The Front Machine Gun War: Spring of 1915 Through Summer 1916

Before the forwarded firing machine gun was introduce in the Western Front, all air to air encounters featured small guns, mostly pistols and single fire rifles, engagements which seldom generated in a shot down. A new method was in need if any of the combatants were to achieve air superiority over the other. The idea for the a nose mounted, forward firing, through the engines propellers; was conceived before the outbreak of hostilities in August 1915 but only France have ordered a model aircraft that was fitted with such a radical system: the Morane Type I. Unfortunately for France, the Type I proved to be an unreliable flying platform and it was quickly replaced by the most modern Type L. It was in a Type L that the famous French aviator Roland Garros (assigned to the Escadrille MS 23) shot down three German airplanes in early April 1915. His “victories” usher in a new age in air operations: the air-to-air combat. Garros’ Type L was fitted with the ingenious component designed by Saulnier. The propeller’s blades were fitted with steel plate deflectors to prevent bullets shooting off them. On the morning of April 19th, Garros’ Morane was shot down behind the German lines. The Germans took the plane and closely examined the propeller steel plates. At the same time, a German engineer named Schneider developed the Interrupter Gear which mechanically prevented the machine gun from firing at the instant a propeller blade passed the gun barrel. This new invention came in just as Anthony Fokker’s new scout, monoplanes were being assembled. Fokker’s team immediately began to fit each new model with the interrupter gear.

Fokker’s latest development was the Eindecker or E type which was a basic conceived scout platform design for reconnaissance patrols but not original intended for air to air encounters. The E type was initially deployed in small numbers in the Fliegerabteilungen. But it was not long before aces such as Oswald Boelcke and Max Immelmann figured it out how to engage and shot down Allied planes with their new, more maneuverable and, now armed with a workable machine gun system. These men, among others, were the ones who introduced the first series of rudimentary air combat tactics in the history of aviation. As more German pilots learned the art of combat tactics, casualties among the British and French air reconnaissance squadrons increased on an alarming rate. History records that on June 1915, four German E types downed the first French piloted aircraft utilizing the new interrupter as their main attack weapon. The following month, two British’s B.E.2Cs were forced to land by a formation of three E types. Those two encounters marked the first time a scout plane have managed to force out of the air an enemy plane. The stage was set for aerial combat to become more realistic and less romantic.

By early November 1915, the German air to air attacks had gathered them the name of “The Fokker Scourge”. But as with any conflict, the other side began to catch up, although slowly at first. In July 19th, the legendary ace pilot George Guinevere shot down a Fokker E type while flying a Morane/Saulnier Type N. On Christmas Eve, 1915, on his 19th birthday, the young flyer was awarded the distinguished Cross of the Legion d’Honeur. He would go one to shot down six more enemy aircraft before the spring of 1916 was over. But for all of his attributes, Guynemer did not generate the kind of excitement that the German ace Immelmann did. Know as the Eagle of Lille by the French, Immelmann was the first of many pilots (a list that included the most famous combat ace of all times, Manfred von Richthofen, the Red Baron) Oswald Boelcke instructed in the new arts of combat tactics. Boelcke’s legacy to flying can still be felt today. This bright and discipline German aviator was the first to put into writing the first series of combat maneuvers and counter actions. His actions on and off the battlefield earned him the prestigious Pour le Merite. Boelcke went on to record forty confirm victories before his death on October 28th 1916. Although Boelcke is now one of the most recognized figures of the early days of combat aviation, at the time of the beginning of the Great War, it was Immelmann, who commanded more respect and admiration, even from Germany’s enemies. Immelmann cold and calculated method of maneuvering coupled with the precision and lethality of his firing sequence, made him the more fear ace of his time. In a furious, albeit, short career; Immelmann managed to shot down fifteen Allied aircraft. But as in the case of many of his peers, he could not elude death in the skies. He was downed on June 18th 1916 near the town of Lens.

