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Center of Gravity

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Old 02-25-2006, 10:51 AM
  #1  
lalaland
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Default Center of Gravity

If an airplane calls for letter B to be the center of gravity, letter A to be forward and letter C to be rearward, which point should the actual balance be to be more areobatic? A, B, or C?

Am I correct that if the actual balance point is at A, the plane is actually Nose Heavy?

please explain...I'm confused, but that's nothing new! lol

big dan
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Old 02-25-2006, 11:12 AM
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HighPlains
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Default RE: Center of Gravity

Most acrobatic is when the CG is to the rear. Pitch and yaw are both increased, while stability is decreased.

When balance in your "A" position, the airplane need greater speed for landing and takeoff for the elevator to have enough power to lift the nose.
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Old 02-25-2006, 11:12 AM
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js3
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Default RE: Center of Gravity

Dan,

Generally speaking, a more rearward CG will result in the plane being more responsive to the same control surface movement. So yes, "C" will be the more aerobatic CG location while "A" would be more stable. "B" is obviously somewhere in between. On all of my planes lately, I've balanced them at the rear-most point of the range recommended by the designer figuring that the range specified on the plan is a bit conservative. Be careful when approaching a rearward CG--too tail heavy is not good.

It all comes down to experimentation and finding what you like best.
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Old 02-25-2006, 11:37 AM
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lalaland
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Default RE: Center of Gravity

Correct me if I'm wrong.....

A = Nose Heavy, B = suggested balance point, and C is considerered Tail Heavy.

If the actual balance point is no more than where point A or C is at, which is normally no more than 1/4 inch either way of point B, can it still be controlled without tremendous difficulty?

sorry for so many questions......

big dan

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Old 02-25-2006, 11:49 AM
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js3
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Default RE: Center of Gravity

Yes. I've never seen a kit or a plan that indicated the balance point as exactly-at-point-such-and-such--it's always a range. As you balance toward the front of the range, the plane will be more stable. More toward the rear of the range the plane will be more responsive/aerobatic.

Even if your plan indicates the balance point at precisely point "B", you may go a little bit on either side of that point to suit your style.
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Old 02-25-2006, 11:54 AM
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lalaland
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Default RE: Center of Gravity

Thank you all for the good advise.

big dan
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Old 02-25-2006, 11:58 AM
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js3
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Default RE: Center of Gravity

Correct me if I'm wrong.....

A = Nose Heavy, B = suggested balance point, and C is considerered Tail Heavy.
Let me try to be more clear than my last post.

Anywhere between A and C is your CG range. Yes, A will be more nose heavy than C and C will be more tail heavy than A--but you may balance the plane level anywhere within this range and the plane will fly fine.
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Old 02-25-2006, 12:31 PM
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Default RE: Center of Gravity

As stated by previous posts, be careful when setting your CG to the rear. Too far back can make your plane too tail heavy resulting in loss of control. I attempted once to take off with my CG too far back which resulted in the tail dropping too far, then a stall resulted as she didn't have enough power to pull it out, she winged over and fell. Good thing I was only about 20 ft in the air when all this happened.
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