Vertical CG, revisited

Back in February, Maverick had a post on trim problems which he solved by making adjustments to his leadout guide location on/at the wingtip. At the time he mentioned having difficulty getting the plane to fly right before making the change.

He changed the Vertical CG to get the correction he needed.

My questions are, 1) what does one look for, in flight, that might point to a Vertical CG problem? 2) does it necessarily need to be corrected?

I'm assuming at least one problem would be tighter turning/turns; inside loops vs outside loops, and perhaps better cornering one way as opposed to the other.

What other flight characteristics might show?

The reason for my 2nd question above is that my Vertical CG is off slightly (I think). The wing hangs about 1.5" towards the undercarriage. By putting old heavier, by 1.75 oz., wheels on, I can get it just about right on. But this adds weight I don't need on an already approaching critical weight plane. It seems to turn just fine without the heavier wheels and not exact Vertical CG, by making adjustments at the handle.

>Back in February, Maverick had a post on trim problems which
>he solved by making adjustments to his leadout guide
>location on/at the wingtip. At the time he mentioned having
>difficulty getting the plane to fly right before making the
>change.
>
>He changed the Vertical CG to get the correction he needed.
>
>My questions are, 1) what does one look for, in flight, that
>might point to a Vertical CG problem? 2) does it necessarily
>need to be corrected?
>
>I'm assuming at least one problem would be tighter
>turning/turns; inside loops vs outside loops, and perhaps
>better cornering one way as opposed to the other.
>
>What other flight characteristics might show?
>
>The reason for my 2nd question above is that my Vertical CG
>is off slightly (I think). The wing hangs about 1.5" towards
>the undercarriage. By putting old heavier, by 1.75 oz.,
>wheels on, I can get it just about right on. But this adds
>weight I don't need on an already approaching critical
>weight plane. It seems to turn just fine without the heavier
>wheels and not exact Vertical CG, by making adjustments at
>the handle.

I don't see where this is going to affect the turn rate at all. What it does, basically, is make the outboard wing hand low one direction and high the other. It is something you might think is caused by a warp and "correct" by trying to twist the flaps, but then you cause other problems.

Basically, if it is off "slightly", that flap twisting technique will work OK. But, as in your case, the other options are to either add weight to the undercarriage, or to raise the leadout guide in the inboard wing tip.

You can check for this by hanging the plane from the rafters by the leadouts and then comparing how the wing hangs to that of a plumb bob hung next to it. Since moving the vertical location of the leadout guide is selcom a viable option, and if you do not wish to add weight to the wheels, the other choice left is the flap twist. It will probably make the plane want to bank in on the glide, however, which is certainly not desireable.

Make a note of it, and the next time you build this same plane (if there is a next time) build the wing just slightly higher in the fuselage.