Saturday, January 7, 2012

CG Finder

Hello all,

I finally decided that using my index fingers was not accurate nor useful enough any more and that I needed a better method to find the CG on my planes.  I checked out commercial CG finders with lots of cool options, but being the cheep Dutchman I am, I decided I could just make my own.  So, the following is the process I went through to make a CG finder.

CG finder pieces
I started by looking for a suitable stand.  I had seen others use a 2x4, but I did not want something that size.  I looked in my scrap wood bin (what do you mean you don't have a scrap wood bin?) and found a piece of primed trim about 3/4x2x12".  This seemed like it would work fine.  Then I looked for something for uprights.  Again to my scrap wood bin and I found some 1/4" wood doweling.  I cut two pieces about 10" long.  I then drilled two 1/4" holes in the base about 8" apart.  All of these measurements so far were just arbitrary and just guessing how much clearance I might need or want.  Enough rod length for fuselage body and landing gear clearance, and separation of rods for a suitable width.
 I wasn't to concerned with the size or stability of the base as it would be at, or close to, the CG or balance point and would not need much stability.
Rounded off rod tips
I did round off the ends of the rods a bit to provide for a smaller more accurate tip, but one that would not poke into foam or covered wings.

All setup
Setup it looks pretty good and works well too.  I did not glue in the rods so that I could take it apart for easier transport.  The pieces fit quite well in the upper tray of the little tool box to the right in the photo.

CG finder being used on my Wild Hawk

Using tape measure against rods
This little unit has worked quite well and for the money, you can't beat it.  Besides, it's really hard to take measurements with a ruler when the plane is balancing on your finger tips.

My conclusion, if you need a CG finder for your plane, just go out and make one!  It's real easy.

Thanks for stopping by my blog.  Please feel free to post comments, good or bad, and be sure to come back and check for future posts.

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