Bombing … the American Way

By E Eugene Miller
Managing Editor, Aviation

Efficiency dominates the thinking of American bombing strategists and tacticians. In the first of two articles on American bombardment doctrines the meaning of strategic bombing is discussed and the tools of tactical employment are appraised in detail.

The Bomber Commands of the Army Air Forces look upon their mission as one of destroying by the most efficient possible methods the enemy's power to resist. Efficiency in the bombardment function applies to both the strategy and tactics of bombing. Although it is sometimes not apparent, the strategic aims of bombardment are pretty similar among all contestants in this war. It is very apparent, however, that the full significance of these strategic aims is not equally appreciated by all contestants. If it were, there would be little variation in the tactics employed by them — if such employment were within the power of all.

In the first place, the older the sport the more standardized are the competitive tactics. This is because, as a matter of evolution, the consistent trend toward more efficiency in sports performance automatically eliminates tactics which are not efficient. It eventually boils down to the point where, within the rules of the sport, a limited number of tactics are available for employment to win, and the only new winning tactics open to development are those of a higher efficiency factor than those currently in use. If such new tactics are developed, they are immediately adopted by all contestants, provided (a) it is within the power of all contestants to employ them, and (b) the full significance of their employment is equally realized by all. Contestants not capable of either (a) or (b) usually lose.

In football, for example, nearly all of the plays in a team's repertoire are standard, tactical moves developed through the years by individual coaches and adopted by all others as their success was observed. Almost every season, a new tactic is devised by a coach which proves successful and gives his team a temporary advantage over others. If this tactic is efficient, it continues to enjoy employment and is generally adopted by other teams as a standard play. The measure of efficiency is the ground-gaining capabilities of the play, and if it is inadequate to the extent that the defense can stop it consistently, it is discarded. With this evolution of development and test, most football teams enter the field with all but one or two of their plays capable of execution by everyone, and the game becomes a contest of employment skill of these standard maneuvers.

To date, air bombardment has a relatively short history. Its strategic implications are realized by almost everybody, but the wide range of divergence in tactical thinking among the contestants indicates that they are a long way from ultimate efficiency, thus presaging a very successful outcome for those whose tactical thinking is based on attaining the maximum in efficiency.

Even a casual analysis of what AAF Bomber Commands are doing will reveal that a striving for efficiency dominates the strategic and tactical thinking.

By and large, their selected targets are strategic, and as almost everyone agrees that to knock out the enemy's source of immediate and cumulative power of resistance is efficient strategy, the record is obviously good. The British have always pursued this highly effective policy; the Russians began as soon as they were able — and they are becoming more able as each week passes.

The Axis blitzkrieg policy led our enemies away from the concepts of strategic bombing. The Germans developed highly efficient tactical weapons such as the dive bomber and attack bomber of medium size. The tactical success of these aircraft in the initial stages of the war is well known, but when tactical envelopment was stopped in the Battle of Britain, and the attrition stage reached, as it must be in global warfare, Germany was found wanting in strategic weapons.

If in her development of air power Germany had adopted the concepts of efficient strategic bombing, she might have stood master of the world in 1941! Despite the fact that Britain was subjected to the most frightful bombardment to that date, her war production mounted at a steadily increasing rate until she had actually amassed enough power to strike back even before American production was thrown in full gear on her side. The Nazis therefore failed to stop Britain's ability to resist.

Rarely has the vaunted German intelligence been so dismally put to shame as in the Nazi error of air. It is not the intent of this article to review this classic series of blunders in detail. But they will be obvious if in the following description of American bombardment concepts it is recalled that the Nazis did not choose targets of production; they did not have bombardment aircraft capable of self defense; and they elected the tactics of inefficient "saturation" bombardment without possessing the essentially colossal resources needed to actually saturate the target areas. The Nazis unwittingly began a battle of attrition in the Battle of Britain and they didn't know it. They exhausted themselves in wasteful employment of aircraft and bombs, and they were finally struck down by the true attrition tactics of the Allies — which, be it noted, did not involve bombardment of Berlin!

It is believed that the prime lessons of air strategy are now learned — and at a time when the Allies have a preponderance of air power and the strategic initiative to prevent the Axis from even attempting to catch up. This favorable balance of arms does not mean that the struggle is won. To be perfectly realistic, we may summarize its meaning to date simply as follows: Through misconception of the use of air power, the Axis lost its ability to win the war quickly and cheaply. This is not to say that our enemies have lost the ability to win the war — because unless we use our air power properly, the cost of total victory may well become prohibitive. The Allies are now starting their offensives against vastly more formidable power than the Axis faced when it undertook the offensive. The penalties of blunder and inefficiency are no less great, and we are to be subjected to violent test. Air bombardment is our principal strategic offensive weapon, and upon its proper employment will depend our ability to do what the Axis failed to do, also the cost of the total effort.