At first, the British were slow to adjust to the new air reality. Unlike the Germans, and to a lesser extend the French; the British were hesitate to, not only use the synchronize system, but to place grater emphasis on the monoplane design. During the late 1915 through the summer of 1916, British aircraft design and development was concentrated around the biplane platform, and to a lesser extend, the pusher airplane. The British thought, correctly at the time, that a biplane platform offer a much higher operational radius than a monoplane. The biplane design, so went the British thinking, maximized its much large lifting area in order to produce faster times and greater climb rate while preserving an overall high level of agility and structural integrity. The biplane, pusher platform was conceived in order to, not only achieve that profile but to gain an element missing from much of the British aircraft inventory: firepower. With the propeller blade sitting on the back of the airframe, the aircraft’s nose could now be fitted with a heavy, forward firing machine gun. This is how the venerable Airco D.H.2 was born. The D.H.2 design was destined to become the Royal Flying Corps’ (RFC) mainstay aircraft during the last months of 1915 and well into 1916. In fact, it was a squadron of D.H.2s, Number 24; that would become the RFC’s first true dedicated fighter formation. Commanded by Major Lanoe G. Hawker VC, the No. 24 reached French territory on February 1916. Until that time, the RFC was mostly utilizing outdated B.E.2Cs which have suffered tremendous losses in head to head encounters with E types during most of the autumn and winter of 1915. The B.E.2C and its companion platform, the F.E.2B suffered from, among other things, lack of fixed defensive armament and maneuverability speed. The new D.H.2s were not better platforms. Although it possessed a forward firing, heavy machine gun, the D.H.2 had a slow rate of turn and thus became an easy pray for the flock of E types now patrolling the skies above northern France. It is a testament to Hawker and the pilots he lead that they could, almost single handling, acquired air parity with Germany over the Western Front.

- Raul Colon

References:
The First World War, Hew Strachan, Penguin Books 2004
The German Army on the Somme 1914-1916, Jack Sheldon, Pen &Sword Books 2005
The World’s Great Fighters, Roberk Jackson, Chartwell Books 2001

Caribbean Intervention: The United States Air Effort over Haiti

The United States have a long standing history of military interventions in the Caribbean since the early 1890s. A trend that continued during much of the Twenty Century with US operations in the Dominican Republic, Grenada, Panama and finally, Haiti. The small country of Haiti on the Island of Hispaniola has been ruled by a military dictatorship during much of its existence. It was not until 1990 and the election of President Jean-Beltran Aristide that the country enjoyed its first true contact with democracy. Unfortunately, that contact was short lived. The fragile Haitian democracy was overthrown by elements of the military within a year of Aristide’s election. What followed him was a series of weak civilian politicians and several military juntas which left the country in an even more precarious position. The last of those military dictators, General Raoul Cedras, assumed control of the country in 1993. Cedras and some of his officials negotiated a series of deals with the United Nations which would have paved the way for Aristide to comeback into power. But time and time again, Cedras neglected to meet UN conditions resulting in the Security Council Resolution No. 940. The (UN 940) authorized all member states to use force, if necessary, to restore Haiti’s legitimate president to power. With the threat of a large American military intervention, Cedras finally capitulated to UN demands and in an August accord with former US president Jimmy Carter the Haitian strongman finally permitted Aristide to return home. A date was set for the ousted President triumphant return home, the 16th of October 1994. This time, the US would not sit back and wait for Cedras to change his mind as he has so often have done before. The Americans wanted to pressure the General to live up to his word this time. Thus the threat of force was viewed by many in Washington as the only alternative to exert that pressure and restore democracy to the Haitians.

Accordingly to the UN mandate of July 1994, the United States took the lead in assembling a Multinational Force (consisting on a huge US contribution and small elements from a few Caribbean nations) to outs Cedras and restore democracy in Haiti. In early 1994, the US’ Department of Defense began preparation for an invasion of that small Caribbean nation. Two plans were carved out. The first, Operation Plan 2370 called for an overwhelming military assault from the air, sea and land against a resisting enemy. While OP 2380 envisioned a large force being deployed into the country with limited, if any, organize resistance. In the end due to the somewhat calm political situation in the country, it was a modified version of OP 2380 which was finally implemented. On September 19th, 1994 a contingency of 2,000 US ground troop, most of whom members of the US Army’s 10th Mountain Division based at Fort Drum, New York; were airlifted to ashore from US Navy warships assigned to Task Force 190 located just off the Haitian coastline. The US Army venerable fleet of UH-60s were use to ferry the troops inland while a force of AH-1 Cobra attack helicopters provided close support to the formation. All Army helicopters, fifty-strong, utilized the USS Eisenhower (CVN-69) as their main staging area during those critical early hours. The first time an Army air operation was launched from a Navy carrier since Vietnam.

