BALANCING, CG, Or whatever you want to call it

[SURREYRCAV8R]

Okay guys I need to clear some things up here, I am perplexed when it comes to balancing aircraft. I have been flying some 3D for the last little while and I want to balance my planes more towards 3D requirements than those of IMAC. My extra flies well but it is nose heavy and hard to hover. My QQ is also nose heavy and when flying a 45 degree upline inverted it will pull towards to the ground. Some of these questions main seem a little mundain and amateurish but how else is a guy to learn.

For a balancer I am using two lengths of 3/4" dowel, 20 inches long (to give me table clearance) with two small rubber balls on the end to stop the dowel from piercing any wing sheeting. I have a line drawn around the circumfrence of the rubber ball which I line up with my CG mark. The plane is free to move up or down on that pivot point. I find that I can get the plane to balance to a point where it no longer goes up or down, then if I take away a tad bit of weight, the tail starts to rise, if I add the little bit of weight back it continues to rise. If I stop it by hand I can get it to rest again but it never seems to rest in the same position like you can get a prop to do. I know I should move batteries and on board equipment around instead of adding weight which is what I will be doing, however I want to find out how nose/tail heavy, I am to begin with.

Question 1...If I move the CG mark forward and get the plane to balance, is that making the plane heavier in the nose or lighter?

Question 2...If I move the CG mark Aft and get the plane to balance, is that making the plane heavier in the tail or lighter?

Question 3...At which point is the plane considered balanced? When I get it on my balancer and it neither goes up or down either way? Is it like prop balancing, because damn it I have that mastered.

I have two planes, a 35% Aeroworks Extra 260 and QQ Pitts Python. Lets deal with the Extra first...

1) Should this plane be balanced right side up or inverted? I have only tried to balance it right side up to this point.

2) What would be considered balanced with this plane, where the line of teh hatch cover is parallel to my table or level?

On the QQ I find I can get it where the hatch cover is level, but if I nudge it ever so slightly the plane will fall or rise that direction rather quickly.

HELP...any and all feedback written in laymans terms is greatly appreciated.

[Vic3D]

Question 1 and 2: The more forward on the wing the balance point is, the heavier the plane is on the NOSE.

Question 3: Yes, when it is balanced it will stay put straight.

Balance your 260 upright. Low wing planes generally should be balanced inverted due to the pivoting of the fuselage.

Personally, I don't worry about setting my CG on the ground. I just fly my plane and feel it up there. Then adjust until it's where I want it.

[Smacka]

	Quote: Originally Posted by Vic3D
	Question 1 and 2: The more forward on the wing the balance point is, the heavier the plane is on the NOSE. Question 3: Yes, when it is balanced it will stay put straight. Balance your 260 upright. Low wing planes generally should be balanced inverted due to the pivoting of the fuselage. Personally, I don't worry about setting my CG on the ground. I just fly my plane and feel it up there. Then adjust until it's where I want it.

Vic be correct!
The whole point of setting your "CG" on the ground is so when you make your first flight you do not take her home in a body bag.

In all 3D or IMAC cases, whichever style you choose to adopt (or both), you should fly the ultracoat off the bird and make changes to the "CG" based upon your particular style of flying.

Hey Surry...you remind me of...well..ME! I am an engineer from multiple disciplines and I am really picky about making everything just right (nothing wrong with that!). In this particular case, get it close and fine tune in the air.

[1bwana1]

To balance your plane to fly the way you want it to.

1.) Take off, trim for hands off level flight.

2.) On a down wind leg, pull to a 45 degree up line, roll inverted, take your hands off the sticks.

A.) If your plane drops the nose, land right away, move some weight back. Repeat step 1.
B.) If your plane rises, land, move some weight forward. Repeat step 1.
C.) If the plane holds the line with no inputs, you are done.

Repeat until it is right.

If you really only want to 3-D you may want the weight even a little further back than this.