Page 615 - PPL-engelsk 2025

Flight performance and planning

If the aircraft is too heavy at the rear, the tailplane must also provide lift to keep

the aircraft's nose down.

7.2.2.1 Determination of center of gravity

When lift is created, drag is also created. So, if we can load the aircraft so that the

center of gravity coincides with the center of pressure (center of lift), the least

drag is created.

Normally, for the sake of stability, we should have the center of gravity in front of

the center of pressure, but economically it would be better to move the center of

gravity back towards the center of pressure.

But do you remember how it was with stability? It wasn't good; we save money
on fuel, but the plane becomes less stable the further back the center of gravity

is.

It is the tailplane / elevator structure that is crucial for stabilizing the wrong load.

To calculate the center of gravity, you need:

- Distance / moment arm

- Weight
- Datum (point used as a starting point for measuring the moment arm)

Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 615