American bombers and transport aircrafts

[gekho]

World War II was not won by bombers alone, but the use of the heavy, strategic bomber was essential to victory both in Europe and in the Pacific Theaters. The Allied powers, led and principally supplied by the United States, pounded from the air every means of production and transport in the Axis held territories. In addition, fleets of bombers hunted submarines, supported offensives, and thwarted enemy tactics by attacking any concentration of troops or war supplies. The combination of air power, sea power and land armies eventually rolled the aggressor nations back to Berlin and Tokyo, ending the war in 1945.

he WW II Bomber air campaign in Europe was called the Combined Bomber Offensive (CBO), a cooperative effort of the United States and Great Britain aimed at defeating the German war waging capability. From 1942 to 1945, the strategy used heavy bombers to destroy German industrial capabilities, military production facilities, supply lines and communication network, and to pound down the German people's will to fight. This campaign was considered as a preliminary step for the D-Day invasion of Normandy. While the CBO did not alone win the war, it was a necessary component of the total effort which did lead to Germany's unconditional surrender in May 1945.

In the Pacific, bombers were used from the outset of U.S. involvement, starting with the Mitchell Raid on Tokyo in April 1942. Bombing of naval and ground targets was first used to defend against Japanese advances, then shifted to support of the American advances, and finally to strategic bombing of the Japanese home islands. Before the war ended on 2 September 1945 with the unconditional surrender of Japan, thousands of heavy bombers were flying around the clock to destroy every valid target. The atomic bombings of Hiroshima and Nagasaki on 6 August and 9 August 1945, were the most dramatic single attacks, but massive conventional bombing operations were also horribly devastating and effective.

Of the many different bombers used by the U.S. and its allies during World War II, the B-17, B-24, B 26, and B-29 were the workhorses of the U.S. Army Air Forces fleet. The B-25 "Mitchell" and B-26 "Marauder" were medium bombers used mainly at altitudes of 8,000 to 14,000 feet. They primarily supported ground forces by targeting fortified positions, depots, railroad yards and other targets behind battle lines in addition to supplementing heavier bombers on strategic raids. The B-17 "Flying Fortress" was the first of the big bombers used during World War II. It was used mainly by 8th Air Force in Europe but was employed, in much smaller numbers, in the Pacific Theater.

 

[gekho]

The Martin MB-1 was a 1910s American large biplane bomber designed and built by the Glenn L. Martin Company for the United States Army Air Service. It was the first purpose-built bomber produced by the United States. In 1921 Martin produced its KG.1 variant of the MB-1, with 10 purchased by the Navy as a torpedo bomber under the designation MBT. After two were purchased, the designation was changed to Martin MT. In response to a requirement from the Air Service for a bomber that was superior to the Handley Page O/400. Martin proposed the MB-1 and were rewarded with an initial production contract for six aircraft. The MB-1 was a conventional biplane design with twin fins and rudders mounted above the tailplane and a fixed tailwheel landing gear with four-wheel main gear. Powered by two 400 hp (298 kW) Liberty 12A engines. It had room for a crew of three in open cockpits.

Initial delivery to the Air Service was in October 1918, with the aircraft designated GMB for Glenn Martin Bomber. The first four produced were configured as observation aircraft, and the next two as bombers. Four others were produced before the end of World War I cancelled all remaining war contracts. The last three aircraft each were configured experimentally, with separate designations: GMT (Glenn Martin Transcontinental), a long range version with a 1,500 mi (2,400 km) range; GMC (Glen Martin Cannon) with a nose-mounted 37 mm (1.46 in) cannon; and GMP (Glenn Martin Passenger) as an enclosed 10-passenger transport. The GMP was later re-designated T-1. Six surviving aircraft were later modified and used by the United States Postal Service as mail carriers. The design was the basis the Martin MB-2, which had a greater load capability but was slower and less maneuverable. Ten aircraft were used by the United States Navy from 1922 under the designations MBT and MT and were used as torpedo bombers, two by the Navy and eight by Marine Corps squadron VF-2M.

