Jet Fighter School

Air Combat Simulator Tactics and Maneuvers
by Richard G. Sheffield

CHAPTER 2
The Airplane

Learn to Turn and Burn

To be a successful jet fighter pilot, you must be able to make your aircraft do what you want, when you want. This chapter offers a basic understanding of how your aircraft maneuvers and the forces which affect it in flight.

To effectively operate in the air combat arena, you must have a basic understanding of how the aircraft maneuvers and of the various forces which affect the aircraft in flight. A proper understanding of these concepts will give you a “gut feeling” for how your aircraft is operating and will let you make quick and accurate decisions concerning what your aircraft can do in a combat situation.

Maneuvering a Jet in Flight

The joystick controls the direction of the aircraft. In normal flight, you pull back on the joystick to climb (gain altitude), push forward to dive, and push left or right to bank (turn) left or right, respectively. Holding the joystick to the right or left makes the aircraft roll.

The aircraft performs these maneuvers by responding to your control inputs and adjusting the various control surfaces: the ailerons, the rudders, and the elevators.

The ailerons are located on each wing and control the banking, turning, and rolling of the aircraft.

The rudders are located on the vertical stabilizer (tail) and control the yaw (right and left) movement.

The elevators are the smaller winglike surfaces on the tail section. These control the pitch of the aircraft, which produces up or down movement.

Figure 2-1. Control Surfaces

Figure 2-2. Aerodynamic Forces

Your F-15 simulator aircraft is controlled in basically the same manner as an actual jet fighter which employs a fly by wire system. In this system, the pilot's controls are not directly connected to the control surfaces. Instead, the control commands from the pilot's joystick are sent to a computer which then adjusts the various control surfaces to change the aircraft's flight path. The jet combat simulators work the same way—you push the joystick in the desired direction and the computer adjusts the control surfaces to point you in that direction.

Basic Aerodynamic Considerations

An aircraft in flight is acted upon by a number of forces, the most important being weight, thrust, lift, and drag.

Weight is the force which pulls your aircraft toward the ground. This is affected not only by the weight of the aircraft itself, but also by the weight of unused fuel and any weapons which are carried.

Thrust is the forward power of the aircraft, produced by the engines. This can be affected by altitude.

Lift is the force produced by the wings moving through the air, which pulls the aircraft up. Lift is affected by the angle of the wing and the speed of the aircraft.

Drag is the force which pulls on your aircraft and tries to slow you down. This can be affected by an external load you're carrying, such as bombs, missiles, or external fuel tanks.

Many hours of classroom training in military flight schools are devoted to understanding these forces, but this knowledge really doesn't help you fly your simulator better. What does help is an understanding of how these forces affect the various performance capabilities of your aircraft.

Aircraft Performance Capabilities

Energy Maneuverability

The concept of energy awareness during air combat is fairly new. Wise use and conservation of energy during combat will increase your chances of victory.

Your aircraft has two kinds of energy: kinetic and potential.

Kinetic energy is related to speed. High levels of kinetic energy, or speed, are needed to perform many combat maneuvers.

Potential energy is related to altitude. If you have low speed (kinetic energy) but high altitude (potential energy), you can dive and pick up speed needed to perform a series of combat maneuvers. Conversely, if you have high speed but low altitude, you can convert this speed (kinetic energy) into altitude (potential energy) by climbing.

To illustrate this concept, consider the following examples.

Example 1. You're at low altitude, approaching an enemy aircraft—which is at the same altitude—head on. You're flying considerably faster than your opponent. As you approach, you pull up into a steep climb, and your opponent pulls up after you. This is called a zoom maneuver. Since you possess more kinetic energy (you are flying faster), you're able to climb higher and gain the advantage.

Example 2. You're following an enemy aircraft that's flying at the same speed that you are. You're at a higher altitude. As your enemy twists and turns in an effort to escape, he'll lose speed (kinetic energy). If you follow him through those turns, you'll lose speed, too. But, because you're at a higher altitude, you have more potential energy, so you can dive to pick up speed, catch the enemy, and maneuver into a good firing position.

