Find the CG from the neutral point

Steps

1. Measure or enter the wing first, in the CG calculator.
2. Open the aircraft and tap Neutral point CG.
3. Under Horizontal stab, tap Measure stab with camera, or type in the stab's dimensions.
4. Under Wing to stab, enter the distance, or tap Measure from a side photo.
5. Set the static margin. 10% is a good first-flight value.
6. Read the CG, then tap the Save button.

Good to know

• The estimate ignores the fuselage. Treat it as the furthest back the CG should go.
• More static margin is more stable, but the model needs more elevator to flare.

Words used here

Neutral point

The CG position where the model would be neither stable nor unstable. The CG must be ahead of it.

Static margin

How far the CG sits ahead of the neutral point, as a percentage of the MAC. More margin is more stable.

CG

Center of gravity: the point where the model balances. Too far back makes it unstable. Too far forward makes the nose hard to lift.

MAC

Mean aerodynamic chord: the average front-to-back width of a tapered wing. CG positions are given as a percentage of it.

Related guides

• Measure the wing-to-stab distancePhotograph the side of the model to find how far the stab sits behind the wing.
• Work out where the CG should beEnter or measure the wing's size to find the range where the model should balance.