Air to Air Gunnery - A primer for Fighter Pilots by Dinghao

The sole purpose for the pursuit aircraft in armed warfare is to seek out and destroy enemy aircraft. The means by which this is accomplished involves knowledge of the Basic Flying Maneuvers (BFM), mastery of Air Combat Maneuvers (ACM), and understanding of Air to Air Gunnery. Knowledge of the BFM means you can get your plane in the air. Mastery of ACM means you can make the enemy your target, rather than you being the target. Understanding of the Air to Air Gunnery problem means you will aim correctly and hit your target.

This guide is intended to provide some sample sight pictures and images that will help you to understand the basics of Air to Air Gunnery and learn where to aim and when to shoot. Most importantly, this may also help you to understand when NOT to Shoot.

The Aircraft

Your fighter aircraft is just a platform for mounting guns. The guns are mounted either on the fuselage or the wings. For the purpose of this game, your guns are adjusted to fire at one point in space. This is called convergence and can be set prior to spawning your aircraft by typing as a text message the command “.conv xxx” where xxx is a distance from 50 to 800 M.

The importance of convergence is two fold. First, “at convergence” the full impact of all your weapons hit the same spot on the target. This transfers the greatest amount of killing energy to the target, and can result in the most damage in the target. Second, outside of convergence, either closer or farther, the impact area of the guns is spread out over an expanding cone of fire.

At .conv 50 the mg tracers cross at a point in space about 50 M in front of the aircraft (Left). At .conv 200 (the default setting) this is farther out (Center). At .conv 500, the convergence point is quite distant (Right). What you set your convergence is a personal preference. However, this value must be known and taken into account if you are to solve the Air to Air Gunnery problem.

At convergence all guns hit the target in a small area.

The Gun Sight

The French optical gun sight is scaled with concentric rings. The wingspan of a Bf109 will protrude beyond the diameter of the largest ring at a distance of 100M. Doubling this range to 200M will reduce the apparent size of the target and the wingspan will fit the next smaller ring. At a distance of 300M, the wingspan will be just larger than the center ring of the gun sight.

50-75M 100M 200M 250-300M

The British optical gun sight is a single ring with a center pipper. The wingspan of a Bf109 will be 1 Radius (1/2 the diameter of the ring) at a range of 200 M. At a range of 100 M the wingspan touches the ring. Closer than 100 M and the wingspan exceeds the diameter of the ring.

200 M 100 M 50 – 75 M

The German Bf110 Revi gun sight is geared towards bomber attack, and is thus one of the larger gun sights. It is a simple ring with intersecting bars. The center lower bar extending to the center of the ring.

By comparison, the Revi gun sight mounted in the Bf109 has a smaller ring, and the intersecting bars are graduated with tic marks.

The ring diameter of the Bf110 will fit the wingspan of a Spitfire at a range of 100 M. In contrast, the wingspan of a Spitfire will fit within the ring of the bf109 at a range of 200 M.

Top to bottom: 100M, 200M and 250M. Left Bf109, Right Bf110.

Comparison of the various gun sights

From Top down, French, British, Bf110, Bf109

Overlay of the gun sights.

Target Size helps you to determine RANGE

Hawk81/P-39 Dewo/Blen Bf109E/F Ju87

Hawk75/Bf109 Db7/Spit/Hurri He111 Bf110

This graphic helps illustrate the relative sizes of the various aircraft. The Fighters are approximately the same wingspan.

The twin-engine aircraft are approximately 1.5x to 2x the wingspan of the fighters. The He111 is the largest aircraft.

When Attacking a larger Aircraft, the apparent size relative the ring sight will be larger for a given range. Thus, while the wingspan

May fill the ring, the He111 is actually 1.5 to 2.5 times farther away, i.e. 150-250M instead of just 100M if it were a Bf109.

100 – 150 M 100 – 150 M

You will note that the aim point is centered on the wing root area, and not the fuselage.

The first rule of Air to Air Gunnery: GET CLOSE

Your bullets will take a finite amount of time to get to the aim point. The farther you are from the target, the longer this time is. The longer the time is, the more movement in your target is likely to occur.

Thus, the closer you are, the more likely you are to hit because the bullets travel the short distance very quickly. The more you hit him, the more likely you are to kill him. By being very close, many of the variables considered when you calculate where to aim, (i.e. target speed, target attitude, target maneuver, rate of closure, angle off) reduce to almost nothing.