 

[gekho]

The Martin NBS-1 was a military aircraft of the United States Army Air Service and its successor, the Air Corps. An improved version of the Martin MB-1, a scout-bomber built during the final months of World War I, the NBS-1 was ordered under the designation MB-2 and is often referred to as such. The designation NBS-1, standing for "Night Bomber-Short Range", was adopted by the Air Service after the first five of the Martin bombers were delivered. The NBS-1 became the standard front line bomber of the Air Service in 1920 and remained so until its replacement in 1928-1929 by the Keystone Aircraft series of bombers. The basic MB-2 design also was the standard against which prospective U.S. Army bombers were judged until the production of the Martin B-10 in 1933.

The NBS-1 was a wood-and-canvas biplane without staggered wings, employing twin rudders on a twin vertical tail. Its two Liberty 12-A engines sat in nacelles on the lower wing, flanking the fuselage. Ordered under the company designation MB-2 in June 1920, the NBS-1 was an improved larger version of the Martin MB-1 bomber built by the Glenn L. Martin Company in 1918, also known as the GMB or Glenn Martin Bomber. The first flight of the MB-2 took place 3 September 1920. In addition to more powerful engines, larger wings and fuselage, and simplified landing gear, the NBS-1 also had a unique folding-wings system, hinged outside the engine nacelles to fold backwards for storage in small hangars. Unlike the MB-1, whose engines were mounted between the wings in a fashion similar to the German Staaken R.VI R-bomber, the engines of the NBS-1 were fixed to the lower wing over the landing gear.

The MB-2 was designed as a night bomber and except for a greater load capacity, had reduced performance characteristics compared to its MB-1 predecessor. The first 20 (five MB-2 and 15 NBS-1) were ordered from the Martin Company, which recommended a further 50 be produced to help its struggling financial condition. However the design was owned by the U.S. Army and subsequent contracts for 110 bombers were awarded by low bid to three other companies: Lowe Willard and Fowler Engineering Company of College Point, New York (35 ordered), Curtiss Aircraft (50), and Aeromarine Plane and Motor Company of Keyport, New Jersey.

The engines of the last 20 bombers of the Curtiss order came equipped with turbosuperchargers manufactured by General Electric, the first such modification made in production quantity. Although enabling the NBS-1 to reach an altitude of over 25,000 ft (7,650 m), the turbosuperchargers were mechanically unreliable and not used operationally. The bomber was equipped defensively with five .30 in (7.62 mm) Lewis Guns, mounted in pairs in positions in the nose and upper rear fuselage, and singly in a bottom mount firing behind and beneath the rear fuselage. The first two Martin MB-2s, Air Service s/n AS64195 and AS64196, were retained at McCook Field in Dayton, Ohio, for R&D flight testing, marked with project numbers P162 and P227 respectively, as was the second NBS-1 (AS64201), marked as P222. Four Curtiss NBS-1s were also assigned to McCook.

The NBS-1 was the primary bomber used by Brigadier General Billy Mitchell during Project B, the demonstration bombing of naval ships in July 1921. Six NBS-1 bombers, led by Captain Walter Lawson of the 96th Squadron operating out of Langley Field, bombed and sank the captured German battleship SMS Ostfriesland on 21 July 1921, using specially-developed 2,000 lb (907 kg) demolition bombs externally mounted beneath the fuselage.

 

[gekho]

In development at the same time as the Keystone XB-1, the Curtiss XB-2 was quite similar but proved to be the superior aircraft. Like the Keystone design, the XB-2 also mounted dual Lewis guns in turrets located in the rear of the engine nacelles.

A crew of five was carried by this bomber with a performance rating that placed it far above any planes in its class. Testing of the XB-2 began in September, 1927, and though the qualities were superior to competing types, the higher cost of the B-2 resulted in a limited production order of only 12 planes in June, 1928. The first B-2 was delivered in May, 1929. In view of the excellent performance of the Condor, it is interesting to note the biplane tail assembly used. Production B-2's were the first aircraft of the type to incorporate tail wheels instead of the skid which assisted in braking, but was also responsible for structural failures.