Therefore tactics and tactical organization and equipment comprise the vital consideration and as the AAF places just as much importance on efficient tactics as efficient strategy, we must define tactics in those terms and see how the AAF measures up. Efficient bombardment tactics involve an efficient organization utilizing efficient equipment to carry and direct the right bombs toward the destruction of a strategic target in the most efficient manner.

Bombardment Organization

A really efficient organization is generally one which is flexible enough to adapt itself to any number of potential situations. The Bomber Command of our Army Air Forces contains the usual echelons of command, but the size of each may vary according to the circumstances. The degree of flexibility is most marked in the higher echelons of command, but in actual practice a considerable degree of flexibility exists right down to the —

Combat Crew
The combat crew is the basic tactical unit of. the bombardment organization. This is differentiated somewhat from the fighter organization where a "Flight" is usually the basic tactical unit. The combat crew will vary in size according to the type of airplane in use but will also vary within similar classification of aircraft depending upon the mission to be performed.

The best bomb, the most accurate bombsight, and the most perfectly designed airplane are no better than the men who use them. Furthermore, the most efficiently organized air force in the world is dependent for its effectiveness upon the performance capabilities of the combat unit, namely, the airplane crew. There are many things that can be stated about air force operations with mathematical certainty, but there is no more emphatic truth than the assertion that bombardment crew efficiency is a direct function of practice. Therefore our policy of protecting and preserving personnel, even at a sacrifice of performance, is sound. It can be stated with equal emphasis that any deterioration in efficiency of a bombardment crew requires a tremendous increase in force and effort, vastly out of proportion to the loss in efficiency, to do a given job. An Army Air Forces commander summed up the whole thing in this single statement: "Nine men in an airplane will never replace the combat team."

It is a simple matter to demonstrate that combat crew efficiency can be projected in terms of air force efficiency. A decrease in the average error of a combat unit is equivalent to an increase in the number of effective airplanes in a given theater of operation. Bombing tables show that to obtain 85 percent assurance of at least three hits on a target 50 x 450 ft in dimension, 20 bombs are required if the radial probable error is 100 ft; 52 bombs are required if the RPE is 1,000 ft. In other words, a bomber force of 52 airplanes with reasonably well trained crews whose radial probable error is 200 ft is equal to a bomber force having 1,200 airplanes with poorly trained crews showing an error of 1,000 ft.

So important is the matter of crew training that many American tacticians hold to the belief that a bomber force should be held in abeyance until the proper degree of both force and practice is accumulated for a particular assignment. These men believe that a mission can be carried out most efficiently by awaiting ideal attack conditions with respect to weather and visibility, meanwhile having the bomber crew practice unceasingly as a combat team. They hold that a given target or series of targets can he destroyed by an organization well practiced in precision bombing in less time than that required in mass “blind” bombing, with considerably less cost.

No little amount of weight was given to this line of thought by the recent British mission against the Ruhr Valley dams in Germany, where the attacking force was carefully trained for a considerable period of time for the job, was held in abeyance until conditions were ripe, and scored one of the war's most staggering blows against the enemy in a single action.

The American bomber command in England is relatively small, yet as practice and experience have been accumulated is reaping dividends considerably out of proportion to its efforts by any other standard. A very large amount of credit is being given to the AAF for its part in diminishing the submarine threat through action against the submarine bases and at an almost ridiculously low cost. As a result of combat team training, and over-all efficiency in all other respects, American bomber forces operating over Europe have accomplished results so great as to cause disbelief even among our Allies. Enemy defenses have suffered bitterly at the hands of our bombers, and enemy installations have been destroyed at a minimum of expense. Actually the percentage loss of our aircraft in daylight attacks has been less than the percentage loss of British bomber forces in night attacks. All of this is the result of combat crew efficiency acquired through untiring practice.

Higher echelons of command are described in the chart:

Bomber Command Aircraft

Airplane types with which the Bomber Command is particularly concerned are the medium and heavy bombers. Medium bomber types include the North American B-25 Mitchell, the Martin B-26 Marauder, and the Vega B-34 Ventura. Heavy bomber types now in operation include the Boeing B-17 Flying Fortress and the Consolidated Vultee B-24 Liberator.