The role of the US Air Force in Operation Uphold Democracy was less visible than on previous conflicts. The AF’s assets were utilized primarily as a supporting structure with a few notable exceptions. Elements of the AF air transport system such as units of C-5s stationed at Dover AFB in Delaware and at Griffiss AFB in New York; augmented by C-141s and C-130s from McGuire AFB in New Jersey; were use to transport troops and equipment from the US mainland to one of the Navy’s largest bases, Roosevelt Roads Naval Base in Puerto Rico. To monitor activity in the skies above the theater, the AF deployed E-3 Sentries from the 552nd ACW based at Tinker AFB, Oklahoma. For air cover, twenty four F-15C Eagles of the 33rd Fighter Wing were dispatched from Eglin AFB in Florida to Roosevelt Roads where they were joined by nine KC-135 refueling tankers. Because a full fledge invasion was not require, all F-15Cs returned to their home base after only four days in the theater. The rest of the AF component consisted of three EC-130E from the 42nd ACCS, 355th Wing based at Davison/Monthan AFB, Arizona. The EC-130s were use extensively to survey the battlefield. A single RC-135 River Joint aircraft was deployed to monitor electronic signals emanating from the theater. For close air support, the AF sent two pair of AC-130H Specter gunships to the area.

The workhorse of the AF’s force was its KCs tankers. KC-135s flew 297 sorties, totaling 1,129 flying hours, during the initial days of the operation. This high sortie number had not been seen in the Caribbean since the Granada operation almost ten years before. The sheer number of US troops, the initial 2,000 deployment was augmented by 15,000 more ground troops within a week, assured the stability of the country as its moved back to democracy. On March 31st, 1995, the powerful US-lead MNF transferred its responsibilities for security to a broader assemble UN Peacekeeping Force which as of today, still guarantees the security and stability of Haiti as it begins to stabilize itself.

- Raul Colon

References:
How to Make War: Fourth Edition, James F. Dunnigan, HarperCollins Publishers 2003
The Encyclopedia of 20th Century Air Warfare, Editor Chris Bishop, Amber Books 2001

South Korean’s Stealth Fighter Takes Shape

As the year 2008 comes to a close, the South Korean government will be faced with a major decision. This decision could alter the balance of power in the Korean peninsula for the next three decades. At the heart of the “cross road” is to continued the developmental stage of the country’s first independent and indigenous produced stealth fighter. In late 2000, President Kim Dea-Jung’s government concluded that after years of an intense lobbying campaign in the United States Congress for the opportunity to acquire first generation F-22 Raptor stealth fighters from the United States, an effort that proved unsuccessful; South Korean would need to develop its own program if they were to have an operational stealth aircraft by the middle of the century. On may 2001 he proceeded to order a Feasibility Study regarding the ability of the country to produce its own stealth platform. The Korean Aerospace Industry (KF) immediately began research into the platform’s characteristics and profile. This study eventually concluded that such aircraft could in fact be designed and developed in-country. The first phase of the program, the Definition Study began in the spring of 2006 and concluded in December 2006. The second part, the Feasibility Study commenced in January 2007. The task was a join effort between KF, the Korean Development Institute, the Teal Group of aerospace consultants and a government-ran think tank. The study phase was finished in February of this year. During the feasibility phase, KF and its partners visited all the major US aircraft manufactures as well as its European counterparts. The visits were intended to gather support for a transoceanic venture involving one or more of the world’s biggest aircraft design and development companies. As of today, only SAAB has demonstrated profound interest in KF effort.

The KFX concept, as outlined by the Definition Study, would be a twin engine fighter with an all internal weapons carriage mechanism similar to the one on board the F-22. The internal carriage limited the aircraft’s cross radar signature. The KFX would have a performance envelop in the vicinity of the Boeing’s F-15K and the Lockheed Martin F-16C-D Block 52 air superiority fighters. The plane’s profile would also mimic that of the two mentioned US fighters.

As a technology “bridge” between South Korea’s Air Force current air inventory of F-15K and F-16C-D Block 52 and the new KFX, KF in partnership with Lockheed Martin, developed the FA-50 Light Attack aircraft. The FA-50 is a de facto upgraded version of the KF-Lockheed Martin join ventured TA-50 advance training airplane. The TA-50 is a light weigh and extremely maneuverable aircraft weight in at just above 6.5 metric tons (without its full weapons and fuel complement). The T-50 version took to the air for the first time on August 20th 2002 and became operational in February 2005. Over one hundred units of the T-50 had been delivered to the South Korean AF.

