question on balancing an aircraft
 

I just can't intuitively get comfortable with this one. Say you mount an engine laterally, and find that the plane balances on it's pitch axis, but is heavy to the right on it's roll axis, and it is likely due to the sidesaddle engine mount. It almost seems to me you might want to add weight first to the cowl to get the roll axis balanced, and then a little to the tail to get the pitch axis back to balanced. Somehow putting weight out on the left wing on the spar, so that it won't affect the pitch, but will offset the roll, seems wrong. You end up with a plane that is heavy in the right side of the cowl and left wing, but balances in total. Am I making this way too complicated??

question on balancing an aircraft
 

Yeah. Your making it too complicated. lol. Use the weight on the left wing since it is farther out, and will have more affect on the plane. The farther out it is, the more leverage it has, and you need less weight. Lighter flys better.

Hope this helps!

question on balancing an aircraft
 

Something I just thought of, see if you can mount the battery on the side of the fuse. It probably wont fix it completely, but it will help and since the battery has to be in there anyway, at least make it help on the balance.

question on balancing an aircraft
 

as jack01 sez: move what ever you can inside the plane to get the c/g as close as possible,any weight added needs to go as close to the ends as possible to keep the amount of weight needed to balance the plane to a minimum.
Have a goodun,John.

question on balancing an aircraft
 

Just a thought, when setting up aerobatic planes, a enough weight to the left wingtip so that the plane is SLIGHTLY heavy on the left wing. This will help in your vertical lines. It also helps with high winghers, though not as much.-Try it.

Jetts

question on balancing an aircraft
 

fraid I balance and set my planes up different than jettstarblue,heavy wing tip is masking other trim problems.
Have a goodun,John.

question on balancing an aircraft
 

TerrellFlyer,
Masks other trim problems? Now I'm confused! Please elaborate on this thought. I read this (left wing slightly heavier) in a series about trimming pattern planes, tried it and it worked well. This IS part of trimming, not "masking a trim problem". Am I way off here? Just thought I'd ask.
Thoughts on this one?
Thanks,

Jetts

question on balancing an aircraft
 

I think what Terrell is saying is that if you need to add extra weight (IE more weight than is needed to balance) in order to make your plane fly correctly, then you have other trim problems other than being out of lateral balance.

As for the original question, yes, you're making it too complicated. Just add weight to the wingtip.

The reason for using the wingtip is that just a few grams of weight (think of about 4 or 5 pennies worth of weight) will do as much at the wingtip as the weight of a cylinder head and a muffler will do way inside at the cowl. Get it? Plus, if you add that much weight to the nose, you'll have to compensate with more tail weight. Next thing you know, your plane will fly like a brick.

On wingtip weight
 

Everyone,
Just to elaborate on the heavy left wing thing,- There were a series of articles in RCM? that covered trimming planes, (mostly for pattern). Among other things in the articles was a piece that said you should purposely make your left wing heavier (slightly-you need to experiment a little). The purpose was to help with verticle lines, i.e. keep them straight, or, straighter on the yaw axis. I have tried this on some of my planes, and did notice a difference, although it depends on the plane as to how effective it is. Didn't mean for this thread to become divergent.
F L Y F O R L I F E !!
Jetts

Balancing longitudinally
 

Had the same problem with Ultra Sport 1000. On take -off the plane would start a very slow motion roll to the right and I couldn't figure it out.
One day it struct home that the total weight of the ST 90 was to the right of the longitudinal axis. So out to the balancing hangar. Using a number of nuts and bolts I determined the exact amount of extra weight that was needed to the left wing tip. I found a small rod 5 inches long equal to the weight needed and shoved it into a small hole drilled front the front into the wing tip. I resealed the monokote and the hole disappeared hiding the small rod foreever.
This plane flew so well that full throttle with a click of up elevator and the plane would take off alone...once with the transmitter on the ground...and flew straight as an arrow.
Good luck

question on balancing an aircraft
 

Hi jettstarblue,check,www.nsrca.org, click on technical,click on airplane trimming.
Have a goodun,John.