The medium bomber is very fast and maneuverable, particularly at medium and lower altitudes, having a moderate bomb load capacity and ability to carry at least one bomb of the largest standard type. It has moderate to fairly large range, depending upon the bomb load, and requires only a small operating crew. A considerable measure of defense lies in its speed and capabilities at minimum altitudes. The prime function of medium bombers is in this minimum altitude work, and its sighting equipment is generally designed for maximum effectiveness at low levels. Furthermore, its "defensive" armament, sometimes including many forward firing guns, is planned for coordinated strafing while on the bomb approach. Another point of defense, however, is the fact that the range capabilities of medium bombers are such that they can be generally accompanied by a fighter escort. In some cases torpedo racks are installed on medium bombers, but the AAF is not inclined to favor this development within its own operations.

The heavy bomber is a highly specialized weapon having a function which can be performed by no other weapon, namely, striking the enemy at the very heart of his source of supply. It has a large bomb load capacity, extreme range capability, and very extensive defensive armament which permits it to operate quite successfully without fighter escort. This is particularly true in formation flying where a mutually defensive fire pattern can be set up against attacking enemy fighters. The heavy bomber is capable of extreme altitude, a characteristic which has value in view of anti-aircraft activity and also provides height that may be required to give the bombs sufficient impetus to penetrate well-armored targets. The matter of altitude for defense requires a considerable qualification, however, and will be discussed later.

Two other principal types of bombardment aircraft — dive bombers and light bombers — have their principal function in the Air Support Command and hence will not be discussed in this review of Bomber Command activities.

Bomb Sights

The Americans have unquestionably outstripped everyone else in the development of a bombsight. The efficiency of our bombsight is in line with the Air Force's over-all doctrine of efficiency. The mechanical imperfections of the bombsight are extremely slight; when it is aimed and operated correctly, the dispersion is less than 4 mils. In other words, when bombing from an altitude of 10,000 ft, something less than 40 ft of the bombing error will be due to the bombsight. All other error would be due to incorrect air speed and altimeter indications and of course to human error in handling the bombsight and airplane. Proper operation of the bombsight requires a straight run of at least 45 sec on the bombing approach. During this time practically nothing can be done to avoid anti-aircraft fire or fire from attacking airplanes. It is found, however, that this apparent disadvantage is offset by the fact that by the time anti-aircraft guns are tracked. to the flight path and by the time the A-A projectile reaches that particular spot, the bomb run is completed and the plane can change its course.

Bombs
In the AAF Bomber Command, efficiency applies right down to the bomb itself. Assuming it is desirable to have the bomb land where it has been directed, (and direction factors are subject to enough ramification) the least we can expect is to have the bomb follow a true course. The principal influencing factor is design of the projectile; and in bombardment ballistic efficiency is very closely allied with aerodynamic efficiency.

Emphasis has been placed by the Americans on aerodynamic efficiency of bombs, a field of development which has been ignored in varying degrees by foreign powers. Many foreign bombs are adaptations of artillery shells and are not specifically designed for their mission. Most of them have cylindrical fins with a minimum of side flat plate area, which the Americans have found to be necessary for true flight characteristics. In copying artillery shell construction, the differences in impact conditions have not been taken into account. The result is considerably less effectiveness in demolition per weight of bomb and an inherent state of unbalance that renders proper placement virtually impossible. Artillery shell design permits but half the explosive content contained in American bombs of the same size.

Bomb Types
There is a great variety of bombs available for employment in air bombardment — each type having a specific purpose. It must be remembered, however, that complexity of supply problems increases in direct proportion to the number of types employed, and therefore this number should be kept to a minimum. Furthermore, experience is demonstrating that many special types are not sufficiently effective over standard types to justify their employment.

Two principal factors in making bomb type selections are case durability and explosive content. The bomb case will determine utility and relative effectiveness, which are particularly. exacting in demolition bombs intended to destroy by force of explosion alone. It is of specific importance that the bomb case remain undistorted and unruptured until the time of explosion. If the case is ruptured upon impact, a considerable reduction in explosive force will result, especially if the bomb is fused for delayed action, even to small fractions of a second.

Most widely used by American forces are "general purpose" bombs ranging from 100 lb up. Here, the case is made from sections of heavy gage seamless steel tubing, with reinforced nose and tail walls. It will stand up under impact against armor of moderate thickness, such as in the upper two or three decks of a battleship, after being dropped from present maximum practicable altitudes.

Another type is the "armor piercing" bomb, constructed along the lines of artillery shells and designed to withstand impact with very heavily armored decks and installations after falling from altitudes of 40,000 ft and higher.

The armor piercing bomb contains not more than 30 percent of its total weight in explosives as compared with 55 percent for general purpose bombs. This fact, coupled with other practical shortcomings, opens their general employment to question. For example, bomb impact velocities, even from the highest altitudes, are not comparable to artillery projectiles; in fact, present limitations in aircraft prevent obtaining sufficient altitude to give bomb velocities needed to penetrate structures stronger than those which can be destroyed by general purpose bombs.

