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Old Sep 07, 2009, 03:21 PM
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Senor Jack's Avatar
United States, AZ, Yuma
Joined Jul 2006
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Determining the Center of Gravity

In order for an airplane to fly correctly, you NEED to determine the CG ( or Center of Gravity) of that airplane & then add weight accordingly to the NOSE or TAIL to get it perfectly balanced, thus, increasing your chances for a successful flight. ( I use to term PERFECTLY very loosely, since NOTHING in this world is PERFECT, except, according to my wife, HER... )

Now you can go and buy something if you have lots of money to burn, but to be honest with you, I would rather put my money into my airplane(s). Wouldn't you ?

So I am posting this "TIP" for making your own little "JIG" to determine where the CG is on ANY given airplane.

First you need a hook of some sort... ( I used a simple "Eye" bolt) and then you need 3 (three) pieces of string. ( I used some left over Venetian Blinds cord).
And you need some sort of "PENDULUM"

Make sure that the 2 of the cords are the same length, make a SLING from both pieces of cord & fasten them to the "Hook" to make 2 "Slings" to hold the airplane.

Load your airplane with EVERYTHING you would like you were getting ready for TAKE-OFF to fly it. (I.E. Battery, ESC, etc.)

Next, place the FIRST sling around the FRONT body of the plane. (In FRONT of the WING.)

Then place the 2nd sling BEHIND the WING. ( See Photo).

You can "Eyeball" it to make sure it is level Parallel to the floor, but I suggest using a small level on the top of the wing to make dead sure that it is level BOTH ways. (Front to Back and Side to Side)

If your wing is FLAT, all the better but if it is CURVED, then you MUST put the Level on the HIGHEST point of the CURVE to make sure it is level.

Once you have it level, then hang the Pendulum from the SAME HOOK as the SLINGS and let it stop swinging. ( I used a pair of TWEEZERS because it had a POINT that showed me the EXACT CG on the wing).
Viola !! Now you know where the CG is of your airplane !

In my case, I have a Skyartec Cessna 182 and they give NO MENTION of the CG in the manual. I determined it to be 55-56 mm from the “Notch” on the LEADING Edge of the wing. (See Picture)

I believe in DOUBLE-CHECKING even if they DID give a CG, just to make sure that the CG is correct.

I hope this helps someone!
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Old Nov 03, 2009, 10:28 AM
Cptn Blinky Broome West Aust
Australia, WA, Cable Beach
Joined Aug 2007
55 Posts
Thanks Ill give it a try..
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