But South Korean “bridge” is getting closer to cross. The Korean government estimated that the $ 12 billion program should produce a workable air vehicle by 2017 with the first units entering frontal service four years later. So, if the decision to move forward is made, South Korea could very well field the forth stealth tactical squadron (Russia, Great Britain and France are working on their own stealth platforms) in the world. A truly remarkable achievement by any standards.

- Raul Colon

The Luftflotten Before D-Day 1944

Before the ground crumbled all around it, before the Allies invaded the Normandy coast, before the Soviet Red Army broke the back of the once vaunted German Wehrmacht, even before the German skies were completely filled with Allied bombers seemingly running without any hassle from German fighters, the once powerful Luftwaffe looked poised to stop the Allied push into Fortress Europe. In fact, real optimism ran through the Luftwaffe’s officer corps as new materials, men and fighting machines began to join the ranks. By the end of May 1944, the much maligned Luftwaffe possessed an impressive amount of fire power. Its ranks now was compromised of 2.8 million men and women. Its overall air assets were now at 4500 combat ready aircraft with new and more powerful platforms, such as the Messerschmitt Me 163 and Me 262 jet fighters as well as the Arado Ar 234 jet bomber; commencing to enter front line service. These aircraft types were augmented by a new force of redesigned Heinkel He 177 heavy bombers. The Luftwaffe was also in the final stages of having the Fi 103 or V-1 flying pulse bomb and the much powerful A-4 (V-2) rocket, ready for operational debut.

This infusion of materials was mainly the work of the Ministry of War Production under the tutelage of one Albert Speer. Since late 1942, German aircraft production had been taken a pounding from the constant bombing done to its infrastructure by the British Bomber Command at night and the United States Army’s Eight Air Force during daylight. Nevertheless, Speer pushed ahead. He streamlined production by removing many unproductive aircraft models, dispersing production of airframes, air systems and more importantly, engine parts; to twenty seven main production centers dispersed in the Fatherland. He also oversaw the construction of a few major underground facilities completely dedicated to the final assembly of aircraft. Most important to the Luftwaffe’s war effort was the development of aviation fuel, which had at times curtail air operations, In 1944, aviation fuel production reached an all time high in March with the production of just under 200000 tons. This figure raised the Luftwaffe’s strategic reserves to an all time high of 580000 available tons. The direct result of all of those measures was that the total output of German air industry increased by fifty percent over the past December. On the downside, by April 1944, the Luftwaffe was looked by an uneasy public with contempt at best. Its main mission role, the defense of the Fatherland, had been a colossal failure by any standard. Thus the public’s faith and respect on what was once their more proud armed service, was lost. But this paled in comparison to the Force’s main problem: the ability to maintain an experience pilot program. The attrition of the German pilot element lead to the rush of untested, and sometimes, unqualified young recruits to the front lines. This “revolving door” policy cut deep into the overall effectiveness of the German Air Force. Because of this, the Luftwaffe’s tactical reserve formations were decimated and in some instances, they were none existent. Nevertheless, by April 1944, the Luftwaffe that the Allies were facing was a more advance and better tactical and strategic force that the one they faced from early 1942 onwards.

The strength of the Luftwaffe laid on its Luftflotten or air fleets. The Luftflotten was the German AF main fighting force. Every Luftflotten formation is compromised by elements of all type of aircraft, pilots, support crew compliment and an Anti-Aircraft Batteries detachments. These formations were grouped by geographical areas. The most powerful Luftflotten force was the Luftflotte Reich. The Luftflotte Reich was based in air bases across Greater Germany area which compromised all of Germany itself, Austrian and the western sections of Czechoslovakia. This was the force that was assigned the bulk of the air defense of the Fatherland at all times. Because of this, this was the most equipped and trained formation the Luftwaffe possessed. Its commander, generaloberst Hans-Jurgen Stumpff, was the commanding officer of Luftflotte Number 5, based on Denmark and Norway, during the Battle of Britain. The Number 5 was basically a tactical reserve force, seeing limited combat action, mostly later in the conflict. Now the confident Stumpff commanded the Luftwaffe’s last line of defense against the combine might of Bomber Command and the 8th Air Force.