Compromises between the two types in the form of "semi-armor-piercing" bombs are being employed experimentally, but for the present the general purpose bombs have the best all-round utility value.

Bomb Fusing

Bombardment effectiveness depends upon control of both the time and place of the bomb explosion. The ultimate in destructive efficiency is where a static charge is placed by hand and the explosion timed by manual fusing or by electrical control. While such efficiency cannot be obtained by aerial bombardment, the AAF attempts to approach that degree of efficiency in so far as possible. This involves the fusing of bombs which controls both the penetration and time of the explosion.

There are three principal conditions of bomb explosion with respect to time, and all three can be controlled by appropriate fusing. In order to obtain a lateral blast effect to damage a number of structures around the point of impact, the bomb may be fused to explode at the instant of impact without any penetration at all. In the case of fragmentation bombs, it may be desired to have the bomb explode before impact. This can be accomplished by extending the fuse to anywhere from 0 to 24 in in front of the bomb and to have the fuse ready for instantaneous contact explosion. The fuse may be arranged to cause explosion of the bomb anywhere from 1/50 sec to a matter of days after impact.

This flexibility of action is of prime importance to bombardment. A demolition bomb explodes with maximum effectiveness when it is tamped in either earth or water, or otherwise confined to space. Therefore, a target can be most effectively destroyed if the bomb is made to explode inside the target or directly alongside. This is where fusing plays an important part because the time of penetration must be calculated as closely as possible. In operation against a surface vessel, for example, the attacking force must use its bombs so that they will explode only after a time interval sufficient to permit the bomb to reach well into the ship's interior. This may amount to 1/50 sec or 1/10 sec, depending upon the armor protection of the deck. Bombs may be employed against submarines if there is sufficient fusing delay to permit the bombs to sink to a depth approximating that of the submarine. If ships are anchored in shallow water, their bottoms may be ruptured by dropping delayed action bombs alongside and having them reach the harbor floor before exploding, thus releasing the force of explosion directly against the relatively thin bottom shell of the ship. In such instances, delays varying from 4 to 45 sec may be desirable.

It is felt that the effectiveness of instantaneous lateral blast is very much exaggerated and may lead to error in bomb and fuse selection. The critical radius of destruction caused by blast decreases very rapidly, and in many instances greater effect can be obtained by using a number of properly fused smaller bombs to destroy an objective than to rely on the effects of a large blast. The British 4,000-lb "block buster" is a large bomb with a relatively thin case which is easily ruptured upon impact and depends for its effect upon instantaneous blast force. By simple physical laws, the radius of destruction of a 4,000-lb bomb will not be twice that of a 2,000-lb bomb. Actually the explosion of two 2,000-lb bombs separated by a distance not less than twice the destructive radius of either bomb will cause destruction over a much greater area than the 4,000-lb bomb.

If the bombs are standard and of good aerodynamic characteristics, the placement of two such bombs in such manner is easily accomplished merely by timing their release. It would seem more desirable practice, therefore, to determine the minimum size of bomb which, when properly placed by precision bombing, will destroy the target — then to use as many of these bombs as may be required. Actually, the total bomb load requirements would be considerably less than if oversized bombs were used. *[See footnote]

It should not be construed from the foregoing, however, that 4,000-lb or even 8,000-lb bombs do not have their place. For example, one of the finer tactical points is the knowledge that a 4,000-lb bomb may be a good thing to use in settled areas in the wintertime, not so much for its demolition effect as for its window shattering effect. Incidentally, the term "block buster" should be. Interpreted with caution. Some American writers have taken the term literally and have written that such bombs could wipe out an entire city block. The British do not employ the word "block" as we do; they usually use it in the expression, "block of flats", meaning an apartment house. A direct or alongside hit by a 4,000-lb bomb might well destroy an ordinary apartment house, but a direct hit from a 2,000-lb bomb would probably do the same!

In addition to demolition and fragmentation bombs, the bombardment employs three different types of incendiary bombs. Two of these are thermite and magnesium bombs, which produce intense heat in a relatively small area. Magnesium burns with less intensity than thermite. The third type of incendiary bomb is the oil bomb which uses oil or thickened gasoline as a burning agent. The intensity of heat of these oil bombs is considerably less than thermite or magnesium, but its burning area is decidedly greater. The flow of oil upon bursting makes this bomb a very effective weapon. It is particularly destructive when it burns around machines where heat can do much more lasting damage than that caused by blast effect from demolition bombs.

