IL-2: Air-to-Air Gunnery, Part 1

by Len "Viking1" Hjalmarson

Article Type: Air Combat Training
Article Date: February 04, 2002

Product Info

Product Name: IL-2 Sturmovik
Category: WWII Air Combat Simulation
Developer: Maddox Games
Publisher: Ubi Soft
Release Date: Released (Nov. 2001)
Min. Spec: PII 400 (or equiv.), 128 MB RAM, 3D Accelerator
Rec'd. Spec: PIII 600 or better, 256 MB RAM, 32 bit 3D accelerator with 32 MB RAM or better
Files & Links: Click Here

Can't Hit The Broad Side of a Barn?

You’ve seen those gun camera films from WWII…a few short bursts from the guns of the ace and it’s all over. Is it really that easy? It sure isn’t for me!

You’ve flown European Air War or Jane's WWII Fighters and you usually got two kills per mission or more. Then along came IL-2 Sturmovik and you can’t hit a thing. What’s the problem anyway?

Air-to-air gunnery often seems like a black art, a hit or miss (pardon the pun) kind of thing. When should you fire? What type of armament is most effective? What convergence settings should you use? How close is close enough?

Welcome to air-to-air gunnery. We’ll address these questions and also consider lethality, lead angles, and more. Furthermore, we’ll help you apply those answers by giving you a set of demo track files, including air-to-air practice missions designed for IL-2 Sturmovik.

Air-to-Air Gunnery: Real World Stats

How many pilots became aces in the real world of WWII air combat? Perhaps one out of thirty men. In reality, air-to-air engagements weren’t that common, and when they did occur, many times all parties returned home without decisive victories. It was very difficult to get an air-to-air kill in WWII. The film clips we see show only the victories, and come from the gun cameras of the more proficient shots.

The reasons why it was so hard to get a kill are many. First, the caliber of the weapon fired was often quite small. Even the larger caliber machine guns (13 mm is roughly the same size as .50 caliber, but the .50 caliber round was generally 40 percent heavier) required many hits to achieve a kill, unless the pilot was killed. Second, too many pilots fired from too great a range. This contributed to a number of problems:
  1. it lowered the hit ratio,
  2. it lowered the lethality of the projectile,
  3. it warned the bandit that there was an enemy nearby.
In the same way one of the most common problems I see with novice air combat pilots is that they fire too soon and from too great a range.

When you begin flying combat and you are a hundred meters from the enemy machine, you get jittery because you are too close to him. That is what you feel in the beginning. By experience you come to know that when you are a hundred meters from the other machine you are still too far away. The inexperienced pilot breaks away for fear of mid-air collision. The experienced pilot brings his machine in much closer…and when he fires, the other machine goes down.
—Erich Hartmann, 352 kills

Estimating the correct range to the target is the first problem. The second problem is lead angle, and it is considerably more complex, since it depends on the angle off the tail of your target (AOT for short). We’ll consider both these problems as well as convergence settings. Before we do so let’s consider the issue of lethality.


I always felt confident flying the Me-109, even down to the armament. In the FW-190 you had four guns, and much more hitting power, against the three guns of the 109.

Nevertheless, I did not like the outboard guns of the FW-190 because the high G-forces caused jamming and mechanical troubles. I preferred three guns in the center of the aircraft, right along the longitudinal axis. This mean you had to aim very carefully, but when you did, our excellent ammunition got the job done. It had high explosive power, and when you hit an enemy aircraft that was "good night."
—Gunther Rall,
in “Fighter Aces of the Luftwaffe”,
Constable and Toliver, 1977.

What is lethality? It is a combination of four factors: range to target, projectile size, muzzle velocity and rate of fire. Actually, these factors can be reduced to two: kinetic energy, and rate of fire. Lethality is a factor of kinetic energy (projectile weight and velocity) and rate of fire. Let’s consider a number of examples.


The 20mm M2 cannon can place 196 pounds of lead in the air per minute (weight of fire, WF), or 50 pounds of lead in the air in fifteen seconds. This is the result of a 5 ounce shell being fired at the rate of 650 per minute. The muzzle velocity (VM) of the M2 cannon is 2850 feet per second. Lethality is equal to WF x VM = 15.9.

Now consider the lethality of a .50 calibre M2 machine gun. The weight of fire is 81 pounds per minute, and the muzzle velocity is 2810 feet per second. WF x VM = 6.4. The lethality is roughly one third that of the 20mm cannon.

In practice in the average combat flight simulation, these figures hold true. It takes an incredible amount of fire from a 12.7mm gun to down an FW 190. In fact, it is rarely done. On the other hand, a 20mm cannon has good effect. But it doesn’t matter what lethality your gun system has unless you can put that lead on target.

