Early Attack Aircraft
|World War II|
During World War II these designators were used: A for attack. B for Bombardment, C for Cargo, L for Liaison, P for Pursuit and T for Training. This letter indicated the function of the plane. The following number indicated sequence within a type as in P-51. If there was a letter after the number it indicated an improved model type such as B-17E.
During World War II the primary mission of attack aircraft was to support ground forces in battle and aircraft were designed with this in mind. The attack aircraft provided support and operated primarily at low altitudes. Also considered a light bomber, the attack planes were known for their high speed, maneuverability and weapons. They carried both machine guns and bombs. The A-20, A-24 and A-26 were the attack aircraft most used by the AAF during the war.
During the Great War, the Germans attempted to employ attack aviation for more than just demoralizing the ground troops. The German High Command developed the "battle plane" (Schlachtflugzeug) as a battlefield breakthrough weapon to provide mobile firepower and shock effect. The Germans in 1917 were the first to organize massed, coordinated, low attacks against personnel targets--called "Sturm Staffeln" or "assault flights". British, French, Italians, and Russians all had attack aviation units in 1927, but were called different names. The Russians, for example, called attack aircraft "istrebityelniye," or "destroyers." The point being made was that the US should be prepared for and expect low flying attacks by "first class" powers.
William Mitchell was also one of the first Americans to recognize the value of attacks on morale along with other underlying principles in the use of attack aviation. In his Provisional Manual of Operations, 23 December 1919, he identified friendly and enemy troop morale as the object of attack squadrons.
By 1926, Air Service attack doctrine was modified to emphasize its value in delaying and disrupting the enemy ground force rather than its destruction. By 1926, Air Service attack doctrine saw fast, maneuverable, selectively armored, forward armed, two-seat aircraft with rear gunner as the best design for an attack aircraft. The Air Corps Act of 1926 changed the name of the Air Service to "Air Corps" and solidified the Air Corps' position as a combat arm within the Army. The Air Corps Act attempted to strengthen Army aviation by expanding the Air Corps over a five year period starting in 1926. For attack aviation, the number of squadrons would double from two to four. Additionally, the attack squadrons would be organized as an attack wing consisting of an attack group (the 3rd Attack Group) and a pursuit group, each with three squadrons, and designated as army aviation.
During the 1930s, Air Corps leaders such as MG Haywood Hansell at the Air Corps Tactical School (ACTS) developed a scientific approach to air power that has not evolved significantly since World War II. The ACTS took the offensive characteristics of air power pioneered by theorists such as Army BG William Mitchell and Italian Giulio Douhet to the next level, espousing a mechanistic approach to air planning. This approach dependson technology and the “uniqueness” of air power, requiring application through an autonomous air force comprised of airmen — Mitchell’s aerial knights — who understand air power’s inherent advantages. A consequence of this mechanistic approach was doctrinal thinking which largely ignored friction in war, instead considering conflict largely a vast engineering problem, solvable with enough effort and technology.
The Army viewed attack in terms of direct battlefield support, or what is called close air support (CAS) today. The direct support approach was based on fundamental beliefs by the Army that attack aviation was an auxiliary combat arm, to be used directly on the battlefield against ground forces and to further the ground campaign plan.
The Air Corps attack concept evolved from direct support to indirect support beyond the battle line (direct support was to be used only during times of emergency, or as the exception), or what is known today as air interdiction. The indirect support approach, or air interdiction, was derived from the fundamental beliefs by the Air Corps that attack aviation was best used beyond the battle line and artillery range, against targets more vulnerable and less heavily defended, to further both the Air Force mission and the ground support mission.
The Air Corps Tactical School advocated the indirect support approach and the subsequent evolution and logic in attack doctrine flowed from this approach. Air Corps theory and doctrine called for attack aviation to be used beyond the battle line. Aircraft were less vulnerable to ground fire and could be used to delay and disrupt enemy ground forces. Less cooperation was required with the ground forces while more cooperation was needed with other aviation branches, especially pursuit aviation. The Army Air Corps deemed that ground attack and observation missions were marginal and shifted toward bombardment. The National Guard stepped in and overtook the observation missions.