The XB-2 competed for a United States Army Air Corps production contract with the similar Keystone XB-1, Sikorsky S-37, and Fokker XLB-2. The other three were immediately ruled out, but the Army board appointed to make the contracts were strongly supportive of the smaller Keystone XLB-6, which cost a third as much as the B-2. Furthermore, the B-2 was large for the time and difficult to fit into existing hangars. However, the superior performance of the XB-2 soon wrought a policy change, and in 1928 a production run of 12 was ordered. A later version of the B-2, dubbed the B-2A, featured dual controls for both the pilot and the copilot. Previously, the control wheel and the pitch controls could only be handled by one person at a time. This "dual control" setup became standard on all bombers by the 1930s. There was no production line for the B-2A, though a B-2 was converted to follow its setup. The B-2 design was also used as a transport. The B-2 was quickly made obsolete by technological advances of the 1930s, and served only briefly with the Army Air Corps, being removed from service by 1934. Following production of the B-2, Curtiss Aircraft left the bomber business, and concentrated on the Hawk series of pursuit aircraft in the 1930s.

 

[gekho]

The Keystone B-3A was a bomber aircraft developed for the United States Army Air Corps in the late 1920s. It was originally ordered as the LB-10A (a single-tail modification of the Keystone LB-6), but the Army dropped the LB- 'light bomber' designation in 1930. Though the performance of the B-3A was hardly better than that of the bombers flown at the end of World War I, it had come a long way. In terms of its safety, it was far superior to its oldest predecessors.

The B-3A was the last biplane disbanded by the Army; it remained in service until 1940. A few years after it was first produced, the introduction of all-metal monoplanes rendered it almost completely obsolete. The B5 version was the same as the B-3A, except for Wright R-1750-3 Cyclone engines; only 27 were delivered.

 

[Wayne Little]

Cool!

 

[vikingBerserker]

Great info!

 

[Gnomey]

Good stuff!

 

[gekho]

The Keystone B-4A Panther was ordered alongside the B-6A, and together they were the last biplane bombers to enter American service. Later in the 1930s the entire Panther range would have been given a single B designation with the changes of engine indicated by model letters, but in the early 30s minor changes were often given new designations. The B-3 and B-4 were both powered by Pratt Whitney engines, the B-5 and B-6 by Wright engines. The B-3 and B-5 of 1930 both had 525hp engines, the B-4 and B-6 of 1932 both had 575hp engines.

Like all of the Panthers the B-4A was armed with three 0.30in guns, one in the nose, one in the rear cockpit and one in a fuselage tunnel. The B-4A carried the same bomb load as the earlier B-3A, and had the same operational range. The more powerful engines did give it a slightly increased top speed, but by the time the B-4A entered service in 1932 the Martin B-10 was already under development, and this modern all-metal monoplane would make the Panther obsolete - it had a maximum range twice that of the B-4A and a top speed of 215mph.

Five Y1B-4 service test aircraft were produced by modifying aircraft first ordered as the LB-13. They were then followed by twenty-five production aircraft, which entered service in 1932. A number of the B-4As were used during the Air Corps' brief airmail experiments during the first half of 1934, but the bombers were not overly successful in that role – the presence of the heavy cargo loads in unexpected placed affected the balance of the aircraft. By the mid 1930s the B-4A was obsolete as a bomber, but some remained in use as observation aircraft into the 1940s.

 

[gekho]

The Keystone LB-6 was an 1920s American light bomber built by the Keystone Aircraft company for the United States Army Air Corps. It was called the Panther by the company but adoption of the name was rejected by the U.S. Army. The LB-6 was the first operational service model of a 13,000 lb (5,897 kg) twin-tail biplane bomber of a series produced by Keystone that included the follow-on LB-7 bomber. A number of variants were built for test and evaluation purposes but never placed into production or service.