Armament changes over the course of development of the 109 types were significant. Six different guns were used: two machine gun types and four cannon types. Four different mounting locations were employed: on top of the engine cowling, just behind the engine, with the gun firing through the propeller hub, within the wings, and under the wings.

The six variety of guns employed were these:

  • 7.92 mm Rheinmetall-Borsig MG 17
  • 13 mm Rheinmetall-Borsig MG 131
  • 20 mm Ikaria MG-FF (the Swiss Oerlikon)
  • 15 mm Mauser MG 151
  • 20 mm Mauser MG 151/20 (used M-Geschoss explosive shells)
  • 30 mm Rheinmetall-Borsig Mk 108

Gun Specs:
  • 7.92 mm MG 17
    rate 950 rpm, muzzle velocity 2475 fps
    round weight 24 gr.

  • 13mm (62 caliber) MG-131
    rate 900 rpm, muzzle 2400 fps
    round weight 34 gr.

  • 20mm MG-FF
    rate of fire 600 rpm, muzzle 1840 fps
    round weight 4.82 oz (115 gr)

  • 15mm MG 151
    rate 650 rpm, muzzle 2500 fps
    round weight 115gr

  • 20mm MG 151-20
    rate 650 rpm, muzzle 2450 fps
    round weight 92 gr.

  • 30mm MK 108
    rate 600 rpm, muzzle 1600 fps
    round weight 312 gr.

MK 108 30mm

Target Profile and Lead Angles

Back in the old days I flew in Jane’s WWII Fighters and in European Air War. Virtually all my combat was offline, and I generally fared very well.

About a year ago I switched to flying primarily in Rowan’s Battle of Britain. My kill ratio dropped significantly. I attribute this to two factors: the hit bubble was smaller, and the damage model was more realistic. My best score in a single mission in European Air War was probably ten kills. The best I scored in many missions in Battle of Britain is two kills and a partial, and then I had to limp home with battle damage.

Gunnery from a Ju88 in BoB

Next came the IL-2 Sturmovik pre-beta. I was amazed to find my kill ratio dropped again.

In IL-2 most pilots should not consider firing a weapon at more than 350 meters. That is, after all, more than one thousand feet of range. In Battle of Britain this was already quite difficult, but the profile of the target is still quite large from the rear quarter when compared to IL-2.

In IL-2 there is no hit bubble at all, and your bullets must actually strike the modeled object in order to score damage. Furthermore, accurate ballistics in IL-2 means that your bullets will drop with distance, and the profile of the target from the tail is much smaller than in Battle of Britain. Trying to hit a wing in profile is like trying to target a piece of cardboard.

Go in close, and then when you think you are too close, go in closer.
—TM “Tommy” McGuire, USAAF, 38 victories

In this situation, it becomes unwise to begin firing at more than 200 meters. In fact, it becomes difficult to get a hit at more than 250 meters unless your target is completely unaware of your presence.

Tactically, the differences between European Air War and IL-2 are significant. You must close on your target to 200 meters and less. Your danger of an overshoot rises rapidly. The amount of time you have to actually fire your guns is reduced if your closure rate remains the same. The difficulty of staying on the tail of a target at less than 75 yards is pronounced.

In order to attack effectively with fixed guns, the pilot of the attacking fighter needs to stop the relative angular motion between the pipper and the target. This relative motion can be broken down into two components when viewed through the shooter’s gunsight: lateral motion and vertical motion relative to the shooter’s windscreen.
—R. Shaw,
“Fighter Combat: Tactics and Maneuvering”

Furthermore, with gun convergence usually set between 150 and 200 yards, your alignment on the target may even work against you at 75 yards. Many times at close range I have seen my cannon shells pass harmlessly by, bracketing either side of the target in my sights. My main gun shells, coming from the nose of my 109, often pass harmlessly over or under a wing.

Killing an La5 in IL-2

In IL-2 Sturmovik a straight tracking shot is no longer a great solution. The hardest hit to get is one with zero deflection. The pilot is far better off to attack from an angle off the tail (AOT) of 15 to 20 degrees, whether horizontally or vertically. From an AOT the profile of the target is much larger, especially the wing profile.

Some pilots suggest that the solution is to pull lead. The problem with this solution is that it often results in firing blind. In order to pull lead on a hard turning target, you must place the target well your gunsight, and effectively guess at the target’s current location and heading. There is another option, and we’ll consider it tomorrow when we look at convergence.

Part II tomorrow!

IL-2 Sturmovik Resources

IL-2: Forgotten Battles

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Interviews with Oleg Maddox

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