Game Development Reference
If you are going to write a flight simulation game, one of the most important aspects of
your game engine will be your flight model. Yes, your 3D graphics, user interface, story,
avionics system simulation, and coding are all important, but what really defines the
behavior of the aircraft that you are simulating is your flight model. Basically, this is
your simplified version of the physics of aircraft flight—that is, your assumptions, ap‐
proximations, and all the formulas you'll use to calculate mass, inertia, and lift and drag
forces and moments.
There are four major forces that act on an airplane in flight: gravity, lift, thrust, and drag.
Gravity, of course, is the force that tends to pull the aircraft to the ground, while lift is
the force generated by the wings (or lifting surfaces) of the aircraft to counteract gravity
and enable the plane to stay aloft. The thrust force generated by the aircraft's propulsor
(jet engine or propeller) increases the aircraft's velocity and enables the lifting surfaces
to generate lift. Finally, drag counteracts the thrust force, tending to impede the aircraft's
motion. Figure 15-1 illustrates these forces.
Figure 15-1. Forces on aircraft in flight