According to the performance figures given by the National Museum of the USAF the LB-6 and LB-7 had exactly the same performance figures. This should not really surprise, as the two aircraft were of identical design, and were both powered by 525hp radial engines. The LB-7 was used as the basis for a number of experiments with new engines. One became the single LB-8 when it was given geared Pratt Whitney R-1860-3 radials. Another became the single LB-9 after receiving geared Wright Cyclone engines, and a third became the XLB-12 and was used to test the Pratt Whitney R-1690-3 engine.

The LB-7 was the last entry in the Light Bomber series to enter production. An order was placed for 63 LB-10s, but these were all produced as either the B-3 Panther or B-5 Panther. On 5 August 1929 nine LB-7s, each with 11-12 hours of gasoline onboard, left Langley Field heading for Rockwell Field California, to take part in the national air races. In 1928 the outward journey had taken six days, but in 1929 the LB-7s reached Rockwell in 40 hours, arriving on the evening of 6 August. Three off them then immediately carried out a practise mission of Point Loma. One was used in the 1930 exercises as a transport aircraft, and despite claims that all LB aircraft were give B designations in 1930, four LB-7s, with their original designation, were used in the 1931 Air Corps exercises.

 

[gekho]

In the late 1920s the US War Department was taking note of developments in aircraft design, such as the technical revolution created by the appearance of all-metal cantilever monoplanes with retractable landing gear. It was decided initially to adopt such features in twin-engined aircraft that were intended for fast long-range reconnaissance, and the War Department ordered two Fokker XO-27 prototypes in this category. Fearing it might lose a valuable source of revenue, Douglas designed an aircraft incorporating such features and in March 1930 received an order for one example each of the Douglas XO-35 and Douglas XO-36. They were intended to differ only in their engines, the former having geared Curtiss Conquerors and the latter a direct-drive version of the same engine. In the event, the XO-36 was redesignated XB-7 and built as a bomber. In a parallel development the second of the Fokker XO-27s was completed as the XB-8 bomber. Later, six YO-27s and six Y1O-27s were delivered to the US Army.

The Douglas XO-35 was test-flown in spring 1931, causing quite a stir among a public used to seeing the lumbering twin-engined biplanes used by the US Army. It was a slim monoplane with a gull wing set high on the fuselage, the main units of its landing gear retracting into streamlined engine nacelles leaving only the lower part of the wheels exposed. The engine nacelles were attached to the wing undersurfaces and fuselage sides by complex strut assemblies, with the fuselage having corrugated metal sheet covering. There were open gunners' cockpits in the nose and amidships; the pilot's open cockpit was located immediately forward of the wing leading edge; and the fourth crew member, the radio-operator, had an enclosed cabin behind the pilot's position. The XB-7 was almost identical, but had underfuselage racks for up to 544kg of bombs. During the US Fiscal Year 1932 orders were placed for seven Y1B-7 and five Y1O-35 service-test aircraft. These differed from the prototypes mainly by having smooth metal sheet covering for the fuselages, and strut- rather than wire-braced horizontal tailplanes.

The Y1B-7s, later designated B-7, were attached to the two US Army bombardment squadrons based at March Field, California, while the O-35 aircraft (previously Y1O-35s) flew with observation units. In February 1934 the five O-35s, six surviving B-7s and XO-35 prototype were all assigned to the air mail route linking Wyoming with the west coast of the United States. Operations at night and in bad weather took their toll and in the four-month emergency period during which the US Army ran the nation's air mail service no fewer than four of the B-7s were lost in crashes. Soon afterwards the remaining B-7s and O-35s were relegated to second-line duties, an O-35 being the last to be grounded in February 1939.