What this means to you, a fighter pilot, is that you must constantly keep an eye on your speed and altitude during combat. A heavy-handed pilot who twists and turns the aircraft around without paying attention to energy losses will soon be unable to maneuver. Once lost, energy is hard to regain—your only hope is to dive hard and regain some speed. (This assumes, of course, that you've left yourself enough altitude to perform the maneuver.) The lesson here is to avoid low altitude, low speed conditions. If you don't, you're a sitting duck for air-to-air or surface-to-air fire.

A good rule of thumb is to maintain a high cruise speed (Mach .9 or so) and a good cushion of altitude (35,000 feet or so) when entering a combat situation. With this speed and altitude, you have all the options—climbing or diving at will.

Climb Performance

The ability of your aircraft to gain altitude, or climb, is hampered by weight and drag. The easiest way to improve your climb performance is to get rid of any unnecessary equipment. If you're going to concentrate on air-to-air combat, get rid of any bombs you're carrying. All that air-to-mud equipment only slows you down, making you more vulnerable.

If you have external fuel tanks that are empty (in the F-15 Strike Eagle, for instance, your external tanks are empty when fuel remaining is less than 13,500 pounds), drop these, too, for they increase drag, hurting your ability to climb.

The F-15 has excellent climb performance when not loaded down with bombs or fuel. The F-15 is considered ballistic because it can produce more pounds of thrust than the plane weighs and therefore can accelerate straight up at full power.

Figure 2-3. Ballistic Climb

An F-15 in an air-to-air configuration (AIM-7 Sparrow and AIM-9 Sidewinder missiles) in a ballistic climb.

For each aircraft, there's an optimum climb rate where trading speed for altitude and altitude for speed is minimized. When performing a sustained climb, keep your airspeed in mind. If you climb too steeply, you'll use fuel faster and lose air speed which will take some time to recover once you reach your desired altitude. If your climb is too shallow, it will take longer to reach your desired altitude.

Acceleration Performance

Acceleration is primarily affected by weight and thrust. Kicking in the afterburner increases your speed somewhat, but the best way to pick up a lot of speed in a short amount of time is to dive.

The trick here is not to push hard on the stick in an attempt to dive straight down, but to perform a maneuver called unloading. In unloading, you're removing the weight of the aircraft that slows acceleration.

To do this, push forward on the stick slightly to obtain a 10° dive. That starts a gradual dive and produces a zero G condition. This is similar to going over a small hill with a car or bicycle—as you go over the crest, you're momentarily weightless and start to come out of the seat. The same thing happens when you unload an aircraft. However, an aircraft can continue to lose altitude and thus remain unloaded for quite some time.

Without the weight of the airplane holding it back, the speed of the plane can be increased rapidly. This can happen so quickly, in fact, that you need to keep your eye on the airspeed indicator to make sure you don't exceed the structural design limits of the aircraft, or Vmax. The Vmax of an aircraft is the maximum airspeed it can attain without ripping its wings off.

The F-15 Strike Eagle simulator gives a visual warning when you're approaching Vmax. When you see this warning, you should immediately cut power, extend your airbrakes, or pull up. (Make sure you already know which key operates the airbrakes, because you won't have time to look it up.)

Another method of increasing acceleration is to use a very steep dive. During a steep or ballistic dive, gravity greatly increases your aircraft's acceleration. In this case, if two planes are equal in all aspects but weight, the heavier plane will accelerate faster and achieve a higher terminal velocity.

And if two planes are equal in weight but one has lower drag (because its shape is more efficient or it's carrying fewer externals such as drop tanks or bombs), the one with the lower drag will have the acceleration advantage.

Even in this kind of steep or ballistic dive, it's best to perform the unloading maneuver first, then progress to steeper dive angles.

Turning Performance

One of the most important performance characteristics of a modern fighter plane is its ability to turn sharply and to maintain a tight turn for an extended period of time. In most contexts maneuverability and turn performance are synonymous. The better an aircraft's turn performance, the better it maneuvers. That, of course, translates into a better chance of winning a fighter/fighter contest.

