them upside down, this is just for illustration).

The method mentioned above by using a cup hook at CG point from info plane kit are arf, really works best as you can also balance wings tip to tip when hanging plane. I built an 12 ft wing span Decathlon and I balanced it using top of wing as balance point. When we flew it i was tail heavy. Turned plane upside down and transfered CG piont to bottom of plane , reblanced it , and it took almost 4oz of lead to make it blanced right. We flew plane and it flew great.

The last plane I balanced on a balance Machine (better cause it cost more than the pencils lol)
anyway upside down just like your supposed to and did not think i would get it back on the ground. Got it down and used my fingers and got it almost perfect. Move the batt. 1/2" and wala had it. The balancer had me way off or the recommended CG was wrong.

Everone has a different answer. Here is picture of balanceing plane, and my work shop.

I wish I had a picture of it now, but I made a really cool CG checker out of 3/4 PVC.

The base was about 24" wide (across the wings) and 10" deep (nose to tail). On the sides of the base I put a T and some 16" verticals with a end cap. The plane's wing sits on the cap. When your all done If you don't glue the vertical's T will fold into a nice flat thing that you can stick anywhere.

Cost was like ummm $4


P.S.
Use the round PVC caps, not the square ones.

Nice looking plane, Bingo Field

Check out this Tinker Toy Balancer

http://webpages.charter.net/rcfu/Con.../BJConstr.html

Seems to fit your description and it looks simple and effective.

My plane holder while i am working on them is a work table from craftsmen that screws in and out (gets wider and narrower) and is about 2ft. long. I drilled 2 holes on each end and set pvc T's in them. Then ran 1ft. pieces stright up and put another T 3/4" put 1/2" thru T's for planes to sit on and about 4" pieces of 3/4 up again to hold them. I can just move the wings up and let them set on the 4" pieces and the pipe in the rear will keep the plane from falling in the rear and then you can pretty much balance with no fear of the plane falling. You can screw the table in and out and the 1/2" just slide thru the 3/4 T's without having to hold the plane. Works great. I still was using a CG machine but won't bother with the hard to use little thing anymore lol.

I don't know how to link to it, but here's a jpg drawing of mine, in my photo gallery:
http://www.rcuniverse.com/gallery/ga...emberID=319717

The quick reply most use to post doesn't provide for uploading a picture, but if you look at the layout around this box......... There is a cluster of buttons in the upper right. One is "reply" and one is "quote", right.

If you click either, you get a response box that has a "Click here to upload images and files" option just to the bottom left of the text box. Click on it and it works just like the photo gallery did.

Hope to see your pictures in your posts soon...........

So, this is the jpg file. Thanks da Rock