 

[gekho]

The Boeing YB-9 was the first all-metal monoplane bomber aircraft designed for the United States Army Air Corps. The YB-9 was an enlarged alteration of Boeing's Model 200 Commercial Transport. In May 1930, Boeing had flown its Model 200 Monomail single-engined mailplane. The Monomail was of radical design for the time, being a semi-monocoque, stressed skin cantilever monoplane with a retractable undercarriage. The United States Army Air Corps bomber squadrons were largely equipped with slow biplanes such as the Keystone B-6, and Boeing decided to design and build a twin-engined bomber using the same techniques used in the Monomail to re-equip the Air Corps.

Using its own money, Boeing decided to build two prototypes of its new bomber design as a private venture. The two aircraft differed only in the engines used, with the Model 214 to be powered by two liquid-cooled Curtiss V-1570-29 Conqueror engines while the Model 215 had two Pratt Whitney R-1860 Hornet radial engines.[3] Both aircraft were low winged cantilever monoplanes with a slim, oval cross-section fuselage accommodating a crew of five. The pilot and co-pilot sat in separate open cockpits, with the co-pilot, who doubled as the bombadier sitting forward of the pilot. Two gunners, each armed with a single machine gun sat in nose and dorsal positions, while a radio operator sat inside the fuselage. Like the Monomail, a retractable tailwheel undercarriage was used.

The first of the two prototypes to fly was the radial powered Model 215 which, carrying civil markings and the aircraft registration X-10633, made its maiden flight on April 13, 1931. It was leased to the Air Corps for testing under the designation XB-901, demonstrating a speed of 163 mph (262 km/h). Testing was successful, and both the XB-901 and the as-yet incomplete Model 214 were purchased as the YB-9 and Y1B-9 respectively on August 13 1931, with an order for a further five for service testing following shortly. The Y1B-9 (Y1 indicating funding outside normal fiscal year procurement), powered by two liquid-cooled Curtiss V-1570-29 'Conqueror' engines, first flew on November 5 1931. The increased power from these engines, combined with increased streamlining of the engine nacelles, increased its top speed to 173 mph (278 km/h). The YB-9, meanwhile, had been re-engined with more powerful Hornets, demonstrating slightly better performance than the Y1B-9, which was therefore also re-engined with Hornets. With the exception of the B-2 Condor, liquid-cooled engines were never used on production bombers for the United States military. The air-cooled radial engine was lighter and more reliable than the liquid-cooled engine, and less vulnerable to enemy damage.

The five Y1B-9A service test aircraft had the R-1860-11 Hornet engines which powered the re-engined YB-9 and Y1B-9 and a redesigned vertical stabilizer. While enclosed canopys were consided and designed, the B-9 was never fitted with them. Although it equalled the speed of all existing American fighter aircraft, no further aircraft were built, as the Glenn L. Martin Company had flown a prototype of a more advanced bomber, the XB-907, which was ordered into production as the Martin B-10. The first of the five Y1B-9As entered service with the 20th Bomb Group on September 14, 1932, with all being in service by the end of March 1933. The new bomber proved impossible to intercept during air exercises in May 1932, strengthening calls for improved air defence warning systems. Two B-9s were destroyed during crashes in 1933, one of the accidents being fatal, while the remaining aircraft were gradually phased out over the next two years, with the last being withdrawn on April 26, 1935.

 

[gekho]

The Martin B-10 medium bomber was a breakthrough design for American military aviation when it appeared on the scene in 1932. Though made obsolete at the outbreak of hostilities in World War Two, the type persevered in other forms thanks to export customers. In the end, over 300 examples of the type would be produced that would cover the B-10 and the marginally improved B-10 in the form of the B-12.

Once in production and reaching operational status, the B-10 became the first American designed and bomber made of all-metal construction practices and produced in any quantity. The system was also the first design for the Americans to feature armament that was fitted to turrets for increased defensive performance against enemy fighters. In any case, the B-10 held many evolutionary breakthroughs in the field of military aviation for the United States - practices and design lessons that would sure play a role in future bomber needs just years later.

