Energy, often called 'E', in the context of flight can be found in two forms. Kinetic energy (KE) and potential energy (PE).
=mass, =velocity, =gravitational acceleration () and =altitude difference.
Since mass is largely fixed, it can then be said that kinetic energy = velocity squared and potential energy = height.
Energy allows for movement in climbing, diving, turning and acceleration. A plane with considerable energy is maneuverable; a plane with insufficient energy for its mass will be less maneuverable and, as some might term it, "easy prey."
Energy State DifferencesEdit
How much energy a fighter has is often called its energy state; if two fighters are at similar energy states they are considered "co-energetic."
Differences in E are paramount to air combat tactics as they quickly sum-up what each fighter is capable of (relative to eachother).
As previously mentioned there are two types of energy, one based on velocity and the other based on the altitude of your plane. Converting between the two then is very simple; dive to convert some of your altitude into speed and climb to convert speed into altitude.
This is a key principle in the Boom and Zoom style of fighting which consists of diving at an enemy to gain speed (and therefore be able to catch a bandit), attacking, then zoom-climbing out to convert speed back into altitude so energy can be conserved to be utilized elsewhere.
Gaining energy is fairly simple, left alone, the engine will accelerate the plane adding to the velocity and therefore kinetic energy of the plane. However this only continues until the plane hits its max speed at which point the energy gained from the engine is simply being bled off as drag.
Alternatively the plane can be put into a climb in order to gain altitude. Since drag increases with velocity, climbing is a more efficient way of storing energy as staying at high speeds just means you're losing a larger portion of your energy gain to drag.
Now that we know that energy is the single most important factor in deciding the winner of an encounter, let's look at how we maintain efficient energy states. Most rookies will fly 100% throttle 100% of the time. This is bad mainly because you run the risk of frying the engine, but also, it doesn't leave a lot of room for energy. When in level flight, you should use as little throttle as possible in order to maintain your cruise speed. The throttle itself is a control surface, just like your vertical elevators, rudders and ailerons.
Another control that can be used is known as Prop Pitch. Prop Pitch is the angle of which your propellor blades cut through the air. With 0 degrees prop pitch, the blades are angled so they are catching no air. This means that it is no longer producing thrust. This is known as "feathering". On bombers and other multi-engined aircraft, this is important because if an engine catches fire or is no longer operable, it is creating drag. Feathering the prop will allow as little drag as possible to be generated from the propellor. The higher angle pitch, the more "bite" the prop will take out of the air, thus more thrust. However, Prop Pitch must be fine tuned depending on the aircraft. Some don't even have manual prop control.
Ultimately, Prop Pitch does not affect the throttle. Prop Pitch affects Revolutions per Minute (RPM). RPM is the key to relieving stress off the engine and maintaining proper control over the engine. Every aircraft has a Power Band. This Power Band is the number of RPMs in which the engine maintains efficient performance. For example, in level flight, the F4UD Corsair has a Power Band of 2700 RPM. At this number of RPM, the engine will be producing maximum thrust. Thrust being convertible to speed and speed to altitude.