His force was compromised of just 555 operational day fighters, 421 night interceptors, 302 bombers and an array of various other type of aircraft for a grand total of 1,348 serviceable airframes. A woeful amount to defense such a vast space against such a powerful opponent. Beside the sheer numbers laid the fact that of 555 day fighters, available, the vast majority were outclassed Bf 109Gs, Fw 190s and Me 410s which were not competition for the new P-47s and P-51s. Luftflotte Reich was able to “post” 302 bombers on its operational lists on 21 Gruppen or squadrons. Five of those Gruppens were not operational between February and May because of their transitions to the new He 177 bomber platform. The pathfinder force consisted on one Gruppen, I/KG66, assigned to support all bomber activity. They were armed with aging Junkers Ju 188s reconnaissance planes. This unit was one of the most hardest hit Gruppens on the Luftwaffe’s list. It had suffered tremendous losses in the Battle of Britain, even to the point of being deemed a “paper force” without any real aircraft, so at the time of D-Day, they were in a re-formation mode. Gruppen III/KG 3 was converting a version of the venerable He 111 to carry the new Fi 103 pulse flying bombs. Others bombers formations were having similar transition issues. By April, the Luftflotte Reich only ground attack unit, the III.-SG 3, was being replenish with improved Fw 190s. This unit would be send to the Eastern Front where it was decimated within just two months. There were two dedicated units attached to the Luftflotte Reich. The first, the Versuchsverband Ob.d.L. was designated to conduct experiments and testing on captured Allied aircraft and systems. The other was the I.KG 200 which operated capture Allied transport planes such as the Douglas DC-3, Boeing’s B-17 and Liore et Oliver 246 seaplanes. All aircraft flown by I.KG 200 were utilized to transport German infiltration units inside Allied lines. Despite what many historians had stated, there’s no official records indicating that any of these aircraft wore any other insignia beside the Nazi logo.

The second major Luftwaffe formation was Luftflotte 3rd or the Western Air Force as its was later known. As its name suggest, Luftflotte 3rd was assigned to exclusively to the Western Front where it awaited the impending massive Allied air assault in preparations to the expected cross Channel invasion of Fortress Europe. The force was commanded by Generalfieldmarshall Hugo Sperrle who had orchestrated the Luftwaffe’s tactical attacks on French formations during the successful 1940 Blitz. At the heart of the Western AF was Fliegerkorps X, an specialized anti-shipping formation which would be crucial if the Germans were to curtail the allied invasion. The force had 539 operational aircraft at its disposal. Seventy five percent of the force consisted of Fw 200s, He 177s and Dornier Do 217s. The Do 217s were modified to carry the new Henschel 293 and Fritz X radio-guided attack missiles. The other aircraft of the X were Junkers Ju 188s armed with torpedoes. The other main force in the Western AF was Fliegerkorps IX with its complement of 137 aircraft including Ju 188s, 88s and Do 217s. The Luftflotte 3rd was based on several airfields in Belgium, Holland, western Germany and eastern France; all within range of the Atlantic Wall. As was the case with Luftflotte Reich, the 3rd were to be completely overwhelming by its assigned task. Its air defense assets were allocated on only six gruppens with an overall total of serviceable airplanes of just 115 Bf 109s and Fw 190s. Augmenting the 3rd were two Gruppens of Ju 88 long range fighters utilized for U-boat screening.

By the beginning of April, the Luftwaffe had made plans to transfer fighter Gruppens from Luftflotte Reich to northern France in an effort to assist the overwhelmed Western AF. This transfer of assets would had depleted the Reich force and had left Germany basically at the mercy of the bombers. Nevertheless, the Luftwaffe counted that during the first weeks of the invasion, the majority of the allies aircraft would be employed supporting the invading troops. It is here were the lack of Luftwaffe’s resources played a pivotal role. The German Air Force knew they would not be able to stop the landings, only, if they were lucky, delayed it until the Wehrmacht’s reserve units could be rushed to the front. To do this, the Luftflotte 3rd needed more close air support fighter/bombers, but thanks to the massive rate of attrition on the Eastern Front, the 3rd only possessed two operational Gruppens with just 48 Fw 190s among them. A woeful number to steam a powerful invasion.

