Balance methods?
 

I have a question or questions concerning aircraft balancing. When balancing my airplane, should I do so with the tank full of fuel? Does anyone have any sugestions regarding the fuel tank placement, to take into account fuel burnoff?

the airplane I am setting up is aerobatic.

Balance methods?
 

It's traditional to balance with the tank empty. This assumes that the tank is in front of the CG so it will be a little nose heavy (safer) when full.

For a serious aerobatic plane the nearer you can get the tank to the CG the better. That way the balance will not change as you burn off the fuel. Of course if you get the tank right on the CG it will make no difference at all whether you balance full or empty.

Steve

Balance methods?
 

Thanks Steve,
I more or less figured that was what I should do. I think I need to find a smaller tank that will fit in my cg range, and hopefully not change much from full through empty, or perhaps slightly nose heavy if not level, than tail heavy when empty.

I'm building a gas bird, and the easiest thing to move around for balance were my batteries. but as I am reading, I should keep my Ignition battery quite seperate from my ships battery. wich means fwd of the cg. my next solution was to play with my fuel tank location.

Balance methods?
 

With a gas engine you shouldn't have a problem with putting the tank at the CG. With glow engines, (except for the pumped Y.S. type) you would need a pump to get the fuel up to the engine in a "nose-up" situation.

Balance methods?
 

How much tubing is safe? Err, how far away is safe?

Balance methods?
 

If you can't get your tank right on the CG, and most planes have the tank well in front of the CG, I would be very careful about having the plane tail heavy with an empty tank. It could make for some very interesting landings. Try not to get the balance point any further back than the rearmost safe CG with the tank empty would be my recommendation

Balance methods?
 

That depends on your engine/pump.

I have a 60 size GP Extra300 with a YS 91AC engine on it. The YS has a built in pump and the tank is right on top of the wing at the CG (a distance of about 12 inches)

I also have a 33% GP Extra 330L powered by a Zenoah G-62 gas engine with the tank also on the CG which in this case is about 2ft. So, it really depends on how far up your engine can draw fuel from.