Turn performance is generally divided into two types—instantaneous turn performance and sustained turn performance.

Instantaneous turn performance is the ability of an aircraft to turn at any given point in time. This is a function of the aircraft's speed and altitude. As the term implies, this turn doesn't have to be sustained for more than an instant. Something called maximum instantaneous turn performance is achieved at very high speeds. Altitude is also a factor here since, as you get higher, the density of air is reduced. The reduced amount of air passing over the wings reduces lift capability. This then reduces the turning performance.

Sustained turn performance is the ability of an aircraft to maintain a turn for an extended period of time. Turn performance is measured three ways:

• Load factor, or G's (gravity units) pulled during the turn. In a 5-G turn, the pilot weighs five times as much as normal.
• Turn radius. This is the area it takes to accomplish a complete turn. Turn radius is normally expressed in feet or miles.
• Turn rate. This is how fast the aircraft is changing course during a level turn. This is expressed in degrees of change per second.

The maximum G force an aircraft can handle is set by the manufacturer and normally allows for a significant safety margin. High-G turns can be performed at low and high speeds, but keep in mind that any time you're performing a maximum G turn, all available lift is used just to maintain the current altitude. If you must climb, you'll have to reduce the angle and severity of the turn.

However, the aircraft's maximum-G turning ability is not the most important factor to a fighter pilot. Turn rate and turn radius are more important because they determine the ability of the aircraft to turn inside another plane—either to escape or to obtain the necessary lead angle for a shot.

Maximum turn rate and minimum turn radius can best be obtained in high G, low speed turns. Normally the speed in these turns is just slightly higher than the stall speed for that aircraft. When turning this slow at maximum G, it becomes imperative that you watch your airspeed—a stall will send you rapidly toward the ground and disrupt any maneuver you're attempting. Once your airspeed starts to bleed off in these turns you must decrease the G load in order to increase airspeed and prevent a stall.

Care should also be taken when you're increasing thrust or decreasing G's during a turning fight. This can easily cause you to overshoot your opponent and quickly change your posture from an offensive one to a defensive one.

Roll Performance

Roll performance is the ability of the aircraft to change its plane (geometrically speaking) of operation, its ability to go from level flight to inverted flight or into a steep bank maneuver.

Roll acceleration determines how fast an aircraft can get into a steep banking maneuver or a continuous roll. This is a good measure of the aircraft's “agility.” The aircraft that can roll the fastest has the advantage during a close turning fight.

Roll performance and roll acceleration are basically determined by the design of the aircraft, though roll acceleration can be increased by unloading the aircraft before performing the roll. Be sure to level out the plane after the roll to prevent an excessive loss of altitude.

Inverted Flight Performance

Figure 2-4. The Inverted Dive Advantage

The F-15 has excellent inverted (upside down) flight-performance characteristics. It's very steady and can even climb while inverted. Sustained inverted flight is rarely necessary in combat situations, but brief periods of inverted flight are necessary to perform many of the offensive and defensive maneuvers used in air combat.

Developing good inverted flight skills takes time and practice. All controls are reversed when you're flying upside down. To fly toward the ground, for instance, you pull back on the stick; to go up, you push forward. To execute a bank to the right, you must push the stick to the left. These skills should be practiced and perfected so you don't make the mistake of flying into trouble rather than away from it.

Jet aircraft wings are very efficient and provide a great amount of lift. When you need to dive in a hurry, this lift capability can be used to pull you down toward the ground by flying inverted and pulling back on the stick. This is an often-used escape maneuver—you not only dive quickly, but when you pull out you're heading 180° from your original course.

Fly by the Seat of Your Pants

It's not important that you memorize all the flight characteristics of your aircraft and all the possible combinations of speed versus weight.

What is important is that you develop a “seat of the pants” feel for what effect these characteristics have on your jet fighter, and, more importantly, that you're able to anticipate the result of a maneuver.

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