Question; I'm at the point, of balancing the plane.. The book does not say to add fuel to the tank; when balancing the plane!! It just give's me a balance point on the blue print. Then if i need to move the R/C equipment forward or back to find the level point do so. then If this does not level the plane, ad some weight.... So my question is, now that the plane is level. Now when i add the fuel to fly the plane. Would't you think the nose would go down.... Then now the plane is out of balance.. Or A'm i making to much out of this Balancing thing.... Thank you for your time and feed back...

that is precicly how you want it!

so when you burn off the fuel, the balance point comes back around! without having the fuel tank right at the CG, hard ta do with anything but gas! its better ta be on the nose heavy side!

Yes

Think of it this way. With the tank in front of CG if you balanced it when full,after the fuel burned off and you need to land you are now tail heavy.

A nose heavy plane flys poorly, a tail heavy plane flys once.

Originally Posted by RCLud

Question; I'm at the point, of balancing the plane.. The book does not say to add fuel to the tank; when balancing the plane!! It just give's me a balance point on the blue print. Then if i need to move the R/C equipment forward or back to find the level point do so. then If this does not level the plane, ad some weight.... So my question is, now that the plane is level. Now when i add the fuel to fly the plane. Would't you think the nose would go down.... Then now the plane is out of balance.. Or A'm i making to much out of this Balancing thing.... Thank you for your time and feed back...

RCLud,

The CG positon shown on the plans is usually to be set with an empty fuel tank.

How much nose heavy the model will be depends on the fuel tank size and the distance of the fuel mass CG from the CG of the plane as a whole.

At the beginning of a flight the nose heaviness is compensated by some up elevator trim.

There is always a range of CG location for any model. That range is not always specified (nearly never is) That range is wider (longer) with a larger elevator area and its moment arm (how far are the elevators from the CG).

Ideally the model full of fuel can have its CG at or near the forward limit of its CG range; as the fuel is consumed the CG will move back toward the balanced location without fuel.

If you have built per plans and use the same fuel tank per plans then just balance for the CG to be as shown on those plans.

Zor

OK thanks; To all of your reply's this helped a lot.. In short when i burn off fuel the C/G comes back...

Yup, you really won't notice it, the extra nose weight from the fuel isn't a big deal.

Ya, I've never had to trim a model in flight, to compensate for fuel usage.

Like Chill says, you won't notice it.

Originally Posted by TomCrump

Ya, I've never had to trim a model in flight, to compensate for fuel usage.

Like Chill says, you won't notice it.

Your tank must be on the CG? fuel weighs 0.8 oz per ounce of volume. Average tank might be 10-12 oz or 8+ oz of nose weight.
I have heard it said and seen it too that the models will start to climb as the fuel is consumed and the CG moves back. Some people do compensate with trim others just lean on the elevator or reduce speed to level the flight.

Like I said, I've never had to change the trim. If I make compensations, it must be an unconscious act.

Models climb because of throttle settings. Raise the power, they go up. Reduce the power, they go down.

Originally Posted by TomCrump

Like I said, I've never had to change the trim. If I make compensations, it must be an unconscious act.

Models climb because of throttle settings. Raise the power, they go up. Reduce the power, they go down.

Any need for adjusting the trim would occur only if noticed.
It can be noticed only in straight and level flight.
Straight and level flight is rarely occurring for more than a few seconds if we do not want the model to become just a dot in the distance.

So I agree with Tom that there is rarely if ever any need to trim due to fuel usage once the CG is properly located.

Zor

If balanced correctly you can take off, climb out, turn to the down wind leg go dead stick as soon as the wings are level and still not notice the CG change due to fuel weight. A nose heavy airplane flies...as long as it sin't stupid nose heavy.
I don't change trim either, never needed to because of fuel weight

Thank you all for the good suggestion's.. Have a good evening..