In the Air Corps Tactical School [ACTS] "Attack Aviation" text of March 1930, sixteen principles of employment were discussed. In brief summary, they included: "The necessity for flying at extremely low altitudes, preceding, during, and following the attack, was thoroughly demonstrated during the World War. The low flying airplane is relatively safe from hostile rifle fire and machine gun fire, and immune from anti-aircraft gun fire. As a protective measure against hostile air attacks, low flying is of special importance. "
The 1934-1935 ACTS text, "Attack Aviation", confirmed the basic principles of employment: "When attack aviation is acting in direct support of the ground forces, its striking power should be used against those targets which cannot be reached by the weapons of the ground arms. In all ground situations there are vital targets beyond the reach of the weapons of ground arms which can be powerfully dealt with by attack aviation."
After years of debate and struggle, the Air Corps' fight to become an independent air organization was again answered by reorganization without independence. On 1 March 1935, the War Department established the GHQ Air Force, primarily "as a new tactical unit of the Army." The 1939 "Attack Aviation" text called for increased range to support bombardment aviation, which signaled a shift in aircraft requirements to larger multi-engine aircraft for attack aviation. This shift was reflected at ACTS when in 1939 the Attack Section was renamed the Light Bombardment Section.
In the Spanish Civil War, the light bomber proved effective in support of ground forces while the machine-gun fire from fast-flying aircraft proved inaccurate. The war in Spain also showed the effectiveness of German anti-aircraft artillery and the need for armor protection for attack aircraft or higher altitudes as a measure of protection.
The Air Corps was extremely slow to develop a successful attack aircraft. The Air Corps used modified 0-1B observation planes for attack, named the A-3 (A-3A improved version). By 1931, the Air Corps lacked a standard attack plane and designated the A-3s and A-3As as "limited standard" and "substitute standard." Although an improvement over the DH-4Bs, the A-3s lacked the desired speed, maneuverability, armament, and armor required for attack operations. Observers attributed the problems to the tension between the size (weight) and the number of engines. Two schools of thought were present. One school argued for a relatively light, single-engine type, while others wanted a larger, two-engine ship.
The development emphasis on the single-engine monoplane type seemed to carry the day for school arguing for lighter and more maneuverable aircraft. The Curtiss XA-7 in 1930 was the first attack monoplane designed with built-in machine guns. In 1931, the Curtiss A-8 was introduced as an all-metal plane with an in-line engine. Then came the Curtiss A-12, "Shrike," an all-metal, two-seat monoplane available in 1934, while the Northrop A-17A was in development. However, all of these aircraft would also fail to meet attack aviation expectations. However, the twin-engine attack designs introduced in the late 1930s were more in accord with ACTS indirect support doctrine.
Having developed from oversized fighters, attack aircraft would come to fruition in the Douglas A-20 (design work started in 1936, and production aircraft began rolling off the line in 1939). With the arrival of the A-20, the Air Corps gained a solid aircraft-essentially a light bomber. The twin-engine Douglas A-20 Havoc was the first “attack-bomber” to enter the inventory. Its dual role was exemplified by the fact that units flying this attack aircraft were designated as bombardment, albeit light bombardment, squadrons.
Light bomber development was influenced by the need for attack aviation to support the air superiority mission of the GHQ Air Force. More range and payload was required of the new light bomber. Additionally, the Curtiss A-18, Douglas B-18, and Martin A-22 were twin-engine tactical bombers developed prior to WWII. Twins blurred the distinction between the low-altitude attack airplane and the medium-to-high altitude medium bomber. In effect, the light and, later, medium bomber would prove effective in the indirect, beyond the battle line, support role.
For the direct support of ground forces, the fighter was modified to be the fighter-bomber by the time of WWII. The first success was the North American A-36 (a converted P-51) which replaced the Brewster A-32 during WWII.
An Air Corps Board study in 1939 recommended standardizing the air fleet with a 5000-mile radius heavy bomber, a 2500-mile radius medium bomber, a 1500-mile radius short-range bomber, and an attack bomber with 500- to 700-mile radius. 148 However, as light bombardment took hold, some in the War Department argued for greater use of dive-bombers.