The farther away you are, the more impact the variables will have on your firing solution because of the longer time your bullets are traveling.

In general, you do not want to be shooting at a target over 200M away. Until you are much more experienced, you should limit yourself to firing at a target only if it is 150M or less away.

Top to bottom: 50 M French and Brit, 50 M Bf109 and Bf110;

100 M Bf109 and Bf110, 200M Bf109 and Bf110.

The second rule of Air to Air Gunnery: Use More Lead than you think

In order to hit a moving target, you must aim ahead of where the target is, at a point where it is expected to be by the time the bullet gets there. This is called “leading” the target, and the amount you “aim ahead” is the amount of “lead” you need to hit it.

It is much better to maneuver so that you have the gun sight just beyond your predicted aim point, and allow the enemy plane to fly into the spot as you fire in short bursts. The main reason for this is that if you are maneuvering your plane/gun sight to track the target your aim point is constantly moving. The bullet stream, if seen from outside your aircraft, will be describing a curving arc apparently deflected by the movement of your aircraft and the effect of gravity on the projectiles. By aiming with more lead, you allow more room for error in your estimate, and for a more linear projectile path, as you ease off any G-forces on your plane firing at the target.

If you are close, you will not need to lead as much as if you were firing from 150M away. If the enemy is moving slowly relative to you, you may not need as much lead.

At 50 – 100M range, just aim for the front of the enemy plane. When close enough, you can even pinpoint your aim to achieve the most damage.

Air to Air Gunnery: Fire In Short Bursts – most of the time!

The reasons why you should only fire in short bursts of 1 second or so, are three fold. First, you conserve ammunition for when you really need it. Second, against a moving target, a longer burst will not necessarily mean you will hit him more. Finally, firing an extended stream of bullets hoping to catch up with the target is more likely than not doomed to failure as you will always be aiming behind the target.

This is more true than not with the Hurricane and Spitfire, and to a certain extent with the Dewo and Bf109 20mm, since you have a pretty limited supply if ammunition. When it comes to the Hawks, the P-39, the Bf110, the Ju87 and the mg ammo of the Bf109, you can afford to be more liberal with the use of your weapons as you have a lot more ammunition.

However in cases where you have saddled up on a target and are sure of hitting, then it may be worth while to unload more than one burst, to make sure you have killed the target.

Air to Air Gunnery: The more Angle-off, The greater the range, The faster the target, The More Lead needed

The simplest aiming problem is the dead 6 attack (left). However, the 109 pilot armor will make this attack ineffective. It is better to achieve some angle-off, either in the vertical plane (right) or the lateral plane (below). For our purposes, angle-off is simply the difference in the line of flight of the target as compared to your own plane. The greater the angle-off involved, typically the greater the amount of lead needed.

Remember, Aim to Hit AT Your Convergence Setting

If your convergence setting is the default (200M) you want to be aiming to hit your target at 200M or less. Otherwise, the total weight of your firepower will not hit the target. Get familiar with the various target aspects and where to aim at 200M. Remember, the amount of lead depends on many factors, and you can eliminate or minimize many of them if you are firing at the same range most every time.

ADVANCED CONCEPTS

There are generally two basic types of gunnery solutions, a. Tracking shot and b. Snap-shot. For the new pilot, it is highly suggested that you stick to Tracking shot guns solutions only. Tracking shots are taken from the rear quarter of the target, and involve matching the flight of the target with your plane to find the proper guns solution. By matching your flight path with the target (actually a pretty intuitive follow-the-leader skill) you minimize and eliminate many of the variables that play a part in finding the guns solution. In a multi-aircraft furball situation, maneuvering for a tracking shot may leave you vulnerable as you are following the target in a relatively predictable path. The classic “drag and bag” takes advantage of target fixation in pursuing a tracking shot.

Snap-shots are taken when you predict the flight path of the target, flying in a different plane than your own. The intent is to place a stream of gunfire into the path so that the target flies into them. Typically in a fur-ball situation, while you are evading other aircraft, the target opportunity presents itself for a snap-shot.

The use of a snap-shot in concluding a pursuit/tracking situation requires the strong transition from lag pursuit to lead, followed by the unloading of the stick forces (no Gs) and firing into the path of the target, with what is now a relatively straight shot (due to the unloading of the stick).

