GUNS AIR

Guns and Gunnery

The idea of launching a fighter into the air is to find and destroy the enemy in the air (and sometimes to blow stuff up on the ground). This can only be achieved by closing to the appropriate range, there to open devastating and destructive fire with your forward-firing armament. This seems straightforward enough but is indeed a rather daunting task, as you will certainly experience. For there is more to air combat than merely pointing your guns at the enemy – you will first have to fly your aircraft to a promising position, and avoid countless dangers on the way to that position, and then stay there long enough to deliver effective fire.

A brief history

Fighters are traditionally armed with rifle-caliber machineguns (7,5 – 7,98 mm) and/or heavy machineguns (typically 12,7 mm) and/or cannons (15 – 30 mm), usually arranged in the nose and/or in the wings. There are many variations, including weapons in underwing gondolas and belly packs, according to the standards and doctrines of the combatant nation. For instance, the German Luftwaffe adopted the 20-mm cannon as its main aerial weapon with RC weaponry as secondary armament while the RAF stuck to multiples of machineguns until well into 1941. France, Russia and the US adopted a combination of RC and cannon armament: the US eventually settled for caliber .50 and equipped all of its combat aircraft with this single caliber.

Guns and convergence

Fighters with nose- or cowling-mounted weaponry enjoy a distinct advantage over fighters with wing-mounted guns. Because the centrally placed guns are aligned wih the fighter’s longitudinal axis, the guns fire straight forward to the limit of their range, making aiming and delivery considerably easier. Wing-mounted guns on the other hand must be harmonized to deliver a concentration at a specific range lest the fire be delivered in a largely ineffective “sheet” pattern. Because of this, fighters with wing-mounted guns are only 100% effective when firing with the target at or close to the convergence point. If the target is closer to or beyond the convergence point, a proportion of the fire will scatter and thus be less effective.

Where to set your convergence is highly dependent on your weapon, your typical fighting style and at what range you normally open destructive fire. RC machineguns lose most of their punch outside 150 meters whereas caliber .50 rounds are effective out to 800-1,000 meters – though you are better served by setting a closer convergence unless you are an expert marksman.

If you like to motor up close and personal before opening fire, such as you need to do anyway if you are armed with RC guns, set your convergence to 75-150 meters.

The default convergence is 200 meters, which is good enough for most pilots and aircraft. If you prefer the long and fast attacks where closure is massive, you will benefit from a convergence setting of 200-300 meters.

A higher convergence setting is possible but not recommended since you will then rob yourself of delivery performance at close range. Go for a happy medium, and above all, evaluate your gunnery and set your convergence to the range where you typically score hits.

You will also need to take bullet drop into account. The projectile trajectory is higher than the aiming point inside convergence and drops off below the aiming point outside 500-600 meters range. This is highly dependent on your guns’ muzzle velocity: the higher the muzzle velocity, the less parabolic the trajectory. As a rule of thumb, a greater caliber round has a more pronounced drop, e.g. the German 30-mm round.

Deflection

In general, the easiest shot is delivered from a position just aft of the enemy with the shooter matching the target’s speed at a range of 100-200 meters. Getting into this position, and staying there for the duration required to deliver destructive fire, is however a whole science of its own. The benefits of firing from six o’clock are that the enemy may be completely unaware of his impending destruction; you get more firing time at his six than from any other direction; and if the bandit breaks you are well placed to match his manouevre and regain a shot position. The drawback is that the bandit offers a small target area and that your bullets may ricochet off the enemy due to the low angle of attack.

Most of the time you will be coming into guns range with the target more or less offset, i.e. travelling across or through your field of view. In all situations other than the true six o’clock attack you will have to ‘’’lead’’’ the target to some degree. The idea is that you must fire ahead of the target, i.e. in his future flight path, so that your bullets and the target arrive at this point at the same instant.

Consider the situation where the target is moving left to right across your steady shot solution: if you aim and fire straight at the target your bullets will arrive too late and fall well behind. Therefore you must aim a certain distance to the right of the target in this case, so that bullets and target coincide in space and time. The amount of lead, also known as deflection, is highly dependent on firing range, target rate of speed across your view, and to a lesser degree on your weapon’s muzzle velocity. The idea is to hold a steady firing solution (so that your fire will be concentrated when it arrives) and allow the enemy to ‘’’fly into’’’ your stream of fire.

In extreme cases you will have to fire blindly, i.e. with the target hidden beneath your nose. A typical situation is when you are cutting across the circle of a bandit moving at a good rate of speed, at short range: your wingline will be roughly level to his, therefore your wings and engine will be hiding him from view at the precise instance when you need to open fire – if you hold your fire until you regain sight of the target you will surely miss. The solution to the dilemma is to roll 180 degrees to inverted so that the bandit travels through your vision from top to bottom instead, though this shot is exceptionally tricky and not for every occasion – and following the shot you will be in a less beneficial position if your fire misses.

Where to aim?

Most of the time you will not have the opportunity to choose a particular aiming point but be happy to fire in the general direction of the target’s centre mass. When you do have the opportunity to aim however, go for the following areas in order of importance:

1. Engine
2. Pilot
3. Fuel tank (usually in the centre fuselage just aft or in front of the pilot)
4. Wingroot (where the wing is attached to the fuselage)
5. Empennage (tail unit)