4 Fundamentals of Flight

4 Forces

Dalam dunia penerbangan kita terlebih dahulu harus mengetahui daya dasar yang
mempengaruhi sebuah pesawat. Adapun hal tersebuat adalah:

1. Lift = Daya angkat
2. Weight = Gaya berat
3. Drag = Daya hambatan
4. Thrust = Daya dorong

1.Lift is the upward force. In order to lift the aircraft off the ground, lift has to overcome the force of gravity which is pulling the aircraft towards the centre of the Earth. Lift has to be greater than the weight of the aircraft in order to let an aircraft climb.

Weight is the downward force. It is the sum of the weight of the aircraft structure,fuel, cargo and passengers. Weight is created by the force of gravity, which is a force produced by the Earth’s magnetic field, pulling the weight of the aircraft towards the centre of the Earth. When weight is greater than lift, the aircraft will not leave the ground. When already airborne, this situation will cause the aircraft to descend.
The standard international unit of mass is Kilograms (kg) In some parts of the world ‘Pounds’are still used though. The equation is as follows: 1 kg = 2.2 Pounds ( 0,83kg = 1L)

Gross weight= Empty a/c weight + Pax weight + Cargo weight + Fuel weight

3.Drag is the force directed opposite to the direction of movement of the aircraft. Drag is caused by the structure of the aircraft. When moving through the air, particles of air have to be pushed aside and this causes resistance. To somewhat simplify reality: when drag-force equals thrust the aircraft will not move or change horizontal speed. When the aircraft is already moving and drag overcomes thrust the aircraft will start to reduce horizontal speed.

4.Thrust is the force directed opposite to the force of drag. Thrust is produced by the engines of an aircraft. When thrust overcomes the force of drag, the aircraft will increase horizontal speed.
When during flight these four forces are balanced out perfectly, i.e lift equals the
weight and thrust equals drag, the aircraft will fly straight ahead without climbing or descending and at a constant horizontal speed. When this balance is disturbed though, the situation of the aircraft will also change.
If lift increases, the aircraft will rise. If more thrust is provided the aircraft will accelerate until the increase in resistance (drag) balances out the increased thrust.

Keempat daya dasar inilah yang mempengaruhi pesawat dapat terbang.