The Martin B-10 was a twin engine medium-class bomber fitted with Wright-brand R-1820 G-102 Cyclone 9-cylinder radial piston engines. The engines were fitted on what would become the USAAC's first attempt at a cantilever low-wing monoplane design. The crew of four were placed about in windowed positions which consisted primarily of the nose compartment, the cockpit and a mid-to-rear glazed area. Armament was strictly defensive and consisted of a single 7.62mm machine gun in the nose, a single 7.62mm machine in a dorsal position and still another single 7.62mm machine gun in a ventral position. Maximum bombload was limited to 2,260 pounds of internal ordnance.

Export customers kept the B-10 production lines moving along well after the United States Army Air Corp had removed the type from its service. Primary customers included the Netherlands with an order of 120, Argentina with 35 and Thailand and Turkey with 26 and 20 respectively. Though outclassed in a few short years, the B-10 was nonetheless a design worth noting as it effectively did away with any future aircraft designs not of all-metal construction. Glenn Martin won the prestigious Collier Trophy in 1932 for his design work on the Martin B-10.

 

[gekho]

In ordinary service, the Martin B-10 classic airplane was used to develop the tactics and the leaders that would bear the brunt of the U.S. air effort during World War II. Its most important task, perhaps, was to prepare the way for the Boeing B-17 Flying Fortress, which would have the development potential to fight the air war over Europe. Martin was spurred on by its success with the Martin B-10 to develop the later Maryland, Baltimore, and Marauder bombers. Martin sold 154 of the B-10 and the basically similar B-12 and B-14s to the Air Corps, which, somewhat remarkably, allowed Martin to sell the basic design to overseas customers. As a result, Martin sold 189 export models to Argentina, China, Holland, Siam (present-day Thailand), Turkey, and the USSR.

The Dutch purchased export versions of the Martin B-10 for use in the Netherlands East Indies, where the planes gave a good account of themselves against the Japanese. The Dutch Martins reportedly made hundreds of sorties and were credited with sinking several Japanese troopships. Ultimately, all but one was destroyed in combat; the sole survivor made it to Australia, where it was used as a squadron hack, a utility plane. The magnificent United States Air Force Museum wanted a Martin B-10 in its collection for many years, and was finally able to locate one in Argentina, where it had served with the Argentine navy. The plane was brought back to the United States and completely restored, and now stands as beautiful today in its blue and yellow finish as it did when it was the pride of the Air Corps.

 

[gekho]

More pics

 

[gekho]

More pics

 

[gekho]

More pics

 

[Wayne Little]

That Martin thingy is just plain ugly....still nice pics though!

 

[vikingBerserker]

Great pics!

 

[gekho]

The Curtiss T-32 Condor II was a 1930s American biplane airliner and bomber aircraft built by the Curtiss Aeroplane and Motor Company. It was used by the United States Army Air Corps as an executive transport. The Condor II was a 1933 two-bay biplane of mixed construction with a single fin and rudder and retractable landing gear. It was powered by two Wright Cyclone radial engines. The first aircraft was flown on 30 January 1933 and a production batch of 21 aircraft were then built. The production aircraft were fitted out as 12-passenger luxury night sleeper transports. They entered service with Eastern Air Transport and American Airways, forerunners of Eastern Air Lines and American Airlines on regular night services for the next 3 years.

Two modified T-32s were bought by the United States Army Air Corps (designated YC-30) for use as executive transports. One Condor was converted with extra fuel tanks and used by the 1938 Byrd Antarctic Expedition, and unique for a Condor had a fixed undercarriage to allow use on floats or skis. Some aircraft were later modified to AT-32 standard with variable-pitch propellers and improved engine nacelles. The AT-32D variant could be converted from sleeper configuration to daytime use with 15 seats. Four T-32s operating in the United Kingdom were impressed into service with the Royal Air Force at the outbreak of the World War II.

Eight bomber variants (BT-32) were built with manually-operated machine gun turrets in the nose and above the rear fuselage. All these aircraft were exported. A military cargo version (CT-32) was also built for Argentina. It had a large loading door on the starboard side of the fuselage.