Bombardment Philosophy

Before going into the tactical employment of these tools, it is well to outline the philosophy of employment which is based on the availability of the tools, and which, on the other hand, has led to their development.

War efficiency, like any other kind, involves the securing of maximum result at minimum expense. It is an unquestionable fact that minimum manpower expense in war is a direct result of training. Therefore, whether or not it is carried out to the ideal degree as a practical matter, perfection through training is a basic goal of the Army Air Force.

Stated simply, the efficiency objective of a bombardment mission is to destroy a target as completely as possible with a minimum expenditure of men and material. Fulfillment of the bombardment mission involves getting to the target, which is a factor dependent upon aircraft design, and destroying the target, which involves hitting it with properly chosen explosive agents. There are two principal methods of scoring hits on a target: One is to saturate the target area with masses of bombs with the knowledge that in so doing the target is bound to be destroyed; the other is to obtain a proper sighting of the target and to hit it with all possible precision. The latter method is certainly the least expensive in terms of bombs required and in terms of mission aircraft requirements. In fact it is exactly what all contestants in this war would do if it were within their power to do it! This is a fair assertion because all have tried, and all but the Americans have failed.

Others failed because in attempting daylight bombing where the target could be sighted, they could not accomplish their missions without exorbitant cost in aircraft crews through fighter defense activity. Until the heavily armed American bomber appeared on the scene, daylight bombers extending beyond the range of fighter escort could not defend themselves against enemy fighter attack.

And here is a peculiar commentary on the ways of men and nations. Pick up any basic manual of war, or review mankind's conflicts since history was written. You will find that the fundamental axiom is that in any fight, whether between two people or two nations, the primary object of either side is to compel the enemy to cease resistance. If this is accomplished, all other general purposes can he realized.

Analysis of any conflict will show that success or failure depended on whether or not this fundamental objective was achieved. The Battle of France was won by the Germans after they had overcome all power of resistance. The Nazis, on the other hand, lost the Battle of Britain because they did not sufficiently reduce the RAF's ability to resist.

The most efficient method of bombardment had to be foregone by both the Germans and the British because, in the design of method, the factor of resistance was not fully accounted for and was therefore not overcome. In broad analysis, immediate fundamentals were overlooked, In other words, in attempting to strike at the enemy's basic power of resistance, ie, his source of military supply, means were not provided for reducing his immediate fighter resistance to such attempts.

What happened? Bombardment went on the defensive! It sought the cover of night and had to acquire sufficient mass and expend vastly more effort, men, and material to compensate for the loss of efficiency and to reach any degree of effectiveness in carrying out its ultimate function. Through superb effort and with assistance from her Allies, Britain was able to acquire and expend this mass of effort. The Nazis could not, and by any scale of comparison the German bombardment effort has ceased to be significant.

With history in mind again, one cannot help wonder how long this recourse to night bombardment will enjoy even what success it has had. How long will it be before effective resistance measures are developed to render this tactic prohibitively costly? If this never happens it will be one of the few instances in history, if not the only one, where efficient countermeasures were not developed.

The AAF bomber commands look upon their function as an offensive one — from beginning to end. The mission is to break down enemy resistance no matter what form it may take. Strategically, it is to destroy the enemy's source of supply as well as any resistance the enemy may make to that accomplishment. The AAF does not believe that the enemy can be destroyed by hiding from him; like the boxer, it is out to break down the opponent's guard and to knock him out! It has the tools to do both. They represent the most efficient tools man has devised and they are intended to be used to do the job by the most efficient method.

* "If the explosion occurs within a building or other confined space, the resulting damage will be much greater (than in open air). This is due both to the increased blast pressure produced by the confined space and to the reflections of the pressure from the surrounding surfaces. In general, the more resistant the walls of a building, the greater the shattering and destructive effect of the explosion …. Since the more a high explosive charge is confined during its detonation the greater will be its shattering and destructive effects, direct hits with even small demolition bombs are immeasurably more destructive than near hits with considerably larger bombs. And particularly is this true when the bomb penetrates into the target before exploding." — Lt Col A M Prentiss, USA, p 35, Civil Air Defense.

Part II

Our doctrines of employment of bombardment forces are taking shape more clearly as experience is gained. Discussed in this article are the fundamental determining factors in their efficient use.

Definitions of Tactics and Strategy

Strategy and tactics are interrelated to the extent that the degree of tactical situations, both with respect to number of occurrences and severity of combat requirements, depend on the results of strategic operations.

Successful and persistent strategic operations reduce the number of times a tactical situation can occur during the course of a campaign and also definitely affect the ability of the enemy to maintain a force of resistance in the course of a tactical operation.

