Measure the wing-to-stab distance

What you need

• A sheet of Letter or A4 paper, or a credit card
• Low-tack tape, such as masking tape

Steps

1. Open the aircraft, tap Neutral point CG, then tap Measure from a side photo.
2. Tape the paper flat on the side of the fuselage, between the wing and the stab.
3. Line up the paper's long edge with the fuselage datum, such as the wing saddle.
4. Stand level with the fuselage. Hold the iPhone square to its side and tap Take photo.
5. Check that each handle sits on a corner of the paper, then tap Continue.
6. Drag the orange handle to the wing's leading edge and the blue one to the stab's leading edge.
7. Tap the Save button.

Good to know

• Mark each leading edge where it meets the fuselage.
• Keep both leading edges and the whole sheet of paper in the photo.

Words used here

Datum

A flat reference on the fuselage, such as the wing saddle. Angles and distances are measured from it.

Leading edge

The front edge of a wing, stab or control surface.

Neutral point

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

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.

Related guides

• Find the CG from the neutral pointUse the wing, the stab and the distance between them to estimate how far back the CG can go.
• Measure a wing from a photoPhotograph the wing with a sheet of paper on it, and Maiden works out its size and where the CG goes.