Since the end of the Great War, Air Corps theory had dictated the destruction of enemy airpower on the ground and en masse. To this end, in the New Guinea campaign, commanders made a conscious decision to target Japanese airdromes, the key to the enemy’s chance for air superiority; indeed, this mission became a specialty of Fifth Air Force. It is impossible to divorce the Fifth from Gen. George Kenney. Without question, his background and personality shaped the air war in the Southwest Pacific Area (SWPA). Kenney’s tactics relied on the creation of attack aircraft that were little more than flying gunships. A-20s in particular had been designed to conduct ground attack in direct support of troops, but neither the A-20 nor the B-25 had sufficient forward firepower in their original configurations.
For the A-20s and B-25s, the addition of forward firepower amounted to more than simple defense or offense. Strafing would become an integral part of attack and bomber tactics — and often an end unto itself. As the war progressed, strafing grew both in capability and application. Forward firepower created strafers out of light- and medium-bombardment aircraft, and the choice of bombs for those planes also changed their role in combat.
If the targets in the SWPA were airdromes, then the bombs applied against them needed to fit the target. Kenney contemplated the problem of destroying airdromes carved out of the jungle and protected by log and soil berms instead of improved concrete bunkers. To attack these “soft” targets, he recalled:
"While I was down at Langley I developed this parachute bomb — this fragmentation bomb with a little parachute on it so that you would be able to get away from the thing at the time it exploded, and as soon as I got out there [SWPA] I got the 3,000 of those bombs that were left over from early testing—back about 1929 or 30 and which nobody wanted — they were stored in some forgotten warehouse. I got them out there and put them to work and the first time we used them we destroyed 12 Japanese airplanes and killed about 50 men that were on the airdrome around the airplanes, and so that resulted in a wire to Hap Arnold to make me about five million of those things right away."
The explosive power of the 23-pound parafrag bomb was relatively small, but the nature of the target determined its effectiveness. The bomb would fall slowly above exposed targets such as airplanes and ground crews, its extremely sensitive fuse (fig. 6) detonating on first contact. The explosion scattered approximately 1,600 pieces of shrapnel, lethal to the unsheltered targets and personnel in the crude jungle airdromes.
The bombardment group also learned that strafing and parafragging made for a very effective combination. Dropping parafrags just above the enemy’s head was one thing, but strafing a clear path on the approach was another. More and more guns were added to light and medium bombers, “mainly for the purpose of covering the approach to drop the bombs, by forcing the man on the ground to seek cover, and to render hurried and ineffective any fire that he may open in return.”45 Crews found, just as prewar tactics had suggested, that fire from their new guns kept the enemy under cover, away from their antiaircraft weapons, and generally minimized the danger of the crews themselves getting shot.
During the first phase of the war, the attacks upon the enemy’s New Guinea airdromes clearly indicated that strategic bombers would play a significant role. As with the first parafrag attack on Buna, medium-altitude attacks by B-17s and B-26s preceded the strafers / parafraggers—contrary to prewar tactics, which assumed attackers were sent ahead of bombers to clear a flight path of antiaircraft artillery.
To say that Fifth Air Force abandoned (instead of modified) traditional bombing is popular but incorrect. The pattern of coordinated high-, medium-, and low-altitude bombing followed the Fifth to the end of the war. Modification and reutilization of medium bombers and light attackers like the B-25 and A-20 were only part of the bigger bombing picture, one that had its roots in prewar attack tactics.
The best example of air-ground effectiveness in Europe was the 3rd Army-XIX TAC team. Based on mutual understanding and proximity, GEN George Patton, commander of 3rd Army and BG Otto Weyland, commander of XIX Tactical Air Command [TAC], espoused close cooperation and forged an effective air-ground team. They used three primary aircraft for CAS, the P-51, P-38, and P-47. The P-47 performed best because of its durability, slower speed, and large, varied weapons load. Unlike aircraft such as the P-51, the P-47 was air-cooled, meaning it could take damage more readily without quickly overheating. This ability to absorb damage coupled with armor piercing ammunition made the P-47 a formidable CAS aircraft. Though the aircraft could carry 2,500lbs of bombs, pilots considered strafing a more effective form of attack, especially against unarmored targets, a method used today. Ironically, the P-38 and P-47 were designed for air-to-air combat, not ground attack.
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