A tactical situation arises as a manifestation of the full force and purpose of a military effort. It may be brought about as a result of strategy, but (just as important) it may be favorably prevented or favorably reduced in degree of intensity by strategic operation.

While strategic operations include tactical operations, they are more fundamental and actually determine the character of the tactical operation. Both strategy and tactics are involved in any contest. Strategy involves all efforts designed to put an opponent in an unfavorable position for combat. Tactics are the measures designed to defeat the opponent, and they are applied upon contact whether the opponent is in a favorable position or not.

To cite an example, an enemy soldier is placed in an unfavorable position if, as a result of strategic operation, he is deprived of his ammunition or food supply. On the other hand — whether or not he is well armed or well fed — a tactical situation occurs when time comes to remove him as a factor of resistance. This ultimate objective of all military operations is attained in a relatively simple manner if a successful strategic operation deprives him of the means of resistance.

This lengthy dwelling on definition is important if the full significance of bombardment is to be realized, for bombardment is the principal strategic force of our Army. Specifically, it is the strategic force in the term "air force."


The air arm is a relatively new military branch, and as a consequence it is almost bound to be frequently misused by all belligerent powers. The problem of determining correct deployment becomes aggravated by the fact that since the present war began, air force requirements have expanded considerably out of proportion to prewar concepts and preparation. Therefore, there are inevitably too fewer commanding in any of the armies who really understand correct employment of air power in all of its phases.

The mere pinning of wings on high ranking officers who have just completed advanced flight training does not make them true air officers, as proved in the case of German generals and admirals who, after being given as much as two years' training with the Luftwaffe, still were found considerably lacking in air force comprehension. Likewise, a thoroughly trained and experienced bomber commander is not really qualified to direct the employment of fighter or ground support equipment any more than an artillery specialist can be trusted with the final word on infantry employment.

With the sudden blossoming of air force requirements, it was necessary, in many instances to place relatively unqualified officers in charge of combat forces. This was not a unique condition in Germany. It was common to all belligerents. To a large extent this condition has been corrected, and as a result we are beginning to see a more well-defined doctrine of air power employment.

The bombing function is unique in that it is principally a strategic force rather than tactical, as are fighter and ground support units. Therefore, its operations are continuous whereas the other air force divisions are employed tactical requirements dictate. Yet, as the doctrines take shape, we can see a subdivision within the bombardment branch which may be further differentiated with respect to tactics and strategy and which fairly parallel the classification of bomber aircraft types, ie, —

It is dangerous to generalize in this manner, however, particularly with respect to equipment, because there is a legitimate and continuous overlapping of employment depending on circumstances. For example, a fighter group may effectively perform the tactical functions of defense and ground support, or it may carry out the strategic function of destroying enemy sources of supply and lines of communication. Likewise, a heavy bomber may be employed tactically at short range against enemy shipping, ammunition dumps, or even troop emplacements. However, it is important that these missions be so performed as to be within the limits of genuine necessity — for to employ specialized equipment indiscriminately is outright and inexcusable misuse of air power.

In total war, the strategic functions outrank those of tactical importance simply because strategy dictates the nature of a tactical situation. So long as a war is conducted there can never be enough strategic weapons — but there may be a limited requirement for tactical weapons. For example, no belligerent nation has really enough submarines with full complement — each could use many times the existing number. Yet it is quite conceivable that there may be sufficient tanks or guns and that production of them may safely be tapered off, or even stopped, barring replacement considerations.

So it is with the strategic heavy bomber. This weapon is the only one which can penetrate, at long range, enemy territory, striking at his source of power to resist. So long as the war goes on, there will never be enough "heavies," and they must be carefully husbanded and employed as efficiently as possible. Their use on any mission that may be carried out by other aircraft types must be dictated by true necessity and only where the combination of conditions is such that other available types cannot effectively do the job.

The long range heavy bomber is used most effectively for operations well behind the enemy lines against production installations. Properly conducted missions of this nature will reduce the enemy's power to fight back and will, in most instances, determine the scope and intensity of future tactical situations. This is the fundamental task, and use for any other purposes is generally considered carefully.

If an enemy airfield is close enough to be dangerous to our own positions it generally lies within the immediate tactical theater. Therefore, weapons designed for strategic purposes, such as heavy bombers, should not as a general rule be risked to make continuous raids against such airfields. Tactical weapons are called for, and medium or light bomber are to be used.

About the only time use of heavy bombers against airfields is justifiable is when a tactical situation calls for employment of all available power. For example, if nearby enemy territory is to be occupied, or if for any other reason enemy air effectiveness is to be nullified for immediate operations, it is proper to employ heavy bombers against these installations. This does not hold true if the enemy is to be permitted to recover use of the field. A possible exception to this is in instances such as the battle of the Bismarck Sea, where enemy air power was pinned down to permit operations against a convoy. But this was a definite tactical situation where it was legitimate to use any weapon available to accomplish a vitally important mission.

