gasilname.blogg.se - Datum aviation

The datum may be located anywhere the manufacturer chooses it is often the leading edge of the wing or some specific distance from an easily identified location.

Some manufacturers specify this range as measured in percentage of the mean aerodynamic chord (MAC), the leading edge of which is located a specified distance from the datum.

The manufacturer establishes the maximum weight and range allowed for the CG, as measured in inches from the reference plane called the datum.

On a larger jet that are several other concepts to wrestle with and everyone assumes the knowledge exists. We all seem to be weight and balance experts with a Cessna 150 or Piper Cherokee because that's where we learned the concepts and it seems most textbooks are aimed to the private pilot audience.

If the CG is too far either way, the aircraft cannot be controlled in pitch. There exists a range of CG positions which the horizontal stabilizer is capable of countering. The aircraft's "center of lift" exerts an upward force, so the center of gravity (CG) must at all times be forward of the center of lift to keep the aircraft in stable flight. Why? An aircraft with a conventional tail-mounted horizontal stabilizer uses that stabilizer to exert a downward force.

In either case, you should have complete understanding of the concepts and a very good idea of where your airplane's range of acceptable centers of gravity lie. Weight and balance is a very big deal on some aircraft and it is possible to load fuel, cargo, or people so the aircraft simply will not fly.