The careful use of rudder can also allow you to slightly adjust your aim as needed. However, this is not something to be done if you have any tendency to smash down on the rudder pedals. Slight rudder inputs will allow you to spray your target. While your goal is to fly your plane into position to fire, sometimes the aggressive use of rudder will allow you to drastically alter your flight path enough to allow you a firing solution, that may not otherwise happen. In a head-on pass, once the planes are aligned to miss each other, use of the rudder will allow you to take a snap-shot at the passing aircraft.

The Zen of Archery – Fly smooth, squeeze the trigger slowly

The masters of Archery in the Japanese Martial Arts teach that in order to hit your target, you must not aim at it. Thus trained, they can meditate on a target and hit it with seemingly only an eye blinks time to aim. Or they can ride a galloping horse and hit a target 50 yards away. The harder you try to hit something, the more tense you make yourself and thus the less likely you are to hit anything. Counter intuitive maybe, but consider the following. The precise aiming needed to hit a moving target from a moving platform requires a light touch on the control stick, and gentle manipulation of the trigger. Marine snipers are taught to exhale slowly as they squeeze their hand to operate the trigger, when firing a shot. This is because there is a natural tendency to hold your breath and tense up when concentrating intently on a target. Exhale, breathe, slowly squeeze the trigger and you may find your self hitting more often than not.

Depending on the range, any extra control movement may magnify into a large change of aim point, possibly leading to a complete miss. The closer the range, the smoother and more deliberate your movements should be! Each control movement is magnified in effect!

Ideally, you are tracking your target as the range slowly decreases. Resist the urge to fire too soon. Remember the ideal range to fire is at your convergence setting. Track the target with your gun sight, as you fly your plane as smoothly as possible. Make large changes/control inputs when still at long range. When finally approaching firing range, slowly squeeze the trigger. Grabbing at the trigger with your entire hand can lead to extra movements in the control surfaces, and thus a change in your aim point. Fire smoothly and follow the pipper through the aim point on the target. This is called follow through and allows for smooth movement. One trick is to swing your pipper through the target deliberately and smoothly, then fire only when ON.

Too far, get closer. Closer still. Be Smooth. Almost there. Breathe. Let him have it!

Long Range Shot

It is a given that the closer you are to your target when you fire, the more likely you are to hit. The problem is that given the comparative strengths of the aircraft, and depending on the tactical situation, you may never get as close as you like. In a typical bounce, Boom and Zoom, unseen attack, the target is flying along oblivious to you and your intention to kill him. In this case you can easily get in very close before firing. However, in a slower plane with no real energy advantage, there may be little or no opportunity to get closer than 200 to 300M. In these instances, a snap-shot deflection shot may present it self. To take it and hit may mean the difference between life or death.

Recall from the topics above, that the Air to Air Gunnery Solution comes from knowing/gestalting the range to target, the proper amount of Lead, and where to Aim.

Range is solved by the size estimation. The proper lead calculation and Where to Aim, must take into account the targets speed, plane of motion/angle off.

Angle-off

Knowing what direction the target is moving, what plane of movement it is in, and speed, feed into the estimate of Lead.

One short cut, presented by Andy Bush on the SimHQ sight (www.simhq.com) uses the aircraft’s tail position to tip off the angle off in the plane of motion.

Using the rudder’s position relative to the wing (from a side view) you can estimate the amount of Angle-Off.

When the rudder is in line with the center line (Red) you have 0 degrees angle off.

When the rudder is in line with the wing root (Green) you have a small angle off (about 5 degrees)

When the rudder is in line with the middle of the wing (Purple) you have a moderate angle off (about 30 degrees)

When the rudder is in line with the end of the wing (Blue) you have a large angle off (about 45 degrees).

Dead 6 with no angle off, there is no lead.

With a small angle off (about 5 degrees) your lead is about ½ a wingspan.

With a moderate angle off (about 30 degrees) your lead is about 2 wingspans.

At a large angle off (about 45 degrees) you should start with a lead of 3 wingspans.

In these pictures, the wingspan is equal to 1 Diameter of the ring. However, at greater ranges this short cut adapts;

i.e. when the wingspan is only 1 R, then the amount of lead IN WINGSPANS can still be estimated from the Ring.

