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Old Mar 20, 2012, 09:05 PM
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Joined Feb 2012
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Discussion
what is this and is this the cg

pics tell the story

what is it
and is this a good cg



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Old Mar 20, 2012, 09:12 PM
Gas Only
Fokker DII's Avatar
USA So. Cal.
Joined Sep 2010
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CG range for a straight wing is normally between 25 and 33% of the chord at the fuse. That looks like it is in the range.
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Old Mar 20, 2012, 09:49 PM
Master of the Figure "9"
hogflyer's Avatar
Wichita, Kansas
Joined Dec 2005
1,662 Posts
nitrosportman,

The plane is a Sig Kougar.

The following is straight from the Kougar manual:

BALANCING
The recommended Center of Gravity locations are:

Test Fly with the balance point located anywhere between the leading edge at the wing tip and 1/2" back from the leading edge at the wing tip.

Sport Fly at 1/2" back from the Leading Edge at the wing tip.

Aerobatics - If your model will spin in both directions at 1/2" it need not be moved back any further. Some models need the balance point at 3/4" back for full response. Flying with the balance point any farther back than 1" from the tip is not recommended unless you are an expert flier, with a purpose for doing so.

For the first test flight, balance the Kougar by suspending it on the finger tips placed on the bottom of the wing on the first mark. Balance with an empty fuel tank, but with all other equipment installed and the model completely finished and painted. Add lead to the nose, if necessary, to get the model to hang level. Be sure and fasten the weight securely. Do not attempt flight tail heavy.

The "Test Flying" position is on the nose heavy side. When slightly nose heavy, the model is more stable and less likely to stall or snap roll from over-elevating. It also cuts down reaction of the model to control movements and this is good during test and practice flights, to help prevent overcontrolling. After the model has been test flown and initial trimming accomplished you may want a little quicker response. Move the balance back slowly and check results in the air.

Some aerobatic capability is sacrificed with the forward C.G. positions, so for making deliberate snap rolls and spins a position farther back may be required. Move the C.G. back slowly and check results and control response in the air at a good altitude. Don't move the C.G. back any farther than necessary.


Hope this gives you what you need.

Hogflyer
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Old Mar 20, 2012, 10:45 PM
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Thanks a ton that's what I was looking for weird you measure it the wing tips I thought you always measures at the root
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Old Mar 21, 2012, 07:51 AM
Fueled by Arabica Beans
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United States, NY, Syracuse
Joined Oct 2008
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Quote:
Originally Posted by nitrosportman View Post
Thanks a ton that's what I was looking for weird you measure it the wing tips I thought you always measures at the root
It's just easier to measure the balance point at the wing tips with a swept leading edge like that... that way you don't need to measure exactly how close to the fuselage you need to balance it.
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Old Mar 22, 2012, 11:55 PM
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Joined Feb 2012
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MINI0012 (5 min 1 sec)


she flew it was still tail heavy though, elevator was way to weak but it looked like the push rod was bending it wasn't doing that before flight oh well replaced that

broke my prop on landing and didn't have an extra with me so i was done for the day
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Old Mar 23, 2012, 07:12 PM
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Joined Feb 2012
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well gents i can tell you 1/2 inch back is not correct i proceeded to just barely get it in the air and subsequently right into the ground not much damage another broken prop popped the canopy off


im gonna take the lead out repair it and just start moving the cg forward till i find a good balance at least i know it flies at the thick part of the wing
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Old Mar 27, 2012, 09:30 AM
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Joined Feb 2012
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RIP sig kougar!

never could get the cg right it was so twitchy throw on the elev was set to 3/8" it was either straight up or straight down it eventually just became too much to handle and i had scrubbed off all my altitude and it decided it wanted to be a part of mother earth broke the wing in half

it's been a bad month for me luckily my a10 edf is still flying perfectly so i can stay in the air and my new motor arrived for my heli
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