The error of using heavy bombers tor routine bombing of airfields may be compounded by wasteful employment of heavy bombs. Fragmentation bombs are most effective against grounded aircraft — which are generally the principal targets unless service installations are extensive.

Operating Technique

Assuming that a correct bombardment philosophy has been established, that the most effective tools have been developed, and that the proper selection of these tools with respect to targets has been made, the next consideration is the actual technique of employment.

The mission of bombardment is to destroy the enemy, and techniques are developed with full consideration of all factors involved. Because bombardment is essentially an offensive mission and involves penetration into enemy territory, resistance must be expected and techniques must be developed to deal with that force so that the mission may be accomplished. Protection of the bombers force is, therefore, a vital factor. An error in concept here may well prove fatal.

Using the terms "defense" to mean bomber force protection, and "offense" to mean bombing the enemy, it, is generally true that defensive techniques detract from the offensive effectiveness of a bomber force, and vice versa. For example night bombing, which is resorted to principally for defensive reasons, is considerably less effective than day bombing. On the other hand, loss risk may be higher in daylight than at night if sufficient defensive firepower is not available.

In air war, relative firepower has the same importance as on land and sea. However, there is another factor which has a profound influence on operations; this we must categorically label "altitude." For consideration of this factor, level bombing is subdefined as "high level" bombing and "minimum altitude" bombing. Each is a distinct and basic technique offering possibilities of a tremendous variety of tactics to accomplish a mission or meet a situation.


Summary of
Altitude Effects
Altitude
Range
Bombing
Considerations
Defense
Considerations
0-300 ftMinimum altitude range. Highly effective tactics employable, particularly against mobile targets. Best weapon is medium and light bomber. Bombing accuracy is excellent.Highly maneuverable aircraft have best advantages. Multitude of forward-firing guns required to "sweep" enemy defenses. Difficult for ground guns to bear on attacking aircraft.
300-
3,000 ft
Beginning of high level bombing range. Minimum altitude tactics not possible. Bombing accuracy is very poor, due to difficult tracking of targets at high speed.Serious exposure to ground automatic weapons in their most effective range.
3,000-
7,000 ft
Still difficult to track ground targets due to relative speed of plane. Bombing accuracy poor due to this human error.Exposure to effective fire of light anti-aircraft. Fighter opposition becomes highly effective here.
7,000-
15,000 ft
Most accurate bombing range. Tracking errors slight. Mechanical errors increase steadily from 7,000 ft, but not enough to affect advantage of minimum tracking error. Best policy is to operate as little above 7,000 ft as possible, compatible with probably losses due to defense.Beginning of most effective range of heavy anti-aircraft and fighter defense.
15,000-
25,000 ft
Still highly effective bombing range, but mechanical errors increase appreciably.Unless A-A concentrations are large and elaborate, its effectiveness falls off markedly in this range. Fighter opposition, however, is still highly effective.
Over
25,000 ft
Fair bombing results possible, but bomb loads must be established and a number of misses are probable. Pattern bombing most effective technique. Bombs can still be confined to relatively small area with precision technique. Desirable altitude where maximum bomb penetration is required.Generally above effective anti-aircraft range, and fighter performance at this altitude favors the bomber.

Altitude Considerations
The term "high level" must be interpreted with caution because minimum bombing is employed at levels up to, roughly, 300 ft, and any level bombing operation above that altitude is high level. There is a definite physical reason for this definition. In minimum altitude bombing, the airplane is flown at the target and the principal component of a trajectory is horizontal. In high level bombing the trajectory is more or less vertical.

A direct hit against a target in minimum altitude bombing can be made only if the airplane speed in mph is something in excess of its altitude expressed in feet. This is illustrated on page 118, which shows a minimum altitude attack against a heavily armored ship where, with units of mph and feet of altitude equal, the bomb strikes the surface and does not reach the target directly. Inasmuch as the height at which minimum altitude attack may be executed is dependent on the airplane speed, it is obvious that this limit can be readily established and that it would rarely exceed 300 ft with airplanes of present day performance.

With respect to employment of bombing aircraft at altitude, the general rule is to operate at the lowest possible altitude consistent with bombing effectiveness and losses that can, be afforded. This may range from ground clearance altitude on up to 35,000 ft and it is well to have equipment available to conduct operations throughout this range.

Loss Factors

Minimum losses should always be an objective, but the term is relative and should be determined in the light of results achieved. For example, the loss of one heavy bomber on a mission against a lone enemy destroyer is far less tolerable than the loss of 30 bombers out of a force operating against the Ploesti oil fields.

