BFM Geometry

BASIC FIGHTER MANEUVERING (BFM) THEORY

CHAPTER NINE

916. BFM GEOMETRY

Overview

With an understanding of basic aerodynamics, we can introduce the geometry of BFM required

to get the bandit into your weapons envelope and kill him. While fleet aircraft are armed with

weapons that can be employed from all aspects, we will simulate our engagements with a rear

quarter 20 MM gun. Our most basic goal therefore is to maneuver our fighter to the bogey's rear

quarter such that we can "shoot" our simulated forward firing cannon.

Range, Angle-Off, And Closure Rate

Range, angle-off the tail, and closure are the three basic geometric variables of BFM that the

fighter crew manages in order to achieve an offensive position on a bogey.

Range is simply the linear distance between two aircraft. All weapon envelopes are defined in

terms of range. You must place your aircraft in the guns envelope in order to get a good shot.

Angle-off the tail (AOT) is your angular position off the bogey's tail. Figure 9-9 illustrates

different AOTs referencing a target aircraft. Weapon envelopes are also defined in terms of

angle-off. For a given range and closure, the smaller the AOT, the more offensive a fighter will

be. Later in this chapter, we will see that the weapons envelope is defined by a combination of

AOT and range.

Figure 9-9 Angle Off The Tail (AOT)

9-15

BASIC FIGHTER MANEUVERING (BFM) THEORY