Figure 9-3 Horizontal Maneuvering

CHAPTER NINE

BASIC FIGHTER MANEUVERING (BFM) THEORY

referred to as "radial G", actually turns the aircraft. Radial g is the horizontal component of lift.

If you pull harder in a turn, which is indicated on your accelerometer and referred to as

"indicated g", you are increasing the load factor. Depending on your situation (your snapshot in

time), this triangle will change. Simply put, the larger the radial g vector, the better the turn

performance. As you see in Figure 9-3, in a purely horizontal turn, the greater the AOB, the

greater the load factor to maintain effective lift. This greater load factor produces greater

induced drag, resulting in a higher energy loss.

Figure 9-3 Horizontal Maneuvering

911. VERTICAL MANEUVERING

Figure 9-4 represents another theoretical loop in the vertical plane at constant TAS and constant

indicated G. This figure isolates pure vertical maneuvering within the "tactical egg". Unlike a

purely horizontal turn, your turn performance in a vertical turn is affected differently by gravity,

depending upon where you are in the turn.

When the aircraft lift vector is above the horizon (at the bottom of the egg), radial g decreases

because gravity opposes the load factor of the aircraft, resulting in a larger turn radius and a

lower turn rate. When the lift vector is below the horizon (at the top of the egg, when the fighter

is inverted), radial G increases because gravity assists the load factor and lift, resulting in a

smaller turn radius and faster turn rate. When the aircraft is pure vertical (side of the egg), the

load factor is parallel to the horizon and therefore equal to radial G, which results in an

intermediate turn performance.

9-6

BASIC FIGHTER MANEUVERING (BFM) THEORY