Aim for where the Target WILL BE when you should fire!

Use the proper amount of lead (or more!) to help you set up the proper pursuit angle. In a typical Boom and Zoom (BnZ) set up,

you will have spotted the target about 1 Km (1000 M) below, and some distance away. If you were to dive down directly on the target with your gun sight centered on the target, you will be far behind the target when you reach firing range. You need to aim/lead in front of the target’s flight path. As you approach firing range, allow the target to fly into the gun sight. With practice, your dive will lead to a full convergence shot, and allow you to pull up and over the target for a 2^nd pass (if needed).

Dive with plenty of lead. Allow target to fly into gun sight. Fire at Convergence!

Geometry and Physics conspire to make you MISS when you fire in a Turn!

If you are flying straight with very little control inputs, the major force acting on your bullet stream will be the force of gravity. This is already taken into account by the harmonization/convergence setting of your gun sight. However, as soon as you depart from straight and level flight (and this is most of the time) you must take into account the effect of your movement (typically turns) and gravity will have on the bullet stream as it appears to you when you fire.

The apparent path of your bullet stream will trail away from the direction of your turn, and can be misleading.

Gravity will always cause the bullets to fall towards the earth. If you are banked 90 degrees, the bullets will fall to earth, rather than fire towards the convergence point. If you are banked 45 degrees, the same effect, but to a lesser degree.

With this in mind, if you are banked AND FLYING STRAIGHT (with unloaded controls), aim the gun sight a bit away from the fall of gravity. Similarly, your vertical lead will be less, as the drop of gravity in the gun sight is being slightly overcorrected for.

If you were flying straight and level, aim for the targets nose (LEFT).

If you were banked 45 degrees left, the fall of gravity is acting left (your apparent view) so aim a bit right. In this case above the target. (CENTER)

If you were banked 90 degrees left, the fall of gravity is straight left (your apparent view) so you should aim above the target to the right (in your apparent view) (RIGHT).

Turns - during combat will cause the apparent bullet stream to arc AWAY from your direction of turn. If you are banking and turning LEFT on the attack, your bullet stream will appear to fall away to the RIGHT in an arc that corresponds to your turn radius. That is because the instantaneous vector of your bullet as it was fired is fixed, and then acted upon by gravity (simplified rule of thumb). As you continue to turn, each subsequent bullet has a slightly different vector and thus the bullet stream appears to trail off behind your turn. What this means to you in your gunnery solution is that if you are turning LEFT, you must INCREASE the amount of lead LEFT and above, beyond that of what you would expect in straight and level flight. This allows you to walk your bullet stream back into the target, rather than always trying to play catch up with the turning target. If you do not pull enough lead, you will never hit the turning target.

If he is turning, but you are not, use simple lead. If he is turning and you are as well, pull much MORE lead.

PULLING LEAD – A Dangerous Balance / Know your limits!

Always trying to PULL enough lead to make a shot is not good. Don’t do it. Pick your shots, don’t force them.

Typically, you will be in a pursuit curve that continues into a turn as the target continues to turn more and more. You may be tempted to pull more and more lead to try to get that pipper out in front of the target so your bullets land on him. Be very careful. IF AFTER 2-3 seconds you cannot pull enough lead to make hits, give it up and convert to LAG pursuit or break off: climb for altitude, or dive away. If you continue to pull, you will very seriously expend your Energy/speed and most likely stall your aircraft.

Can’t get proper lead. Convert to LAG pursuit. Later, transition back to Lead and shoot!

There are many reasons for NOT pursuing a target into a tighter and tighter turn trying to always Pull Lead.

To list a few:

1. You may stall your aircraft and loose control.

2. You may become target fixated and become THE TARGET for another plane.

3. You may never reach a firing solution (your turn/E cannot beat the target’s turn and E state).

Lag pursuit is only 1 solution. There are several other tactical solutions that fall within the realm of ACM. This point is only brought up to WARN YOU about the dangers of trying to PULL enough lead to make the shot.

Practice, Practice, Practice.

The large Air to Ground target just happens to be the wingspan of a fighter. Practice firing at convergence, It will help adjust your eye and let you get a feel for how rapidly range changes in moving aircraft. Fire short bursts, and try to get all hits in the center dot. Do this and you will be flaming up aircraft in no time.