As sad as the state of the Luftflotte forces on the West was, their counterparts on the Eastern Front were on the verge of total collapse. In May 1944, the Luftwaffe deployed four Luftflotte forces, the 1st, 4th, 5th and 6th on a vast 1500 mile front extending from the Arctic Ocean on the north to the Black Sea on the south. The 5th had its bases located on Norway and Finland and was assigned the northern part of the front. The 1st was stationed along a moving set of bases in the Baltic coast and the ever shrinking Leningrad sector. Luftflotte 6th operated on the center of the front while the 4th covered the south portion of it. The 5th, under the command of general Josef Kammhuber had only 193 operational aircraft. It only possessed two day fighter Gruppens of Bf 109s. One Gruppen of Ju 88s and Fw 190 for close ground support plus a Gruppen of Ju 87s for night operations. There were also a Gruppen of Ju 52 floatplanes and three small Staffeln (sub-groups of 10 to 15 aircraft) of Ju 188s and 88s long distance reconnaissance platforms. The 1st was in better shape. Its commanding officer, general Kurt Pfugbeil, commanded a force of two fully equipped day fighter Gruppens, two Staffeln of night fighter/bombers and another one of He 111 bombers. This force was augmented by three additional night attack and two close air support Gruppens.

The 6th was lead by generaloberst von Greim. Although the 6th covered the most space among the Eastern Luftflotte, it only had two operational Gruppens plus two Staffeln of day fighters at its disposal. What the force lacked in fighters it made it up with its bombers. Luftflotte 6th had eleven Gruppens of He 111 bombers, three Fw 190s and Ju 87s Gruppens for ground attack missions and a single night fighter Gruppen of Ju 87s. It also possessed three Staffeln of long range reconnaissance planes plus two additional Staffeln for short-to-medium range reconnaissance operations. A sole Gruppen of Ju 52s transport planes was also at Greim’s disposal.

The last of the Eastern Front forces was the southern air fleet, Luftflotte 4. The 4th was under the command of generaloberst Desloch. Since his force sat on the area of front where the Germans expected the main axis of the Soviet offensive to come in, Desloch’s group was well equipped with ten Gruppens of ground attack planes, seven of day fighters and two more of night fighters. These formations were augmented by four Staffeln of long range reconnaissance airplanes. There were also two and a half Gruppens of transport aircraft equipped with Ju 52s and Italian Savoia Marchetti SM.82s which were manned by Italian pilots loyal to Fascist leader Benito Mussolini.

On the extreme southern part of the 1500-mile front rested the last Luftflotte formation, the 2nd. Based in Italy, the 2nd was assigned the central and western Mediterranean area of air operations. Lead by generalfeldmarschall Wolfram von Richthofen, the 2nd was basically a “paper” force. In “paper” it can field four day fighter, three bomber and two close air support Gruppens. Augmented by two long range and one short range reconnaissance Staffeln. A Gruppen of transport aircraft was also “available”. In paper this force looked impressive, specially for their area of operations, by this time, the central and western parts of the Mediterranean Sea were basically off-limits to German air formations. But this was on paper alone. The reality was That because of the massive Allied air superiority on the Mediterranean and the absent of any major German operations in the area, the air assets of many of those Gruppens were re-allocated to other Luftflotte forces.

Beside the great air fleets, the Luftwaffe operated several other smaller air formations. Chief among them was Luftwaffenkommando Sudost, a force compromised of two day and one night fighter Gruppens, a Staffeln of Ju 88s plus three Staffeln of reconnaissance aircraft. There was also a depleted Staffeln of Ju 87s for close air support. But its main air asset was one Gruppen of Me 323s transport airplanes plus two Staffeln of Ju 52s seaplanes. The transport aspect of the force was at the heart of its mission profile which was the resupplying of German Army garrisons on the Greek Islands.

Overall, before the Allied invasion of Hitler’s Europe, the state of the various Luftwaffe formations was impressive. By May 1944, he Luftwaffe presented a massive air armada. A force that, in any other occasion, take out any one. But constant fighting on four continuing fronts had and would again take the bite out of this re-constituted force.

- Raul Colon

References:
German Aircraft of the Second World War, EJ Creek and JR Smith, Putnam Books 1972
Six Months to Oblivion, Allan Ian, Shepperton 1975
Air Power: The Men, Machines, and Ideas that Revolutionized War, Stephen Budiansky, Penguin Group 2004
The German Navy, Edward Von der Porten, Thomas Crowell Company 1969
The Bomber War: The Allied Air Offensive Against Nazi Germany, Robin Neillands, The Overlook Press 2001