Simple RC Plane CG Balancer

These rod ends will help you make a very good balancing tool for accurately setting the CG of your plane. Works with most monoplanes. Biplanes and some high-wing planes may have special CG requirements.

Printing and build tips:

1. Print in any material. Any nozzle or layer height should be fine. I would go with 3 perimeters and 3 top/bottom layers. 30% infill is probably plenty.
2. I intentionally left a slot over the hole so you don't need to print with supports. It also makes gluing the rod easier.
3. Use 3/8" or 10mm round wood dowel or aluminum bars available from any big box store or Amazon, plus a random scrap of wood for the base. 
4. Drill two holes the width of your plane's fuselage in a board and insert the dowels. 
5. The caps can be glued on or left loose, they'll still hold your plane.

How to set the CG for your plane:

1. Take a piece of masking tape and put a line at the leading edge of your wing, and make another line at the correct CG point recommended by the manufacturer. If you're scratch building something, aim for approximately 30% of the wing chord length (usually near the main wing spar).
2. Place the plane on top of the balancer and move it forward or backwards until it balances level
3. Notice where the arrow points in relation to the lines you made on the tape.
4. If it's forward of the lines (like in the pictures above), you'll need to move the battery back or add weight in the back. Shift things around until you're perfectly on your lines. It's safest to be slightly nose heavy for a first flight. You can always move the CG back a bit for sharper handling after the first flight. A tail heavy aircraft is very tricky to fly, so be careful!
5. (Optional) The arrows on the have a raised flat edge that lines up with the centerline. You can use the flat edge with a ruler to double-check your measurement to the leading edge of the wing.