Assuming that the enemy has "adequate" defenses, the greatest margin of safety for bombers lies at either extreme minimum altitude or extreme high altitudes. At minimum altitude it is difficult for ground elements to track a speeding low-flying airplane and to bring their guns to bear, except where gun emplacements are extensive enough to set up a barrage. At the same time, fighter aircraft are at a disadvantage because of limited diving ability. Medium and light bombers are most suitable for minimum altitude work because their relative maneuverability and high speed enable them to dodge defense barrage patterns more effectively and to elude fighter opposition. The heavy bomber is not sufficiently agile against determined opposition at low levels.

As the pattern of employment of aircraft types takes more definite shape with experience we see the medium bomber gradually taking over exclusive assignment to the minimum altitude technique while the heavy bomber specializes in the upstairs department. With simple fixed-angle sights, minimum altitude bombing is highly accurate — a highly thought-of technique where conditions permit.

Medium bombers are used for high level bombing, too, just as heavies have been employed in minimum altitude operations.

Generally, however, the heavy bomber is equipped with a synchronous precision bombsight which requires tracking the target by the bombardier. Just as it is difficult for ground gunners to track a speeding low-flying airplane, a bombardier has considerable difficulty in tracking a target on the ground.

Tracking error is a human error which diminishes markedly with altitude above 3,000 ft. However, the mechanical error of a bombsight and other instruments increases with altitude. With an average total error of 4 mil per 1,000 ft, this does not become too serious unless the operation is from extreme altitudes. However, it is a good reason for operating at lowest altitude consistent with average human error and adequate defense considerations.

Adequate ground defenses are most effective within the ranges of 300 ft (automatic weapons) to 12,000 or 15,000 ft (heavy anti-aircraft weapons). However, there are many instances where ground defenses are not adequate or where the target justifies losses — in which case operations may proceed at most favorable altitudes.

Formation

As stated before, factors which tend to enhance bombardment effectiveness also tend to decrease a bombardment force's defensive ability. As a matter of perfection, if a single bomb is aimed anywhere but directly at a target, it implies area bombing technique and involves a waste of bombs. By far, the most efficient employment of bomber aircraft is for each machine in the raiding force to make an attempt at the target with all possible precision. The hit probability per raid rises enormously under such employment conditions.

If a single plane attacked in such a manner, however, it would be seriously exposed to the combined effort of antiaircraft installations as well as enemy fighter opposition. A considerable number of individual bombers attacking a target simultaneously from a variety of directions and at varying altitudes will offer considerably less opportunity for accurate anti-aircraft tracking, but exposure of individual bombers to fighter opposition remains a problem. This is best solved by tight formation flying where a concentration of fire power can be mustered in any direction against fighter opposition and all bombers in the formation can act for mutual protection. Such formations, however, reduce the offensive efficiency of the bomber force.

Efficiency Growing Apace

The question of formation flying is very much open to development and perfection. Agreement on precise tactics is difficult to find among a group of tacticians. Some hold that the answer to both successful attack and defense is larger formations. Others hold that formations should include a. minimum number of aircraft which can provide adequate mutual protection against attack from any direction. This number has not been determined and the answer is, so far, elusive. "Minimum number" is in line with the efficiency theory, just as minimum bomb load to accomplish a mission is predicated on the striving for efficiency.

However, the AAF is operating substantial forces in a great variety of theaters and it seems certain that if there is an answer to this problem of correct formations, where a number of answers appear to be probable, the AAF will develop it along the lines of accomplishing its mission with the greatest possible efficiency. From this, the incorrect impression may be gained that our bomber forces are now flying in hit or miss fashion. On the contrary, the extreme flexibility of organization stressed in the preceding article (Aug Aviation) has provided for maximum adaptability to mission requirements. Much of this detail cannot be revealed for security reasons, but the determining factors are outlined in essence above.

In summary, the AAF bomber commands have developed a positive approach to their mission of destroying the enemy. They have developed a workable philosophy, highly effective tools, and a forceful organization. They have shown a high degree of ingenuity in employment. The entire structure has been built on the solid rock of efficiency.

This two-part article was originally published in the August and September, 1943, issues of Aviation magazine, vol 42, nos 8 and 9:
Part 1 in the August issue, vol 42, no 8, pp 114-121, 338-339.
Part 2 in the September issue, vol 42, no 9, pp 118-119, 333, 335, 337-338, 341.
The
PDF of this article includes nine charts, graphs and diagrams: along with sidebars on "Definitions of Tactics and Strategy" and
"Summary of Altitude Effects"